Chief Justice Rehnquist

delivered the opinion of the Court.

On February 10, 1984, a police officer in Boulder, Colorado, arrested respondent Steven Lee Bertine for driving while under the influence of alcohol. After Bertine was taken into custody and before the arrival of a tow truck to take Bertine’s van to an impoundment lot,1 a backup officer *369inventoried the contents of the van. The officer opened a closed backpack in which he found controlled substances, cocaine paraphernalia, and a large amount of cash. Bertine was subsequently charged with driving while under the influence of alcohol, unlawful possession of cocaine with intent to dispense, sell, and distribute, and unlawful possession of methaqualone. We are asked to decide whether the Fourth Amendment prohibits the State from proving these charges with the evidence discovered during the inventory of Ber-tine’s van. We hold that it does not.

The backup officer inventoried the van in accordance with local police procedures, which require a detailed inspection and inventory of impounded vehicles. He found the backpack directly behind the frontseat of the van. Inside the pack, the officer observed a nylon bag containing metal canisters. Opening the canisters, the officer discovered that they contained cocaine, methaqualone tablets, cocaine paraphernalia, and $700 in cash. In an outside zippered pouch of the backpack, he also found $210 in cash in a sealed envelope. After completing the inventory of the van, the officer had the van towed to an impound lot and brought the backpack, money, and contraband to the police station.

After Bertine was charged with the offenses described above, he moved to suppress the evidence found during the inventory search on the ground, inter alia, that the search of the closed backpack and containers exceeded the permissible scope of such a search under the Fourth Amendment. The Colorado trial court ruled that probable causé supported Bertine’s arrest and that the police officers had made the decisions to impound the vehicle and to conduct a thorough inventory search in good faith. Although noting that the inventory of the vehicle was performed in a “somewhat slipshod” manner, the District Court concluded that “the search of the backpack was done for the purpose of protecting the *370owner’s property, protection of the police from subsequent claims of loss or stolen property, and the protection of the police from dangerous instrumentalities.” App. 81-83. The court observed that the standard procedures for impounding vehicles mandated a “detailed inventory involving the opening of containers and the listing of [their] contents.” Id., at 81. Based on these findings, the court determined that the inventory search did not violate Bertine’s rights under the Fourth Amendment of the United States Constitution. Id., at 83. The court, nevertheless, granted Bertine’s motion to suppress, holding that the inventory search violated the Colorado Constitution.

On the State’s interlocutory appeal, the Supreme Court of Colorado affirmed. 706 P. 2d 411 (1985). In contrast to the District Court, however, the Colorado Supreme Court premised its ruling on the United States Constitution. The court recognized that in South Dakota v. Opperman, 428 U. S. 364 (1976), we had held inventory searches of automobiles to be consistent with the Fourth Amendment, and that in Illinois v. Lafayette, 462 U. S. 640 (1983), we had held that the inventory search of personal effects of an arrestee at a police station was also permissible under that Amendment. The Supreme Court of Colorado felt, however, that our decisions in Arkansas v. Sanders, 442 U. S. 753 (1979), and United States v. Chadwick, 433 U. S. 1 (1977), holding searches of closed trunks and suitcases to violate the Fourth Amendment, meant that Opperman and Lafayette did not govern this case.2

We granted certiorari to consider the important and recurring question of federal law decided by the Colorado Supreme *371Court.3 475 U. S. 1081 (1986). As that court recognized, inventory searches are now a well-defined exception to the warrant requirement of the Fourth Amendment. See Lafayette, supra, at 643; Opperman, supra, at 367-376. The policies behind the warrant requirement are not implicated in an inventory search, Opperman, 428 U. S., at 370, n. 5, nor is the related concept of probable cause:

“The standard of probable cause is peculiarly related to criminal investigations, not routine, noncriminal procedures. . . . The probable-cause approach is unhelpful when analysis centers upon the reasonableness of routine administrative caretaking functions, particularly when no claim is made that the protective procedures are a subterfuge for criminal investigations.” Ibid.

See also United States v. Chadwick, supra, at 10, n. 5. For these reasons, the Colorado Supreme Court’s reliance on Arkansas v. Sanders, supra, and United States v. Chadwick, supra, was incorrect. Both of these cases concerned searches solely for the purpose of investigating criminal conduct, with the validity of the searches therefore dependent on the application of the probable-cause and warrant requirements of the Fourth Amendment.

By contrast, an inventory search may be “reasonable” under the Fourth Amendment even though it is not conducted pursuant to a warrant based upon probable cause. In *372 Opperman, this Court assessed the reasonableness of an inventory search of the glove compartment in an abandoned automobile impounded by the police. We found that inventory procedures serve to protect an owner’s property while it is in the custody of the police, to insure against claims of lost, stolen, or vandalized property, and to guard the police from danger. In light of these strong governmental interests and the diminished expectation of privacy in an automobile, we upheld the search. In reaching this decision, we observed that our cases accorded deference to police caretaking procedures designed to secure and protect vehicles and their contents within police custody. See Cooper v. California, 386 U. S. 58, 61-62 (1967); Harris v. United States, 390 U. S. 234, 236 (1968); Cady v. Dombrowski, 413 U. S. 433, 447-448 (1973).4

In our more recent decision, Lafayette, a police officer conducted an inventory search of the contents of a shoulder bag in the possession of an individual being taken into custody. In deciding whether this search was reasonable, we recognized that the search served legitimate governmental interests similar to those identified in Opperman. We determined that those interests outweighed the individual’s Fourth Amendment interests and upheld the search.

In the present case, as in Opperman and Lafayette, there was no showing that the police, who were following standardized procedures, acted in bad faith or for the sole purpose of investigation. In addition, the governmental interests justifying the inventory searches in Opperman and Lafayette are *373nearly the same as those which obtain here. In each case, the police were potentially responsible for the property taken into their custody. By securing the property, the police protected the property from unauthorized interference. Knowledge of the precise nature of the property helped guard against claims of theft, vandalism, or negligence. Such knowledge also helped to avert any danger to police or others that may have been posed by the property.5

The Supreme Court of Colorado opined that Lafayette was not controlling here because there was no danger of introducing contraband or weapons into a jail facility. Our opinion in Lafayette, however, did not suggest that the station-house setting of the inventory search was critical to our holding in that case. Both in the present case and in Lafayette, the common governmental interests described above were served by the inventory searches.

The Supreme Court of Colorado also expressed the view that the search in this case was unreasonable because Bertine’s van was towed to a secure, lighted facility and because Bertine himself could have been offered the opportunity to make other arrangements for the safekeeping of his property. But the security of the storage facility does not completely eliminate the need for inventorying; the police may still wish to protect themselves or the owners of the lot against false claims of theft or dangerous instrumentalities. And while giving Bertine an opportunity to make alterna*374tive arrangements would undoubtedly have been possible, we said in Lafayette:

“[T]he real question is not what ‘could have been achieved,’ but whether the Fourth Amendment requires such steps ....

“The reasonableness of any particular governmental activity does not necessarily or invariably turn on the existence of alternative ‘less intrusive’ means.” Lafayette, 462 U. S., at 647 (emphasis in original).

See Cady v. Dombrowski, supra, at 447; United States v. Martinez-Fuerte, 428 U. S. 543, 557, n. 12 (1976). We conclude that here, as in Lafayette, reasonable police regulations relating to inventory procedures administered in good faith satisfy the Fourth Amendment, even though courts might as a matter of hindsight be able to devise equally reasonable rules requiring a different procedure.6

The Supreme Court of Colorado also thought it necessary to require that police, before inventorying a container, weigh the strength of the individual’s privacy interest in the container against the possibility that the container might serve as a repository for dangerous or valuable items. We think that such a requirement is contrary to our decisions in *375 Opperman and Lafayette, and by analogy to our decision in United States v. Ross, 456 U. S. 798 (1982):

“Even if less intrusive means existed of protecting some particular types of property, it would be unreasonable to expect police officers in the everyday course of business to make fine and subtle distinctions in deciding which containers or items may be searched and which must be sealed as a unit.” Lafayette, supra, at 648.

“When a legitimate search is under way, and when its purpose and its limits have been precisely defined, nice distinctions between closets, drawers, and containers, in the case of a home, or between glove compartments, upholstered seats, trunks, and wrapped packages, in the case of a vehicle, must give way to the interest in the prompt and efficient completion of the task at hand.” United States v. Ross, supra, at 821.

We reaffirm these principles here: “‘[a] single familiar standard is essential to guide police officers, who have only limited time and expertise to reflect on and balance the social and individual interests involved in the specific circumstances they confront.’ ” Lafayette, supra, at 648 (quoting New York v. Belton, 453 U. S. 454, 458 (1981)).

Bertine finally argues that the inventory search of his van was unconstitutional because departmental regulations gave the police officers discretion to choose between impounding his van and parking and locking it in a public parking place. The Supreme Court of Colorado did not rely on this argument in reaching its conclusion, and we reject it. Nothing in Opperman or Lafayette prohibits the exercise of police discretion so long as that discretion is exercised according to standard criteria and on the basis of something other than suspicion of evidence of criminal activity. Here, the discretion afforded the Boulder police was exercised in light of *376standardized criteria, related to the feasibility and appropriateness of parking and locking a vehicle rather than impounding it.7 There was no showing that the police chose to impound Bertine’s van in order to investigate suspected criminal activity.

While both Opperman and Lafayette are distinguishable from the present case on their facts, we think that the principles enunciated in those cases govern the present one. The judgment of the Supreme Court of Colorado is therefore

Reversed.

Justice Blackmun,

with whom Justice Powell and Justice O’Connor join, concurring.

The Court today holds that police officers may open closed containers while conducting a routine inventory search of an impounded vehicle. I join the Court’s opinion, but write separately to underscore the importance of having such inventories conducted only pursuant to standardized police procedures. The underlying rationale for allowing an inventory exception to the Fourth Amendment warrant rule is that police officers are not vested with discretion to determine the scope of the inventory search. See South Dakota v. Opperman, 428 U. S. 364, 382-383 (1976) (Powell, J., concurring). This absence of discretion ensures that inventory searches will not be used as a purposeful and general means of discovering evidence of crime. Thus, it is permis*377sible for police officers to open closed containers in an inventory search only if they are following standard police procedures that mandate the opening of such containers in every impounded vehicle. As the Court emphasizes, the trial court in this case found that the Police Department’s standard procedures did mandate the opening of closed containers and the fisting of their contents. See ante, at 374, n. 6.

Justice Marshall,

with whom Justice Brennan joins, dissenting.

Recognizing that “both Opperman and Lafayette are distinguishable from the present case on their facts,” ante, at 376, the majority applies the balancing test enunciated in those cases to uphold as reasonable the inventory of a closed container in a car impounded when its driver was placed under arrest. However, the distinctive facts of this case require a different result. This search — it cannot legitimately be labeled an inventory — was unreasonable and violated the Fourth Amendment. Unlike the inventories in South Dakota v. Opperman, 428 U. S. 364 (1976), and Illinois v. Lafayette, 462 U. S. 640 (1983), it was not conducted according to standardized procedures. Furthermore, the governmental interests justifying the intrusion are significantly weaker than the interests identified in either Opperman or Lafayette and the expectation of privacy is considerably stronger.

I

As the Court acknowledges, ante, at 374, and n. 6, and 375-376, inventory searches are reasonable only if conducted according to standardized procedures. In both Opperman and Lafayette, the Court relied on the absence of police discretion in determining that the inventory searches in question were reasonable. Chief Justice Burger’s opinion in Opperman repeatedly referred to this standardized nature of inventory procedures. See 428 U. S., at 369, 372, 376. Justice Powell’s concurring opinion in that case also *378stressed that “no significant discretion is placed in the hands of the individual officer: he usually has no choice as to the subject of the search or its scope.” Id., at 384 (footnote omitted). Similarly, the Court in Lafayette emphasized the standardized procedure under which the station-house inventory was conducted. See 462 U. S., at 646, 647, 648; see also id., at 649 (Marshall, J., concurring in judgment). In assessing the reasonableness of searches conducted in limited situations such as these, where we do not require probable cause or a warrant, we have consistently emphasized the need for such set procedures: “standardless and unconstrained discretion is the evil the Court has discerned when in previous cases it has insisted that the discretion of the official in the field be circumscribed, at least to some extent.” Delaware v. Prouse, 440 U. S. 648, 661 (1979). See Almeida-Sanchez v. United States, 413 U. S. 266, 270 (1973); Cady v. Dombrowski, 413 U. S. 433, 443 (1973); Harris v. United States, 390 U. S. 234, 235 (1968); Camara v. Municipal Court, 387 U. S. 523, 532-533 (1967).

The Court today attempts to evade these clear prohibitions on unfettered police discretion by declaring that “the discretion afforded the Boulder police was exercised in light of standardized criteria, related to the feasibility and appropriateness of parking and locking a vehicle rather than impounding it.” Ante, at 375-376. This vital assertion is flatly contradicted by the record in this case. The officer who conducted the inventory, Officer Reichenbach, testified at the suppression hearing that the decision not to “park and lock” respondent’s vehicle was his “own individual discretionary decision.” Tr. 76. Indeed, application of these supposedly standardized “criteria” upon which the Court so heavily relies would have yielded a different result in this case. Since there was ample public parking adjacent to the intersection where respondent was stopped, consideration of “feasibility” would certainly have militated in favor of the “park and lock” *379option, not against it. I do not comprehend how consideration of “appropriateness” serves to channel a field officer’s discretion; nonetheless, the “park and lock” option would seem particularly appropriate in this case, where respondent was stopped for a traffic offense and was not likely to be in custody for a significant length of time.

Indeed, the record indicates that no standardized criteria limit a Boulder police officer’s discretion. According to a departmental directive,1 after placing a driver under arrest, an officer has three options for disposing of the vehicle. First, he can allow a third party to take custody.2 Second, the officer or the driver (depending on the nature of the arrest) may take the car to the nearest public parking facility, lock it, and take the keys.3 Finally, the officer can do what was done in *380this case: impound the vehicle, and search and inventory its contents, including closed containers.4

Under the first option, the police have no occasion to search the automobile. Under'the “park and lock” option, “[c]losed containers that give no indication of containing either valuables or a weapon may not be opened and the contents searched (i. e., inventoried).” App. 92-93 (emphasis added). Only if the police choose the third option are they entitled to search closed containers in the vehicle. Where the vehicle is not itself evidence of a crime,5 as in this case, the police apparently have totally unbridled discretion as to which procedure to use. See 706 P. 2d 411, 413, n. 3 (Colo. 1985) (“[T]he Boulder Police Department’s regulations and rules do not require that an automobile be inventoried and searched in accordance with the procedures followed in this *381case”). Consistent with this conclusion, Officer Reichenbach testified that such decisions were left to the discretion of the officer on the scene. App. 60.

Once a Boulder police officer has made this initial completely discretionary decision to impound a vehicle, he is given little guidance as to which areas to search and what sort of items to inventory. The arresting officer, Officer Toporek, testified at the suppression hearing as to what items would be inventoried: “That would I think be very individualistic as far as what an officer may or may not go into. I think whatever arouses his suspicious [sic] as far as what may be contained in any type of article in the car.” Id., at 78. In application, these so-called procedures left the breadth of the “inventory” to the whim of the individual officer. Clearly, “[t]he practical effect of this system is to leave the [owner] subject to the discretion of the official in the field.” Camara v. Municipal Court, 387 U. S., at 532.

Inventory searches are not subject to the warrant requirement because they are conducted by the government as part of a “community caretaking” function, “totally divorced from the detection, investigation, or acquisition of evidence relating to the violation of a criminal statute.” Cady v. Dombrowski, 413 U. S., at 441. Standardized procedures are necessary to ensure that this narrow exception is not improperly used to justify, after the fact, a warrantless investigative foray. Accordingly, to invalidate a search that is conducted without established procedures, it is not necessary to establish that the police actually acted in bad faith, or that the inventory was in fact a “pretext.” By allowing the police unfettered discretion, Boulder’s discretionary scheme, like the random spot checks in Delaware v. Prouse, is unreasonable because of the “‘grave danger’ of abuse of discretion.” 440 U. S., at 662.

II

In South Dakota v. Opperman, 428 U. S. 364 (1976), and Illinois v. Lafayette, 462 U. S. 640 (1983), both of which *382involved inventories conducted pursuant to standardized procedures, we balanced the individual’s expectation of privacy against the government’s interests to determine whether the search was reasonable. Even if the search in this case did constitute a legitimate inventory, it would nonetheless be unreasonable under this analysis.

A

The Court greatly overstates the justifications for the inventory exception to the Fourth Amendment. Chief Justice Burger, writing for the majority in Opperman, relied on three governmental interests to justify the inventory search of an unlocked glove compartment in an automobile impounded for overtime parking: (i) “the protection of the owner’s property while it remains in police custody”; (ii) “the protection of the police against claims or disputes over lost or stolen property”; and (iii) “the protection of the police from potential danger.” 428 U. S., at 369. The majority finds that “nearly the same” interests obtain in this case. See ante, at 373. As Justice Powell’s concurring opinion in Opperman reveals, however, only the first of these interests is actually served by an automobile inventory search.

The protection-against-claims interest did not justify the inventory search either in Opperman, see 428 U. S., at 378, n. 3 (Powell, J., concurring), or in this case. As the majority apparently concedes, ante, at 373, the use of secure im-poundment facilities effectively eliminates this concern.6 As *383to false claims, “inventories are [not] a completely effective means of discouraging false claims, since there remains the possibility of accompanying such claims with an assertion that an item was stolen prior to the inventory or was intentionally omitted from the police records.” 428 U. S., at 378-379 (Powell, J., concurring). See also id., at 391, and nn. 9 and 10 (Marshall, J., dissenting); 2 W. LaFave, Search and Seizure § 5.5, p. 360, n. 50 (1978 and Supp. 1986).

Officer Reichenbach’s inventory in this case would not have protected the police against claims lodged by respondent, false or otherwise. Indeed, the trial court’s characterization of the inventory as “slip-shod” is the height of understatement. For example, Officer Reichenbach failed to list $150 in cash found in respondent’s wallet or the contents of a sealed envelope marked “rent,” $210, in the relevant section of the property form. Tr. 40-41; App. 41-42. His reports make no reference to other items of value, including respondent’s credit cards, and a converter, a hydraulic jack, and a set of tire chains, worth a total of $125. Tr. 41, 62-63. The $700 in cash found in respondent’s backpack, along with the contraband, appeared only on a property form completed later by someone other than Officer Reichenbach. Id., at 81-82. The interior of the vehicle was lef t in disarray, id., at 99, and the officer “inadvertently” retained respondent’s keys — including his house keys — for two days following his arrest. Id., at 116, 133-134.

The third interest — protecting the police from potential danger — failed to receive the endorsement of a majority of the Court in Opperman. After noting that “there is little danger associated with impounding unsearched vehicles,” Justice Powell recognized that “there does not appear to be any effective way of identifying in advance those circumstances or classes of automobile impoundments which represent a greater risk.” 428 U. S., at 378. See also id., at 390 (Marshall, J., dissenting) (safety rationale “cannot justify the search of every car upon the basis of undifferentiated pos*384sibility of harm”). As with the charge of overtime parking in Opperman, there is nothing in the nature of the offense for which respondent was arrested that suggests he was likely to be carrying weapons, explosives, or other dangerous items. Cf. Cady v. Dombrowski, 413 U. S., at 436-437 (police reasonably believed that the defendant’s service revolver was in the car). Not only is protecting the police from dangerous instrumentalities an attenuated justification for most automobile inventory searches, but opening closed containers to inventory the contents can only increase the risk. In the words of the District Court in United States v. Cooper, 428 F. Supp. 652, 654-655 (SD Ohio 1977): “The argument that the search was necessary to avoid a possible booby-trap is . . . easily refuted. No sane individual inspects for booby-traps by simply opening the container.”

Thus, only the government’s interest in protecting the owner’s property actually justifies an inventory search of an impounded vehicle. See 428 U. S., at 379 (Powell, J., concurring); id., at 391 (Marshall, J., dissenting). While I continue to believe that preservation of property does not outweigh the privacy and security interests protected by the Fourth Amendment, I fail to see how preservation can even be asserted as a justification for the search in this case. In Opperman, the owner of the impounded car was not available to safeguard his possessions, see id., at 375, and it could plausibly be argued that, in his absence, the police were entitled to act for his presumed benefit. See also Cady v. Dombrowski, supra, at 436 (comatose defendant). When the police conducted the inventory in Opperman, they could not predict how long the car would be left in their possession. See 428 U. S., at 379 (Powell, J., concurring) (“[M]any owners might leave valuables in their automobiles temporarily that they would not leave there unattended for the several days that police custody may last”); cf. Cooper v. California, 386 U. S. 58, 61 (1967) (police retained car for four months pending forfeiture; length of time considered by the Court in as*385sessing reasonableness of inventory). In this case, however, the owner was “present to make other arrangements for the safekeeping of his belongings,” Opperman, 428 U. S., at 375, yet the police made no attempt to ascertain whether in fact he wanted them to “safeguard” his property. Furthermore, since respondent was charged with a traffic offense, he was unlikely to remain in custody for more than a few hours. He might well have been willing to leave his valuables unattended in the locked van for such a short period of time. See Tr. 110 (had he been given the choice, respondent indicated at the suppression hearing that he “would have parked [the van] in the lot across the street [and] [h]ad somebody come and get it”).

Thus, the government’s interests in this case are weaker than in Opperman, but the search here is much more intrusive. Opperman did not involve a search of closed containers or other items that “ ‘touch upon intimate areas of an individual’s personal affairs,’” 428 U. S., at 380, and n. 7 (Powell, J., concurring) (quoting California Bankers Assn. v. Shultz, 416 U. S. 21, 78-79 (1974) (Powell, J., concurring)); nor can the Court’s opinion be read to authorize the inspection of “containers which might themselves be sealed, removed and secured without further intrusion.” 428 U. S., at 388, n. 6 (Marshall, J., dissenting). To expand the Opperman rationale to include containers in which the owner clearly has a reasonable expectation of privacy, the Court relies on Illinois v. Lafayette, 462 U. S. 640 (1983). Such reb-anee is fundamentally misplaced, however; the inventory in Lafayette was justified by considerations which are totally absent in this context.

In Lafayette, we upheld a station-house inventory search of an arrestee’s shoulder bag. Notwithstanding the Court’s assertions to the contrary, ante, at 373, the inventory in that case was justified primarily by compelling governmental interests unique to the station house, preincarceration context. There is a powerful interest in preventing the introduction *386of contraband or weapons into a jail.7 “Arrested persons have also been known to injure themselves — or others — with belts, knives, drugs, or other items on their person while being detained. Dangerous instrumentalities — such as razor blades, bombs, or weapons — can be concealed in innocent-looking articles taken from the arrestee’s possession.” 462 U. S., at 646. Removing such items from persons about to be incarcerated is necessary to reasonable jail security; once these items have been identified and removed, “inventorying them is an entirely reasonable administrative procedure.” Ibid. Although Lafayette also involved the property justifications relied on in Opperman, I do not believe it can fairly be read to expand the scope of inventory searches where the pressing security concerns of the station house are absent.

B

Not only are the government’s interests weaker here than in Opperman and Lafayette, but respondent’s privacy interest is greater. In upholding the search in Opperman, the Court emphasized the fact that the defendant had a diminished expectation of privacy in his automobile, due to “pervasive and continuing governmental regulation and controls, including periodic inspection and licensing requirements” and “the obviously public nature of automobile travel.” 428 U. S., at 368. See also id., at 379 (Powell, J., concurring); but see id., at 386-388 (Marshall, J., dissenting). Similarly, in Lafayette, the Court emphasized the *387fact that the defendant was in custody at the time the inventory took place. 462 U. S., at 645-646.

Here the Court completely ignores respondent’s expectation of privacy in his backpack. Whatever his expectation of privacy in his automobile generally, our prior decisions clearly establish that he retained a reasonable expectation of privacy in the backpack and its contents. See Arkansas v. Sanders, 442 U. S. 753, 762 (1979) (“[L]uggage is a common repository for one’s personal effects, and therefore is inevitably associated with the expectation of privacy”); United States v. Chadwick, 433 U. S. 1, 13 (1977) (“[A] person’s expectations of privacy in personal luggage are substantially greater than in an automobile”). Indeed, the Boulder police officer who conducted the inventory acknowledged that backpacks commonly serve as repositories for personal effects.8 Thus, even if the governmental interests in this case were the same as those in Opperman, they would nonetheless be outweighed by respondent’s comparatively greater expectation of privacy in his luggage.

f — i HH I — I

In Coolidge v. New Hampshire, 403 U. S. 443, 461-462 (1971), a plurality of this Court stated: “The word ‘automobile’ is not a talisman in whose presence the Fourth Amendment fades away and disappears.” By upholding the search in this case, the Court not only ignores that principle, but creates another talisman to overcome the requirements of the Fourth Amendment — the term “inventory.” Accordingly, I dissent.

Mr. Chief Justice Burger

delivered the opinion of the Court.

We review the judgment of the Supreme Court of South Dakota, holding that local police violated the Fourth Amendment to the Federal Constitution, as applicable to the States under the Fourteenth Amendment, when they conducted a routine inventory search of an automobile lawfully impounded by police for violations of municipal parking ordinances.

(1)

Local ordinances prohibit parking in certain areas of downtown Vermillion, S. D., between the hours of 2 a. m. and 6 a. m. During the early morning hours of December 10, 1973, a Vermillion police officer observed respondent’s unoccupied vehicle illegally parked in the restricted zone. At approximately 3 a. m., the officer issued an overtime parking ticket and placed it on the car’s windshield. The citation warned:

“Vehicles in violation of any parking ordinance may be towed from the area.”

At approximately 10 o’clock on the same morning, an*366other officer issued a second ticket for an overtime parking violation. These circumstances were routinely reported to police headquarters, and after the vehicle was inspected, the car was towed to the city impound lot.

From outside the car at the impound lot, a police officer observed a watch on the dashboard and other items of personal property located on the back seat and back floorboard. At the officer's direction, the car door was then unlocked and, using a standard inventory form pursuant to standard police procedures, the officer inventoried the contents of the car, including the contents of the glove compartment, which was unlocked. There he found marihuana contained in a plastic bag. All items, including the contraband, were removed to the police department for safekeeping.1 During the late afternoon of December 10, respondent appeared at the police department to claim his property. The marihuana was retained by police.

Respondent was subsequently arrested on charges of possession of marihuana. His motion to suppress the evidence yielded by the inventory search was denied; he was convicted after a jury trial and sentenced to a fine of $100 and 14 days’ incarceration in the county jail. On appeal, the Supreme Court of South Dakota reversed *367the conviction. 89 S. D. -, 228 N. W. 2d 152. The court concluded that the evidence had been obtained in violation of the Fourth Amendment prohibition against unreasonable searches and seizures. We granted certiorari, 423 U. S. 923 (1975), and we reverse.

(2)

This Court has traditionally drawn a distinction between automobiles and homes or offices in relation to the Fourth Amendment. Although automobiles are “effects” and thus within the reach of the Fourth Amendment, Cady v. Dombrowski, 413 U. S. 433, 439 (1973), war-rantless examinations of automobiles have been upheld in circumstances in which a search of a home or office would not. Cardwell v. Lewis, 417 U. S. 583, 589 (1974); Cady v. Dombrowski, supra, at 439-440; Chambers v. Maroney, 399 U. S. 42, 48 (1970).

The reason for this well-settled distinction is twofold. First, the inherent mobility of automobiles creates circumstances of such exigency that, as a practical necessity, rigorous enforcement of the warrant requirement is impossible. Carroll v. United States, 267 U. S. 132, 153-154 (1925); Coolidge v. New Hampshire, 403 U. S. 443, 459-460 (1971). But the Court has also upheld warrant-less searches where no immediate danger was presented that the car would be removed from the jurisdiction. Chambers v. Maroney, supra, at 51-52; Cooper v. California, 386 U. S. 58 (1967). Besides the element of mobility, less rigorous warrant requirements govern because the expectation of privacy with respect to one’s automobile is significantly less than that relating to one’s home or office.2 In discharging their varied re*368sponsibilities for ensuring the public safety, law enforcement officials are necessarily brought into frequent contact with automobiles. Most of this contact is distinctly noncriminal in nature. Cady v. Dombrowski, supra, at 442. Automobiles, unlike homes, are subjected to pervasive and continuing governmental regulation and controls, including periodic inspection and licensing requirements. As an everyday occurrence, police stop and examine vehicles when license plates or inspection stickers have expired, or if other violations, such as exhaust fumes or excessive noise, are noted, or if headlights or other safety equipment are not in proper working order.

The expectation of privacy as to automobiles is further diminished by the obviously public nature of automobile travel. Only two Terms ago, the Court noted:

“One has a lesser expectation of privacy in a motor vehicle because its function is transportation and it seldom serves as one’s residence or as the repository of personal effects. ... It travels public thoroughfares where both its occupants and its contents are in plain view.” Cardwell v. Lewis, supra, at 590.

In the interests of public safety and as part of what the Court has called “community caretaking functions,” Cady v. Dombrowski, supra, at 441, automobiles are frequently taken into police custody. Vehicle accidents present one such occasion. To permit the uninterrupted flow of traffic and in some circumstances to preserve evidence, disabled or damaged vehicles will often be removed from the highways or streets at the behest of police engaged solely in caretaking and traffic-control activi*369ties. Police will also frequently remove and impound automobiles which violate parking ordinances and which thereby jeopardize both the public safety and the efficient movement of vehicular traffic.3 The authority of police to seize and remove from the streets vehicles impeding traffic or threatening public safety and convenience is beyond challenge.

When vehicles are impounded, local police departments generally follow a routine practice of securing and inventorying the automobiles’ contents. These procedures developed in response to three distinct needs: the protection of the owner’s property while it remains in police custody, United States v. Mitchell, 458 F. 2d 960, 961 (CA9 1972); the protection of the police against claims or disputes over lost or stolen property, United States v. Kelehar, 470 F. 2d 176, 178 (CA5 1972); and the protection of the police from potential danger, Cooper v. California, supra, at 61-62. The practice has been viewed as essential to respond to incidents of theft or vandalism. See Cobbler v. Commonwealth, 212 Va. 520, 522, 184 S. E. 2d 781, 782 (1971), cert. denied, 405 U. S. 1073 (1972); Warrix v. State, 50 Wis. 2d 368, 376, 184 N. W. 2d 189, 194 (1971). In addition, police frequently attempt to determine whether a vehicle has been stolen and thereafter abandoned.

These caretaking procedures have almost uniformly been upheld by the state courts, which by virtue of the localized nature of traffic regulation have had considerable occasion to deal with the issue.4 Applying the *370Fourth Amendment standard of “reasonableness,” 5 the state courts have overwhelmingly concluded that, even if an inventory is characterized as a “search,”6 the *371intrusion is constitutionally permissible. See, e. g., City of St. Paul v. Myles, 298 Minn. 298, 300-301, 218 N. W. 2d 697, 699 (1974); State v. Tully, 166 Conn. 126, 136, 348 A. 2d 603, 609 (1974); People v. Trusty, 183 Colo. 291, 296-297, 516 P. 2d 423, 425-426 (1973); People v. Sullivan, 29 N. Y. 2d 69, 73, 272 N. E. 2d 464, 466 (1971); Cobbler v. Commonwealth, supra; Warrix v. State, supra; State v. Wallen, 185 Neb. 44, 173 N. W. 2d 372, cert. denied, 399 U. S. 912 (1970); State v. Criscola, 21 Utah 2d 272, 444 P. 2d 517 (1968); State v. Montague, 73 Wash. 2d 381, 438 P. 2d 571 (1968); People v. Clark, 32 Ill. App. 3d 898, 336 N. E. 2d 892 (1975); State v. Achter, 512 S. W. 2d 894 (Mo. Ct. App. 1974); Bennett v. State, 507 P. 2d 1252 (Okla. Crim. App. 1973); People v. Willis, 46 Mich. App. 436, 208 N. W. 2d 204 (1973); State v. All, 17 N. C. App. 284, 193 S. E. 2d 770, cert. denied, 414 U. S. 866 (1973); Godbee v. State, 224 So. 2d 441 (Fla. Dist. Ct. App. 1969). Even the seminal state decision relied on by the South Dakota Supreme Court in reaching the contrary result, Mozzetti v. Superior Court, 4 Cal. 3d 699, 484 P. 2d 84 (1971), expressly approved police caretaking activities resulting in the securing of property within the officer’s plain view.

The majority of the Federal Courts of Appeals have likewise sustained inventory procedures as reasonable police intrusions. As Judge Wisdom has observed: *372See also Cabbler v. Superintendent, 528 F. 2d 1142 (CA4 1975), cert. pending, No. 75-1463; Barker v. Johnson, 484 F. 2d 941 (CA6 1973); United States v. Mitchell, 458 F. 2d 960 (CA9 1972); United States v. Lipscomb, 435 F. 2d 795 (CA5 1970), cert. denied, 401 U. S. 980 (1971); United States v. Pennington, 441 F. 2d 249 (CA5), cert. denied, 404 U. S. 854 (1971); United States v. Boyd, 436 F. 2d 1203 (CA5 1971); Cotton v. United States, 371 F. 2d 385 (CA9 1967). Accord, Lowe v. Hopper, 400 F. Supp. 970, 976-977 (SD Ga. 1975); United States v. Spitalieri, 391 F. Supp, 167, 169-170 (ND Ohio 1975); United States v. Smith, 340 F. Supp. 1023 (Conn. 1972); United States v. Fuller, 277 F. Supp. 97 (DC 1967), conviction aff'd, 139 U. S. App. D. C. 375, 433 F. 2d 533 (1970). These cases have recognized that standard inventories often include an examination of the glove compartment, since it is a customary place for documents of ownership and registration, United States v. Pennington, supra, at 251, as well as a place for the temporary storage of valuables.

*371“[W]hen the police take custody of any sort of container [such as] an automobile ... it is reasonable to search the container to itemize the property to be held by the police. [This reflects] the underlying principle that the fourth amendment proscribes only unreasonable searches.” United States v. Gravitt, 484 F. 2d 375, 378 (CA5 1973), cert. denied, 414 U. S. 1135 (1974) (emphasis in original).

*372(3)

The decisions of this Court point unmistakably to the conclusion reached by both federal and state courts that inventories pursuant to standard police procedures are reasonable. In the first such case, Mr. Justice Black made plain the nature of the inquiry before us:

“But the question here is not whether the search was authorized by state law. The question is rather whether the search was reasonable under the Fourth Amendment.” Cooper v. California, 386 U. S., at 61 (emphasis added).

And, in his last writing on the Fourth Amendment, Mr. Justice Black said:

“[T]he Fourth Amendment does not require that every search be made pursuant to a warrant. It *373prohibits only ‘unreasonable searches and seizures.’ The relevant test is not the reasonableness 0/ the opportunity to procure a warrant, but the reasonableness of the seizure under all the circumstances. The test of reasonableness cannot be fixed by per se rules; each case must be decided on its own facts.” Coolidge v. New Hampshire, 403 U. S., at 509-510 (concurring and dissenting) (emphasis added).

In applying the reasonableness standard adopted by the Framers, this Court has consistently sustained police intrusions into automobiles impounded or otherwise in lawful police custody where the process is aimed at securing or protecting the car and its contents. In Cooper v. California, supra, the Court upheld the inventory of a car impounded under the authority of a state forfeiture statute. Even though the inventory was conducted in a distinctly criminal setting7 and carried out a week after the car had been impounded, the Court nonetheless found that the car search, including examination of the glove compartment where contraband was found, was reasonable under the circumstances. This conclusion was reached despite the fact that no warrant had issued and probable cause to search for the contraband in the vehicle had not been established. The Court said in language explicitly applicable here:

“It would be unreasonable to hold that the police, having to retain the car in their custody for such a length of time, had no right, even for their own protection, to search it.” 386 U. S., at 61-62.8

*374In the following Term, the Court in Harris v. United States, 390 U. S. 234 (1968), upheld the introduction of evidence, seized by an officer who, after conducting an inventory search of a car and while taking means to safeguard it, observed a car registration card lying on the metal stripping of the car door. Rejecting the argument that a warrant was necessary, the Court held that the intrusion was justifiable since it was “taken to protect the car while it was in police custody.” Id., at 236.9

Finally, in Cady v. Dombrowski, supra, the Court upheld a warrantless search of an automobile towed to a private garage even though no probable cause existed to believe that the vehicle contained fruits of a crime. The sole justification for the warrantless incursion was that it was incident to the caretaking function of the local police to protect the community’s safety. Indeed, the protective search was instituted solely because local police “were under the impression” that the incapacitated driver, a Chicago police officer, was required to carry his service revolver at all times; the police had reasonable grounds to believe a weapon might be in the car, and thus available to vandals. 413 U. S., at 436. The Court carefully noted that the protective search was *375carried out in accordance with standard procedures in the local police department, ibid., a factor tending to ensure that the intrusion would be limited in scope to the extent necessary to carry out the caretaking function. See United States v. Spitalieri, 391 F. Supp., at 169. In reaching this result, the Court in Cady distinguished Preston v. United States, 376 U. S. 364 (1964), on the grounds that the holding, invalidating a car search conducted after a vagrancy arrest, “stands only for the proposition that the search challenged there could not be justified as one incident to an arrest.” 413 U. S., at 444. Preston therefore did not raise the issue of the constitutionality of a protective inventory of a car lawfully within police custody.

The holdings in Cooper, Harris, and Cady point the way to the correct resolution of this case. None of the three cases, of course, involves the precise situation presented here; but, as in all Fourth Amendment cases, we are obliged to look to all the facts and circumstances of this case in light of the principles set forth in these prior decisions.

“[W]hether a search and seizure is unreasonable within the meaning of the Fourth Amendment depends upon the facts and circumstances of each case . . . .” Cooper v. California, 386 U. S., at 59.

The Vermillion police were indisputably engaged in a caretaking search of a lawfully impounded automobile. Cf. United States v. Lawson, 487 F. 2d 468, 471 (CA8 1973). The inventory was conducted only after the car had been impounded for multiple parking violations. The owner, having left his car illegally parked for an extended period, and thus subject to impoundment, was not present to make other arrangements for the safekeeping of his belongings. The inventory itself was prompted by the presence in plain view of a number of *376valuables inside the car. As in Cady, there is no suggestion whatever that this standard procedure, essentially like that followed throughout the country, was a pretext concealing an investigatory police motive.10

On this record we conclude that in following standard police procedures, prevailing throughout the country and approved by the overwhelming majority of courts, the conduct of the police was not “unreasonable” under the Fourth Amendment.

The judgment of the South Dakota Supreme Court is therefore reversed, and the case is remanded for further proceedings not inconsistent with this opinion.

Reversed and remanded.

Me. Justice Powell,

concurring.

While I join the opinion of the Court, I add this opinion to express additional views as to why the search conducted in this case is valid under the Fourth and Fourteenth Amendments. This inquiry involves two distinct questions: (i) whether routine inventory searches are impermissible, and (ii) if not, whether they must be conducted pursuant to a warrant.

*377I

The central purpose of the Fourth Amendment is to safeguard the privacy and security of individuals against arbitrary invasions by government officials. See, e. g., United States v. Brignoni-Ponce, 422 U. S. 873, 878 (1975); Camara v. Municipal Court, 387 U. S. 523, 528 (1967). None of our prior decisions is dispositive of the issue whether the Amendment permits routine inventory “searches” 1 of automobiles.2 Resolution of this *378question requires a weighing of the governmental and societal interests advanced to justify such intrusions against the constitutionally protected interest of the individual citizen in the privacy of his effects. United States v. Martinez-Fuerte, post, at 555; United States v. Brignoni-Ponce, supra, at 878-879; United States v. Ortiz, 422 U. S. 891, 892 (1975); Cady v. Dombrowski, 413 U. S. 433, 447-448 (1973); Terry v. Ohio, 392 U. S. 1, 20-21 (1968). Cf. Camara v. Municipal Court, supra, at 534—535. As noted in the Court’s opinion, see ante, at 369, three interests generally have been advanced in support of inventory searches: (i) protection of the police from danger; (ii) protection of the police against claims and disputes over lost or stolen property; and (iii) protection of the owner’s property while it remains in police custody.

Except in rare cases, there is little danger associated with impounding unsearched automobiles. But the occasional danger that may exist cannot be discounted entirely. See Cooper v. California, 386 U. S. 58, 61-62 (1967). The harmful consequences in those rare cases may be great, and there does not appear to be any effective way of identifying in advance those circumstances or classes of automobile impoundments which represent a greater risk. Society also has an important interest in minimizing the number of false claims filed against police since they may diminish the community’s respect for law enforcement generally and lower department morale, thereby impairing the effectiveness of the police.3 It *379is not clear, however, that inventories are a completely effective means of discouraging false claims, since there remains the possibility of accompanying such claims with an assertion that an item was stolen prior to the inventory or was intentionally omitted from the police records.

The protection of the owner’s property is a significant interest for both the policeman and the citizen. It is argued that an inventory is not necessary since locked doors and rolled-up windows afford the same protection that the contents of a parked automobile normally enjoy.4 But many owners might leave valuables in their automobile temporarily that they would not leave there unattended for the several days that police custody may last. There is thus a substantial gain in security if automobiles are inventoried and valuable items removed for storage. And, while the same security could be attained by posting a guard at the storage lot, that alternative may be prohibitively expensive, especially for smaller jurisdictions.5

Against these interests must be weighed the citizen’s interest in the privacy of the contents of his automobile. Although the expectation of privacy in an automobile is significantly less than the traditional expectation of privacy associated with the home, United States v. Martinez-Fuerte, post, at 561-562; United States v. Ortiz, supra, at 896 n. 2; see Cardwell v. Lewis, 417 U. S. 583, 590-591 (1974) (plurality opinion), the unrestrained search *380of an automobile and its contents would constitute a serious intrusion upon the privacy of the individual in many circumstances. But such a search is not at issue in this case. As the Court’s opinion emphasizes, the search here was limited to an inventory of the unoccupied automobile and was conducted strictly in accord with the regulations of the Vermillion Police Department.6 Upholding searches of this type provides no general license for the police to examine all the contents of such automobiles.7

I agree with the Court that the Constitution permits routine inventory searches, and turn next to the question whether they must be conducted pursuant to a warrant.

*381II

While the Fourth Amendment speaks broadly in terms of “unreasonable searches and seizures,” 8 the decisions of this Court have recognized that the definition of “reasonableness” turns, at least in part, on the more specific dictates of the Warrant Clause. See United States v. United States District Court, 407 U. S. 297, 315 (1972); Katz v. United States, 389 U. S. 347, 356 (1967); Camara v. Municipal Court, 387 U. S., at 528. As the Court explained in Katz v. United States, supra, at 357, “[s]earches conducted without warrants have been held unlawful 'notwithstanding facts unquestionably showing probable cause Agnello v. United States, 269 U. S. 20, 33, for the Constitution requires 'that the deliberate, impartial judgment of a judicial officer ... be interposed between the citizen and the police ... Wong Sun v. United States, 371 U. S. 471, 481-482.” Thus, although “[s]ome have argued that '[t]he relevant test is not whether it is reasonable to procure a search warrant, but whether the search was reasonable/ United States v. Rabinowitz, 339 U. S. 56, 66 (1950),” " [t] his view has not been accepted.” United States v. United States District Court, supra, at 315, and n. 16. See Chimel v. California, 395 U. S. 752 (1969). Except in a few carefully defined classes of cases, a search of private property without valid consent is “unreasonable” unless it has been authorized by a valid search warrant. See, e. g., Almeida-Sanchez v. United States, 413 U. S. 266, 269 (1973); Stoner v. California, 376 U. S. 483, 486 (1964); *382 Camara v. Municipal Court, supra, at 528; United States v. Jeffers, 342 U. S. 48, 51 (1951); Agnello v. United States, 269 U. S. 20, 30 (1925).

Although the Court has validated warrantless searches of automobiles in circumstances that would not justify a search of a home or office, Cady v. Dombrowski, 413 U. S. 433 (1973); Chambers v. Maroney, 399 U. S. 42 (1970); Carroll v. United States, 267 U. S. 132 (1925), these decisions establish no general “automobile exception” to the warrant requirement. See Preston v. United States, 376 U. S. 364 (1964). Rather, they demonstrate that “ 'for the purposes of the Fourth Amendment there is a constitutional difference between houses and cars ” Cady v. Dombrowski, supra, at 439, quoting Chambers v. Maroney, supra, at 52, a difference that may in some cases justify a warrantless search.9

The routine inventory search under consideration in this case does not fall within any of the established exceptions to the warrant requirement.10 But examination of the interests which are protected when searches are *383conditioned on warrants issued by a judicial officer reveals that none of these is implicated here. A warrant may issue only upon “probable cause.” In the criminal context the requirement of a warrant protects the individual’s legitimate expectation of privacy against the overzealous police officer. “Its protection consists in requiring that those inferences [concerning probable cause] be drawn by a neutral and detached magistrate instead of being judged by the officer engaged in the often competitive enterprise of ferreting out crime.” Johnson v. United States, 333 U. S. 10, 14 (1948). See, e. g., United States v. United States District Court, supra, at 316-318. Inventory searches, however, are not conducted in order to discover evidence of crime. The officer does not make a discretionary determination to search based on a judgment that certain conditions are present. Inventory searches are conducted in accordance with established police department rules or policy and occur whenever an automobile is seized. There are thus no special facts for a neutral magistrate to evaluate.

A related purpose of the warrant requirement is to prevent hindsight from affecting the evaluation of the reasonableness of a search. See United States v. Martinez-Fuerte, post, at 565; cf. United States v. Watson, 423 U. S. 411, 455 n. 22 (1976) (Marshall, J., dissenting). In the case of an inventory search conducted in accordance with standard police department procedures, there is no significant danger of hindsight justification. The absence of a warrant will not impair the effectiveness of post-search review of the reasonableness of a particular inventory search.

Warrants also have been required outside the context of a criminal investigation. In Camara v. Municipal Court, the Court held that, absent consent, a warrant was necessary to conduct an areawide building code in*384spection, even though the search could be made absent cause to believe that there were violations in the particular buildings being searched. In requiring a warrant the Court emphasized that “[t]he practical effect of [the existing warrantless search procedures had been] to leave the occupant subject to the discretion of the official in the field/' since

“when [an] inspector demands entry, the occupant ha[d] no way of knowing whether enforcement of the municipal code involved require [d] inspection of his premises, no way of knowing the lawful limits of the inspector’s power to search, and no way of knowing whether the inspector himself [was] acting under proper authorization.” 387 U. S., at 532.

In the inventory search context these concerns are absent. The owner or prior occupant of the automobile is not present, nor, in many cases, is there any real likelihood that he could be located within a reasonable period of time. More importantly, no significant discretion is placed in the hands of the individual officer: he usually has no choice as to the subject of the search or its scope.11

In sum, I agree with the Court that the routine inventory search in this case is constitutional.

Mr. Justice Marshall,

with whom Mr. Justice Brennan and Mr. Justice Stewart join,

dissenting.

The Court today holds that the Fourth Amendment permits a routine police inventory search of the closed *385glove compartment of a locked automobile impounded for ordinary traffic violations. Under the Court’s holding, such a search may be made without attempting to secure the consent of the owner and without any particular reason to believe the impounded automobile contains contraband, evidence, or valuables, or presents any danger to its custodians or the public.1 Because I believe this holding to be contrary to sound elaboration of established Fourth Amendment principles, I dissent.

As Mr. Justice Powell recognizes, the requirement of a warrant aside, resolution of the question whether an inventory search of closed compartments inside a locked automobile can ever be justified as a constitutionally “reasonable” search2 depends upon a reconciliation of the owner’s constitutionally protected privacy interests against governmental intrusion, and legitimate governmental interests furthered by securing the car and its contents. Terry v. Ohio, 392 U. S. 1, 20-21 (1968); Camara v. Municipal Court, 387 U. S. 523, 534-535, 536-537 (1967). The Court fails clearly to articulate the reasons for its reconciliation of these interests in this case, but it is at least clear to me that the considerations *386alluded to by the Court, and further discussed by Mr. Justice Powell, are insufficient to justify the Court’s result in this case.

To begin with, the Court appears to suggest by reference to a “diminished” expectation of privacy, ante, at 368, that a person’s constitutional interest in protecting the integrity of closed compartments of his locked automobile may routinely be sacrificed to governmental interests requiring interference with that privacy that are less compelling than would be necessary to justify a search of similar scope of the person’s home or office. This has never been the law. The Court correctly observes that some prior cases have drawn distinctions between automobiles and homes or offices in Fourth Amendment cases; but even as the Court’s discussion makes clear, the reasons for distinction in those cases are not present here. Thus, Chambers v. Maroney, 399 U. S. 42 (1970), and Carroll v. United States, 267 U. S. 132 (1925), permitted certain probable-cause searches to be carried out without warrants in view of the exigencies created by the mobility of automobiles, but both decisions reaffirmed that the standard of probable cause necessary to authorize such a search was no less than the standard applicable to search of a home or office. Chambers, supra, at 51; Carroll, supra, at 155-156.3 In other contexts the Court has recognized that automobile travel sacrifices some privacy interests to the publicity of plain view, e. g., Cardwell v. Lewis, 417 U. S. 583, 590 (1974) (plurality opinion); cf. Harris v. United States, 390 U. S. 234 (1968). But this recognition, too, is in-apposite here, for there is no question of plain view in *387this case.4 Nor does this case concern intrusions of the scope that the Court apparently assumes would ordinarily be permissible in order to insure the running safety of a car. While it may be that privacy expectations associated with automobile travel are in some regards less than those associated with a home or office, see United States v. Martinez-Fuerte, post, at 561-562, it is equally clear that “[t]he word 'automobile' is not a talisman in whose presence the Fourth Amendment fades away . . . Coolidge v. New Hampshire, 403 U. S. 443, *388461 (1971).5 Thus, we have recognized that “[a] search, even of an automobile, is a substantial invasion of privacy,” United States v. Ortiz, 422 U. S. 891, 896 (1975) (emphasis added), and accordingly our cases have consistently recognized that the nature and substantiality of interest required to justify a search of private areas of an automobile is no less than that necessary to justify an intrusion of similar scope into a home or office. See, e. g., United States v. Ortiz, supra; Almeida-Sanchez v. United States, 413 U. S. 266, 269-270 (1973); Coolidge, supra; Dyke v. Taylor Implement Mfg. Co., 391 U. S. 216, 221-222 (1968); Preston v. United States, 376 U. S. 364 (1964).6

*389The Court's opinion appears to suggest that its result may in any event be justified because the inventory search procedure is a “reasonable” response to

“three distinct needs: the protection of the owner’s property while it remains in police custody . . . ; the protection of the police against claims or disputes over lost or stolen property . . . ; and the protection of the police from potential danger.” Ante, at 369.7

This suggestion is flagrantly misleading, however, because the record of this case explicitly belies any relevance of the last two concerns. In any event it is my view that none of these “needs,” separately or together, can suffice to justify the inventory search procedure approved by the Court.

First, this search cannot be justified in any way as a safety measure, for — though the Court ignores it — the sole purpose given by the State for the Vermillion police’s inventory procedure was to secure valuables, Record 75, 98. Nor is there any indication that the officer’s search in this case was tailored in any way to safety concerns, or that ordinarily it is so circumscribed. Even aside from the actual basis for the police practice in this case, however, I do not believe that any blanket safety argument could justify a program of routine *390searches of the scope permitted here. As Mr. Justice Powell recognizes, ordinarily “there is little danger associated with impounding unsearched automobiles,” ante, at 378.8 Thus, while the safety rationale may not be entirely discounted when it is actually relied upon, it surely cannot justify the search of every car upon the basis of undifferentiated possibility of harm; on the contrary, such an intrusion could ordinarily be justified only in those individual cases where the officer’s inspection was prompted by specific circumstances indicating the pos*391sibility of a particular danger. See Terry v. Ohio, 392 U. S., at 21, 27; cf. Cady v. Dombrowski, 413 U. S. 433, 448 (1973).

Second, the Court suggests that the search for valuables in the closed glove compartment might be justified as a measure to protect the police against lost property claims. Again, this suggestion is belied by the record, since — although the Court declines to discuss it — the South Dakota Supreme Court’s interpretation of state law explicitly absolves the police, as “gratuitous depositors,” from any obligation beyond inventorying objects in plain view and locking the car. 89 S. D. , -, 228 N. W. 2d 152, 159 (1975).9 Moreover, as Mr. Justice Powell notes, ante, at 378-379, it may well be doubted that an inventory procedure would in any event work significantly to minimize the frustrations of false claims.10

Finally, the Court suggests that the public interest in protecting valuables that may be found inside a closed compartment of an impounded car may justify the inventory procedure. I recognize the genuineness of this governmental interest in protecting property from pilferage. But even if I assume that the posting of a guard would be fiscally impossible as an alternative means to *392the same protective end,111 cannot agree with the Court’s conclusion. The Court’s result authorizes — indeed it appears to require — the routine search of nearly every12 car impounded.13 In my view, the Constitution does not permit such searches as a matter of routine; absent specific consent, such a search is permissible only in exceptional circumstances of particular necessity.

It is at least clear that any owner might prohibit the police from executing a protective search of his impounded car, since by hypothesis the inventory is conducted for the owner’s benefit. Moreover, it is obvious that not everyone whose car is impounded would want it to be searched. Respondent himself proves this; but *393one need not carry contraband to prefer that the police not examine one’s private possessions. Indeed, that preference is the premise of the Fourth Amendment. Nevertheless, according to the Court’s result the law may presume that each owner in respondent’s position consents to the search. I cannot agree. In my view, the Court’s approach is squarely contrary to the law of consent;14 it ignores the duty, in the absence of consent, to analyze in each individual case whether there is a need to search a particular car for the protection of its owner which is sufficient to outweigh the particular invasion. It is clear to me under established principles that in order to override the absence of explicit consent, such a search must at least be conditioned upon the fulfillment of two requirements.15 First, there must be specific cause to believe that a search of the scope to be undertaken is necessary in order to preserve the integrity of particular valuable property threatened by the impoundment:

“[I]n justifying the particular intrusion the police officer must be able to point to specific and articu-lable facts which . . . reasonably warrant that intrusion.” Terry v. Ohio, 392 U. S., at 21.

Such a requirement of “specificity in the information upon which police action is predicated is the central teaching of this Court’s Fourth Amendment jurisprudence,” id., at 21 n. 18, for “[t]he basic purpose of this *394Amendment, as recognized in countless decisions of this Court, is to safeguard the privacy and security of individuals against arbitrary invasions by governmental officials.” Camara v. Municipal Court, 387 U. S., at 528. Cf. United States v. Brignoni-Ponce, 422 U. S. 873, 883-884 (1975); Cady v. Dombrowski, 413 U. S., at 448; Terry v. Ohio, supra, at 27. Second, even where a search might be appropriate, such an intrusion may only follow the exhaustion and failure of reasonable efforts under the circumstances to identify and reach the owner of the property in order to facilitate alternative means of security or to obtain his consent to the search, for in this context the right to refuse the search remains with the owner. Cf. Bumper v. North Carolina, 391 U. S. 543 (1968).16

Because the record in this case shows that the procedures followed by the Vermillion police in searching respondent’s car fall far short of these standards, in my view the search was impermissible and its fruits must be suppressed. First, so far as the record shows, the police in this case had no reason to believe that the glove compartment of the impounded car contained particular property of any substantial value. Moreover, the owner had apparently thought it adequate to protect whatever he left in the car overnight on the street in a business area simply to lock the car, and there is nothing in the record to show that the im-*395poundment lot would prove a less secure location against pilferage,17 cf. Mozzetti v. Superior Court, 4 Cal. 3d 699, 707, 484 P. 2d 84, 89 (1971), particularly when it would seem likely that the owner would claim his car and its contents promptly, at least if it contained valuables worth protecting.18 Even if the police had cause to believe that the impounded car’s glove compartment contained particular valuables, however, they made no effort to secure the owner’s consent to the search. Although the Court relies, as it must, upon the fact that respondent was not present to make other arrangements for the care of his belongings, ante, at 376, in my view that is not the end of the inquiry. Here the police readily ascertained the ownership of the vehicle, Record 98-99, yet they searched it immediately without taking any steps to locate respondent and procure his consent to the inventory or advise him to make alternative arrangements to safeguard his property, id., at 32, 72, 73, 79. Such a failure is inconsistent with the rationale that the inventory procedure is carried out for the benefit of the owner.

The Court’s result in this case elevates the conservation of property interests — indeed mere possibilities of property interests — above the privacy and security in*396terests protected by the Fourth Amendment. For this reason I dissent. On the remand it should be clear in any event that this Court's holding does not preclude a contrary resolution of this case or others involving the same issues under any applicable state law. See Oregon v. Hass, 420 U. S. 714, 726 (1975) (Marshall, J., dissenting).

Statement of Mr. Justice White.

Although I do not subscribe to all of my Brother Marshall’s dissenting opinion, particularly some aspects of his discussion concerning the necessity for obtaining the consent of the car owner, I agree with most of his analysis and conclusions and consequently dissent from the judgment of the Court.

*447Chief Justice Rehnquist

delivered the opinion of the Court.

This case poses the question whether a State’s use of highway sobriety checkpoints violates the Fourth and Fourteenth Amendments to the United States Constitution. We hold that it does not and therefore reverse the contrary holding of the Court of Appeals of Michigan.

Petitioners, the Michigan Department of State Police and its director, established a sobriety checkpoint pilot program in early 1986. The director appointed a Sobriety Checkpoint Advisory Committee comprising representatives of the State Police force, local police forces, state prosecutors, and the University of Michigan Transportation Research Institute. Pursuant to its charge, the advisory committee created guidelines setting forth procedures governing checkpoint operations, site selection, and publicity.

Under the guidelines, checkpoints would be set up at selected sites along state roads. All vehicles passing through a checkpoint would be stopped and their drivers briefly examined for signs of intoxication. In cases where a checkpoint officer detected signs of intoxication, the motorist would be directed to a location out of the traffic flow where an officer would check the motorist’s driver’s license and car registration and, if warranted, conduct further sobriety tests. Should the field tests and the officer’s observations suggest that the driver was intoxicated, an arrest would be made. All other drivers would be permitted to resume their journey immediately.

*448The first—and to date the only—sobriety checkpoint operated under the program was conducted in Saginaw County with the assistance of the Saginaw County Sheriff’s Department. During the 75-minute duration of the checkpoint’s operation, 126 vehicles passed through the checkpoint. The average delay for each vehicle was approximately 25 seconds. Two drivers were detained for field sobriety testing, and one of the two was arrested for driving under the influence of alcohol. A third driver who drove through without stopping was pulled over by an officer in an observation vehicle and arrested for driving under the influence.

On the day before the operation of the Saginaw County checkpoint, respondents filed a complaint in the Circuit Court of Wayne County seeking declaratory and injunctive relief from potential subjection to the checkpoints. Each of the respondents “is a licensed driver in the State of Michigan . . . who regularly travels throughout the State in his automobile.” See Complaint, App. 3a-4a. During pretrial proceedings, petitioners agreed to delay further implementation of the checkpoint program pending the outcome of this litigation.

After the trial, at which the court heard extensive testimony concerning, inter alia, the “effectiveness” of highway sobriety checkpoint programs, the court ruled that the Michigan program violated the Fourth Amendment and Art. 1, § 11, of the Michigan Constitution. App. to Pet. for Cert. 132a. On appeal, the Michigan Court of Appeals affirmed the holding that the program violated the Fourth Amendment and, for that reason, did not consider whether the program violated the Michigan Constitution. 170 Mich. App. 433, 445, 429 N. W. 2d 180, 185 (1988). After the Michigan Supreme Court denied petitioners’ application for leave to appeal, we granted certiorari. 493 U. S. 806 (1989).

To decide this case the trial court performed a balancing test derived from our opinion in Brown v. Texas, 443 U. S. 47 (1979). As described by the Court of Appeals, the test in*449volved “balancing the state’s interest in preventing accidents caused by drunk drivers, the effectiveness of sobriety checkpoints in achieving that goal, and the level of intrusion on an individual’s privacy caused by the checkpoints.” 170 Mich. App., at 439, 429 N. W. 2d, at 182 (citing Brown, supra, at 50-51). The Court of Appeals agreed that “the Brown three-prong balancing test was the correct test to be used to determine the constitutionality of the sobriety checkpoint plan.” 170 Mich. App., at 439, 429 N. W. 2d, at 182.

As characterized by the Court of Appeals, the trial court’s findings with respect to the balancing factors were that the State has “a grave and legitimate” interest in curbing drunken driving; that sobriety checkpoint programs are generally “ineffective” and, therefore, do not significantly further that interest; and that the checkpoints’ “subjective intrusion” on individual liberties is substantial. Id., at 439, 440, 429 N. W. 2d, at 183, 184. According to the court, the record disclosed no basis for disturbing the trial court’s findings, which were made within the context of an analytical framework prescribed by this Court for determining the constitutionality of seizures less intrusive than traditional arrests. Id., at 445, 429 N. W. 2d, at 185.

In this Court respondents seek to defend the judgment in their favor by insisting that the balancing test derived from Brown v. Texas, supra, was not the proper method of analysis. Respondents maintain that the analysis must proceed from a basis of probable cause or reasonable suspicion, and rely for support on language from our decision last Term in Treasury Employees v. Von Raab, 489 U. S. 656 (1989). We said in Von Raab:

“[W]here a Fourth Amendment intrusion serves special governmental needs, beyond the normal need for law enforcement, it is necessary to balance the individual’s privacy expectations against the Government’s interests to determine whether it is impractical to require a warrant *450or some level of individualized suspicion in the particular context.” Id., at 665-666.

Respondents argue that there must be a showing of some special governmental need “beyond the normal need” for criminal law enforcement before a balancing analysis is appropriate, and that petitioners have demonstrated no such special need.

But it is perfectly plain from a reading of Von Raab, which cited and discussed with approval our earlier decision in United States v. Martinez-Fuerte, 428 U. S. 543 (1976), that it was in no way designed to repudiate our prior cases dealing with police stops of motorists on public highways. Martinez-Fuerte, supra, which utilized a balancing analysis in approving highway checkpoints for detecting illegal aliens, and Brown v. Texas, supra, are the relevant authorities here.

Petitioners concede, correctly in our view, that a Fourth Amendment “seizure” occurs when a vehicle is stopped at a checkpoint. Tr. of Oral Arg. 11; see Martinez-Fuerte, supra, at 556 (“It is agreed that checkpoint stops are ‘seizures’ within the meaning of the Fourth Amendment”); Brower v. County of Inyo, 489 U. S. 593, 597 (1989) (Fourth Amendment seizure occurs “when there is a governmental termination of freedom of movement through means intentionally applied” (emphasis in original)). The question thus becomes whether such seizures are “reasonable” under the Fourth Amendment.

It is important to recognize what our inquiry is not about. No allegations are before us of unreasonable treatment of any person after an actual detention at a particular checkpoint. See Martinez-Fuerte, 428 U. S., at 559 (“[C]laim that a particular exercise of discretion in locating or operating a checkpoint is unreasonable is subject to post-stop judicial review”). As pursued in the lower courts, the instant action challenges only the use of sobriety checkpoints generally. We address only the initial stop of each motorist passing through a checkpoint and the associated preliminary questioning and ob*451servation by checkpoint officers. Detention of particular motorists for more extensive field sobriety testing may require satisfaction of an individualized suspicion standard. Id., at 567.

No one can seriously dispute the magnitude of the drunken driving problem or the States’ interest in eradicating it. Media reports of alcohol-related death and mutilation on the Nation’s roads are legion. The anecdotal is confirmed by the statistical. “Drunk drivers cause an annual death toll of over 25,000 [ * ] and in the same time span cause nearly one million personal injuries and more than five billion dollars in property damage.” 4 W. LaFave, Search and Seizure: A Treatise on the Fourth Amendment § 10.8(d), p. 71 (2d ed. 1987). For decades, this Court has “repeatedly lamented the tragedy.” South Dakota v. Neville, 459 U. S. 553, 558 (1983); see Breithaupt v. Abram, 352 U. S. 432, 439 (1957) (“The increasing slaughter on our highways . . . now reaches the astounding figures only heard of on the battlefield”).

Conversely, the weight bearing on the other scale—the measure of the intrusion on motorists stopped briefly at sobriety checkpoints—is slight. We reached a similar conclusion as to the intrusion on motorists subjected to a brief stop at a highway checkpoint for detecting illegal aliens. See Martinez-Fuerte, supra, at 558. We see virtually no difference between the levels of intrusion on law-abiding motorists *452from the brief stops necessary to the effectuation of these two types of checkpoints, which to the average motorist would seem identical save for the nature of the questions the checkpoint officers might ask. The trial court and the Court of Appeals, thus, accurately gauged the “objective” intrusion, measured by the duration of the seizure and the intensity of the investigation, as minimal. See 170 Mich. App., at 444, 429 N. W. 2d, at 184.

With respect to what it perceived to be the “subjective” intrusion on motorists, however, the Court of Appeals found such intrusion substantial. See supra, at 449. The court first affirmed the trial court's finding that the guidelines governing checkpoint operation minimize the discretion of the officers on the scene. But the court also agreed with the trial court’s conclusion that the checkpoints have the potential to generate fear and surprise in motorists. This was so because the record failed to demonstrate that approaching motorists would be aware of their option to make U-turns or turnoffs to avoid the checkpoints. On that basis, the court deemed the subjective intrusion from the checkpoints unreasonable. Id., at 443-444, 429 N. W. 2d, at 184-185.

We believe the Michigan courts misread our cases concerning the degree of “subjective intrusion” and the potential for generating fear and surprise. The “fear and surprise” to be considered are not the natural fear of one who has been drinking over the prospect of being stopped at a sobriety checkpoint but, rather, the fear and surprise engendered in law-abiding motorists by the nature of the stop. This was made clear in Martinez-Fuerte. Comparing checkpoint stops to roving patrol stops considered in prior cases, we said:

“[W]e view checkpoint stops in a different light because the subjective intrusion—the generating of concern or even fright on the part of lawful travelers—is appreciably less in the case of a checkpoint stop. In [United States v.] Ortiz, [422 U. S. 891 (1975),] we noted:

*453“‘[T]he circumstances surrounding a checkpoint stop and search are far less intrusive than those attending a roving-patrol stop. Roving patrols often operate at night on seldom-traveled roads, and their approach may frighten motorists. At traffic checkpoints the motorist can see that other vehicles are being stopped, he can see visible signs of the officers’ authority, and he is much less likely to be frightened or annoyed by the intrusion. 422 U. S., at 894-895.’” Martinez-Fuerte, 428 U. S., at 558.

See also id, at 559. Here, checkpoints are selected pursuant to the guidelines, and uniformed police officers stop every approaching vehicle. The intrusion resulting from the brief stop at the sobriety checkpoint is for constitutional purposes indistinguishable from the checkpoint stops we upheld in Martinez-Fuerte.

The Court of Appeals went on to consider as part of the balancing analysis the “effectiveness” of the proposed checkpoint program. Based on extensive testimony in the trial record, the court concluded that the checkpoint program failed the “effectiveness” part of the test, and that this failure materially discounted petitioners’ strong interest in implementing the program. We think the Court of Appeals was wrong on this point as well.

The actual language from Brown v. Texas, upon which the Michigan courts based their evaluation of “effectiveness,” describes the balancing factor as “the degree to which the seizure advances the public interest.” 443 U. S., at 51. This passage from Brown was not meant to transfer from politically accountable officials to the courts the decision as to which among reasonable alternative law enforcement techniques should be employed to deal with a serious public danger. Experts in police science might disagree over which of several methods of apprehending drunken drivers is preferrable as an ideal. But for purposes of Fourth Amendment analysis, the choice among such reasonable alternatives *454remains with the governmental officials who have a unique understanding of, and a responsibility for, limited public resources, including a finite number of police officers. Brown’s rather general reference to “the degree to which the seizure advances the public interest” was derived, as the opinion makes clear, from the line of cases culminating in Martinez-Fuerte, supra. Neither Martinez-Fuerte nor Delaware v. Prouse, 440 U. S. 648 (1979), however, the two cases cited by the Court of Appeals as providing the basis for its “effectiveness” review, see 170 Mich. App., at 442, 429 N. W. 2d, at 183, supports the searching examination of “effectiveness” undertaken by the Michigan court.

In Delaware v. Prouse, supra, we disapproved random stops made by Delaware Highway Patrol officers in an effort to apprehend unlicensed drivers and unsafe vehicles. We observed that no empirical evidence indicated that such stops would be an effective means of promoting roadway safety and said that “[i]t seems common sense that the percentage of all drivers on the road who are driving without a license is very small and that the number of licensed drivers who will be stopped in order to find one unlicensed operator will be large indeed.” Id., at 659-660. We observed that the random stops involved the “kind of standardless and unconstrained discretion [which] is the evil the Court has discerned when in previous cases it has insisted that the discretion of the official in the field be circumscribed, at least to some extent.” Id., at 661. We went on to state that our holding did not “cast doubt on the permissibility of roadside truck weigh-stations and inspection checkpoints, at which some vehicles may be subject to further detention for safety and regulatory inspection than are others.” Id., at 663, n. 26.

Unlike Prouse, this case involves neither a complete absence of empirical data nor a challenge to random highway stops. During the operation of the Saginaw County checkpoint, the detention of the 126 vehicles that entered the checkpoint resulted in the arrest of two drunken drivers. *455Stated as a percentage, approximately 1.6 percent of the drivers passing through the checkpoint were arrested for alcohol impairment. In addition, an expert witness testified at the trial that experience in other States demonstrated that, on the whole, sobriety checkpoints resulted in drunken driving arrests of around 1 percent of all motorists stopped. 170 Mich. App., at 441, 429 N. W. 2d, at 183. By way of comparison, the record from one of the consolidated cases in Martinez-Fuerte showed that in the associated checkpoint, illegal aliens were found in only 0.12 percent of the vehicles passing through the checkpoint. See 428 U. S., at 554. The ratio of illegal aliens detected to vehicles stopped (considering that on occasion two or more illegal aliens were found in a single vehicle) was approximately 0.5 percent. See ibid. We concluded that this “record . . . provides a rather complete picture of the effectiveness of the San Clemente checkpoint,” ibid., and we sustained its constitutionality. We see no justification for a different conclusion here.

In sum, the balance of the State’s interest in preventing drunken driving, the extent to which this system can reasonably be said to advance that interest, and the degree of intrusion upon individual motorists who are briefly stopped, weighs in favor of the state program. We therefore hold that it is consistent with the Fourth Amendment. The judgment of the Michigan Court of Appeals is accordingly reversed, and the cause is remanded for further proceedings not inconsistent with this opinion.

It is so ordered.

Justice Blackmun,

concurring in the judgment.

I concur only in the judgment.

I fully agree with the Court’s lamentations about the slaughter on our highways and about the dangers posed to almost everyone by the driver who is under the influence of alcohol or other drug. I add this comment only to remind the Court that it has been almost 20 years since, in Perez v. *456 Campbell, 402 U. S. 637, 657 (1971), in writing for three others (no longer on the Court) and myself, I noted that the “slaughter on the highways of this Nation exceeds the death toll of all our wars,” and that I detected “little genuine public concern about what takes place in our very midst and on our daily travel routes.” See also Tate v. Short, 401 U. S. 395, 401 (1971) (concurring statement). And in the Appendix to my writing in Perez, 402 U. S., at 672, I set forth official figures to the effect that for the period from 1900 through 1969 motor-vehicle deaths in the United States exceeded the death toll of all our wars. I have little doubt that those figures, when supplemented for the two decades since 1969, would disclose an even more discouraging comparison. I am pleased, of course, that the Court is now stressing this tragic aspect of American life. See ante, at 451.

Justice Brennan,

with whom Justice Marshall joins, dissenting.

Today, the Court rejects a Fourth Amendment challenge to a sobriety checkpoint policy in which police stop all cars and inspect all drivers for signs of intoxication without any individualized suspicion that a specific driver is intoxicated. The Court does so by balancing “the State’s interest in preventing drunken driving, the extent to which this system can reasonably be said to advance that interest, and the degree of intrusion upon individual motorists who are briefly stopped.” Ante, at 455. For the reasons stated by Justice Stevens in Parts I and II of his dissenting opinion, I agree that the Court misapplies that test by undervaluing the nature of the intrusion and exaggerating the law enforcement need to use the roadblocks to prevent drunken driving. See also United States v. Martinez-Fuerte, 428 U. S. 543, 567 (1976) (Brennan, J., dissenting). I write separately to express a few additional points.

The majority opinion creates the impression that the Court generally engages in a balancing test in order to determine *457the constitutionality of all seizures, or at least those “dealing with police stops of motorists on public highways.” Ante, at 450. This is not the case. In most cases, the police must possess probable cause for a seizure to be judged reasonable. See Dunaway v. New York, 442 U. S. 200, 209 (1979). Only when a seizure is “substantially less intrusive,” id., at 210 (emphasis added), than a typical arrest is the general rule replaced by a balancing test. I agree with the Court that the initial stop of a car at a roadblock under the Michigan State Police sobriety checkpoint policy is sufficiently less intrusive than an arrest so that the reasonableness of the seizure may be judged, not by the presence of probable cause, but by balancing “the gravity of the public concerns served by the seizure, the degree to which the seizure advances the public interest, and the severity of the interference with individual liberty.” Brown v. Texas, 443 U. S. 47, 51 (1979). But one searches the majority opinion in vain for any acknowledgment that the reason for employing the balancing test is that the seizure is minimally intrusive.

Indeed, the opinion reads as if the minimal nature of the seizure ends rather than begins the inquiry into reasonableness. Once the Court establishes that the seizure is “slight,” ante, at 451, it asserts without explanation that the balance “weighs in favor of the state program.” Ante, at 455. The Court ignores the fact that in this class of minimally intrusive searches, we have generally required the government to prove that it had reasonable suspicion for a minimally intrusive seizure to be considered reasonable. See, e. g., Delaware v. Prouse, 440 U. S. 648, 661 (1979); United States v. Brignoni-Ponce, 422 U. S. 873, 882-883 (1975); Terry v. Ohio, 392 U. S. 1, 27 (1968). Some level of individualized suspicion is a core component of the protection the Fourth Amendment provides against arbitrary government action. See Prouse, supra, at 654-655; Martinez-Fuerte, supra, at 577 (Brennan, J., dissenting) (“Action based merely on *458whatever may pique the curiousity of a particular officer is the antithesis of the objective standards requisite to reasonable conduct and to avoiding abuse and harassment”). By holding that no level of suspicion is necessary before the police may stop a car for the purpose of preventing drunken driving, the Court potentially subjects the general public to arbitrary or harassing conduct by the police. I would have hoped that before taking such a step, the Court would carefully explain how such a plan fits within our constitutional framework.

Presumably, the Court purports to draw support from Martinez-Fuerte, supra, which is the only case in which the Court has upheld a program that subjects the general public to suspicionless seizures. But as Justice Stevens demonstrates, post, at 463-466, 471-472, the Michigan State Police policy is sufficiently different from the progam at issue in Martinez-Fuerte that such reliance is unavailing. Moreover, even if the policy at issue here were comparable to the program at issue in Martinez-Fuerte, it does not follow that the balance of factors in this case also justifies abandoning a requirement of individualized suspicion. In Martinez-Fuerte, the Court explained that suspicionless stops were justified since “[a] requirement that stops . . . be based on reasonable suspicion would be impractical because the flow of traffic tends to be too heavy to allow the particularized study of a given car that would enable it to be identified as a possible carrier of illegal aliens.” 428 U. S., at 557. There has been no showing in this case that there is a similar difficulty in detecting individuals who are driving under the influence of alcohol, nor is it intuitively obvious that such a difficulty exists. See Prouse, supra, at 661. That stopping every car might make it easier to prevent drunken driving, but see post, at 469-471, is an insufficient justification for abandoning the requirement of individualized suspicion. “The needs of law enforcement stand in constant tension with the Constitution’s protections *459of the individual against certain exercises of official power. It is precisely the predictability of these pressures that counsels a resolute loyalty to constitutional safeguards.” Almeida-Sanchez v. United States, 413 U. S. 266, 273 (1973). Without proof that the police cannot develop individualized suspicion that a person is driving while impaired by alcohol, I believe the constitutional balance must be struck in favor of protecting the public against even the “minimally intrusive” seizures involved in this case.

I do not dispute the immense social cost caused by drunken drivers, nor do I slight the government’s efforts to prevent such tragic losses. Indeed, I would hazard a guess that today’s opinion will be received favorably by a majority of our society, who would willingly suffer the minimal intrusion of a sobriety checkpoint stop in order to prevent drunken driving. But consensus that a particular law enforcement technique serves a laudable purpose has never been the touchstone of constitutional analysis.

“The Fourth Amendment was designed not merely to protect against official intrusions whose social utility was less as measured by some ‘balancing test’ than its intrusion on individual privacy; it was designed in addition to grant the individual a zone of privacy whose protections could be breached only where the ‘reasonable’ requirements of the probable-cause standard were met. Moved by whatever momentary evil has aroused their fears, officials—perhaps even supported by a majority of citizens—may be tempted to conduct searches that sacrifice the liberty of each citizen to assuage the perceived evil. But the Fourth Amendment rests on the principle that a true balance between the individual and society depends on the recognition of ‘the right to be let alone—the most comprehensive of rights and the right most valued by civilized men.’ Olmstead v. United States, 277 U. S. 438, 478 (1928) (Brandeis, J., dissenting).” New Jersey *460v. T. L. O., 469 U. S. 325, 361-362 (1985) (Brennan, J., concurring in part and dissenting in part) (footnote omitted).

In the face of the “momentary evil” of drunken driving, the Court today abdicates its role as the protector of that fundamental right. I respectfully dissent.

Justice Stevens,

with whom Justice Brennan and Justice Marshall join as to Parts I and II, dissenting.

A sobriety checkpoint is usually operated at night at an unannounced location. Surprise is crucial to its method. The test operation conducted by the Michigan State Police and the Saginaw County Sheriff’s Department began shortly after midnight and lasted until about 1 a.m. During that period, the 19 officers participating in the operation made two arrests and stopped and questioned 124 other unsuspecting and innocent drivers.1 It is, of course, not known how many arrests would have been made during that period if those officers had been engaged in normal patrol activities. However, the findings of the trial court, based on an extensive record and affirmed by the Michigan Court of Appeals, indicate that the net effect of sobriety checkpoints on traffic safety is infinitesimal and possibly negative.

Indeed, the record in this case makes clear that a decision holding these suspicionless seizures unconstitutional would not impede the law enforcement community’s remarkable progress in reducing the death toll on our highways.2 Be*461cause the Michigan program was patterned after an older program in Maryland, the trial judge gave special attention to that State’s experience. Over a period of several years, Maryland operated 125 checkpoints; of the 41,000 motorists passing through those checkpoints, only 143 persons (0.3%) were arrested.3 The number of man-hours devoted to these *462operations is not in the record, but it seems inconceivable that a higher arrest rate could not have been achieved by more conventional means.4 Yet, even if the 143 checkpoint arrests were assumed to involve a net increase in the number of drunken driving arrests per year, the figure would still be insignificant by comparison to the 71,000 such arrests made by Michigan State Police without checkpoints in 1984 alone. See App. to Pet. for Cert. 97a.

Any relationship between sobriety checkpoints and an actual reduction in highway fatalities is even less substantial than the minimal impact on arrest rates. As the Michigan Court of Appeals pointed out: “Maryland had conducted a study comparing traffic statistics between a county using checkpoints and a control county. The results of the study showed that alcohol-related accidents in the checkpoint county decreased by ten percent, whereas the control county saw an eleven percent decrease; and while fatal accidents in the control county fell from sixteen to three, fatal accidents in the checkpoint county actually doubled from the prior year.” 170 Mich. App. 433, 443, 429 N. W. 2d 180, 184 (1988).

In light of these considerations, it seems evident that the Court today misapplies the balancing test announced in Brown v. Texas, 443 U. S. 47, 50-51 (1979). The Court overvalues the law enforcement interest in using sobriety checkpoints, undervalues the citizen’s interest in freedom from random, unannounced investigatory seizures, and mistakenly assumes that there is “virtually no difference” between a routine stop at a permanent, fixed checkpoint and a *463surprise stop at a sobriety checkpoint. I believe this case is controlled by our several precedents condemning suspicionless random stops of motorists for investigatory purposes. Delaware v. Prouse, 440 U. S. 648 (1979); United States v. Brignoni-Ponce, 422 U. S. 873 (1975); United States v. Ortiz, 422 U. S. 891 (1975); Almeida-Sanchez v. United States, 413 U. S. 266 (1973); cf. Carroll v. United States, 267 U. S. 132, 153-154 (1925).

I

There is a critical difference between a seizure that is preceded by fair notice and one that is effected by surprise. See Wyman v. James, 400 U. S. 309, 320-321 (1971); United States v. Martinez-Fuerte, 428 U. S. 543, 559 (1976); Michigan v. Tyler, 436 U. S. 499, 513-514 (1978) (Stevens, J., concurring in part and concurring in judgment). That is one reason why a border search, or indeed any search at a permanent and fixed checkpoint, is much less intrusive than a random stop. A motorist with advance notice of the location of a permanent checkpoint has an opportunity to avoid the search entirely, or at least to prepare for, and limit, the intrusion on her privacy.

No such opportunity is available in the case of a random stop or a temporary checkpoint, which both depend for their effectiveness on the element of surprise. A driver who discovers an unexpected checkpoint on a familiar local road will be startled and distressed. She may infer, correctly, that the checkpoint is not simply “business as usual,” and may likewise infer, again correctly, that the police have made a discretionary decision to focus their law enforcement efforts upon her and others who pass the chosen point.

This element of surprise is the most obvious distinction between the sobriety checkpoints permitted by today’s majority and the interior border checkpoints approved by this Court in Martinez-Fuerte. The distinction casts immediate doubt upon the majority’s argument, for Martinez-Fuerte is the only case in which we have upheld suspicionless seizures *464of motorists. But the difference between notice and surprise is only one of the important reasons for distinguishing between permanent and mobile checkpoints. With respect to the former, there is no room for discretion in either the timing or the location of the stop—it is a permanent part of the landscape. In the latter case, however, although the checkpoint is most frequently employed during the hours of darkness on weekends (because that is when drivers with alcohol in their blood are most apt to be found on the road), the police have extremely broad discretion in determining the exact timing and placement of the roadblock.5

There is also a significant difference between the kind of discretion that the officer exercises after the stop is made. A check for a driver’s license, or for identification papers at an immigration checkpoint, is far more easily standardized than is a search for evidence of intoxication. A Michigan officer who questions a motorist at a sobriety checkpoint has virtually unlimited discretion to detain the driver on the basis *465of the slightest suspicion. A ruddy complexion, an unbuttoned shirt, bloodshot eyes, or a speech impediment may suffice to prolong the detention. Any driver who had just consumed a glass of beer, or even a sip of wine, would almost certainly have the burden of demonstrating to the officer that his or her driving ability was not impaired.6

Finally, it is significant that many of the stops at permanent checkpoints occur during daylight hours, whereas the sobriety checkpoints are almost invariably operated at night. A seizure followed by interrogation and even a cursory search at night is surely more offensive than a daytime stop that is almost as routine as going through a tollgate. Thus we thought it important to point out that the random stops at issue in Ortiz frequently occurred at night. 422 U. S., at 894.

These fears are not, as the Court would have it, solely the lot of the guilty. See ante, at 452. To be law abiding is not necessarily to be spotless, and even the most virtuous can be unlucky. Unwanted attention from the local police need not be less discomforting simply because one’s secrets are not the stuff of criminal prosecutions. Moreover, those who have found—by reason of prejudice or misfortune—that encounters with the police may become adversarial or unpleasant without good cause will have grounds for worrying at any stop designed to elicit signs of suspicious behavior. Being stopped by the police is distressing even when it should not be terrifying, and what begins mildly may by happenstance turn severe.

For all these reasons, I do not believe that this case is analogous to Martinez-Fuerte. In my opinion, the sobriety checkpoints are instead similar to—and in some respects more intrusive than—the random investigative stops that the Court held unconstitutional in Brignoni-Ponce and Prouse. In the latter case the Court explained:

*466“We cannot agree that stopping or detaining a vehicle on an ordinary city street is less intrusive than a roving-patrol stop on a major highway and that it bears greater resemblance to a permissible stop and secondary detention at a checkpoint near the border. In this regard, we note that Brignoni-Ponce was not limited to roving-patrol stops on limited-access roads, but applied to any roving-patrol stop by Border Patrol agents on any type of roadway on less than reasonable suspicion. See 422 U. S., at 882-883; United States v. Ortiz, 422 U. S. 891, 894 (1975). We cannot assume that the physical and psychological intrusion visited upon the occupants of a vehicle by a random stop to check documents is of any less moment than that occasioned by a stop by border agents on roving patrol. Both of these stops generally entail law enforcement officers signaling a moving automobile to pull over to the side of the roadway, by means of a possibly unsettling show of authority. Both interfere with freedom of movement, are inconvenient, and consume time. Both may create substantial anxiety.” 440 U. S., at 657.

We accordingly held that the State must produce evidence comparing the challenged seizure to other means of law enforcement, so as to show that the seizure

“is a sufficiently productive mechanism to justify the intrusion upon Fourth Amendment interests which such stops entail. On the record before us, that question must be answered in the negative. Given the alternative mechanisms available, both those in use and those that might be adopted, we are unconvinced that the incremental contribution to highway safety of the random spot check justifies the practice under the Fourth Amendment.” Id., at 659.

*467II

The Court, unable to draw any persuasive analogy to Martinez-Fuerte, rests its decision today on application of a more general balancing test taken from Brown v. Texas, 443 U. S. 47 (1979). In that case the appellant, a pedestrian, had been stopped for questioning in an area of El Paso, Texas, that had “a high incidence of drug traffic” because he “looked suspicious. ” Id., at 49. He was then arrested and convicted for refusing to identify himself to police officers. We set aside his conviction because the officers stopped him when they lacked any reasonable suspicion that he was engaged in criminal activity. In our opinion, we stated:

“Consideration of the constitutionality of such seizures involves a weighing of the gravity of the public concerns served by the seizure, the degree to which the seizure advances the public interest, and the severity of the interference with individual liberty.” Id., at 50-51.

The gravity of the public concern with highway safety that is implicated by this case is, of course, undisputed.7 *468Yet, that same grave concern was implicated in Delaware v. Prouse. Moreover, I do not understand the Court to have placed any lesser value on the importance of the drug problem implicated in Brown v. Texas or on the need to control the illegal border crossings that were at stake in Almeida-Sanchez and its progeny.8 A different result in this case must be justified by the other two factors in the Brown formulation.

As I have already explained, I believe the Court is quite wrong in blithely asserting that a sobriety checkpoint is no more intrusive than a permanent checkpoint. In my opinion, unannounced investigatory seizures are, particularly when *469they take place at night, the hallmark of regimes far different from ours;9 the surprise intrusion upon individual liberty is not minimal. On that issue, my difference with the Court may amount to nothing less than a difference in our respective evaluations of the importance of individual liberty, a serious, albeit inevitable, source of constitutional disagreement.10 On the degree to which the sobriety checkpoint seizures advance the public interest, however, the Court’s position is wholly indefensible.

The Court’s analysis of this issue resembles a business decision that measures profits by counting gross receipts and ignoring expenses. The evidence in this case indicates that sobriety checkpoints result in the arrest of a fraction of one percent of the drivers who are stopped,11 but there is absolutely no evidence that this figure represents an increase over the number of arrests that would have been made by using the same law enforcement resources in conventional patrols.12 Thus, although the gross number of arrests is more *470than zero, there is a complete failure of proof on the question whether the wholesale seizures have produced any net advance in the public interest in arresting intoxicated drivers.

Indeed, the position adopted today by the Court is not one endorsed by any of the law enforcement authorities to whom the Court purports to defer, see ante, at 453-454. The Michigan police do not rely, as the Court does, ante, at 454-455, on the arrest rate at sobriety checkpoints to justify the stops made there. Colonel Hough, the commander of the Michigan State Police and a leading proponent of the checkpoints, admitted at trial that the arrest rate at the checkpoints was “very low.” 1 Record 87. Instead, Colonel Hough and the State have maintained that the mere threat of such arrests is sufficient to deter drunken driving and so to reduce the accident rate.13 The Maryland police officer who testified *471at trial took the same position with respect to his State’s program.14 There is, obviously, nothing wrong with a law enforcement technique that reduces crime by pure deterrence without punishing anybody; on the contrary, such an approach is highly commendable. One cannot, however, prove its efficacy by counting the arrests that were made. One must instead measure the number of crimes that were avoided. Perhaps because the record is wanting, the Court simply ignores this point.

The Court’s sparse analysis of this issue differs markedly from Justice Powell’s opinion for the Court in Martinez-Fuerte. He did not merely count the 17,000 arrests made at the San Clemente checkpoint in 1973, 428 U. S., at 554; he also carefully explained why those arrests represented a net benefit to the law enforcement interest at stake.15 Common *472sense, moreover, suggests that immigration checkpoints are more necessary than sobriety checkpoints: There is no reason why smuggling illegal aliens should impair a motorist’s driving ability, but if intoxication did not noticeably affect driving ability it would not be unlawful. Drunken driving, unlike smuggling, may thus be detected absent any checkpoints. A program that produces thousands of otherwise impossible arrests is not a relevant precedent for a program that produces only a handful of arrests which would be more easily obtained without resort to suspicionless seizures of hundreds of innocent citizens.16

*473III

The most disturbing aspect of the Court’s decision today is that it appears to give no weight to the citizen’s interest in freedom from suspicionless unannounced investigatory seizures. Although the author of the opinion does not reiterate his description of that interest as “diaphanous,” see Delaware v. Prouse, 440 U. S., at 666 (Rehnquist, J., dissenting), the Court’s opinion implicitly adopts that characterization. On the other hand, the Court places a heavy thumb on the law enforcement interest by looking only at gross receipts instead of net benefits. Perhaps this tampering with the scales of justice can be explained by the Court’s obvious concern about the slaughter on our highways and a resultant tolerance for policies designed to alleviate the problem by “setting an example” of a few motorists. This possibility prompts two observations.

First, my objections to random seizures or temporary checkpoints do not apply to a host of other investigatory procedures that do not depend upon surprise and are unquestionably permissible. These procedures have been used to address other threats to human life no less pressing than the threat posed by drunken drivers. It is, for example, common practice to require every prospective airline passenger, or every visitor to a public building, to pass through a metal detector that will reveal the presence of a firearm or an explosive. Permanent, nondiscretionary checkpoints could be used to control serious dangers at other publicly operated facilities. Because concealed weapons obviously represent one such substantial threat to public safety,17 I would suppose *474that all subway passengers could be required to pass through metal detectors, so long as the detectors were permanent and every passenger was subjected to the same search.18 Likewise, I would suppose that a State could condition access to its toll roads upon not only paying the toll but also taking a uniformly administered breathalyzer test. That requirement might well keep all drunken drivers off the highways that serve the fastest and most dangerous traffic. This procedure would not be subject to the constitutional objections that control this case: The checkpoints would be permanently fixed, the stopping procedure would apply to all users of the toll road in precisely the same way, and police officers would not be free to make arbitrary choices about which neighborhoods should be targeted or about which individuals should be more thoroughly searched. Random, suspicionless seizures designed to search for evidence of firearms, drugs, or intoxication belong, however, in a fundamentally different category. These seizures play upon the detained individual’s reasonable expectations of privacy, injecting a suspicionless search into a context where none would normally occur. The imposition that seems diaphanous today may be intolerable tomorrow. See Boyd v. United States, 116 U. S. 616, 635 (1886).

*475Second, sobriety checkpoints are elaborate, and disquieting, publicity stunts. The possibility that anybody, no matter how innocent, may be stopped for police inspection is nothing if not attention getting. The shock value of the checkpoint program may be its most effective feature: Lieutenant Cotten of the Maryland State Police, a defense witness, testified that “the media coverage . . . has been absolutely overwhelming .... Quite frankly we got benefits just from the controversy of the sobriety checkpoints.”19 In*476sofar as the State seeks to justify its use of sobriety checkpoints on the basis that they dramatize the public interest in the prevention of alcohol-related accidents, the Court should heed Justice Scalia’s comment upon a similar justification for a drug screening program:

“The only plausible explanation, in my view, is what the Commissioner himself offered in the concluding sentence of his memorandum to Customs Service employees announcing the program: ‘Implementation of the drug screening program would set an important example in our country’s struggle with this most serious threat to our national health and security.’ App. 12. Or as respondent’s brief to this Court asserted: ‘if a law enforcement agency and its employees do not take the law seriously, neither will the public on which the agency’s effectiveness depends.’ Brief for Respondent 36. What better way to show that the Government is serious about its ‘war on drugs’ than to subject its employees on the front line of that war to this invasion of their privacy and affront to their dignity? To be sure, there is only a slight chance that it will prevent some serious public harm resulting from Service employee drug use, but it will show to the world that the Service is ‘clean,’ and— most important of all—will demonstrate the determination of the Government to eliminate this scourge of our society! I think it obvious that this justification is unacceptable; that the impairment of individual liberties cannot be the means of making a point; that symbolism, *477even symbolism for so worthy a cause as the abolition of unlawful drugs, cannot validate an otherwise unreasonable search.” Treasury Employees v. Von Raab, 489 U. S. 656, 686-687 (1989) (dissenting opinion).

This is a case that is driven by nothing more than symbolic state action—an insufficient justification for an otherwise unreasonable program of random seizures. Unfortunately, the Court is transfixed by the wrong symbol—the illusory prospect of punishing countless intoxicated motorists—when it should keep its eyes on the road plainly marked by the Constitution.

I respectfully dissent.

The opinion of the court was delivered by

Holmes, J.:

This is an interlocutory appeal, pursuant to K.S.A. 22-3603, by the State of Kansas from an order of the district court suppressing certain evidence in a prosecution for driving while under the influence of alcohol (DUI) and possession of marijuana.

Defendant, Rick L. Deskins, was arrested after his automobile was stopped by police officers at a roadblock ostensibly set up for the purpose of checking drivers’ licenses. Prior to trial defendant filed a motion to suppress all evidence of DUI and the small bag of marijuana found in the automobile glove-box after defendant’s arrest. The court found the roadblock to be an unconstitutional violation of the Kansas Constitution Bill of Rights § 15, the Kansas equivalent to the Fourth Amendment to the United States Constitution. The trial court found as a matter of fact, and counsel for the State candidly conceded in argument before this court, that the roadblock was set up to catch drunk drivers and that the checking of drivers’ licenses was a facade for such purposes. Therefore, the narrow question before this court is whether the use of a DUI roadblock under the factual situation *531existing in this case is an unconstitutional infringement upon a person’s right to be free from unreasonable searches and seizures under the Kansas Bill of Rights and the Fourth Amendment, In considering the application of § 15 of the Kansas Bill of Rights to any particular factual situation, its scope is identical to that of the Fourth Amendment. State v. Wood, 190 Kan. 778, 788, 378 P.2d 536 (1963).

At 10:00 p.m. on November 20, 1982, thirty-five to forty police officers from the Kansas State Highway Patrol, the Shawnee County Sheriff s Office, and the Topeka Police Department, set up a roadblock at the intersection of 45th Street and Topeka Avenue in Topeka, ostensibly to check drivers’ licenses. All vehicles proceeding both north and south on Topeka Avenue were stopped and their drivers checked to determine if they were carrying valid licenses. Mr. Deskins was driving south on Topeka Avenue around 1:20 a.m. the next morning, and was stopped in the check lane. A state trooper approached the car and requested Deskins’ license which was found to be in order and at that point he had satisfied all the requirements for the license check.

The officer had not observed the defendant operate the automobile, as it was standing still in a line of stopped vehicles when the officer approached, and the officer, prior to the vehicle being stopped, had no facts or knowledge which would constitute probable cause or even a reasonable suspicion that defendant had committed, was committing, or was about to commit a violation of Kansas criminal statutes. However, from his position outside Deskins’ car, the trooper “could smell a strong odor of alcohol, some type of alcoholic beverage on [defendant’s] breath and his eyes were kind of bloodshot and watery.” The officer asked Deskins to step out of the car to take a sobriety and coordination test. His performance was less than satisfactory to the officer and, as the officer was of the opinion defendant was under the influence of alcohol, he arrested defendant and read him the Miranda rights. The trooper moved defendant to a squad car and another officer, with defendant’s permission, moved his car out of the check lane. While defendant remained in the police car, one of the officers searched the defendant’s automobile and found in the glove-box a plastic bag containing marijuana.

*532Defense counsel filed a motion to suppress all evidence gathered after defendant’s vehicle was stopped, on grounds the roadblock was designed not to check drivers’ licenses but solely to “stop all vehicles for the purpose of arresting individuals that the police suspected of driving while intoxicated.” Defendant claimed the roadblock stop violated his constitutional rights under the Fourth Amendment. At the hearing on the motion, the arresting officer testified that during a briefing before establishing the roadblock it was made clear to the officers that if, after stopping someone in the lane, they smelled alcohol or had any “suspicion” of drinking, they could question the driver further. The State, as previously indicated, has conceded the primary purpose of the roadblock was to catch drunk drivers, and this appeal will be considered in that light, although incidental to that purpose arrests were also made for a number of other reasons, including some involving license violations.

There can be no doubt that the stopping of a motorist for the sole purpose of checking for a valid driver’s license, let alone to seek evidence of the commission of a crime such as DUI, constitutes a “seizure” under the Fourth Amendment. In Union Pacific Railway Co. v. Botsford, 141 U.S. 250, 35 L.Ed. 734, 11 S.Ct. 1000 (1891), the court stated:

“No right is held more sacred, or is more carefully guarded, by the common law, than the right of every individual to the possession and control of his own person, free from all restraint or interference of others, unless by clear and unquestionable authority of law.” 141 U.S. at 251.

The Supreme Court in Terry v. Ohio, 392 U.S. 1, 20 L.Ed.2d 889, 88 S.Ct. 1868 (1968), was faced with a Fourth Amendment challenge to the admission of evidence recovered in a “stop and frisk” encounter between police and defendant Terry. The defendant, while walking on the street, had been stopped by a veteran police officer merely on the officer’s suspicion that Terry and his companions might be considering a robbery. For his own protection the officer patted down the outer clothing of the men and found Terry to be carrying a pistol. Terry was later convicted of carrying a concealed weapon and the case eventually made its way to the Supreme Court on the question of whether his rights under the Fourth Amendment had been violated and whether the evidence recovered in the “stop and frisk” should have been suppressed. In its opinion the Court stated:

*533“It is quite plain that the Fourth Amendment governs ‘seizures’ of the person which do not eventuate in a trip to the station house and prosecution for crime — ‘arrests’ in traditional terminology. It must be recognized that whenever a police officer accosts an individual and restrains his freedom to walk away, he has ‘seized’ that person.” 392 U.S. at 16.

In Delaware v. Prouse, 440 U.S. 648, 59 L.Ed.2d 660, 99 S.Ct. 1391 (1979), the Court stated:

“The Fourth and Fourteenth Amendments are implicated in this case because stopping an automobile and detaining its occupants constitute a ‘seizure’ within the meaning of those Amendments, even though the purpose of the stop is limited and the resulting detention quite brief.” 440 U.S. at 653.

In Prouse, upon which the State relies heavily, the court stated the facts in the following manner:

“At 7:20 p.m. on November 30, 1976, a New Castle County, Del., patrolman in a police cruiser stopped the automobile occupied by respondent. The patrolman smelled marihuana smoke as he was walking toward the stopped vehicle, and he seized marihuana in plain view on the car floor. Respondent was subsequently indicted for illegal possession of a controlled substance. At a hearing on respondent’s motion to suppress the marihuana seized as a result of the stop, the patrolman testified that prior to stopping the vehicle he had observed neither traffic or equipment violations nor any suspicious activity, and that he made the stop only in order to check the driver’s license and registration. The patrolman was not acting pursuant to any standards, guidelines, or procedures pertaining to document spot checks, promulgated by either his department or the State Attorney General. Characterizing the stop as ‘routine,’ the patrolman explained, T saw the car in the area and wasn’t answering any complaints, so I decided to pull them off.’ . . . The trial court granted the motion to suppress, finding the stop and detention to have been wholly capricious and therefore violative of the Fourth Amendment.” pp. 650-651.

The Delaware Supreme Court affirmed the trial court and the United States Supreme Court affirmed with only Justice Rehnquist dissenting. The majority opinion, in its conclusion, stated:

“Accordingly, we hold that except in those situations in which there is at least articulable and reasonable suspicion that a motorist is unlicensed or that an automobile is not registered, or that either the vehicle or an occupant is otherwise subject to seizure for violation of law, stopping an automobile and detaining the driver in order to check his driver’s license and the registration of the automobile are unreasonable under the Fourth Amendment. This holding does not preclude the State of Delaware or other States from developing methods for spot checks that involve less intrusion or that do not involve the unconstrained exercise of discretion. Questioning of all oncoming traffic at roadblock-type stops is one possible alternative. We hold only that persons in automobiles on public roadways may not for that reason alone have their travel and privacy interfered with at the unbridled discretion of police officers, "p. 663. (Emphasis added.)

*534In reaching its ultimate conclusion that the random stopping of a motorist without at least some reasonable suspicion that a violation may be occurring violates the Fourth Amendment, the court relied heavily on its earlier opinions in what are referred to as the border patrol cases. The Court stated:

“The essential purpose of the proscriptions in the Fourth Amendment is to impose a standard of‘reasonableness’ upon the exercise of discretion by government officials, including law enforcement agents, in order ‘ “to safeguard the privacy and security of individuals against arbitrary invasions. . . ” (Citations omitted.) Thus, the permissibility of a particular law enforcement practice is judged by balancing its intrusion on the individual’s Fourth Amendment interests against its promotion of legitimate governmental interest. Implemented in this manner, the reasonableness standard usually requires, at a minimum, that the facts upon which an intrusion is based be capable of measurement against ‘an objective standard,’ whether this be probable cause or a less stringent test. In those situations in which the balance of interests precludes insistence upon ‘some quantum of individualized suspicion,’ other safeguards are generally relied upon to assure that the individual’s reasonable expectation of privacy is not ‘subject to the discretion of the official in the field.” pp. 653-55.

“We have only recently considered the legality of investigative stops of automobiles where the officers making the stop have neither probable cause to believe nor reasonable suspicion that either the automobile or its occupants are subject to seizure under the applicable criminal laws. In United States v. Brignoni-Ponce, [422 U.S. 873 (1975),] Border Patrol agents conducting roving patrols in areas near the international border asserted statutory authority to stop at random any vehicle in order to determine whether it contained illegal aliens or was involved in smuggling operations. The practice was held to violate the Fourth Amendment, but the Court did not invalidate all warrantless automobile stops upon less than probable cause. Given ‘the importance of the governmental interest at stake, the minimal intrusion of a brief stop, and the absence of practical alternatives for policing the border,’ 422 U.S., at 881, the Court analogized the roving-patrol stop to the on-the-street encounter addressed in Terry v. Ohio, [392 U.S. 1 (1968),] and held:

‘Except at the border and its functional equivalents, officers on roving patrol may stop vehicles only if they are aware of specific articulable facts, together with rational inferences from those facts, that reasonably warrant suspicion that the vehicles contain aliens who may be illegally in the country.’ 422 U.S., at 884 (footnote omitted).

Because ‘the nature of illegal alien traffic and the characteristics of smuggling operations tend to generate articulable grounds for identifying violators,’ id., at 883, ‘a requirement of reasonable suspicion for stops allows the Government adequate means of guarding the public interest and also protects residents of the border areas from indiscriminate official interference.’ Ibid.

“The constitutionality of stops by Border Patrol agents was again before the Court in United States v. Martinez-Fuerte, [428 U.S. 543 (1976),] in which we *535addressed the permissibility of checkpoint operations. This practice involved slowing all oncoming traffic ‘to a virtual, if not a complete, halt,’ 428 U.S., at 546, ata highway roadblock, and referring vehicles chosen at the discretion of Border Patrol agents to an area for secondary inspection. See id., at 546, 558. Recognizing that the governmental interest involved was the same as that furthered by roving-patrol stops, the Court nonetheless sustained the constitutionality of the Border Patrol’s checkpoint operations. The crucial distinction was the lesser intrusion upon the motorist’s Fourth Amendment interests:

‘[The] objective intrusion — the stop itself, the questioning, and the visual inspection — also existed in roving-patrol stops. But we view checkpoint stops in a different light because the subjective intrusion — the generating of concern or even fright on the part of lawful travelers — is appreciably less in the case of checkpoint stop.’ [428 U.S.] at 558.

Although not dispositive, these decisions undoubtedly provide guidance in balancing the public interest against the individual’s Fourth Amendment interests implicated by the practice of spot checks such as occurred in this case. We cannot agree that stopping or detaining a vehicle on an ordinary city street is less intrusive than a roving-patrol stop on a major highway and that it bears greater resemblance to a permissible stop and secondary detention at a checkpoint near the border. In this regard, we note that Brignoni-Ponce was not limited to roving-patrol stops on limited-access roads, but applied to any roving-patrol stop by Border Patrol agents on any type of roadway on less than reasonable suspicion. See 422 U.S., at 882-883; United States v. Ortiz, 422 U.S. 891, 894 (1975). We cannot assume that the physical and psychological intrusion visited upon the occupants of a vehicle by a random stop to check documents is of any less moment that that occasioned by a stop by border agents on roving patrol. Both of these stops generally entail law enforcement officers signaling a moving automobile to pull over to the side of the roadway, by means of a possibly unsettling show of authority. Both interfere with freedom of movement, are inconvenient, and consume time. Both may create substantial anxiety. For Fourth Amendment purposes, we also see insufficient resemblance between sporadic and random stops of individual vehicles making their way through city traffic and those stops occasioned by roadblocks where all vehicles are brought to a halt or to a near halt, and all are subjected to a show of the police power of the community. ‘At traffic checkpoints the motorist can see visible signs of the officers’ authority, and he is much less likely to be frightened or annoyed by the intrusion.’ [422 U.S.] at 894-895, quoted in United States v. Martinez-Fuerte, 428 U.S. at 558.” pp. 655-657.

“When there is not probable cause to believe that a driver is violating any one of the multitude of applicable traffic and equipment regulations — or other articulable basis amounting to reasonable suspicion that the driver is unlicensed or his vehicle unregistered — we cannot conceive of any legitimate basis upon which a patrolman could decide that stopping a particular driver for a spot check would be more productive than stopping any other driver. This kind of standardless and unconstrained discretion is the evil the Court has discerned when in previous cases it has insisted that the discretion of the official in the field be circumscribed, at least to some extent. Almeida-Sanchez v. United States, 413 U.S. 266, 270 (1973); Camara v. Municipal Court, 387 U.S., at 532-533.” p. 661

*536Thus it is clear that the random stop to check a motorist’s driver’s license without probable cause or at the very least some reasonable suspicion, which a majority of this court approved in City of Overland Park v. Sandy, 225 Kan. 102, 587 P.2d 883 (1978), is a violation of the Fourth Amendment rights of the driver and that holding in Sandy to the contrary has clearly been overruled by Prouse. Since its decision in Prouse, the Supreme Court has not had an opportunity to explore the issue further in the context of vehicle roadblocks.

However, in Brown v. Texas, 443 U.S. 47, 61 L.Ed.2d 357, 99 S.Ct. 2637 (1979), the court relied upon part of its Fourth Amendment analysis and approach taken in Prouse. Brown held a Texas statute unconstitutional under the Fourth Amendment where it allowed police to detain a person, and require that person to identify himself, even where the officers lacked probable cause or any reasonable suspicion to believe that defendant was engaged or had engaged in criminal conduct. 443 U.S. at 53. In the course of its opinion, the Court said:

"A central concern in balancing [the competing considerations of public need and individual liberty] has been to assure than an individual’s reasonable expectation of privacy is not subject to arbitrary invasions solely at the unfettered discretion of officers in the field. (Citations omitted.) To this end, the Fourth Amendment requires that a seizure must be based on specific, objective facts indicating that society’s legitimate interests require the seizure of the particular individual, or that the seizure must be carried out pursuant to a plan embodying explicit, neutral limitations on the conduct of individual officers.” Brown, 443 U.S. at 51.

Several states have considered the issue in connection with driver’s license check roadblocks or in some cases more candidly described as DUI roadblocks. It is obvious, without resort to the record or otherwise, that the problem of the drunk driver is one of enormous magnitude affecting every citizen who ventures forth upon the streets and highways. There can be no doubt that there is an overwhelming public and governmental interest in pursuing methods to curtail the drunk driver. Most states, however, which have considered the validity of roadblocks to “check drivers’ licenses and auto registration” or to check for drunk drivers have found the methods used to be violative of Fourth Amendment rights and as failing to meet the implied tests set forth in the extensive dicta in Prouse. The use of a DUI roadblock has principally two purposes: (1) to apprehend and remove *537the drunk driver from the streets before injury or property damage results, and (2) in serving as a deterrent to convince the potential drunk driver to refrain from driving in the first place. As a fringe benefit the DUI roadblock also serves to disclose other violations pertaining to licenses, vehicle defects, open containers, etc.

In State v. Olgaard, 248 N.W.2d 392 (S.D. 1976), the South Dakota Supreme Court held “that unless authorized by prior judicial warrant, the establishment of a roadblock for the purpose of investigating all motorists for possible liquor law violations constitutes an unconstitutional seizure within the meaning of the Fourth Amendment.” 248 N.W.2d at 395. In contrast to United States v. Martinez-Fuerte, 428 U.S. 543, 49 L.Ed.2d 1116, 96 S.Ct. 3074 (1976), the court found that the roadblock in Olgaard was not at a permanent location; there was no notice of the roadblock, “for by its very nature the roadblock was set up to stop without prior warning, and perforce by surprise, all motorists . . .”; and, absent evidence that the decision to establish the roadblock was made by anyone other than officers in the field, “the roadblock in question had certain characteristics of a roving patrol, a type of intrusion into a motorist’s privacy interest that was held unconstitutional in Almeida-Sanchez v. United States, 413 U.S. 266, 93 S.Ct. 2535, 37 L.Ed.2d 596 .. . .” 248 N.W.2d at 394-95. Although Olgaard was decided before Prouse, the South Dakota court relied heavily on the border patrol cases and recognized some of the same factors later considered in Prouse. The court was concerned with the lack of any permanent location for the roadblock resulting in what it termed “certain characteristics of a roving patrol,” lack of notice and possible abuse of discretion by officers in the field.

Arizona reached the same result in State ex rel. Ekstrom v. Justice Ct. of State, 136 Ariz. 1, 663 P.2d 992 (1983). The Arizona Supreme Court said:

“[W]e cannot agree that the intrusion generated by the Kingman roadblocks was minimal. The record establishes that the Kingman checkpoints involved a not insubstantial amount of discretionary law enforcement activity and that the manner in which the roadblocks were operated was somewhat irregular. The roadblocks were set up at the discretion of a local highway patrolman and were operated without specific directions or guidelines. Officers were uncertain whether they should simply question the occupants of motor vehicles or whether they should seize the opportunity to cursorily search the vehicles for evidence of *538a violation. Motorists were taken by surprise, not having had prior notice of the location and purpose of the checkpoints. We find present in the Kingman operation the grave danger that such discretion might be abused by the officer in the field, a factor which caused the Court in [Delaware] v. Prouse, supra, much concern.” p. 5.

A scholarly and well-reasoned concurring opinion in Ekstrom explored the conditions under which a roadblock checkpoint might pass constitutional scrutiny, and noted that advance warning of a roadblock by notice on the highway and publicity in the media would not only increase the efficacy of a deterrent roadblock but would also limit the resulting intrusion on individual interests, because those being stopped would anticipate and understand what was occurring.

In Commonwealth v. McGeoghegan, 389 Mass. 137, 449 N.E.2d 349 (1983), the facts were quite similar to those in the instant case:

“McGeoghegan was in a motor vehicle that had been stopped at a roadblock, that the police asked him for his ‘papers,’ that he showed signs of having been drinking and was taken from his vehicle to a nearby van, where he took and failed a breathalyzer test, and that he was arrested and his vehicle was towed away. It was also agreed that the police had no cause initially to stop McGeoghegan ‘except that he was one ... of two hundred or more motorists that were stopped as they passed the roadblock stoppoint.’

“There are additional undisputed facts. The roadblock was conducted by the Revere police department on North Shore Road and Mills Avenue in that city on the evening of January 15, 1982. This was the result of a plan formulated earlier that day by the police chief and four subordinates. The area of the roadblock was a heavily travelled highway. The main purpose of the roadblock was to detect drunk drivers.” pp. 138-39.

The court, in reaching its conclusion, relied upon findings of the trial court that “the roadblock area was poorly illuminated and unsafe for motorists, that the mechanics of the roadblock were left to the discretion of the officers carrying it out, that the officers used their own discretion in deciding which cars to stop, and that motorists were backed up on the highway for at least two-thirds of a mile.” 389 Mass, at 144.

The Court of Appeals of Texas in Koonce v. State, 651 S.W.2d 46 (Tex. Crim. App. 1983), found evidence recovered in the search of a car at a driver’s license roadblock inadmissible as the State failed to show the initial stop was reasonable under the guidelines of Prouse. The court stated:

“Without evidence that an objective, non-discretionary procedure was being used, we find that the initial stop of appellant’s automobile was unreasonable, *539and thus, the fruit of that stop and subsequent search was tainted.” 651 S.W.2d at 48.

New Jersey, on the other hand, has taken an opposite position from that of a majority of the states that have confronted the issue. In State v. Coccomo, 177 N.J. Super. 575, 427 A.2d 131 (1980), the court was again faced with a motion to suppress evidence recovered at a driver’s license check roadblock. The roadblock was evidently conducted by township police under a written policy of the Roxbury township police department. The facts were similar to those in the other cases we have discussed except that the procedure was to stop every fifth vehicle while the roadblock was in operation. In distinguishing Prouse the court stated:

“In prohibiting random, discretionary vehicular stops the Supreme Court did not ‘preclude the [states] from developing methods for spot checks that do not involve the unconstrained exercise of discretion. Questioning of all oncoming traffic at roadblock type stops is one possible alternative.’ 440 U.S. at 663, 99 S.Ct. at 1041.” 177 N.J. Super. at 581.

The court went on to state:

“No one can deny the State’s vital interest in promoting public safety upon our roads by detecting and prosecuting drunk drivers. These drivers are a threat to other motorists, to pedestrians and to themselves. Unfit drivers should be identified and removed from the highways. However, there is obviously a competing interest to be considered. Whether the practice adopted in Roxbury Township is reasonable depends upon a balancing of the State’s interest in promoting highway safety against the individual motorist’s interest in his expectation of privacy.” 177 N.J. Super. at 582.

The court found that the roadblocks were operated during early morning hours when traffic was light, that the manner of stopping vehicles was done safely and was designed to reduce anxiety on the part of the motorists, that the Roxbury police were following specific, defined standards and that the system was completely objective in its operation. The court held:

“After balancing the State’s strong interest in protecting the public from the substantial risk posed by drunk drivers with the minor inconvenience which may be caused to every fifth motorist and the fleeting, minimal intrusion upon his privacy, the State’s action must be considered as á reasonable infringement upon the motorist’s expectation of privacy. Nor did the stop become overly intrusive when defendant was asked to produce his license and registration. When the initial detention is lawful as it was here, the police may require the driver to produce his driving credentials.” 177 N.J. Super. at 583-84.

*540In United States v. Prichard, 645 F.2d 854 (1981), the Tenth Circuit Court considered a roadblock operated by two New Mexico state police officers for the avowed purpose of checking drivers’ licenses and vehicle registration. The roadblock was set up with the permission of the officers’ supervisor. All westbound vehicles, except semi-trucks, were to be stopped although when the vehicles began to pile up, the officers waved them on through and did not resume their checking until traffic had cleared. This was evidently a discretionary decision made by the two officers in the field for the purpose of preventing the development of a potentially dangerous and time-consuming accumulation of traffic. The court stated:

“In our view, the roadblock stop of the Ford Bronco does not run afoul of the rule of Prouse. While this may not have been a ‘100% roadblock’ of the type referred to in Prouse, it is nonetheless a long way from the selective, single car stop denounced in Prouse. In the instant case, the New Mexico state police were attempting to stop all westbound traffic on an interstate highway, insofar as was humanly possible. The decision not to stop trucks was reasonable under the circumstances, because, presumably, they had all been stopped at a port of entry. The purpose of the roadblock, i.e., to check drivers’ licenses and car registrations, was a legitimate one. If, in the process of so doing, the officers saw evidence of other crimes, they had the right to take reasonable investigative steps and were not required to close their eyes. See United States v. Merryman, 630 F.2d 780, 782-85 (10th Cir. 1980). Furthermore, allowing all the stopped cars through when traffic became congested was also reasonable and, in our view, nonviolative of the rule of Prouse. In sum, the roadblock stop of the Ford Bronco was, under the described circumstances, constitutional.” pp. 856-57.

The border patrol cases, Prouse and decisions from other state and federal appellate courts make it clear that not every driver’s license check or DUI roadblock is constitutionally impermissible. Certain principles, standards and guidelines may be gleaned from the various decisions. Stopping an automobile and detaining its occupants constitutes a seizure within the meaning of the Fourth and Fourteenth Amendments, which prohibit searches and seizures of an unreasonable nature. Delaware v. Prouse, 440 U.S. 648, 653, 59 L.Ed.2d 660, 99 S.Ct. 1391 (1979). The essence of the Fourth Amendment prohibition is to “safeguard the privacy and security of individuals against arbitrary invasions by governmental officials” by imposing a standard of reasonableness upon the exercise of those officials’ discretion. Camara v. Municipal Court, 387 U.S. 523, 528, 18 L.Ed.2d 930, 87 S.Ct. 1727 (1967); Prouse, 440 U.S.at 653-54. The governing principle *541of the amendment is that except in certain carefully defined classes of cases, a search of private property without proper consent is unreasonable unless it has been authorized by a valid search warrant. Camara, 387 U.S. at 528-29. Whether a warrant-less search and seizure falls within these limited exceptions is determined by balancing the degree of legitimate governmental interests against the resulting intrusion of the particular law enforcement practice on individuals’ Fourth Amendment rights. Prouse, 440 U.S. at 654. However, as exceptions to the overriding mandate requiring warrants based on probable cause, these “carefully defined classes of cases” permitting warrantless searches and seizures should be construed narrowly to preserve the integrity of the Fourth Amendment.

In applying the balancing test of the degree of governmental or public interest against the degree of intrusion upon the individual’s constitutionally protected rights, the courts have developed a three-factor test or analysis which was stated in Brown as:

“a weighing of the gravity of the public concerns served by the seizure, the degree to which the seizure advances the public interest, and the severity of the interference with individual liberty.” Brown v. Texas, 443 U.S. at 50-51.

Numerous conditions and factors must be considered in determining whether a DUI roadblock meets the balancing test in favor of the state. Among the factors which should be considered are: (1) The degree of discretion, if any, left to the officer in the field; (2) the location designated for the roadblock; (3) the time and duration of the roadblock; (4) standards set by superior officers; (5) advance notice to the public at large; (6) advance warning to the individual approaching motorist; (7) maintenance of safety conditions; (8) degree of fear or anxiety generated by the mode of operation; (9) average length of time each motorist is detained; (10) physical factors surrounding the location, type and method of operation; (11) the availability of less intrusive methods for combating the problem; (12) the degree of effectiveness of the procedure; and (13) any other relevant circumstances which might bear upon the test. Not all of the factors need to be favorable to the State but all which are applicable to a given roadblock should be considered. Some, of course, such as unbridled discretion of the officer in the field, would run afoul of Prouse regardless of other favorable factors.

When the test enunciated in the cases and the foregoing factors *542are taken into consideration and applied to the DUI roadblock in question does it pass constitutional muster? We think it does. The roadblock in question was a joint effort of the highway patrol, Shawnee County sheriff s office and Topeka police department. Thirty-five to forty officers were briefed ahead of time by supervisory personnel of the Topeka police department. The officers were specifically advised to check for driver’s license violations and signs of drunk driving. The roadblock was established in a well-lighted area of a four-lane highway. Several police cars were utilized, with a car with its red lights flashing located at each of the four corners of the roadblock. The time of detention was minimal, unless violations were noted, and sufficient officers were present to assure minimum intrusion, time-wise. All vehicles going in either direction were stopped and subjected to the license check. The officers in the field had no discretion to pick and choose who would or would not be stopped. The officers were in uniform and readily recognizable as being police officers. The location was selected by supervisory personnel and not the officers in the field.

The Topeka DUI roadblock did not involve the unbridled discretion of the officer in the field which was held oppressive and subject to abuse in Prouse. When we consider the enormity of the injury and damage caused by the drinking driver and the vital interest of every citizen in being protected so far as possible upon the streets and roadways, we find that the public interest in a properly conducted DUI roadblock containing appropriate safeguards outweighs the individual’s right to be free from unfettered intrusion upon his Fourth Amendment rights. The initial stop of the defendant in this case was under conditions which at least met the minimum requirements for a constitutional momentary seizure and, based upon obvious evidence of DUI, the resultant search and seizure in this case was not unreasonable under the Fourth Amendment or the Kansas Bill of Rights.

Due to the seriousness of any warrantless intrusion into an individual’s right to privacy under the Fourth Amendment, we wish to make it clear that the decision herein applies solely to the facts surrounding this particular roadblock. We do not condone blanket, arbitrary exercises of power by governmental authorities which violate Fourth Amendment rights, and any roadblock lacking sufficient standards, guidelines and protec*543tions of the individual’s right to privacy would run afoul of constitutional protections guaranteed by the Fourth Amendment and the Kansas Bill of Rights. It might well be advisable that minimum uniform standards for the operation of vehicular roadblocks be adopted and established by the legislature or attorney general, rather than leave the determination thereof to local officials.

Having determined that the initial stop or seizure was not constitutionally invalid, the officer had sufficient reason and probable cause to place defendant under arrest when it appeared he was under the influence of alcohol. The arrest of the defendant being lawful, the search of the passenger compartment of his automobile was also lawful. State v. White, 230 Kan. 679, 640 P.2d 1231 (1982).

The trial court erred in its suppression of the evidence and the case is reversed and remanded for further proceedings.

Prager, J.,

dissenting: I respectfully dissent. Today’s decision will result in the erosion of one of the basic freedoms contained in the Bill of Rights of both the United States and Kansas Constitutions — the right of every individual to be free from unfettered intrusions on his or her right of privacy by government officials, the right to be left alone. The controversy presented in this case is an extremely difficult one. It cannot be denied there there is a wide difference of opinion on this issue held by reasonable persons of good faith. I have no disagreement with the excellent review of the legal precedents on this issue as contained in the majority opinion by Justice Holmes. However, I disagree with the majority’s application of the law to the factual circumstances in the case which is now before us.

The majority opinion declares, without equivocation, that when a police officer accosts an individual and restricts his freedom to depart the scene, he has seized that person. Stopping an automobile and detaining its occupants constitutes a seizure within the meaning of the Fourth Amendment to the United States Constitution, even though the purpose of the stop is limited and the resulting detention is quite brief. The essence of the Fourth Amendment prohibition against unreasonable searches and seizures is to safeguard the privacy and security of individuals against arbitrary invasion by governmental officials *544by imposing a standard of reasonableness upon the exercise of those officials’ discretion. The majority opinion states that whether a warrantless search and seizure is constitutional is determined by balancing the degree of legitimate governmental interests against the resulting intrusion on the individual’s Fourth Amendment rights. In applying the balancing test, the courts must weigh the gravity of the public concerns served by the seizure, the degree to which the seizure advances the public interest, and the severity of the interference with individual liberty.

The majority opinion suggests 13 specific factors to be considered in applying the balancing test. The district court considered the evidence in the light of the various factors and concluded that the warrantless search and seizure presented in this case could not be upheld. I agree with the trial court. It is important to emphasize that this is not a case involving a driver’s license checkpoint. The police officer who testified at the hearing in district court and counsel for the State on this appeal at oral argument conceded that the primary purpose of the roadblock was to catch drunk drivers, although incidental to that purpose arrests were also made for a number of other reasons, including some involving license violations. The trial court found that the roadblock in this case was there to catch drivers under the influence of alcohol (DUI). That same conclusion is accepted by the court on this appeal.

As I see it, the basic issue is this: Does the public interest in a DUI roadblock of the type established in this case outweigh the individual’s right to be free from intrusion on his or her right of privacy? The majority opinion correctly states that the burden of proof rests upon the State to prove the validity of the roadblock.

As to the public interest involved, no one can seriously contest the grave concern over the public peril created by drunk drivers. It is safe to say that official efforts to discover and deter drunk drivers are, and should remain, a high priority. Certainly, the need to identify and apprehend drunken drivers is just as clear and pervasive as the need to discover illegal aliens, which was determined to be a sufficient public concern to justify the checkpoint stops in United States v. Martinez-Fuerte, 428 U.S. 543, 49 L.Ed.2d 1116, 96 S.Ct. 3074 (1976).

The most pressing question before us is the degree to which *545this roadblock checkpoint actually promoted the public interest in deterring drunk drivers. In this regard, we must recognize the fundamental distinction between the offenses of drunk driving, transporting illegal aliens, and failure to carry a valid driver’s license. This distinction turns on the way each of these violations is discovered by law enforcement officers. Violations of motor vehicle license laws and the transportation of illegal aliens are in no way physically apparent through mere observation of traffic. The same is not true for DUI violations. It is here that the distinction between the cases arise.

Generally drunk drivers, through their behavior behind the wheel, manifest their presence to even lay observers. They can easily be discerned by law enforcement officers skilled in identifying the signals indicating a driver is operating the vehicle under the influence of alcohol or drugs. In this case, the trial court specifically found that there are alternative less intrusive means available to officers to identify drunk drivers, and police officials need not go to the degree of stopping all traffic at a roadblock. The record in this case shows that the roadblock was in effect for a period of four hours from 10:00 p.m. to 2:00 a.m. The officer testified that during that period, between 2,000 and 3,000 motor vehicles were stopped at the roadblock. A total of 74 violations were discovered at the checkpoint, only 15 of which were for driving while intoxicated. During this period of time 35 police officers were on duty, which for the four-hour period involved a total of 140 man hours. Although it does not specifically appear in the record before us, it was not unreasonable for the trial court to assume that the same or greater productivity in arresting drunk drivers could have been achieved by distributing the 35 officers at various places throughout the city for the sole purpose of observing erratic driving and stopping and checking drunk drivers. In my judgment, the trial court correctly concluded that the State failed in its burden of proof in establishing that the roadblock checkpoint promoted the public interest in light of available less drastic alternative measures which could have been used by the officers to combat the problem, without setting up a roadblock and stopping between 2,000 and 3,000 motorists.

We should not consider the factors suggested in the majority opinion. Factor No. 1 is concerned with the degree of discretion, *546if any, left to the officer in the field. It should be considered along with factor No. 4 pertaining to standards set by superior officers for setting up the roadblock or to structure the procedure to be followed by the officers present at the scene. Would a team of three officers, consisting of two patrolmen and a sergeant acting as supervisor, have the authority to set up a roadblock anywhere in the city at any time at their discretion? In the present case, the State has not shown the existence of standards or limitations on the discretion of police officers at the roadblock.

Factor Nos. 2 and 3 have to do with the location designated for the roadblock and the time and duration of the roadblock. These factors have in mind the permanency of the location of the checkpoint which is considered as essential in a number of the cases discussed in the majority opinion. In the case before us, the trial court noted that the. checkpoint in question had no permanency whatsoever and could have been moved to other locations. Thus it clearly appears that the checkpoint under consideration would not have the essential characteristics of permanency of location required by many of the cases.

Factor No. 6 is concerned with advance warning to the individual approaching motorist. The trial court found, and the record is clear, that advance warning to a motorist approaching the roadblock was practically nonexistent. In his testimony, the police officer admitted that no advance warning, like signs indicating “Danger, roadblock ahead” was present. He testified that no such warning was given because, under the law, a driver’s license checkpoint is not required to have an advance warning of any kind. At one point in his testimony, he stated that the only warning to approaching drivers at the scene was the police vehicles with their red lights operating. Four police cars with red lights were parked alongside the road near the curb. This factor of advance warning to approaching motorists is emphasized again and again in the cases. Here there was practically none.

Factor No. 12 is the degree of effectiveness of the checkpoint procedure. As noted above, during the period of four hours in which the roadblock was maintained, 2,000 to 3,000 cars were stopped and only 15 persons arrested for DUI. There was no evidence whatsoever presented by the State that the roadblock procedure had been more effective than the traditional, less intrusive method of detecting drunk drivers. The question again *547arises whether or not roadblocks are worth the price of public inconvenience and interference with the individual’s right of privacy.

I, likewise, believe that the majority of the court have failed to consider another important factor in this case. In substance, the majority opinion would seem to authorize any police agency in Kansas to set up a roadblock to discover DUI violations. If this is a proper procedure, why should not a police agency be able to maintain a roadblock to discover violators of other criminal statutes or city ordinances? Does the majority opinion contemplate that every individual police agency established in the state may, on its own, authorize DUI roadblocks of this type? In Kansas, we have 105 counties and 625 incorporated cities. If each of these political subdivisions decides to maintain a roadblock, we could have “Checkpoint Charley” at the boundary of every city and every county. Motorists could legally be stopped five times or even more often in driving from Wichita to Kansas City. My basic concern is that, without legislative standards and limitations, the rights of Kansas citizens to privacy and freedom from unreasonable intrusion by governmental officials would be destroyed. I cannot in good conscience accept that as a way of life in this land of freedom.

For the reasons set forth above, I would affirm the trial court, and I respectfully dissent.

Opinion

KAUFMAN, J.

This case presents the question whether sobriety checkpoints are permissible under the federal and state Constitutions. We conclude that within certain limitations a sobriety checkpoint may be operated in a manner consistent with the federal and state Constitutions.

Facts

Petitioners are California taxpayers who seek to prohibit the operation of sobriety checkpoints in California. Respondents are chiefs of police of various California cities and the Commissioner of the California Highway Patrol. Petitioners alleged that the respondent law enforcement officers in the various jurisdictions around the state had begun or planned to begin using sobriety checkpoints.

In November 1984, in response to a request by the Commissioner of the California Highway Patrol, the Attorney General issued an opinion that roadblocks could constitutionally be used to detect and apprehend drunk drivers if certain safeguards were maintained to minimize the intrusion on motorists. (67 Ops.Cal.Atty.Gen. 471 (1984).)

That same month, the Burlingame Police Department (the Department) set up the first sobriety checkpoint program to operate in California, *1326following the guidelines set forth in the Attorney General’s opinion.1 The Burlingame checkpoint was expected to serve as a model for others. We therefore examine the Burlingame checkpoint as illustrative of checkpoint operation procedures.

The Department promulgated a detailed manual to govern the checkpoint operations. The manual covered legal considerations, including the Attorney General’s guidelines; a cost analysis; factors affecting location selection; required personnel and equipment; training and briefing of checkpoint personnel; press relations and publicity; as well as procedures for a follow-up evaluation.

The location for the Burlingame checkpoint was selected by taking into account frequency of drunk driving arrests and accidents, and safety factors such as traffic patterns and street layout. A suitable location was selected on El Camino Real for a checkpoint intercepting northbound traffic.2 Warning signs (including a sign announcing a sobriety checkpoint) were posted. A cone taper diverted traffic to a single northbound lane. The signs and cone taper were set up according to Caltrans regulations for signing and lane closure.

The checkpoint operation was supervised by a commander under whom two sergeants served. One sergeant supervised a team of traffic control and screening officers, and the second sergeant supervised the field sobriety test teams. Two traffic control officers, with support staff, set up the checkpoint and selected every fifth car for screening. There were one to four screening officers who contacted the motorists. Nonswom reserve personnel were available for recording information and timing each contact. One to four officers, each with a nonswom reserve assistant, were on duty to administer the field sobriety tests. There was also a booking officer, an officer to operate an intoxilizer, one for photographing and one alternate. There were also nonswom personnel available for interpreting, transportation and booking assistance. All the officers chosen for checkpoint duty had a good record of “driving under the influence” (DUI) detection and arrest, all had recent refresher training on recognizing the symptoms of drug and alcohol use, and all had special training in checkpoint procedures, including conducting a simulated checkpoint. All officers on duty at the checkpoint were in full uniform.

*1327On the night of the checkpoint operation, every fifth car was stopped and directed to a screening officer. The screening officer gave the driver a brief prescribed oral explanation of the checkpoint, and handed him or her an information flyer and a postage paid opinion survey card.3 During the contact, the screening officer observed the driver for bloodshot eyes, alcohol on the breath, and any other signs of impairment. The officer also shined a flashlight into the vehicle, looking for any open containers or other evidence of alcohol consumption. If no symptoms of impairment were observed, the driver was directed to continue into the northbound traffic lanes. If signs of impairment were observed, the driver was directed to a secondary testing area, where another officer would administer a field sobriety test. A sign announcing the checkpoint was posted sufficiently in advance of the checkpoint location to permit motorists to turn aside, and under the operational guidelines no motorist was to be stopped merely for choosing to avoid the checkpoint.

The sobriety checkpoint was given advance publicity, including its date and general location. During the checkpoint operation, from 9:30 p.m. to 2:30 a.m. on November 16-17, 1984, 233 motorists were screened. Only 10 were asked to perform field sobriety tests, and all 10 passed. The checkpoint resulted in no arrests. The average detention periods for those cars stopped was 28 seconds. The average time for those who took the field sobriety tests was 6.13 minutes.

Petitioners filed an original petition for writ of mandate in this court within three days after Burlingame established its first sobriety checkpoint. We transferred the matter to the Court of Appeal. The First District, Division Three, denied petitioners’ request for a stay and issued an alternative writ. The Court of Appeal issued an opinion in which the majority held sobriety checkpoints conducted in accordance with certain guidelines are permissible under the United States and California Constitutions. We granted the taxpayers’ petition for review.4

Discussion

Petitioners contend the validity of a sobriety checkpoint stop must be determined by the standard set forth in In re Tony C. (1978) 21 Cal.3d 888 [148 Cal.Rptr. 366, 582 P.2d 957], requiring an individualized suspicion of wrongdoing. If the primary purpose of the stop here were to detect crime *1328or gather evidence of crime, we would agree with the contention that an individualized suspicion of wrongdoing is required. But, as we shall explain, the primary purpose of the stop here was not to discover evidence of crime or to make arrests of drunk drivers but to promote public safety by deterring intoxicated persons from driving on the public streets and highways. We therefore conclude the propriety of the sobriety checkpoint stops involved here is to be determined not by the standard pertinent to traditional criminal investigative stops, but rather by the standard applicable to investigative detentions and inspections conducted as part of a regulatory scheme in furtherance of an administrative purpose. (See People v. Hyde (1974) 12 Cal.3d 158, 165-166, 173 [115 Cal.Rptr. 358, 524 P.2d 830].)

In upholding airport screening searches, a majority of this court in Hyde applied the administrative search rationale. (12 Cal.3d at p. 165 et seq.) The concurring minority, reaching the same result, preferred a more generic balancing test of reasonableness. (12 Cal.3d at p. 172 et seq.) But, verbal formulations aside, both the majority and the concurring minority in Hyde relied upon essentially the same principles and factors.

The majority noted: “Like all searches subject to the Fourth Amendment, an administrative screening must be measured against the constitutional mandate of reasonableness. In the case of administrative searches, however, ‘there can be no ready test for determining reasonableness other than by balancing the need to search against the invasion which the search entails.’ (Camara v. Municipal Court (1967) supra, 387 U.S. 523, 536-537 [18 L.Ed.2d 930, 940, 87 S.Ct. 1727].) It is ironic, therefore, that by adopting the administrative search doctrine to evaluate the validity of airport screening procedures we must undertake a similar process of balancing to that which would have followed from a reliance upon Terry [v. Ohio (1968) 392 U.S. 1 (20 L.Ed.2d 889, 88 S.Ct. 1868)].” (People v. Hyde, supra, 12 Cal.3d 158, 166, italics added.) The concurring minority reasoned: “It is now settled . . . that there is no fixed standard of reasonableness that applies to all types of governmental action which is subject to the mandates of the Fourth Amendment. Where, as here, we deal with a type of official conduct that (1) has objectives qualitatively different from those of the conventional search and seizure in the criminal context and (2) cannot feasibly be subjected to regulation through the traditional probable cause standard of justification, we may assess the reasonableness of the particular type of search and seizure by examining and balancing the governmental interest justifying the search and the invasion which the search entails. [Citations.]” (Id., conc. opn. at p. 173. Italics added, fns. and original italics omitted.) We perceive no real inconsistency in the two analyses. They both employed a balancing test for reasonableness.

*13291. Reasonableness Standard Under the Fourth Amendment and the California Constitution

The touchstone for all issues under the Fourth Amendment and article I, section 13 of the California Constitution is reasonableness. (See Terry v. Ohio, supra, 392 U.S. 1, 19 [20 L.Ed.2d 889, 904]; People v. Hyde, supra, 12 Cal.3d 158, 166, conc. opn. at pp. 172-173.)

The federal test for determining whether a detention or seizure is justified balances the public interest served by the seizure, the degree to which the seizure advances the public interest and the severity of the interference with individual liberty. (Brown v. Texas (1979) 443 U.S. 47, 50-51 [61 L.Ed.2d 357, 361-362, 99 S.Ct. 2637].) In addition, federal constitutional principles require a showing of either the officer’s reasonable suspicion that a crime has occurred or is occurring or, as an alternative, that the seizure is “carried out pursuant to a plan embodying explicit, neutral limitations on the conduct of individual officers.” (Brown v. Texas, supra, 443 U.S. at p. 51 [61 L.Ed.2d at p. 362], citing Delaware v. Prouse (1979) 440 U.S. 648, 663 [59 L.Ed.2d 660, 673-674] and United States v. Martinez-Fuerte (1976) 428 U.S. 543, 558-562 [49 L.Ed.2d 1116, 1128-1131].)

California constitutional principles are based on the same considerations, i.e., balancing the governmental interests served against the intrusiveness of the detention. (See People v. Hyde, supra, 12 Cal.3d 158, 166, also cone, opn. at pp. 172-173.) With respect to a seizure for conventional investigation of criminal activity, standards similar to federal standards have been articulated. “[I]n order to justify an investigative stop or detention the circumstances known or apparent to the officer must include specific and articulable facts causing him to suspect that (1) some activity relating to crime has taken place or is occurring or about to occur, and (2) the person he intends to stop or detain is involved in that activity. Not only must he subjectively entertain such a suspicion, but it must be objectively reasonable for him to do so: the facts must be such as would cause any reasonable police officer in a like position, drawing when appropriate on his training and experience (People v. Superior Court (Kiefer) [1970] 3 Cal.3d [807,] at p. 827 [91 Cal.Rptr. 729, 478 P.2d 449]), to suspect the same criminal activity and the same involvement by the person in question.” (In re Tony C., supra, 21 Cal.3d 888, 893, fn. omitted.)

But Tony C. itself further pointed out that, for purposes of analysis under the Fourth Amendment and under California constitutional law, “[a] more fruitful approach focuses on the purpose of the intrusion itself. If the individual is stopped or detained because the officer suspects he may be personally involved in some criminal activity, his Fourth Amendment rights are *1330implicated and he is entitled to the safeguards of the rules set forth above. But similar safeguards are not required if the officer acts for other proper reasons.” (In re Tony C., supra, 21 Cal.3d 888, at p. 895, italics added.) Thus, the court in Tony C., like the United States Supreme Court in Brown, supra, 443 U.S. 47, expressly recognized that individualized suspicion that the contactee is involved in criminal activity is not required in certain types of police-citizen contacts.

We therefore turn to a consideration of the kinds of stops permitted under federal and state law upon less than a reasonable suspicion of personal involvement in criminal wrongdoing.

2. Seizures Not Requiring a Reasonable Suspicion

In People v. Hyde, supra, 12 Cal.3d 158, this court considered the question of airport security screening searches. The majority in an opinion authored by Justice Mosk reasoned that airport searches could not be justified on the basis of Terry v. Ohio, supra, 392 U.S. 1, because Terry carefully limited the permissible search to a patdown necessary to discover weapons, and because, before even the limited patdown search could be conducted, Terry required there to be specific and articulable facts which would lead a reasonable officer to believe the safety of the officer was in danger.

“Nevertheless,” we stated, “we do find support under the Fourth Amendment for the pre-departure screening of prospective passengers in the series of United States Supreme Court decisions relating to administrative searches. (United States v. Biswell (1972) 406 U.S. 311 [32 L.Ed.2d 87, 92 S.Ct. 1593]; Wyman v. James (1971) 400 U.S. 309 [27 L.Ed.2d 408, 91 S.Ct. 381]; Colonnade Corp. v. United States (1970) 397 U.S. 72 [25 L.Ed.2d 60, 90 S.Ct. 774]; See v. City of Seattle (1967) 387 U.S. 541 [18 L.Ed.2d 943, 87 S.Ct. 1737]; Camara v. Municipal Court (1967) 387 U.S. 523 [18 L.Ed.2d 930, 87 S.Ct. 1727]; see also United States v. Davis (9th Cir. 1973) 482 F.2d 893; United States v. Schafer (9th Cir. 1972) 461 F.2d 856; Downing v. Kunzig (6th Cir. 1972) 454 F.2d 1230 [15 A.L.R.Fed. 926].) These cases recognize that ‘searches conducted as part of a general regulatory scheme in furtherance of an administrative purpose, rather than as part of a criminal investigation to secure evidence of crime, may be permissible under the Fourth Amendment though not supported by a showing of probable cause directed to a particular place or person to be searched.’ [Citation.]” (People v. Hyde, supra, 12 Cal.3d 158, 165.)

We pointed out that the purpose of the airport search is not to ferret out contraband or preserve for trial evidence of criminal activity, although the mechanics of the search itself take the form of a search to detect criminal *1331activity (carrying weapons or explosives aboard an aircraft). Rather, we characterized the search as “a central phase of a comprehensive regulatory program designed to insure that dangerous weapons will not be carried onto an airplane and to deter potential hijackers from attempting to board. [Citations.]” (People v. Hyde, supra, 12 Cal.3d 158, 166.) In the reasonableness analysis under the Fourth Amendment, we found the governmental interest substantial, the intrusion minimal, and the method effective for its purpose (in fact, we found in that case that there was no other effective means of achieving the purpose). We pointed out it was possible for a traveler to avoid the intrusion by either checking his or her hand luggage or foregoing air travel and opting for alternate means of transportation. Finally, we pointed out that airport searches were singularly unsuited to the warrant procedure because of the extremely high volume of air passenger traffic, rendering it impractical if not impossible to issue a warrant for any individual passenger. In addition, the consequences of not having a warrant were found mitigated by (1) neutral application of the screening process to all air passengers, minimizing the discretion of the officials in the field, and (2) limiting the intrusiveness of the search to those actions strictly necessary to disclose the presence of weapons or explosives.

The three concurring justices in Hyde agreed that the airport screening procedures were constitutionally permissible but questioned whether the airport search could properly be labelled an “administrative search” like the building inspection in Camara v. Municipal Court (1967) 387 U.S. 523 [18 L.Ed.2d 930, 87 S.Ct. 1727]. In the view of the concurring justices in Hyde, supra, 12 Cal.3d 158, the Fourth Amendment considerations should simply be evaluated pursuant to a balancing test of reasonableness, consisting of an assessment of the governmental interest justifying the search and the intrusiveness entailed in the search. The concurring minority had no difficulty in concluding the governmental interest was compelling and the intrusion resulting from the search was minimal. Thus, the airport searches were concluded to be reasonable. No warrant was required because compliance with the warrant procedure, as the majority had also pointed out, would completely frustrate the legitimate governmental purpose.

The sobriety checkpoint presents a compelling parallel to the airport screening search. While the label “administrative search” is open to some criticism in application to either the airport search or the sobriety checkpoint stop, both, although they operate mechanically as a search or inspection for the violation of law, actually serve a primary and overriding regulatory purpose of promoting public safety. Their primary purpose is to prevent and deter conduct injurious to persons and property; they are not conventional criminal searches and seizures. The fact that sobriety checkpoint stops will lead to the detection of some individuals involved in *1332criminal conduct does not alter the fundamental regulatory character of the screening procedure. (See People v. Hyde, supra, 12 Cal.3d 158, at p. 166; see also New York v. Burger (1987) 482 U.S. _, _ [96 L.Ed.2d 601, 622-623, 107 S.Ct. 2636, 2651].)

Our analysis in Hyde is supported by decisions of the United States Supreme Court which have similarly approved regulatory searches in appropriate circumstances in the absence of any particularized suspicion of wrongdoing. Camara v. Municipal Court, supra, 387 U.S. 523 and Marshall v. Barlow’s, Inc. (1978) 436 U.S. 307 [56 L.Ed.2d 305, 98 S.Ct. 1816] are examples.

In Camara, a city ordinance gave authorized city employees, upon presentation of credentials, the right to enter buildings or structures to perform necessary duties. The United States Supreme Court recognized that in performing a function such as building inspections, the governmental entity will rarely have knowledge of conditions in a particular building, but must necessarily rely on general conditions in an area. The court held that a warrant for building inspections based on area conditions, rather than upon probable cause to believe violations exist in a particular dwelling, was reasonable. The Supreme Court stated, “In determining whether a particular inspection is reasonable—and thus in determining whether there is probable cause to issue a warrant for that inspection—the need for the inspection must be weighed in terms of [the] reasonable goals of code enforcement • • • • [10 • • • [Tf] • • • [T]here can be no ready test for determining reasonableness other than by balancing the need to search against the invasion which the search entails.” (Camara v. Municipal Court, supra, 387 U.S. 523, 535-537 [18 L.Ed.2d 930, 939-940].)

In Marshall v. Barlow’s, Inc., supra, 436 U.S. 307, the court examined the regulatory scheme for administrative inspections of business premises under the Occupational Safety and Health Act of 1970 (OSHA) (29 U.S.C.A. § 657(a)). The court held that the OSHA inspections should be subject to a warrant requirement, but significantly did not require an individualized suspicion of violation of OSHA regulations before the warrant could be issued.

Some industries aré so heavily regulated that government inspections are held constitutionally permissible, without notice, warrant, or individualized suspicion of wrongdoing. (Donovan v. Dewey (1981) 452 U.S. 594 [69 L.Ed.2d 262, 101 S.Ct. 2534] [mines]; United States v. Biswell (1972) 406 U.S. 311 [32 L.Ed.2d 87, 92 S.Ct. 1593] [firearms]; Colonnade Corp. v. United States (1970) 397 U.S. 72 [25 L.Ed.2d 60, 90 S.Ct. 774] [liquor].) Business owners in the heavily regulated industries are presumed to know *1333that they are subject to the periodic inspections which are specified by and regularly carried out pursuant to enabling legislation.

Regulatory inspections and stops have also been permitted under decisions of the United States Supreme Court and the California courts in the absence of an individualized suspicion of wrongdoing in border patrol checkpoint inspections (United States v. Martinez-Fuerte, supra, 428 U.S. 543), agricultural inspection checkpoints (People v. Dickinson (1980) 104 Cal.App.3d 505 [163 Cal.Rptr. 575]), vehicle mechanical inspection checkpoints (People v. De La Torre (1967) 257 Cal.App.2d 162 [64 Cal.Rptr. 804]), and license and registration inspection checkpoints (People v. Washburn (1968) 265 Cal.App.2d 665 [71 Cal.Rptr. 577]).

The United States Supreme Court in United States v. Martinez-Fuerte, supra, 428 U.S. 543, held with respect to immigration checkpoints that neither a warrant nor particularized suspicion is required. The court upheld the constitutionality of an immigration stop without particularized suspicion at a checkpoint away from the international border by balancing the governmental interests served against the intrusion on Fourth Amendment interests. The court concluded the need for routine checkpoint stops was great because the flow of illegal aliens cannot be controlled effectively at the border. (Martinez-Fuerte, supra, 428 U.S. 543, at pp. 556-557 [49 L.Ed.2d 1116 at pp. 1127-1128].) By contrast, the checkpoint stop was a “quite limited intrusion” on Fourth Amendment interests. Such a stop entailed only a brief detention, requiring no more than a response to a question or two and possible production of a document. Neither the vehicle nor the occupant was searched. The court also concluded the “subjective intrusion” of a fixed checkpoint stop was minimal, unlike a random or roving stop, because motorists could see that other vehicles were being stopped, could see visible signs of the officers’ authority, and were much less likely to be frightened or annoyed by the intrusion. (Id., at pp. 557-558 [49 L.Ed.2d at p. 1128].)

Moreover, the court found an area warrant was not required, and distinguished Camara, supra, 387 U.S. 523, both on the ground the checkpoint seizure of an automobile involves significantly different expectations of privacy from the traditional expectations of privacy in one’s residence, as to which a warrant traditionally has been required, and on the ground the warrant requirement in Camara served purposes under the Fourth Amendment which were not relevant to a checkpoint operation.

The need to provide an assurance of legitimacy of the search/seizure required a warrant in the building inspection context, but that need was served alternatively in the checkpoint operation by the visible manifesta*1334tions of authorization in the form of signs announcing the roadblock, official insignia and vehicles, and fully uniformed personnel. Another purpose of the warrant requirement in Camara was to prevent hindsight from coloring the evaluation of the reasonableness of a search or seizure. In the checkpoint operation, however, “The reasonableness of checkpoint stops . . . turns on factors such as the location and method of operation of the checkpoint, factors that are not susceptible to the distortion of hindsight, and therefore will be open to post-stop review notwithstanding the absence of a warrant. Another purpose for a warrant requirement is to substitute the judgment of the magistrate for that of the searching or seizing officer. [Citation.] But the need for this is reduced when the decision to ‘seize’ is not entirely in the hands of the officer in the field, and deference is to be given to the administrative decisions of higher ranking officials.” (United States v. Martinez-Fuerte, supra, 428 U.S. 543, 565-566 [49 L.Ed.2d 1116, 1133].)

The United States Supreme Court also strongly suggested that other checkpoint type stops would be viewed similarly. “Stops for questioning, not dissimilar to those involved here, are used widely at state and local levels to enforce laws regarding drivers’ licenses, safety requirements, weight limits, and similar matters. The fact that the purpose of such laws is said to be administrative is of limited relevance in weighing their intrusiveness on one’s right to travel; and the logic of the defendants’ position, if realistically pursued, might prevent enforcement officials from stopping motorists for questioning on these matters in the absence of reasonable suspicion that a law was being violated. As such laws are not before us, we intimate no view respecting them other than to note that this practice of stopping automobiles briefly for questioning has a long history evidencing its utility and is accepted by motorists as incident to highway use.” (United States v. Martinez-Fuerte, supra, 428 U.S. 543, 560, fn. 14 [49 L.Ed.2d 1116, 1130].)

The intimation that neutrally operated checkpoint stops are permissible was reiterated in dictum in Delaware v. Prouse, supra, 440 U.S. 648. In that case, a single patrol officer decided to make a roving stop for the purpose of a license or registration “spot check,” but he had no information or reasonable suspicion either that the driver was unlicensed or that the vehicle was improperly registered. The Supreme Court held that such a random roving stop made without a reasonable suspicion of law violation was contrary to the Fourth Amendment. However, the court was careful to state that “This holding does not preclude the State of Delaware or other States from developing methods for spot checks that involve less intrusion or that do not involve the unconstrained exercise of discretion. Questioning of all oncoming traffic at roadblock-type stops is one possible alternative.” (Id., at p. 663, fn. omitted [59 L.Ed.2d at pp. 673-674].) This dictum was not mere rheto*1335ric, however. It is analytically consistent with the court’s holdings in other cases. Standardless and unconstrained discretion on the part of government officers is what the court sought to circumscribe in the regulatory inspection and stop cases. (Almeida-Sanchez v. United States (1973) 413 U.S. 266, 270 [37 L.Ed.2d 596, 601, 93 S.Ct. 2535]; Camara v. Municipal Court, supra, 387 U.S. 523, 532-533 [18 L.Ed.2d 930, 937-938].) Accordingly, such stops and inspections for regulatory purposes may be permitted if undertaken pursuant to predetermined specified neutral criteria (Delaware v. Prouse, supra, 440 U.S. 648, 662 [59 L.Ed.2d 660, 673]) such as the criteria articulated for a checkpoint stop (United States v. Martinez-Fuerte, supra, 428 U.S. 543, 553-554, 556-564 [49 L.Ed.2d 1116, 1126, 1127-1132]).

3. Regulatory Purpose

Petitioners argue the sobriety checkpoint stop we examine here is a criminal investigation roadblock, subject not only to Tony C., supra, 21 Cal.3d 888, but barred by the Fourth Amendment under this court’s decision in People v. Gale (1956) 46 Cal.2d 253 [294 P.2d 13]. (See also Wirin v. Horrall (1948) 85 Cal.App.2d 497 [193 P.2d 470].) In Gale, sheriff’s officers stopped and searched cars at a roadblock explicitly for the purpose of “ ‘curbing] the juvenile problem and also check for, well, anything that we might find, anything that looked suspicious.’” (People v. Gale, supra, 46 Cal.2d 253, 255.) We do not agree.

Dragnet searches, explicitly undertaken for the purpose of uncovering evidence of crime but without any reason to believe any criminal activity has taken place, are unreasonable. (People v. Gale, supra, 46 Cal.2d 253, 256; Wirin v. Horrall, supra, 85 Cal.App.2d 497, 504.) However, the sobriety checkpoint here was operated not for the primary purpose of discovering or preserving evidence of crime or arresting lawbreakers, but primarily for the regulatory purpose of keeping intoxicated drivers off the highways to the end of enhancing public safety. Analytically it is much the same as an immigration checkpoint or a checkpoint to inspect for the safety of equipment or compliance with agricultural regulations. The threat to public safety is at least as great and the intrusion into Fourth Amendment interests is no greater here than in those other regulatory checkpoint inspections which have invariably been held constitutionally permissible.

Our conclusion in this regard is based on factors related to the operation of the checkpoint in this case, on the stated goals of law enforcement agencies in implementing sobriety checkpoint programs, on the observable, albeit limited, experience with checkpoint operations in this and other states, as well as common sense.

*1336In the Burlingame program, the sobriety checkpoints received substantial advance publicity, which was clearly designed both to inform the public of the serious problem of drunk driving and to deter potential drinking drivers before they decided to drink and drive. An important part of the Burlingame procedure was to educate by giving each stopped driver a leaflet about the checkpoint program, as well as a survey postcard. In addition, the checkpoint was not conducted as a criminal dragnet. Checkpoint personnel were specifically instructed that drivers were not to be stopped merely for avoiding the checkpoint.5 The road sign announcing the checkpoint was placed sufficiently in advance of the checkpoint that motorists could choose to avoid the checkpoint.

The stated goals of several law enforcement agencies explicitly point to deterrence as a primary objective of the checkpoint program. The Burlingame manual described the objectives of its program, noting the historical use of roving patrols as the principal law enforcement response to the drunk driving problem. Despite increased patrols, public awareness campaigns, stiffer drunk driving penalties, and increased arrests, the Burlingame Police Department found the major problem was that the public’s perceived (and actual) risk of apprehension was very low. Two major goals of the checkpoint as stated in the manual were to increase public awareness of the seriousness of the problem and to increase the perceived risk of apprehension.

The evaluation report on the pilot project carried out by the California Highway Patrol (CHP) stated that, although a project of stepped up roving patrols in 1980 had resulted in approximately twice the number of arrests per work hour, “it must be remembered that accomplishing more arrests is not the intent of sobriety checkpoints. Rather, they are intended to deter persons who have been drinking from driving for fear of encountering a checkpoint. If checkpoints are truly accomplishing their purpose, DUI arrests, as well as DUI accidents, should decrease.” (Italics added.) In addition, the report recommended a six-month long-term study to be carried out in two CHP test areas. The report recommended using two different patterns of roadblock implementation—employing sobriety checkpoints during major holiday seasons at one test location, and using twice monthly checkpoints at the other location. Significantly, the recommendation report stated that “This dual study method will not only permit long term evaluation of checkpoint deterrence, but may also identify the frequency necessary to produce deterrence.”

A sobriety checkpoint program operated by the Arizona Highway Patrol is assertedly designed “to develop a public perception of the high risk of *1337apprehension of drinking drivers,” and the program abstract for the Maryland sobriety checkpoint project stated it was intended to function as a general deterrent to drinking drivers by instilling the perception that there was an increased likelihood of detection and arrest. An integral aspect of the Maryland program was publicity, to attain maximum public awareness and voluntary compliance with DUI laws.

Not only is deterrence the stated objective of DUI roadblock programs, but actual, though admittedly limited, experience with checkpoint programs indicates deterrence is in fact a significant result of such programs. In written responses to interrogatories posed by the Court of Appeal in the instant case, Burlingame Police Chief Alfred Palmer pointed out that deterrent value was demonstrated in two test areas of the Maryland program: incidence of alcohol related traffic accidents was reduced by 71 percent in Prince Georges County and fatalities were reduced 75 percent in Montgomery County in 1981. The follow-up report relating to the Burlingame checkpoint noted that some level of deterrence was indicated by the facts that traffic volume fell considerably below normal during the last two hours of their checkpoint operation, that the volume of business in Burlingame bars was also significantly below normal after 10 p.m., that calls for taxicabs were 12 percent above normal, and that, as officers on duty at the checkpoint noticed, several cars with sober drivers but intoxicated passengers proceeded through the checkpoint (the “designated driver” phenomenon). In New York, the Governor’s Alcohol and Highway Safety Task Force found “‘that the systematic . . . traffic checkpoint is the single most effective action in raising the community’s perception of the risk of being detected and apprehended for drunk driving’ (Report, at p. 103).” (People v. Scott (1984) 63 N.Y.2d 518 [483 N.Y.S.2d 649, 473 N.E.2d 1, 4-5].)

Petitioners argue in their discussion of the balancing test that roadblocks are not effective for apprehending DUI violators, and point out that the CHP experience showed that roving patrols were over twice as effective as roadblocks per work hour in producing drunk driving arrests, and that the Burlingame checkpoint in fact resulted in no arrests. The absence of arrests, however, is both explained by and affords substantial support for the conclusion that increasing drunk driving arrests—i.e., conducting investigations for the purpose of gathering evidence of criminal activity—is not the primary purpose of sobriety checkpoints. An absence of arrests does not indicate a sobriety checkpoint is a futile exercise. It more likely indicates that the existence of the checkpoint program has succeeded in inducing voluntary compliance with the law, thus fulfilling the program’s primary objective of keeping automobiles operated by impaired drivers off the roads. Drunk driving is not merely a crime, it is a serious public safety problem. A vehicle driven by an intoxicated person is as much a road hazard as a *1338vehicle with defective brakes or a defective steering mechanism. Sobriety checkpoints serve to keep such hazardous instrumentalities off the road in the first instance. If checkpoints perform a significant deterrent function, it follows that drunk driving arrests would decrease in areas of checkpoint operation.

It is perhaps the characteristic of the automobile as a hazardous instrumentality that affords the greatest distinction between the sobriety checkpoint and an impermissible criminal dragnet. While the sobriety checkpoint differs from, e.g., an agricultural inspection, because the item to be examined is a person and not an offending plant, nevertheless, the automobile is stopped for reasons directly related to public safety, and not for purposes of criminal investigation. In this sense it is as we have said analogous to a permissible equipment inspection checkpoint. The fact that the officer’s observations of a driver’s demeanor have the potential to result in criminal sanctions is not determinative. Just as an airport screening search may result in criminal arrests and prosecutions, but is nevertheless not a criminal investigative search, the sobriety checkpoint inspection primarily serves the proper regulatory purpose of deterring intoxicated persons from driving and thus endangering the public.

4. The Balancing Test

As we have explained, both the majority and concurring minority in Hyde, supra, 12 Cal.3d 158, and, ultimately, all other pertinent authorities determine the constitutional reasonableness of searches and seizures by a balancing test: weighing the gravity of the governmental interest or public concern served and the degree to which the program advances that concern against the intrusiveness of the interference with individual liberty. (See, e.g., Brown v. Texas, supra, 443 U.S. 47, at pp. 50-51 [61 L.Ed.2d 357, at pp. 361-362]; People v. Hyde, supra, 12 Cal.3d 158, at pp. 166-169, conc. opn. at pp. 172-178.)

Deterring drunk driving and identifying and removing drunk drivers from the roadways undeniably serves a highly important governmental interest. As we noted in Burg v. Municipal Court (1983) 35 Cal.3d 257, at page 262 [198 Cal.Rptr. 145, 673 P.2d 732], “The drunk driver cuts a wide swath of death, pain, grief, and untold physical and emotional injury across the roads of California and the nation. The monstrous proportions of the problem have often been lamented in graphic terms by this court and the United States Supreme Court. [Citations.] . . . [I]n the years 1976 to 1980 there were many more injuries to California residents in alcohol-related traffic accidents than were suffered by the entire Union Army during the Civil War, and more were killed than in the bloodiest year of the Vietnam *1339War. [Citations.] Given this setting, our observation that ‘[djrunken drivers are extremely dangerous people’ [citation] seems almost to understate the horrific risk posed by those who drink and drive.” Stopping the carnage wrought on California highways by drunk drivers is a concern the importance of which is difficult to overestimate.

While it may be less self evident, the record here also supports a reasonable inference sobriety checkpoints of the sort here described do advance this important public goal. Petitioners contend that sobriety checkpoints are not as effective in detecting drunk drivers as other less intrusive alternatives, such as roving patrols. However, officers on a roving patrol can effect a stop only upon observable indications of impairment (i.e., reasonable suspicion). Petitioners point to the observation in the CHP report that a CHP project in 1980 utilizing stepped up patrols resulted in an arrest rate per work hour over twice that resulting from use of the roadblocks. But, as we have pointed out, the number of arrests does not necessarily measure the effectiveness of the sobriety checkpoint. If the checkpoint is properly serving its function—deterrence —it may result in no arrests at all. An Arizona court considering the question concluded that although a sobriety checkpoint may be no more efficient than a roving patrol in detecting, drunk drivers it is more effective in deterring drunk driving. (State v. Super. Ct. in & for County of Pima (1984) 143 Ariz. 45 [691 P.2d 1073, 1076-1077].) This is consonant with our conclusion that the primary purpose of sobriety checkpoints is deterrence.

Petitioners argue respondents have not made a sufficient showing of the effectiveness of sobriety checkpoints. However, such effectiveness is difficult to quantify. The experience both in California and in other states with sobriety checkpoints has been very limited, and no definitive statistics are yet available. It would be presumptuous in the extreme for this court to prohibit the use of an otherwise permissible and potentially effective procedure merely because its effectiveness is at the present time largely untested. Indeed, to do so would prevent the compilation of any data to show its effectiveness.

Nevertheless, there are indications of the effectiveness of the roadblocks even in the absence of statistical evidence. For example, the Maryland court in Little v. State (1984) 300 Md. 485 [479 A.2d 903, 913], noted certain evidence in that record that on the night of the checkpoint operation many people who had been drinking asked a sober companion to drive instead, that calls for taxi service by drunk individuals increased, and that certain groups anticipating consumption of alcohol at social events chartered vehicles instead of driving. “The prospect of being stopped at a roadblock thus convinced some intoxicated individuals to find alternate means of transpor*1340tation.” (Little v. State, supra, 479 A.2d 903, 913.) Similar results were observed in connection with the Burlingame checkpoint in the instant case, and at oral argument counsel for petitioners conceded the likely deterrent effect of the sobriety checkpoints involved here.

We further observe that roving stops may not be a more effective alternative means of enforcing drunk driving laws. Constitutionally permissible roving stops must be based on an articulable suspicion of law violation. With respect to drunk driving, this requires an officer’s observation of some objectively manifested behavior indicating impairment. By this method, the number of drunk drivers detected and arrested is estimated between one in two hundred to one in two thousand. Stepped up holiday patrols, with attendant publicity, have been used in many jurisdictions for many years, without appreciable effect on the drunk driving toll to people and property. In addition, although stiffer penalties for drunk driving in California appeared to result in a decline in alcohol-related accident incidence in 1981 and 1982, thereafter alcohol-involved accidents and fatalities began to increase again, to nearly pre-1981 levels. As noted in the Burlingame manual, despite countermeasures consisting of publicity, heightened patrol efforts and more severe penalties, an attitude of impunity continues to exist with respect to drinking and driving.

The failure of traditional methods of enforcement was commented on by Professor LaFave: “[A] rather strong argument can be made that mere patrol and stoppings based upon the Terry standard [of reasonable suspicion, supra, 391 U.S. 1] do not produce what the Camara Court [, supra, 387 U.S. 523] referred to as ‘acceptable results.’ For one thing, even if a patrolling officer is . . .in the vicinity where a drunk driver is operating his vehicle, it does not necessarily follow that the driver will at that particular time drive his car in such a fashion as to create a reasonable suspicion justifying a stop. And the chances of such observation in the first place are rather slight, given the substantial number of intoxicated drivers on the roads . . . . It is by no means surprising, therefore, that it has been reliably estimated that only one of every 2,000 drinking drivers is apprehended.” (4 LaFave, Search and Seizure: A Treatise on the Fourth Amendment (2d ed. 1987) Vehicle Use Regulation, § 10.8(d), pp. 72-73.)

Justice Feldman, in a concurring opinion in State ex rel. Ekstrom v. Justice Ct. of State (1983) 136 Ariz. 1 [663 P.2d 992], observed that “The governmental interest sought to be protected by the roadblocks is greater than merely detecting and apprehending drunk drivers. Given the carnage on our highways, there is a unique societal interest in enforcing compliance with the law by deterring driving while under the influence of alcohol or other drugs, [fl] . . . [T]he state cannot satisfy this interest by traditional *1341methods which satisfy the Terry test. The traditional system has left us far short of achieving the law’s objective. ... It is only fortuitous that an officer happens to be in a position to see a drunk entering the freeway on the off-ramp [sic] before that drunk happens to kill some innocent person. . . . [jf] . . . [It is] obvious that traditional law enforcement methods, involving the arrest by roving officers of only those whom they can stop upon a founded suspicion of drunk driving, fall short of satisfying society’s compelling interest in enforcing compliance with the laws prohibiting drunk driving.” (Id., 663 P.2d 992 at pp. 998-999, conc. opn. Feldman, J.)

Not only are roving patrol stops inadequate generally, but there are also indications that roving patrols are less effective than sobriety checkpoints in detecting lower but nonetheless dangerous levels of intoxication. The average person arrested for drunk driving by roving patrols tends to have a significantly higher blood-alcohol level than the average sobriety checkpoint drunk driving arrestee. The CHP evaluation report showed that in all four test areas, the blood-alcohol level of checkpoint arrestees was lower (though still above the presumptive drunk driving level) than the blood-alcohol level of roving patrol arrestees in the same area for the same period. Thus, there may in fact be no effective alternate means of detecting those drivers whose judgment has actually been seriously impaired by alcohol and whose blood-alcohol level is illegal, but who do not consistently manifest outwardly observable impaired driving behavior.6

The third balancing factor is the intrusiveness on individual liberties engendered by the sobriety checkpoints. Upon examination of the record, we conclude that the programs at issue in this case have implemented procedures designed to provide minimal interference with individual liberties. The decisions of courts of other states and the California Attorney General’s opinion which originally sanctioned the kind of checkpoints operated here have analyzed the issue of intrusiveness extensively and have identified a number of factors important in assessing intrusiveness. The standards articulated in these cases provide functional guidelines for minimizing the intrusiveness of the sobriety checkpoint stop.

A. Decisionmaking at the Supervisory Level

The decision to establish a sobriety checkpoint, the selection of the site and the procedures for the checkpoint operation should be made and established by supervisory law enforcement personnel, and not by an officer in *1342the field. This requirement is important to reduce the potential for arbitrary and capricious enforcement. (See United States v. Martinez-Fuerte, supra, 428 U.S. at p. 559 [49 L.Ed.2d at p. 1129].)

Several out-of-state decisions are in accord on this point. Sobriety checkpoints have been upheld in a variety of situations in which the chief commanding officer of a law enforcement agency has drawn up a comprehensive procedures document (in some cases reviewed by other officials) or where the regulations were promulgated by supervisory personnel. (People v. Scott, supra, 473 N.E.2d 1 [program set up by county sheriff]; State v. Super. Ct. in & for County of Pima, supra, 691 P.2d 1073 [commander of traffic enforcement division issued detailed command directive]; Little v. State, supra, 479 A.2d 903 [regulations reviewed by Superintendent of State Police, the Governor and the Attorney General]; State v. Coccomo (1980) 177 N.J.Super. 575 [427 A.2d 131] [township police chief adopted regulations approved by state Attorney General]; State v. Golden (1984) 171 Ga.App. 27 [318 S.E.2d 693] [roadblock set up by supervising DUI task force project coordinator]; State v. Deskins (1983) 234 Kan. 529 [673 P.2d 1174] [roadblock a joint effort of several law enforcement agencies, and all personnel briefed by supervisory officers].)

In each of the sobriety checkpoint projects here, the decision to implement the checkpoints, the site selection and the establishment of operational procedures were made or done by command level personnel, and detailed program regulations were promulgated.

B. Limits on Discretion of Field Officers

A related concern is that motorists should not be subject to the unbridled discretion of the officer in the field as to who is to be stopped. Instead, a neutral formula such as every driver or every third, fifth or tenth driver should be employed. To permit an officer to determine to stop any particular driver or car when there is no legitimate basis for the determination would be to sanction the kind of unconstrained and standardless discretion which the United States Supreme Court sought to circumscribe in its decisions in Prouse, supra, 440 U.S. 648, Almeida-Sanchez, supra, 413 U.S. 266, and Camara, supra, 387 U.S. 523. In all the checkpoint programs at issue here, neutral mathematical selection criteria were used.

C. Maintenance of Safety Conditions

Primary consideration must be given to maintaining safety for motorists and officers. Proper lighting, warning signs and signals, and clearly identifiable official vehicles and personnel are necessary to minimize the risk of *1343danger to motorists and police. (Cf. Jones v. State (Fla.Dist.Ct.App. 1984) 459 So.2d 1068, 1079.) The checkpoint should be operated only when traffic volume allows the operation to be conducted safely. Screening procedures may at times be altered consistent with traffic volume, such that, for example, every car might be stopped when traffic is light, but if traffic began to back up, a different neutral formula might be applied, such as every fifth or tenth car, or operations might be temporarily suspended until traffic volume permitted resumption of safe checkpoint operation.

The Burlingame and CHP checkpoints were operated with a very high degree of safety assurance. The sites of the checkpoint operations were carefully selected with safety considerations in mind, including ample offroad or shoulder area for screening or field sobriety test procedures. The lane closures and road signs complied with all Caltrans safety guidelines. During operations, designated officers were responsible for maintaining the safety of the traffic lanes and cone patterns. There were no safety problems with respect to traffic backups.

D. Reasonable Location

The location of checkpoints should be determined by policy-making officials rather than by officers in the field. The sites chosen should be those which will be most effective in achieving the governmental interest; i.e., on roads having a high incidence of alcohol related accidents and/or arrests. (See State v. Coccomo, supra, 427 A.2d 131, 134.) Safety factors must also be considered in choosing an appropriate location.

One state court has found a sobriety checkpoint unconstitutional largely because it was not at a permanent location. (State v. Olgaard (S.D. 1976) 248 N.W.2d 392.) A decision of the Ninth Circuit also held that a border patrol stop at a temporary checkpoint was unlawful. (United States v. Maxwell (9th Cir. 1977) 565 F.2d 596.) We believe, however, that the temporary nature of sobriety checkpoints does not affect their constitutionality. The Olgaard court’s concern with lack of permanency was solely based on its worry about surprise and lack of publicity in connection with the checkpoint. Although it is not precisely clear from the record in Olgaard, it is inferrable from the circumstances that the Olgaard checkpoint was set up on a surprise basis. The checkpoint was operated by only four officers utilizing nothing but the red flashing lights on several patrol cars. They stopped all traffic in both directions. No lights or signs were used that would have given advance notice of the checkpoint. There was no advance publicity about the checkpoint. The checkpoint plainly also lacked sufficient indicia of legitimacy in terms of staffing strength. In addition, there was no showing who made the decision to set up the checkpoint, or how the *1344location was selected. Thus the Olgaard court appears to have acted with propriety in holding the checkpoint unlawful.

Similarly, the “temporary” border patrol checkpoint at issue in Maxwell, supra, 565 F.2d 596, was deficient with respect to notice and indicia of legitimacy. The checkpoint was marked only by a “stop ahead” sign with battery operated blinking yellow lights, half a dozen traffic cones, one ordinary stop sign, and a border patrol car with a flashing red light. Whereas motorists know or may learn of a permanent immigration checkpoint, the checkpoint in Maxwell was in operation on an intermittent basis without advance notice. There were no structures or electrical equipment connections. So far as the motorist was concerned, he was called to a halt on a lonely road by a blinking red light which could belong to anybody. In addition, the location of the checkpoint may have been inappropriate for an immigration checkpoint. The immigration checkpoint in Martinez-Fuerte, supra, 428 U.S. 543, was justified in part by its being placed on a major highway to prevent easy access by illegal aliens into the interior. Just as a sobriety checkpoint would be improper at a location without any significant traffic or incidence of drunk driving, the location of the Maxwell checkpoint on a route without any significant traffic, by illegal aliens or otherwise, may have been improper. (United States v. Maxwell supra, 565 F.2d. 596, 597-598.)

As was pointed out in People v. Scott, supra, 473 N.E.2d 1, at page 5, “The fact that the [United States] Supreme Court has approved permanent roadblocks but disapproved roving patrol stops is not determinative. What is critical is the intrusiveness of the checkpoint in relation to the governmental purpose involved. The subjective effect upon a vehicle driver approaching a roadblock is unrelated to whether it is permanent or was established but a few minutes before the driver approached it; in either instance his or her observation of it will be measured in minutes if not seconds. The likelihood of there being the kind of fright or annoyance that invalidates a random stop made by a roving patrol is obviated in the case of a temporary checkpoint by the visible signs of authority which the checkpoint entails —signs announcing the purpose, lighting, and identifiable police vehicles and the observable fact that there is a uniform system for stopping cars [citations].” (Accord, Little v. State, supra, 479 A.2d 903, 914.)

With respect to the Burlingame checkpoint, the lighting, signing, substantial uniformed police presence, official vehicles, etc., provided advance notice to the motorist sufficient to ward off surprise and fright. In fact, sufficient advance notice was provided so a motorist could choose to avoid the checkpoint altogether. The objective and subjective intrusion into *1345Fourth Amendment rights was no greater than that resulting from a permanent checkpoint. The checkpoints at issue here were reasonable as to location.

E. Time and Duration

The time of day that a checkpoint is established and how long it lasts also bear on its intrusiveness as well as its effectiveness. For example, a nighttime stop may be more hazardous and possibly more frightening to motorists, but it will also probably prove more effective. While mentioned as a factor in State v. Deskins, supra, 673 P.2d 1174, time and duration have received little attention in the decisions addressing sobriety checkpoints, although most of the checkpoints approved have been operated in the late evening and early morning hours. (People v. Scott, supra, 473 N.E.2d 1; Little v. State, supra, 479 A.2d 903; State v. Coccomo, supra, 427 A.2d 131; State v. Golden, supra, 318 S.E.2d 693; State v. Deskins, supra, 673 P.2d 1174.) We agree with the assessment of the Court of Appeal that no hard and fast rules as to timing or duration can be laid down, but law enforcement officials will be expected to exercise good judgment in setting times and durations, with an eye to effectiveness of the operation, and with the safety of motorists a coordinate consideration.

F. Indicia of Official Nature of Roadblock

Those aspects of a sobriety roadblock which evidence its official nature are critical in minimizing its intrusiveness. The roadblock should be established with high visibility, including warning signs, flashing lights, adequate lighting, police vehicles and the presence of uniformed officers. Not only are such factors important for safety reasons, advance warning will reassure motorists that the stop is duly authorized.

Clearly visible warning lights and other signs of authority have been present in most of the checkpoints upheld by the courts of other states. (See People v. Scott, supra, 473 N.E.2d 1, 3; Little v. State, supra, 479 A.2d 903, 905-906; State v. Golden, supra, 318 S.E.2d 693, 694.) In contrast, most of the checkpoints found unlawful have not provided adequate warning to motorists. (See State v. McLaughlin (Ind.Ct.App. 1984) 471 N.E.2d 1125, overruled in State v. Garcia (Ind. 1986) 500 N.E.2d 158, 162 [holding checkpoints lawful]; Com. v. McGeoghegan (1983) 389 Mass. 137 [449 N.E.2d 349, 353]; State v. Olgaard, supra, 248 N.W.2d 392, 394; State ex rel. Ekstrom v. Justice Ct. of State, supra, 663 P.2d 992, 993; State v. Hilleshiem (Iowa 1980) 291 N.W.2d 314 [vandalism roadblock]; cf. State v. Smith (Okla.Crim.App. 1984) 674 P.2d 562, 564.)

*1346The checkpoints at issue here clearly complied with requirements for proper lighting, signing, and official presence, both in the comprehensive regulations developed for the checkpoint operation and in actual practice.

G. Length and Nature of Detention

Minimizing the average time each motorist is detained is critical both to reducing the intrusiveness of the stop on the individual driver and to maintaining safety by avoiding traffic tie-ups. As occurred in the Burlingame and CHP checkpoints, each motorist stopped should be detained only long enough for the officer to question the driver briefly and to look for signs of intoxication, such as alcohol on the breath, slurred speech, and glassy or bloodshot eyes. If the driver does not display signs of impairment, he or she should be permitted to drive on without further delay. If the officer does observe symptoms of impairment, the driver may be directed to a separate area for a roadside sobriety test. At that point, further investigation would of course be based on probable cause, and general principles of detention and arrest would apply.

H. Advance Publicity

Advance publicity is important to the maintenance of a constitutionally permissible sobriety checkpoint. Publicity both reduces the intrusiveness of the stop and increases the deterrent effect of the roadblock.

The concurring opinion in State ex rel. Ekstrom v. Justice Ct. of State, supra, 663 P.2d 992, at page 1001 explained the value of advance publicity: “Such publicity would warn those using the highways that they might expect to find roadblocks designed to check for sobriety; the warning may well decrease the chance of apprehending ‘ordinary’ criminals, but should certainly have a considerable deterring effect by either dissuading people from taking ‘one more for the road,’ persuading them to drink at home, or inducing them to take taxicabs. Any one of these goals, if achieved, would have the salutary effect of interfering with the lethal combination of alcohol and gasoline. Advance notice would limit intrusion upon personal dignity and security because those being stopped would anticipate and understand what was happening.” (663 P.2d 992, 1001, conc. opn. Feldman, J.; see also State v. Deskins, supra, 673 P.2d 1174, 1182.)

Publicity also serves to establish the legitimacy of sobriety checkpoints in the minds of motorists. Although the court in Jones v. State, supra, 459 So.2d 1068, found that advance publicity was not constitutionally mandated for all sobriety roadblocks, nevertheless the court offered the observation, consistent with finding reasonableness under the Fourth Amendment, that *1347“ ‘[A]dvance publication of the date of an intended roadblock, even without announcing its precise location, would have the virtue of reducing surprise, fear, and inconvenience.’ [Citation.]” (Id., at p. 1080.)

In the instant case, substantial advance publicity accompanied each sobriety checkpoint instituted.

I. Conclusions as to Intrusiveness

We conclude that, while the intrusiveness of a sobriety checkpoint stop is not trivial, the enumerated safeguards operate to minimize the intrusiveness to the extent possible. The fright or annoyance to motorists condemned in connection with roving stops is absent when the checkpoint is operated according to the guidelines followed here.

On balance, the intrusion on Fourth Amendment interests is sufficiently circumscribed so that it is easily outweighed and justified by the magnitude of the drunk driving menace and the potential for deterrence.

5. Statutory Authorization

Petitioners contend that sobriety roadblocks are impermissible in the absence of specific authorizing legislation. Petitioners make three points. The first and broadest argument is that the police may not enforce traffic laws in any manner not specifically authorized by statute. The second is that the Vehicle Code provides for uniform statewide rules governing vehicle use and police regulation of that use, so that to allow municipalities to set up roadblocks on an ad hoc basis would allow a balkanization of vehicle use regulation that various sections of the Vehicle Code show the Legislature did not intend. The third point is that the Vehicle Code specifically permits police officers to use roadblocks in limited circumstances. Pointing out that two recent bills to amend the Vehicle Code to permit drunk driving roadblocks have died in committee, petitioners advance the proposition that since the Legislature has only permitted roadblocks in limited circumstances, roadblocks in any other circumstances are impermissible.

Petitioners cite no persuasive authority for the proposition that police officers may not enforce the Vehicle Code in any manner not specifically provided for by statute. Citing People v. One 1960 Cadillac Coupe (1964) 62 Cal.2d 92, 95-96 [41 Cal.Rptr. 290, 396 P.2d 706], they claim that the general police power only permits detention on reasonable suspicion when a motorist is engaged in wrongdoing unless there is statutory authority for other police action. The cited case is inapposite; it merely applies *1348familiar principles as to the circumstances necessary to justify a detention, and establishes that the exclusionary rule applies in a civil action for forfeiture of a car believed to be involved in drug trafficking.

Petitioners also cite People v. McGaughran (1979) 25 Cal.3d 577, 583-584 [159 Cal.Rptr. 191, 601 P.2d 207] (warrant checks during traffic stops); People v. Superior Court (Simon) (1972) 7 Cal.3d 186, 199-200 [101 Cal.Rptr 837, 496 P.2d 1205] (search incident to arrest for violations for which accused would not be booked) and People v. Franklin (1968) 261 Cal.App.2d 703, 707 [68 Cal.Rptr. 231] (scope of statutes allowing stops for vehicle safety and registration inspection) for the proposition that the Vehicle Code is comprehensive and controls methods of enforcement of its provisions. None of these cases, however, establishes that unless a method of law enforcement is specifically authorized in the Vehicle Code, it is prohibited. Rather, these cases interpret the limits on officers’ authority which have been expressly established by statute.

For similar reasons, petitioners’ position is not aided by their citation to People v. Welsch (1984) 151 Cal.App.3d 1038 [199 Cal.Rptr. 87] (warrant-less arrest for hit and run outside officer’s presence not authorized by statute); People v. Horvath (1982) 127 Cal.App.3d 398 [179 Cal.Rptr. 577] (neither Pen. Code nor Pub. Util. Code authorized arrest of pilot who flew while intoxicated outside officer’s presence); or People v. Aldapa (1971) 17 Cal.App.3d 184 [94 Cal.Rptr. 579] (arrest outside jurisdiction not authorized by former Pen. Code, § 817). In each case, the officer breached a statutory limitation on his authority; none of these decisions holds that methods of law enforcement not specifically authorized are prohibited.

It is illogical to suggest that an officer who has a reasonable suspicion an individual is driving under the influence of intoxicants and thus endangering the public may take corrective action, but that a law enforcement agency having knowledge that on any given night hundreds of drivers will be under the influence of intoxicants and thus endangering the public may not. The threat to public safety in the second instance is immeasurably greater than in the first. We conclude, as did the Court of Appeal majority, that the requisite authority is implicit in law enforcement’s statutory authority to enforce criminal laws generally or traffic laws specifically. (See, e.g., Veh. Code, § 2400; Gov. Code, §§ 26600, 26601.)

With respect to the second point, it is true that the Vehicle Code generally preempts the field of traffic regulation vis-a-vis local ordinances. *1349(See Veh. Code, § 21.)7 We have observed that unless the Legislature so provides, a city has no authority over traffic control. (See Rumford v. City of Berkeley (1982) 31 Cal.3d 545, 550 [183 Cal.Rptr. 73, 645 P.2d 124] [city has no authority to erect traffic barriers not qualifying as traffic control devices under Veh. Code].) While this rule of preemption might conceivably prevent municipalities from establishing permanent drunk driving roadblocks that might in effect regulate traffic, it does not affect the statutory authority of the CHP and local police to enforce the Vehicle Code and other laws with checkpoints at more temporary locations. (See, e.g., Veh. Code, § 2400; Gov. Code, §§ 26600, 26601.)

Petitioners’ arguments as to their third point, again go far beyond the authority they cite. Petitioners point out examples in which the Legislature has permitted police to stop or inspect cars. The Vehicle Code authorizes police officers to require motorists to stop and submit their vehicles for safety inspections upon reasonable cause to believe that the vehicle is in violation of the code. (Veh. Code, § 2806.) CHP and law enforcement officers “whose primary responsibility is to conduct vehicle theft investigations” may make warrantless inspections for vehicle registration. (Veh. Code, § 2805.) The CHP is authorized to run mechanical inspection stations. (Veh. Code, § 2814.) And the Legislature has provided for agricultural inspection stations at state borders. (Food & Agr. Code, § 5341 et seq.) But it does not follow that because the Legislature has specifically authorized these inspections, no other inspections are permissible under the general police power. Indeed, it may be more reasonable to assume the Legislature would not feel obliged to enact specific legislation authorizing conduct it deemed to be constitutional and appropriate within the scope of existing police power. Legislative silence is an unreliable indicator of legislative intent in the absence of other indicia. We can rarely determine from the failure of the Legislature to pass a particular bill what the intent of the Legislature is with respect to existing law.8 “As evidences of legislative intent they [unpassed bills] have little value.” (Sacramento Newspaper Guild v. Sacramento County Bd. of Suprs. (1968) 263 Cal.App.2d 41, 58 [69 Cal.Rptr. 480]; see Marina Point, Ltd. v. Wolfson (1982) 30 Cal.3d 721, 735, fn. 7 [180 Cal.Rptr. 496, 640 P.2d 115, 30 A.L.R.4th 1161]; Miles v. Workers' Comp. Appeals Bd. (1977) 67 Cal.App.3d 243, 248, fn. 4 [136 Cal.Rptr. *1350508]; see also United States v. Wise (1962) 370 U.S. 405, 411 [8 L.Ed.2d 590, 594-595, 82 S.Ct. 1354]; Gregory v. City of San Juan Capistrano (1983) 142 Cal.App.3d 72, 84 [191 Cal.Rptr. 47]; cf. 2A Sutherland, Statutory Construction (4th ed. 1984) § 49.10, pp. 407-408.)

Disposition

For the reasons stated, the judgment of the Court of Appeal denying the writ of mandate is affirmed.

Lucas, C. J., Arguelles, J., and Eagleson, J., concurred.

BROUSSARD, J.

I dissent. The majority uphold drunk driving1 roadblocks on the theory that they are administrative inspections, not subject to the usual rule that any detention be justified by reasonable suspicion of individual wrongdoing. In my opinion, when uniformed law enforcement officers stop motorists to check them for intoxication, shine a light in the car to look for open containers of alcohol or other evidence of intoxication, with special officers ready to administer blood-alcohol tests and booking officers and police vans ready to take offenders to jail, it is not an administrative inspection but an ordinary police detention, which must be justified on the same grounds as any other detention for the purpose of law enforcement.

Administrative Search Doctrine

The majority concede that if the primary purpose of the roadblock were to detect crime, the detention of a driver without individualized suspicion that the driver had engaged in criminal activity would be unconstitutional. In fact, the roadblock has two purposes: detection of drunk drivers and collection of evidence. The majority maintain, however, that the primary purpose of these roadblocks is to promote public safety by deterring drunk driving. The majority assert that this is a regulatory or administrative purpose, and conclude that detention without individualized suspicion is permissible by analogy to the administrative search doctrine we adopted in People v. Hyde (1974) 12 Cal.3d 158 [115 Cal.Rptr. 358, 524 P.2d 830].

In Hyde, we permitted predeparture screening of airline passengers, without individualized suspicion of wrongdoing. Our theory was that the screening was a central part of a general regulatory scheme in furtherance of an *1351administrative purpose, not an effort to seize contraband or evidence of crime. (People v. Hyde, supra, 12 Cal.3d at p. 166.)

Hyde does not bring the drunk driving roadblock into the administrative search doctrine. First of all, the Vehicle Code provisions prohibiting drunk driving are not a “regulatory scheme.” In Hyde, we used federal cases approving warrantless inspection of the firearms and liquor industry as examples of pervasively regulated activities in which a warrantless inspection was permissible. (People v. Hyde, supra, 12 Cal.3d 158, 165, citing United States v. Biswell (1972) 406 U.S. 311 [32 L.Ed.2d 87, 92 S.Ct. 1593]; Colonnade Corp. v. United States (1970) 397 U.S. 72 [25 L.Ed.2d 60, 90 S.Ct. 774].) The rationale of those cases is that a person engaging in the pervasively regulated industry is on notice that he has a limited expectation of privacy because the regulations provide for effective inspection. (United States v. Biswell, supra, 406 U.S. 311, 316 [32 L.Ed.2d 87, 92], see also Marshall v. Barlow’s, Inc. (1978) 436 U.S. 307, 313 [56 L.Ed.2d 305, 311-312, 98 S.Ct. 1816].) No such “regulatory scheme” puts California drivers on notice that they are subject to detention without reasonable suspicion to determine whether they are driving under the influence of alcohol or drugs. Drivers do not “impliedly consent” to being inspected for alcohol on their breath.

The United States Supreme Court has rejected the Colonnade/Biswell analogy for automobile inspections on the ground that motorists have a considerable and legitimate expectation of privacy in the automobile, including an expectation of freedom of movement. (Delaware v. Prouse (1979) 440 U.S. 648, 662-663 [59 L.Ed.2d 660, 673, 99 S.Ct. 1391].) The Supreme Court also has rejected the argument that driving is a pervasively regulated activity subjecting motorists to suspicionless roving immigration stops. (Almeida-Sanchez v. United States (1973) 413 U.S. 266 [37 L.Ed.2d 596, 93 S.Ct. 2535].) The court has explained that a roving stop of a motorist to check for illegal aliens was unreasonable; the driver was not in the same position as the gun manufacturer or liquor distributor who had in effect consented to inspection by entering a heavily regulated industry. (Id. at pp. 271-272 [37 L.Ed.2d at p. 602].)

A drunk driving roadblock also differs from the usual administrative or regulatory inspection because there is no “regulatory” agency to enforce the drunk driving prohibitions other than the police and the criminal courts.2 The clear purpose of these laws is not to regulate, but to detect and punish criminal drunk driving. Nothing distinguishes this crime from any other serious one.

*1352The majority suggest that as long as the purpose of a drunk driving roadblock is to deter rather than detect crime, the roadblock is “regulatory.” But we certainly did not hold in Hyde, supra, 12 Cal.3d 158, as the majority suggest, that if the purpose of a detention is to deter rather than detect crime, it may be justified as an administrative search. Criminal law enforcement encompasses both detection and deterrence. If we allowed detentions without individualized suspicion to deter crime, we would allow preventive detentions in high crime areas. But we do not allow such practices. (See People v. Loewen (1983) 35 Cal.3d 117, 124 [196 Cal.Rptr. 846, 672 P.2d 436].) What distinguishes the permissible administrative inspection from other searches is not that they are only intended to deter, but that they carry out an administrative scheme that is not part of the penal system. There is no such administrative scheme here. In fact, the majority would permit roadblocks carried out without uniform regulation, without statewide oversight, in a Balkanized system varying from jurisdiction to jurisdiction.

The majority also rely on dictum in Delaware v. Prouse, supra, 440 U.S. 648, another case involving random stops of automobiles. There the high court disapproved a roving patrol stop conducted without individualized suspicion to check for current license and vehicle registration. The court said that its holding did not mean that police could not try other methods to enforce license and registration laws, such as a permanent roadblock to inspect for license and registration violations. But the Prouse dictum is inapposite. A roadblock inspection for license and vehicle registration is an administrative inspection, since these aspects of motoring are closely regulated. Since license and registration violations do not involve criminal sanctions primarily, the inspections themselves are less intrusive for the average motorist. A request to look at one’s license is far less accusatory than an inspection for red, watery eyes, slurred speech, alcohol on the breath, open containers in the car, and the other signs of intoxication. It does not follow that, because a roadblock may be permissible to check for drivers’ licenses, it must be permissible to check for drunk driving.

To call a drunk driving roadblock an administrative inspection ignores its true purpose —apprehension of drunk drivers. The fact is that the apparatus of the law enforcement system is moved to the scene of the roadblock — with breathalyzers ready to take evidence for introduction at a criminal trial, police officers ready to arrest offenders, and police vans ready to take suspects away. If we call the Burlingame roadblock an administrative inspection, then a detention to investigate any crime could be deemed an administrative inspection. The Constitution cannot, and should not, be stretched so far.

*1353Application of the Balancing Test

The propriety of an administrative search is judged under a balancing test in which the invasion of individual liberty is weighed against the necessity for the invasion and its effectiveness in achieving the state’s goal. (See Camara v. Municipal Court (1967) 387 U.S. 523, 536-537 [18 L.Ed.2d 930, 940, 87 S.Ct. 1727]; People v. Hyde, supra, 12 Cal.3d 158, 166.) Even assuming that the analogy to administrative searches is proper, and that we should abandon individualized suspicion in favor of a balancing test, I would conclude that roadblocks are neither necessary nor effective enough to warrant the intrusion on the individual that they cause.

We all agree that the government has a profound interest in deterring and punishing drunk driving. We have recently lamented the “. . . horrific risk posed [to public safety] by those who drink and drive.” (Burg v. Municipal Court (1983) 35 Cal.3d 257, 262 [198 Cal.Rptr. 145, 673 P.2d 732].) Yet the necessity for and effectiveness of drunk driving roadblocks remains to be demonstrated. And the intrusion is far from minimal.

In the federal cases allowing detentions and other intrusions without individualized reasonable suspicion that wrongdoing was taking place, there was little alternative available to the state, and this entered into the balance in determining whether the stop was reasonable. In those cases, the suspicionless intrusions were literally necessary, since the transgressions to be detected could not be observed unless the inspectors entered the premises; there were no objective indicators visible from the outside upon which an official could form a reasonable suspicion. (See United States v. Biswell, supra, 406 U.S. 311, 316 [32 L.Ed.2d 87, 92]; Colonnade Corp. v. United States, supra, 397 U.S. 72, 74, 76-77 [25 L.Ed.2d 60, 64]; Camara v. Municipal Court, supra, 387 U.S. 523, 537 [18 L.Ed.2d 930, 940]; cf. United States v. Martinez-Fuerte (1976) 428 U.S. 543, 557 [49 L.Ed.2d 1116, 1128, 96 S.Ct. 3074].) By contrast, drunk drivers are conspicuous. We have all observed drunks weaving down the road, speeding up and slowing down, straddling lanes, and ignoring traffic and traffic signs. It is preposterous to claim that police have no way other than a roadblock to detect or deter drunk drivers.

The majority suggest that roadblocks are necessary because existing enforcement techniques have not eradicated the problem of drunk driving. If this were a proper consideration, the Fourth Amendment would have little meaning. Existing enforcement techniques have not eradicated the scourge of crime in our society, yet no one would seriously propose that the Constitution therefore permits the police to make unprecedented invasions of personal liberty. If we allow mass detentions through the means of roadblocks merely because the police claim that they may be more effective and *1354helpful to law enforcement, we have gone a long way towards abandoning the protection of the Fourth Amendment.

The majority find that the deterrent effect of drunk driving roadblocks weighs heavily in the balance. (The majority concede that roadblocks do not produce nearly as many arrests per officer hour as patrols in which drivers are stopped for cause.)3 This assertion is based on anecdotal evidence and flawed logic. Some states justify roadblocks by comparing accident rates in counties having roadblocks with others having none, but to conclude that it was the roadblock that caused the difference is the rankest speculation.4 The California Highway Patrol concedes that such evidence is inconclusive. In fact, some studies indicate that whatever deterrent effect a roadblock may have is entirely the result of its novelty and the waywardness of publicity. For example, as European drivers became accustomed to roadblocks and the publicity about them died down, their deterrent effect disappeared. (See ABA, Assessment of Effectiveness, supra, at p. 3.)

The majority admit that the deterrent effect of drunk driving roadblocks is not established and that “[t]he experience both in California and in other states with sobriety checkpoints has been very limited, and no definitive statistics are yet available.” (Maj. opn., ante, at p. 1339.) Yet, the majority insist that “[i]t would be presumptuous in the extreme for this court to prohibit the use of an otherwise permissible and potentially effective procedure merely because its effectiveness is at the present time largely untested.” (Ibid.) This distorts the balancing test and makes it possible for any law enforcement method to pass constitutional muster as long as a plausible argument can be made that it might turn out to be effective. If this is the balancing test, it is not a test but a rubber stamp.

We also must weigh the intrusion of the roadblock on the individual. There can be no question of the reasonableness of the motorist’s expectation of privacy. Though the expectation of privacy in the automobile is not as great as in the home, it is clear from Almeida-Sanchez, supra, 413 U.S. 266, *1355and Delaware v. Prouse, supra, 440 U.S. 648, that motorists do retain a reasonable expectation of considerable privacy in the automobile. The invasiveness of a drunk driving roadblock is far greater than the invasion that the high court has characterized as minimal in the immigration checkpoint. (See United States v. Martinez-Fuerte, supra, 448 U.S. 543, 559 [49 L.Ed.2d 1116, 1129].) In the immigration checkpoint, the immigration agent’s primary purpose is not to make arrests. But at a drunk driving roadblock, officers stop individuals with the purpose of determining if they are then committing the crime of drunk driving —a crime now involving considerable public stigma, to say nothing of the substantial criminal penalties that now result from a drunk driving conviction. The United States Supreme Court has repeatedly distinguished the minimal invasion of the administrative inspection from the necessarily hostile, threatening, and frightening intrusion of an investigation for crime. (See, e.g., Camara v. Municipal Court, supra, 387 U.S. 523 at pp. 530, 537 [18 L.Ed.2d 930 at pp. 936, 940].) Moreover, the detention at a drunk driving roadblock is necessarily experienced as personally intrusive, since unlike in the license inspection or immigration checkpoint, the officer’s object is to inspect the interior of the vehicle for evidence of crime and to examine the present mental and physical condition of the driver to determine if he or she should be arrested.

The majority seem to suggest that as long as a neutral plan assures that the roadblock is run safely and without arbitrariness, the individual’s interest in being free from police detention does not weigh in the balance at all. This antiseptic approach denies the unavoidable invasion of privacy which occurs when a citizen is confronted by the police and his demeanor inspected for evidence that he is committing a crime. Furthermore, the protection of the neutral plan is illusory. What recourse does any driver have if the neutral plan was not being followed when he or she was stopped? In the Burlingame example, the plan provided that motorists who refused to stop would be allowed to proceed. Yet one of the participating officers said he would have pursued any motorist who refused to stop. As there is apparently no remedy for violations of the neutral plan, the plan is no protection against arbitrariness.

The pervasiveness of the invasion also must be considered. Take one example. The New York City police used 100 officers to operate a series of drunk driving roadblocks from May 27 to June 26, 1983. The police stopped 184,828 cars. There were 222 arrests for drunk driving. (N.Y. Times (June 27, 1983) at p. Bl, col. 2, described in Grossman, Sobriety Checkpoints: Roadblocks to Fourth Amendment Protections, supra, 12 Am. J. Crim. L. 123, 157.)5 During a one-month period, 184,606 people who *1356turned out to be innocent were detained by the police. For every arrest there were 831 innocent drivers whose privacy was infringed. We certainly would be concerned about the propriety of detaining the same number of citizens on our streets for “inspection” for drug abuse or other crimes. It is one thing to invade personal privacy in order to apprehend dangerous criminals, but when the purported object is deterrence, such mass detentions are a very high price to pay when the effectiveness of such detentions is questionable at best.

The invasion of privacy occasioned by these roadblocks also may become pervasive in the sense that the roadblocks will be everywhere. If we approve drunk driving roadblocks, they may appear in every community. This could mean 20 or 30 or more roadblocks in any urban area on any given night. Omnipresent police blockades at each community’s border would be not only inconvenient for motorists, but also would be a contradiction of our values as an open and free society.

The Fourth Amendment is highly inexpedient to law enforcement, yet to date we have not allowed mass detentions on the theory that these might prove useful in combatting crime. I see no basis for distinguishing a drunk driving roadblock from any other mass detention established to prevent crime or apprehend wrongdoers. While drunk driving is a revolting crime, it is not the only one which the community abhors. If we abandon constitutional protections to combat every abhorrent crime which has captured the public’s attention, we will find ourselves naked and unprotected in a hurry.

Conclusion

Since I regard a drunk driving roadblock under which a motorist is stopped with no reasonable suspicion that he is intoxicated inconsistent with the federal and state Constitutions, I would reverse the decision of the Court of Appeal and order the issuance of a peremptory writ.

Mosk, J., and Panelli, J., concurred.

BOWEN, Judge.

Clayton Cains was convicted of driving under the influence of alcohol, a violation of § 32-5A-191(a)(2), Code of Alabama 1975, and sentenced to pay a fine of $500. On appeal, he claims that he was illegally arrested and that the State did not establish the proper predicate for introduction of his blood alcohol test results into evidence.

I

On March 13, 1988, State Troopers McGlothlin, Peacock, and Tolbert set up a roadblock on Alabama highway 59, between Stapleton and Loxley, to check for “drivers’ licenses, equipment violations, persons who were driving under the influence, [and] anything that would be in violation of the law.” Trooper Tim McGlothlin testified that they decided to set up the roadblock “based on problems that we were having in the area.” They received approval for the roadblock from their supervisor, Corporal Larry Linden, and Linden later came by to check on the roadblock.

McGlothlin testified ■ that he stopped every car in both the northbound and southbound lanes of traffic, asked the drivers for their licenses, and then waved them on if there were no problems. The duration of each stop was for “five, ten seconds or so, just long enough to pull out their license.” When McGlothlin asked the defendant for his license, McGlothlin noticed that the defendant’s eyes were “extremely bloodshot,” that he acted “sluggish,” and that he “looked intoxicated.”

At that point, the trooper asked the defendant to pull his vehicle to the side of the road, to step out of the car, and to walk to a nearby patrol car. McGlothlin, who observed the defendant walk about 30 yards, stated that the defendant was “very unsteady on his feet,” and “staggered the whole time.” When the defendant got in *292the patrol car, he had a strong odor of alcohol on his breath, he was “thick-tongued,” and it was difficult to understand him. McGlothlin gave him an alco-sensor field test for sobriety and, when he failed the test, the officer arrested him for DUI. He was then taken to the Roberts-dale police headquarters and administered an Intoxilyzer 5000 test. The results of that test indicated that the defendant had a blood alcohol content of .20%.

Although the defendant does not challenge the constitutionality of his initial stop at the roadblock, he claims that his being directed to pull out of the line of traffic for further inquiry constituted an arrest without probable cause in violation of his Fourth Amendment rights. We hold that no arrest occurred at that time.

Instead, the defendant was detained on reasonable suspicion of DUI pursuant to § 15-5-30, Code of Alabama 1975, and the Terry v. Ohio, 392 U.S. 1, 88 S.Ct. 1868, 20 L.Ed.2d 889 (1968), line of cases. Following further observation of the defendant’s condition, including his failure to pass the field sobriety test, the officer then had probable cause to arrest him for DUI and transport him to police headquarters for an intoxilyzer test. See Buchanan v. City of Auburn, 512 So.2d 145, 146 (Ala.Cr.App.1987), overruled on other grounds, Hays v. City of Jacksonville, 518 So.2d 892 (Ala.Cr.App.1987).

Our holding that the defendant was not arrested, but merely subjected to a Terry-type detention when he was directed to the secondary inspection area for further inquiry necessarily includes the determination that his initial stop at the roadblock was permissible. If the primary stop had been constitutionally infirm, then any additional detention would, of course, have been invalid. See State v. Calhoun, 502 So.2d 808 (Ala.1986).

It is undisputed that “stopping an automobile and detaining its occupants constitute a ‘seizure’ within the meaning of [the Fourth Amendment],” Delaware v. Prouse, 440 U.S. 648, 653, 99 S.Ct. 1391, 1396, 59 L.Ed.2d 660 (1979). “Checkpoint stops are ‘seizures,’ ” United States v. Martinez-Fuerte, 428 U.S. 543, 556, 96 S.Ct. 3074, 3082, 49 L.Ed.2d 1116 (1976). The Fourth Amendment requires that such seizures be reasonable. Delaware v. Prouse; Martinez-Fuerte; Terry v. Ohio. Generally, a seizure less intrusive than a traditional arrest is reasonable if based on individualized suspicion, gathered from specific and articulate facts, that the individual is, or is about to be, engaged in criminal activity, Terry v. Ohio; see also United States v. Cortez, 449 U.S. 411, 417, 101 S.Ct. 690, 694, 66 L.Ed.2d 621 (1981), or if the seizure is “carried out pursuant to a plan embodying explicit, neutral limitations on the conduct of individual officers,” Brown v. Texas, 443 U.S. 47, 51, 99 S.Ct. 2637, 2640, 61 L.Ed.2d 357 (1979).

The nature of a roadblock requires the stopping of cars without individualized suspicion of wrongdoing. Thus, if a roadblock stop is to be upheld, it must be on the second basis, i.e., because it is “carried out pursuant to a plan embodying explicit, neutral limitations on the conduct of individual officers.” In a series of decisions stemming from the immigration control cases, the United States Supreme Court has rejected the individualized suspicion requirement for fixed, non-random automobile checkpoints or roadblock stops, and instead has established some criteria for “a plan embodying explicit, neutral limitations on the conduct of individual officers.”

In United States v. Brignoni-Ponce, 422 U.S. 873, 95 S.Ct. 2574, 45 L.Ed.2d 607 (1975), the Court held that random vehicle stops by roving border patrols must be based on reasonable and individualized suspicion of criminal activity, but it approved, in United States v. Martinez-Fuerte, 428 U.S. 543, 96 S.Ct. 3074, 49 L.Ed.2d 1116 (1976), the stop of all oncoming traffic at a fixed immigration roadblock-type checkpoint in the absence of individualized suspicion. In Martinez-Fuerte, the Court observed that “the Fourth Amendment imposes no irreducible requirement of such suspicion,” 428 U.S. at 561, 96 S.Ct. at 3084, and it utilized a balancing approach to determine reasonableness, weighing the strong public interest in stopping the flow of il*293legal aliens against the minimal intrusion on “ ‘the constitutionally protected interests of the private citizen,’ ” id. (quoting Camara v. Municipal Court of City and County of San Francisco, 387 U.S. 523, 538, 87 S.Ct. 1727, 1735, 18 L.Ed.2d 930 (1967)). In addition to noting a lesser expectation of privacy in an automobile, the Court also found that roadblock stops “both appear to and actually involve less discretionary enforcement activity,” id. 428 U.S. at 559, 561, 96 S.Ct. at 3083, 3084.

Then, in Delaware v. Prouse, the Court again focused on the critical element of “discretionary enforcement activity” by holding that a random stop, by an officer on roving patrol, of an automobile to check vehicle registration and licensing requirements violated the Fourth Amendment because it was not based on individualized suspicion. Finding that the “essential purpose of the proscriptions in the Fourth Amendment is to impose a standard of ‘reasonableness’ upon the exercise of discretion by government officials,” the Court determined that the absence of “an objective standard” for making a particular stop made random stops unreasonable. 440 U.S. at 653-54, 99 S.Ct. at 1395-96. The Court concluded with the following observation, which has been the basis for roadblock stops ever since:

“This holding does not preclude the State of Delaware or other States from developing methods for spot checks that involve less intrusion or that do not involve the unconstrained exercise of discretion. Questioning of all oncoming traffic at roadblock-type stops is one possible alternative.” Id. at 663, 99 S.Ct. at 1401 (emphasis added).

Four years later, the Court specifically approved drivers’ license checkpoints in Texas v. Brown, 460 U.S. 730, 103 S.Ct. 1535, 75 L.Ed.2d 502 (1983). In Brown, while the accused was detained at a roadblock the officer noticed a balloon which, based on his experience, he suspected contained narcotics. The Court upheld the seizure of the balloon and the subsequent search of the vehicle based on the “plain view” exception to the warrant requirement outlined in Coolidge v. New Hampshire, 403 U.S. 443, 91 S.Ct. 2022, 29 L.Ed.2d 564 (1971). For the plain view exception to apply, “[fjirst, the police officer must lawfully make an ‘initial intrusion’ or otherwise properly be in a position from which he can view a particular area.” Texas v. Brown, 460 U.S. at 737, 103 S.Ct. at 1540; Coolidge v. New Hampshire, 403 U.S. at 465-68, 91 S.Ct. at 2037-39. Regarding the legitimacy of the officer’s initial intrusion in Brown, the Court noted the following:

“The [Texas] Court of Criminal Appeals stated that it did not ‘question ... the validity of the officer’s initial stop of appellant’s vehicle as a part of a license check,’ [Brown v. State] 617 S.W.2d [196], at 200 [Tex.Cr.App.1981], and we agree. Delaware v. Prouse, supra [440 U.S.] at 654-655 [99 S.Ct. at 1396].” Texas v. Brown, 460 U.S. at 739, 103 S.Ct. at 1542. (Emphasis added.)

When read together, Brignoni-Ponce, Martinez-Fuerte, Prouse, and Texas v. Brown stand for the proposition that random stops or spot checks are unreasonable in the absence of individualized suspicion of wrongdoing; on the other hand, stops at fixed checkpoints or roadblocks are reasonable if they are carried out pursuant to a neutral and objective plan, are supported by a strong public interest, and are only minimally intrusive to the individual motorist. See generally Hall, Search and Seizure § 10:31.1 (Cum.Supp. § 1986); 4 W. LaFave, Search and Seizure § 10.8(a) and (d) (2d ed. 1987); Ringel, Searches and Seizures, Arrests and Confessions § 11.6 (1986); Pellieciotti, The Law and Administration of Sobriety Checkpoints, 16 Journal of Police Science and Administration (1988), Note, Curbing the Drunk Driver Under the Fourth Amendment: The Constitutionality of Roadblock Seizures, 71 Geo.L.J. 1457 (1983).

Since Prouse, sobriety checkpoints have been the subject of extensive litigation and commentary. As one commentator noted recently, as of the fall of 1988,

“Twenty-nine state courts ... have ruled on the constitutionality of roadblocks. *294Nine state courts have held roadblocks to be unconstitutional; three of these courts later ruled that subsequent roadblocks were constitutional_ Upon reviewing the various decisions among state courts, the Florida Supreme Court called the issue an ‘amorphous area.’ State v. Jones, 483 So.2d 433, 437 (Fla.1986).” Bruce, State v. Welch: Drunk Drivers, Roadblocks and the Fourth Amendment, 57 U.M.K.C.L.Rev. 29, 30 n. 8 (1988). However, “it seems fair to conclude that a DWI roadblock is constitutional if properly conducted.” 4 LaFave at 70.

In balancing the gravity of the public interest in conducting DUI roadblocks against the degree of intrusion on the individual motorist, most courts and commentators have used the following three-part test set out in Brown v. Texas:

“[A] weighing of the gravity of the public concerns served by the seizure, the degree to which the seizure advances the public interest, and the severity of the interference with individual liberty.” 443 U.S. at 51, 99 S.Ct. at 2640.

See, e.g. State v. Deskins, 234 Kan. 529, 673 P.2d 1174, 1184-85 (1983); State v. Welch, 755 S.W.2d 624, 632-33 (Mo.App.1988); 4 LaFave, at 71-76; Bruce, 57 U.M.K.C.L.Rev. at 35 (1988).

There is at least one factor of the balancing test on which all courts agree: the public interest in promoting highway safety by detecting, removing, and prosecuting drunk drivers is extremely great. As the Supreme Court has observed, “The slaughter on the highways of our Nation exceeds the death toll of all our wars.” Perez v. Campbell, 402 U.S. 637, 657, 91 S.Ct. 1704, 1715, 29 L.Ed.2d 233 (1971) (Blackmun, J., concurring). “The carnage caused by drunk drivers is well documented and needs no detailed recital here,” South Dakota v. Neville, 459 U.S. 553, 558, 103 S.Ct. 916, 920, 74 L.Ed.2d 748 (1983). “Certainly, the need to identify and apprehend drunken drivers is just as clear and pervasive as the need to discover illegal aliens, which was determined to be a sufficient public concern to justify the checkpoint stops in United States v. Martinez-Fuerte. . . .” State v. Deskins, 673 P.2d at 1186—87 (Prager, J., dissenting). We do not believe this first factor is open to argument or dispute.

The only debatable questions in the sobriety checkpoint cases are whether roadblocks sufficiently advance the legitimate public interest, and whether the interference with individual liberty occasioned by a roadblock stop outweighs the public interest.

Many of the critics of DUI checkpoints have suggested that roadblock stops do not adequately promote the public interest because the problem of drunk drivers can be more effectively combated by the traditional law enforcement practice of stopping vehicles whose drivers display, by their improper driving, signs of being under the influence. See e.g., State ex rel. Ekstrom v. Justice Court of the State of Arizona, 136 Ariz. 1, 663 P.2d 992 (1983); State v. Koppel, 127 N.H. 286, 499 A.2d 977 (1985). See also Jacobs & Strossen, Mass Investigations Without Individual Suspicion: A Constitutional and Policy Critique of Drunk Driving Roadblocks, 18 U.C.D.I. Rev. 595 (1985).

One dissenter has concluded that, on a cost-effectiveness scale, roadblocks do not “promote the public interest in light of available less drastic alternative measures.” State v. Deskins, 673 P.2d at 1187 (Prager, J., dissenting). In that case, a four-hour roadblock which stopped between 2000 and 3000 vehicles netted 15 DUI arrests and consumed 140 manhours of law enforcement time. Id.

One answer to the “cost-effectiveness,” or “success-of-apprehension” argument was provided by the Supreme Court in Martinez-Fuerte when it recognized immigration roadblocks as a “deterrent to the conduct of well-disguised smuggling operations.” 428 U.S. at 557, 96 S.Ct. at 3083 (emphasis added). “Certainly the deterrence function is just as important (if not more important) with respect to the problem of drunken driving.... [0]ne very important purpose of a DWI roadblock is ‘in serving as a deterrent to convince the *295potential drunk driver to refrain from driving in the first place.’ ” 4 LaFave at 74-75 (quoting People v. Bartley, 109 Ill.2d 273, 93 Ill.Dec. 347, 486 N.E.2d 880 (1985), cert. denied, 475 U.S. 1068, 106 S.Ct. 1384, 89 L.Ed.2d 608 (1986).)

Another answer to the “success of apprehension” argument was provided by the Missouri court in State v. Welch, when it observed:

“Appellant’s plea that only a fraction of those vehicles stopped on this particular occasion revealed operators who were intoxicated does not rise to a constitutional level. There is no necessity of numbers to establish the constitutionality validity of such operations. There is no magic and certainly no basis for holding roadblocks are unconstitutional simply because a small number of intoxicated drivers were intercepted. Indeed, it takes only one impaired driver to possibly extinguish other lives, cause serious and life-long disability, and destroy property of otherwise innocent travelers upon our roadways.” 755 S.W.2d at 633.

Finally, as one commentator has noted, “The decision how police manpower should best be utilized should lie • with a police administrator and not an appellate court.” 57 U.M.K.C.L.Rev. at 40.

“A particular police procedure is not necessarily ineffective or, more important, unconstitutional simply because it is not the ‘best’ method available. For example, the United States Supreme Court has recognized the right of police officers to make warrantless searches of automobiles, regardless of whether or not the police have the time or opportunity to obtain a warrant. [United States v. Ross, 456 U.S. 798, 102 S.Ct. 2157, 72 L.Ed.2d 572 (1982)].” Id.

Although the record before us contains no statistics on the number of drunk drivers apprehended at this roadblock, we do not consider the omission critical. We know that at least one impaired driver was removed from the road, and we can assume that, as a result of this and similar roadblocks in the area, other individuals under the influence of alcohol or drugs were deterred from driving. In light of testimony that the location of this roadblock was chosen “based on problems ... in the area,” we cannot say that the roadblock did not advance the public interest. In sum, we find that the location of this checkpoint was not arbitrarily chosen and it thus advanced the State’s interest in highway safety to a degree that statistical evidence of “success of apprehension” is not necessary to uphold it.

We do not foreclose the possibility that other roadblocks — because of their location or manner of operation — could fail to promote the public interest. However, because “a claim that a particular exercise of discretion in locating or operating a checkpoint is unreasonable is subject to post-stop judicial review,” Martinez-Fuerte, 428 U.S. at 559, 96 S.Ct. at 3083-84, we deem it appropriate for the defendant to establish that the particular roadblock at which he was detained did not sufficiently advance society’s legitimate interest in apprehending drunk drivers, rather than to attack the efficacy of sobriety checkpoints per se.

The third factor in the balancing test requires us to examine the severity of the intrusion on individual rights caused by a roadblock stop. On this point, the Supreme Court has found that checkpoint operations present a “lesser intrusion upon [a] motorist’s Fourth Amendment interests” than random, roving-patrol stops. Delaware v. Prouse, 440 U.S. at 656, 99 S.Ct. at 1397.

“[The] objective intrusion — the stop itself, the questioning, and the visual inspection — also existed in roving-patrol stops. But we view checkpoint stops in a different light because the subjective intrusion — the generating of concern or even fright on the part of lawful travelers — is appreciably less in the case of a checkpoint stop.” Id. (quoting Martinez-Fuerte, 428 U.S. at 558, 96 S.Ct. at 3083).

“At traffic checkpoints the motorist can see that other vehicles are being stopped, he can see visible signs of the officers’ authority, and he is much less likely to be frightened or annoyed by the intrusion.” United States v. Ortiz, 422 U.S. 891, 894-*29695, 95 S.Ct. 2585, 2587-88, 45 L.Ed.2d 623 (1975) (quoted in Delaware v. Prouse, 440 U.S. at 658, 99 S.Ct. at 1398).

Following this logic, many courts have held that the manner of operation and the physical characteristics of a roadblock affect the intrusiveness of a checkpoint stop. See generally Note, 71 Geo.L.J. at 1475-79. Many jurisdictions have adopted the thirteen-factor analysis set out in State v. Deskins, 673 P.2d at 1185:

“Numerous conditions and factors must be considered in determining whether a DUI roadblock meets the balancing test in favor of the state. Among the factors which should be considered are: (1) The degree of discretion, if any, left to the officer in the field; (2) the location designated for the roadblock; (3) the time and duration of the roadblock; (4) standards set by superior officers; (5) advance notice to the public at large; (6) advance warning to the individual approaching motorist; (7) maintenance of safety conditions; (8) degree of fear or anxiety generated by the mode of operation; (9) average length of time each motorist is detained; (10) physical factors surrounding the location, type and method of operation; (11) the availability of less intrusive methods for combating the problem; (12) the degree of effectiveness of the procedure; and (13) any other relevant circumstances which might bear upon the test.”

See, e.g., State v. Jones, 483 So.2d at 439 (“we follow many of our sister states in adopting the bulk of the Deskins criteria”).

While the operation of a roadblock undoubtedly bears on its reasonableness, reliance on the purely mechanical aspects of roadblock operation can lead to results which appear to elevate form over substance. For example, some courts have found roadblock stops invalid because, among other things, safety devices such as “flares, flashing lights or signs” were not used. See, e.g., Jones v. State, 459 So.2d 1068, 1079 (Fla.Dist.Ct.App.1984). Other courts have upheld roadblocks in part because safety measures such as approach signs and traffic cones were employed, see, e.g., State v. Superior Court In and For Pima County, 143 Ariz. 45, 691 P.2d 1073, 1076 (1984).

While such considerations are not totally irrelevant to the reasonableness of a roadblock, neither are they pivotal to its constitutionality. As the Supreme Court observed in Martinez-Fuerte, “Many incidents of checkpoint operation ... must be committed to the discretion of [law enforcement] officials.” 428 U.S. at 560 n. 13, 96 S.Ct. at 3084 n. 13.

In our judgment, roadblocks operated pursuant to an objective and neutral plan of briefly halting all oncoming traffic are only minimally intrusive to the individual motorist and are thus constitutionally reasonable seizures. The primary reason that the random stops in Brignoni-Ponce and Prouse were condemned, while the checkpoint operations in Martinez-Fuerte and Texas v. Brown were approved, had little to do with the relatively minor mechanical operation of either kind of seizure. The approved stops were upheld because they were conducted pursuant to an “objective standard,” Delaware v. Prouse, 440 U.S. at 661, 99 S.Ct. at 1400, and because they “both appeared] to and actually involve^] less discretionary enforcement activity,” Martinez-Fuerte, 428 U.S. at 559, 96 S.Ct. at 3083. The condemned stops were invalidated because they involved the “standardless and unconstrained discretion” of officers in the field, Delaware v. Prouse, 440 U.S. at 661, 99 S.Ct. at 1400.

Factors (1) and (4) of the Deskins criteria (uniform standards set by law enforcement agencies rather than by officers in the field) are based on the following observation by the Court in Martinez-Fuerte:

“The location of a fixed checkpoint is not chosen by officers in the field, but by officials responsible for making overall decisions as to the most effective allocation of limited enforcement resources. We may assume that such officials will be unlikely to locate a checkpoint where it bears arbitrarily or oppressively on motorists as a class.” 428 U.S. at 559, 96 S.Ct. at 3083.

*297It is true in this case that the site, time, and duration of the roadblock were chosen by “officers in the field.” Based on this factor alone, some courts might hold this roadblock unconstitutional. See, e.g. State v. Olgaard, 248 N.W.2d 392 (S.D.1976) (wherein the court held that because there were no limits on police discretion in selecting the roadblock location, a warrant was required for the operation of the roadblock).

While we join the Supreme Court of Kansas in observing that “[i]t might be advisable that minimum uniform standards for the operation of vehicular roadblocks be adopted and established by [the Department of Public Safety], the legislature or attorney general, rather than leave the determination thereof to local officials,” State v. Deskins, 234 Kan. at 543, 673 P.2d at 1185-86, we do not believe that the field officers’ decision to establish this roadblock makes it unconstitutional. First, we note that in Delaware v. Prouse the Court did not insist on a total absence of discretion by officers in the field. Instead, it “insisted that the discretion of the official in the field be circumscribed, at least to some extent” 440 U.S. at 661, 99 S.Ct. at 1400 (emphasis added). Here the field officers’ discretion was circumscribed by the approval they sought and received from their supervisor in setting up the roadblock and by his later presence at the site to “check on” the roadblock. More importantly, however, their discretion was limited by the neutral and objective criteria they employed in conducting the roadblock: every vehicle in both lanes of traffic was stopped and the driver was asked to show his license and was then waved on after a few seconds’ opportunity for observation.

In United States v. Prichard, 645 F.2d 854 (10th Cir.), cert. denied, 454 U.S. 832, 102 S.Ct. 130, 70 L.Ed.2d 110 (1981), the Circuit Court of Appeals upheld a roadblock stop established by officers in the field with the permission of the officers’ supervisor. All westbound vehicles except semi-trucks were halted until traffic began to back up, at which time cars were waved through the roadblock until traffic cleared. The Court held the following:

“In our view, the roadblock stop of the Ford Bronco does not run afoul of the rule of Prouse. While this may not have been a ‘100% roadblock’ of the type referred to in Prouse, it is nonetheless a long way from the selective, single car stop denounced in Prouse. In the instant case, the New Mexico state police were attempting to stop all westbound traffic on an interstate highway, insofar as was humanly possible. The decision not to stop trucks was reasonable under the circumstances, because, presumably, they had all been stopped at a port of entry. The purpose of the roadblock, i.e., to check drivers’ license and car registrations, was a legitimate one. If, in the process of so doing, the officers saw evidence of other crimes, they had the right to take reasonable investigative steps and were not required to close their eyes. See United States v. Merryman, 630 F.2d 780, 782-85 (10th Cir.1980). Furthermore, allowing all the stopped cars through when traffic became congested was also reasonable and, in our view, nonviolative of the rule of Prouse. In sum, the roadblock stop of the Ford Bronco was, under the described circumstances, constitutional.” 645 F.2d at 856-57.

In State v. Cloukey, 486 A.2d 143 (Me.1985), the accused argued that a roadblock was unreasonable because it was conducted without a written policy or the involvement of law enforcement supervisory personnel and was, therefore, subject to being used as a “pretext” stop. The Maine court observed:

“We are fully cognizant of the fact that a license checkpoint can be used as a subterfuge. Those state courts that have emphasized the importance of the involvement of supervisory personnel in planning a roadblock undoubtedly had that in mind. Although we recognize it is preferable, we are not persuaded that a written policy and supervision are essential. Subterfuge can occur even in the presence of such factors. The [court] below found that the purpose of the roadblock was as stated by the offi*298cers. The facts and circumstances are highly corroborative of that finding.” 486 A.2d at 147.

In the case, before us, testimony that the officers set up the roadblock in an area where they had been having “problems” is likewise corroborated by the facts that the sobriety checkpoint was established on a well-travelled route north of the beach at the end of a spring weekend, a time and place at which it is likely that drunk drivers would be found.

Thus, although we are aware that officers could abuse their discretion in setting up a roadblock, see State v. Swift, 232 Ga. 535, 207 S.E.2d 459 (1974) (license and registration roadblock at the entrance to a rock festival), we do not believe that this roadblock was characterized by such abuse or was established as a pretext or subterfuge. Moreover, as we have previously observed, “a claim that a particular exercise of discretion in locating or operating a checkpoint is unreasonable is subject to post-stop judicial review,” Martinez-Fuerte, 428 U.S. at 559, 96 S.Ct. at 3083-84, and does not provide a blanket reason for invalidating all roadblocks conceived of by officers in the field.

Having determined that the roadblock at issue here was reasonable under the balancing tests set out by the Supreme Court in Martinez-Fuerte, Delaware v. Prouse, and Texas v. Brown, we hold that Trooper McGlothlin had reasonable suspicion, based on his initial observation of the defendant, to divert the defendant from the line of traffic for further inquiry as to his sobriety. Then, upon the defendant’s failure to pass the field sobriety test, the officer had probable cause to arrest him for DUI and transport him to police headquarters for a blood alcohol test.

Recently, in Buckner v. City of Huntsville, 549 So.2d 451 (Ala.1989), the Alabama Supreme Court held that in a prosecution for driving under the influence of alcohol pursuant to § 32-5A-191(a)(2), where no blood alcohol test is given, the State has the burden of proving that the defendant was under the influence “to the extent that it affected his abib'ty to operate his vehicle in a safe manner.” Buckner does not apply in this case. Here, the defendant was given a test which showed that he had a blood alcohol content of .20%, and the State relied on the statutory presumption contained in § 32-5A-194(b)(3) as proof that he was “under the influence.” Buckner’s holding that the State must prove impaired driving ability to establish that the accused was “under the influence” applies only when the accused was charged under Section 32-5A-191(a)(2).

II

The defendant claims that the State did not establish a proper predicate prior to the introduction of the results of his Intoxilyzer 5000 test. A proper predicate for the admissibility of blood alcohol test results may be established by showing:

“[FJirst, that the law enforcement agency has adopted the particular form of testing that was in fact used_ Second, there must be a showing that the test was performed according to methods approved by the State Board of Health. This may be proved by the introduction of the rules and regulations the officer followed while administering the test and the officer’s testimony that he did, in fact, follow those rules when he administered the test in question.... Third, there must be a showing that the person administering the test has a valid permit issued by the State Board of Health for that purpose.” Bush v. City of Troy, 474 So.2d 168, 170 (Ala.1985).

The testimony of Trooper McGlothlin established the foregoing elements of the Bush predicate. The defendant objected to the introduction of the test results on the grounds of “failure to lay a proper predicate,” without specifying in what respect he claimed the predicate was deficient.

“[Wjhere a predicate is required for the admission of particular testimony and ‘where a predicate has in fact been laid,’ *299an objection that a proper or a sufficient predicate has not been laid is a ‘general objection merely, and will not be referred to any specific objection which could have been obviated if pointed out at the time.’ Southern Railway Company v. Dickson, 211 Ala. 481, 487, 488, 100 So. 665, 671 (1924).” Suarez v. State, 369 So.2d 858, 862 (Ala.Cr.App.), cert. denied, Ex parte Suarez, 369 So.2d 863 (Ala.1979).

The judgment of the circuit court is affirmed.

AFFIRMED.

All Judges concur.

PER CURIAM.

On March 13, 2002, a Mobile County jury convicted Hayden Jerome Jackson of first-degree unlawful possession of marijuana, a violation of Ala.Code 1975, § 13A-12-213(a)(1).1 The trial court sentenced him, as a habitual offender, to 15 years in prison. Ala.Code 1975, § 13A-5-9(b)(l). It then split the sentence and ordered him to serve three years; the balance of the sentence was suspended and he was placed on supervised probation for five years. The trial court also imposed a $2,000 fine pursuant to the Demand Reduction Assessment Act, § 13A-12-280 et seq., Ala. Code 1975. The Court of Criminal Appeals affirmed Jackson’s conviction and sentence without an opinion. Jackson v. State, 886 So.2d 153 (Ala.Crim.App.2003). Jackson petitioned this Court for certiorari review. We granted the petition to review whether the roadblock-type stop conducted by the Mobile County Sheriffs Department, which resulted in Jackson’s arrest, *158was a valid stop or an invalid seizure that violated the Fourth Amendment. We hold that the roadblock-type stop was a valid stop that did not violate the United States Constitution, and we affirm.

Facts

The Mobile Housing Authority entered into a contract with the Mobile County Sheriffs Department pursuant to which the sheriffs department is permitted to enter housing areas governed by the housing authority at the request of the housing authority and performs such policing activities as rolling patrols, foot patrols, community policing, and safety checkpoints to establish some sort of “police presence.” Pursuant to that contract, the Mobile County Sheriffs Department entered the R..V. Taylor housing project in Mobile on the evening of May 10, 2001, to set up what they called a “safety checkpoint” at a major intersection in the housing community. The housing authority had made no particular request for a roadblock-type stop in this instance; a captain in the sheriffs department made the decision to set up the roadblock-type stop. The officers checked driver’s licenses, automobile insurance documentation, and vehicle “safety devices,” e.g., seat belts, child restraints, etc., at the roadblock-type stop. They put in place seven marked sheriffs department vehicles at the intersection and stopped every vehicle that came through the intersection. They followed guidelines established by the sheriffs department while conducting the roadblock-type stop; those guidelines required that they perform no random searches and that the officers’ activities be supervised by superior officers in the sheriffs department.

An officer stopped Jackson’s vehicle at the roadblock. The officer discovered marijuana and two rolls of cash on Jackson’s person; a larger quantity of marijuana in the console between the driver’s seat and the passenger’s seat; hidden under the tire cover in the trunk of Jackson’s vehicle was an “Old Navy” store shopping bag that contained more marijuana, scales, and numerous plastic sandwich bags.

At trial, Jackson filed a motion to suppress the marijuana found on his person and in his vehicle on the basis that the roadblock-type stop was an unreasonable seizure that violated the Fourth Amendment to the United States Constitution.2 After his conviction for first-degree unlawful possession of marijuana, Jackson filed a motion for a new trial, which the trial court denied. The trial court sentenced Jackson, as a habitual offender, to 15 years in prison; that sentence was split, and Jackson was ordered to serve 3 years in prison and 5 years’ supervised probation. In his appeal to the Alabama Court of Criminal Appeals, Jackson argued that the trial court erred on the basis that the roadblock-style stop was an unreasonable seizure that violated the Fourth Amendment to the United States Constitution. *159The Alabama Court of Criminal Appeals affirmed without an opinion. We affirm.

Standard of Revieio

The trial court held the suppression hearing outside the hearing of the jury; therefore, we review the evidentiary findings of the trial court at that hearing under the ore tenus standard.

“ ‘Where evidence is presented to the trial court ore tenus in a nonjury case, a presumption of correctness exists as to the court’s conclusions on issues of fact; its determination will not be disturbed unless clearly erroneous, without supporting evidence, manifestly unjust, or against the great weight of the evidence. Odom v. Hull, 658 So.2d 442 (Ala.1995). However, when the trial court improperly applies the law to the facts, no presumption of correctness exists as to the court’s judgment. Ex parte Board of Zoning Adjustment of the City of Mobile, 636 So.2d 415 (Ala.1994).’

“[Ex parte Agee,] 669 So.2d [102,] at 104 [(Ala.1995)]. ‘Where the evidence before the trial court was undisputed the ore tenus rule is inapplicable, and the Supreme Court will sit in judgment on the evidence de novo, indulging no presumption in favor of the trial court’s application of the law to those facts.’ Stiles v. Brown, 380 So.2d 792, 794 (Ala.1980) (citations omitted).”

State v. Hill, 690 So.2d 1201, 1203 (Ala.1996).

Jackson contends that the trial court, in determining not to grant his motion to suppress, misapplied the law to the facts, which were undisputed; therefore, we review de novo the trial court’s decision to not suppress the evidence. However, Jackson also contends that the evidence, specifically an officer’s testimony with regard to both the purpose of the roadblock-type stop and the contract between the housing authority and the Mobile County Sheriffs Department, proves that the officers’ intent was to use the roadblock-type stop not just to check driver’s licenses and safety devices but to perform a general law-enforcement roadblock-type stop, thus making the stop an unreasonable seizure under the Fourth Amendment. The State contended, and the trial court agreed, that the roadblock-type stop was conducted solely to check driver’s licenses and safety devices.

Analysis

Jackson contends that the Alabama Court of Criminal Appeals’ unpublished memorandum conflicts with its decisions in Hagood v. Town of Town Creek, 628 So.2d 1057 (Ala.Crim.App.1993), and Cains v. State, 555 So.2d 290 (Ala.Crim.App.1989). In Jackson’s case, the Court of Criminal Appeals found in its unpublished memorandum that.the roadblock-type stop was valid because

“its primary purpose was to check for driver’s licenses and safety equipment; that purpose could reasonably be advanced by a roadblock; the officers conducted the roadblock pursuant to department guidelines that allowed for very little discretion on the part of the officers conducting the roadblock; the roadblock was set up at a four-way stop in a highly visible area; there were seven marked vehicles parked around that location; and a typical stop lasted approximately one minute.”

Based on that finding, the Court of Criminal Appeals concluded that the stop was reasonable and valid, and it affirmed the trial court’s judgment. Jackson argues that the roadblock failed the “purpose” prong for determining whether such a stop is constitutional.

The United States Supreme Court has established criteria for deter*160mining whether a roadblock-type stop is constitutional. “The Fourth Amendment imposes limits on search-and-seizure powers in order to prevent arbitrary and oppressive interference by enforcement officials with the privacy and personal security of individuals.” United States v. Martinez-Fuerte, 428 U.S. 543, 554, 96 S.Ct. 3074, 49 L.Ed.2d 1116 (1976). In circumstances like the seizure here, courts must “weight] the public interest against the Fourth Amendment interest of the individual.” 428 U.S. at 554, 96 S.Ct. 3074. “[S]ome quantum of individualized suspicion is usually a prerequisite to a constitutional search or seizure.” 428 U.S. at 560, 96 S.Ct. 3074. A suspi-cionless roadblock-type stop is a seizure.

“[S]topping an automobile and detaining its occupants constitute a ‘seizure’ within the meaning of [the Fourth and Fourteenth] Amendments, even though the purpose of the stop is limited and the resulting detention quite brief.”

Delaware v. Prouse, 440 U.S. 648, 653, 99 S.Ct. 1391, 59 L.Ed.2d 660 (1979).

However, the Supreme Court has made an exception to the suspicion requirement with respect to the routine roadblock-type stop:

“The [routine roadblock-type] stop does intrude to a limited extent on motorists’ right to ‘free passage without interruption,’ Carroll v. United States, 267 U.S. 132, 154 (1925), and arguably on their right to personal security. But it involves only a brief detention of travelers during which

“ ‘ “[a]ll that is required of the vehicle’s occupants is a response to a brief question or two and possibly the production of a document....” ’ United States v. Brignoni-Ponce, [422 U.S. 873], at 880 [(1975)].”

Martinez-Fuerte, 428 U.S. at 557-58, 96 S.Ct. 3074. The Court reasoned:

“[T]his objective intrusion — the stop itself, the questioning, and the visual inspection — also existed in roving-patrol stops. But we view checkpoint stops in a different light because the subjective intrusion — the generating of concern or even fright on the part of lawful travelers — is appreciably less in the case of a checkpoint stop. In [United States v. Ortiz, [422 U.S. 891 (1975),] we noted:

“ ‘[T]he circumstances surrounding a checkpoint stop and search are far less intrusive than those attending a roving-patrol stop. Roving patrols often operate at night on seldom-traveled roads, and their approach may frighten motorists. At traffic checkpoints the motorist can see that other vehicles are being stopped, he can see visible signs of the officers’ authority, and he is much less likely to be frightened or annoyed by the intrusion.’ 422 U.S., at 894-895[, 95 S.Ct. 2585].”

428 U.S. at 558, 96 S.Ct. 3074 (emphasis added).

In Delaware v. Prouse, supra, the Supreme Court conditioned such stops of automobiles on the existence of an objective standard to check the arbitrary discretion of the officer in the field:

“[T]he reasonableness standard usually requires, at a minimum, that the facts upon which an intrusion is based be capable of measurement against ‘an objective standard,’ whether this be probable cause or a less stringent test. In those situations in which the balance of interests precludes insistence upon ‘some quantum of individualized suspicion,’ other safeguards are generally relied upon to assure that the individual’s reasonable expectation of privacy is not ‘subject to the discretion of the official in *161the field,’ Camara v. Municipal Court, 387 U.S. [523], at 532 [(1967)]

440 U.S. at 654-55, 99 S.Ct. 1391 (footnotes omitted). In Prouse a police officer conducting a “roving-patrol stop” stopped a ear at random to check the driver’s license and the vehicle registration, without suspecting any improper driving on the driver’s part. The United States Supreme Court determined that, unless the police officer has “at least articulable and reasonable suspicion that a motorist is unlicensed or that an automobile is not registered,” such stops are unreasonable under the Fourth Amendment. 440 U.S. at 663, 99 S.Ct. 1391. However, that Court also said:

“This holding does not preclude the State of Delaware or other States from developing methods for spot checks that involve less intrusion or that do not involve the unconstrained exercise of discretion. Questioning of all oncoming traffic at roadblock-type stops is one possible alternative. We hold only that persons in automobiles on public roadways may not for that reason alone have their travel and privacy interfered with at the unbridled discretion of police officers.”

440 U.S. at 663, 99 S.Ct. 1391 (footnote omitted; emphasis added). Therefore, the Supreme Court has distinguished between the “roving-patrol stop” and the roadblock-type stop, holding that under certain conditions the latter can be reasonable and, therefore, not unconstitutional.

In Brown v. Texas, 443 U.S. 47, 99 S.Ct. 2637, 61 L.Ed.2d 357 (1979), the Supreme Court created a three-prong balancing test for determining whether a seizure is considered reasonable. In that case, the question was whether the officers’ detention of a pedestrian, who, in violation of a Texas statute, refused to identify himself, was an unreasonable “seizure.”

“Consideration of the constitutionality of such seizures involves a weighing of [1] the gravity of the public concerns served by the seizure, [2] the degree to which the seizure advances the public interest, and [3] the severity of the interference with individual liberty.”

443 U.S. at 50-51, 99 S.Ct. 2637. In Michigan Department of State Police v. Sitz, 496 U.S. 444, 448-49, 110 S.Ct. 2481, 110 L.Ed.2d 412 (1990), the Supreme Court extended the application of' these three conditions beyond the traditional arrest situation to roadblock-type stops, specifically to “sobriety checkpoints.” The United States Supreme Court has explicitly upheld roadblock-type stops against constitutional challenges in four situations— stops gathering information concerning a recent crime in the area when the questions asked during the stop did not seek self-incriminating information; stops checking driver’s licenses; drivers’ sobriety; and the presence of illegal aliens. See Illinois v. Lidster, 540 U.S. 419, 124 S.Ct. 885, 157 L.Ed.2d 843 (2004); Texas v. Brown, 460 U.S. 730, 103 S.Ct. 1535, 75 L.Ed.2d 502 (1983); Sitz, supra; and Martinez-Fuerte, supra. The Alabama Court of Criminal Appeals ably summarized the United States Supreme Court precedent as to this issue in Cains v. State, 555 So.2d 290 (1989):

“Generally, a seizure less intrusive than a traditional arrest is reasonable if based on individualized suspicion, gathered from specific and articulate facts, that the individual is, or is about to be, engaged in criminal activity, Terry v. Ohio [, 392 U.S. 1 (1968)]; see also United States v. Cortez, 449 U.S. 411, 417, 101 S.Ct. 690, 694, 66 L.Ed.2d 621 (1981), or if the seizure is ‘carried out pursuant to a plan embodying explicit, neutral limitations on the conduct of individual officers,’ Brown v. Texas, 443 *162U.S. 47, 51, 99 S.Ct. 2637, 2640, 61 L.Ed.2d 357 (1979).

“The nature of a roadblock requires the stopping of cars without individualized suspicion of wrongdoing. Thus, if a roadblock stop is to be upheld, it must be on the second basis, ie., because it is ‘carried out pursuant to a plan embodying explicit, neutral limitations on the conduct of individual officers.’ In a series of decisions stemming from the immigration control cases, the United States Supreme Court has rejected the individualized suspicion requirement for fixed, non-random automobile checkpoints or roadblock stops, and instead has established some criteria for ‘a plan embodying explicit, neutral limitations on the conduct of individual officers.’

“Four years [after the Supreme Court’s decision in Delaware v. Prouse, 440 U.S. 648 (1979)], the Court specifically approved drivers’ license checkpoints in Texas v. Brown, 460 U.S. 730, 103 S.Ct. 1535, 75 L.Ed.2d 502 (1983)....

“When read together, [United States v.] Brignoni-Ponce[, 422 U.S. 873 (1975)], [United States v.] Martinez-Fuerte[, 428 U.S. 543 (1976)], Prouse, and Texas v. Brownl, 460 U.S. 730 (1983),] stand for the proposition that random stops or spot checks are unreasonable in the absence of individualized suspicion of wrongdoing; on the other hand, stops at fixed checkpoints or roadblocks are reasonable if they are carried out pursuant to a neutral and objective plan, are supported by a strong public interest, and are only minimally intrusive to the individual motorist.”

555 So.2d at 292-93 (emphasis added).

The United States Supreme Court has held that driver’s license checkpoints satisfy the first factor' — 'that “the gravity of the public concerns served by the seizure” outweigh the Fourth Amendment interest of individuals. See Brown v. Texas, 443 U.S. at 51, 99 S.Ct. 2637; Texas v. Brown, supra. As for the second factor' — “the degree to which the seizure advances the public interest” — there is no question that the public has an interest in making sure that drivers of vehicles are properly licensed and that the vehicles they are driving are registered and equipped with safety devices. The Court of Criminal Appeals stated in Hagood:

“ ‘The states’ interest in enforcing its registration and licensing laws and the difficulty in enforcing the laws by any other method’ ... [has] been held sufficient to outweigh a minor intrusion upon persons stopped at roadblocks conducted for [that] purposeQ.”

628 So.2d at 1060. Because the United States Supreme Court in Texas v. Brown, supra, has specifically upheld driver’s license checkpoints as advancing the public interest, thus satisfying the second factor, we must ensure that in Jackson’s case the State satisfied the third factor.

To analyze the third factor — “the severity of the interference with individual liberty” — we must determine whether the officers conducted the roadblock-type stop in a neutral and objective manner. As the Court of Criminal Appeals stated in Cains: “[S]tops [of vehicles] at fixed checkpoints or roadblocks are reasonable if they are carried out pursuant to a neutral and objective plan, are supported by a strong public interest, and are only minimally intrusive to the individual motorist.” 555 So.2d at 293. We must determine if the *163stop in Jackson’s case was “minimally intrusive to the individual motorist.” The Court of Criminal Appeals stated in Cains that “the manner of operation and the physical characteristics of a roadblock,” 555 So.2d at 296, affect the intrusiveness of the stop. The Court of Criminal Appeals then quoted a 13-factor analysis adopted by the Kansas Supreme Court:

“ ‘(1) The degree of discretion, if any, left to the officer in the field; (2) the location designated for the roadblock; (3) the time and duration of the roadblock; (4) standards set by superior officers; (5) advance notice to the public at large; (6) advance warning to the individual approaching motorist; (7) maintenance of safety conditions; (8) degree of fear or anxiety generated by the mode of operation; (9) average length of time each motorist is detained; (10) physical factors surrounding the location, type and method of operation; (11) the availability of less intrusive methods for combating the problem; (12) the degree of effectiveness of the procedure; and (13) any other relevant circumstances which might bear upon the test.’ ”

555 So.2d at 296 (quoting State v. Deskins, 234 Kan. 529, 541, 673 P.2d 1174, 1185 (1983)). We agree with the Court of Criminal Appeals that we should not exalt form over substance and that some of the 13 factors outlined above are not pivotal to determining whether a particular roadblock-type stop is “minimally intrusive.” However, those factors are helpful considerations to take into account when determining whether the officers conducted the stop pursuant to an “objective standard.”

We also agree with the Court of Criminal Appeals that because a roadblock-type stop to examine driver’s licenses is warrantless and not based on an “articulable and reasonable suspicion that a motorist is unlicensed or that an automobile is not registered,” Prouse, 440 U.S. at 663, 99 S.Ct. 1391, the State has the burden of proving that it was reasonable under the Fourth Amendment. Hagood, 628 So.2d at 1062.

In the case of the stop and seizure of Jackson, Sgt. Frank Cassidy authorized the “safety checkpoint” to be conducted on the evening of May 10, 2001, in a heavily traveled area in the R.V. Taylor Housing Project; the roadblock-type stop was to be conducted in accordance with guidelines for such stops established by the Mobile County Sheriffs Department. For example, in compliance with the guidelines, the officers checked the driver of every vehicle for a driver’s license, proof of automobile liability insurance, and safety equipment; there were no random checks. Therefore, the officers in the field had no discretion in deciding whom to stop. Each stop lasted approximately one minute, unless the officers found problems with the paperwork or safety equipment. “Superior officers” were involved in the planning, placement, and timing of the roadblock; Cpt. Crosby, of the criminal section of the sheriffs department, had instructed Sgt. Cassidy to set up the stop at the R.V. Taylor Housing Project. The contract between the housing authority and the sheriffs department mentions “safety checkpoints,” but it does hot instruct the sheriffs department as to how to set up such checkpoints.

Based on the facts presented at the suppression hearing, the trial court did not err in determining that the roadblock-type stop was a valid and constitutional means of protecting the public from unlicensed drivers and unsafe vehicles. The officers’ discretion was limited by the guidelines established by the sheriffs department for conducting such stops, thereby creating a neutral and objective plan, which limited the officers’ discretion. A “superior” officer was involved in planning and authoriz*164ing the stop. The intrusion upon the drivers was minimal because it involved only checking to determine whether the driver had the paperwork drivers are required to carry in their vehicles, and the stops lasted only about one minute. There was no evidence to indicate what safety precautions the officers took; however, that is not a controlling factor. The presence of seven marked law-enforcement vehicles gave adequate warning to oncoming drivers that the stop was authorized and organized by law-enforcement personnel.

Jackson essentially alleges that the roadblock-type stop was unconstitutional because, he argues, it was in reality a subterfuge for a general law-enforcement-type checkpoint. If a trial court determines that the roadblock-type stop is valid, the burden is on the defendant to prove that the expressed reason for the stop is a subterfuge and that the stop was actually conducted for an invalid purpose.

Jackson focuses on the testimony of Sgt. Cassidy and the contract between the housing authority and the Mobile County Sheriffs Department to support his claim. He quotes the following excerpts from the trial transcript:

“Q. All right. So your testimony is the Mobile Housing [Authority] was concerned about the traffic violations in the projects and wanted you guys to go in and check on people’s driver’s licenses? “A. Housing projects — housing board authorities did not specify what they wanted us to do. We were asked to put a presence inside R.V. Taylor and we arrived. I took a six-man unit into R.V. Taylor.

“Q. Is there anything in writing from the Housing [Authority] that you received showing what type of presence you were supposed to be doing?

“A. We have a contract with them that specifies that we will go into an area that they govern at their request. It states that we will do rolling patrol, foot patrol, community policing, safety checkpoints.

“Q. And it’s your testimony that the Housing [Authority] has given a contract with the Sheriffs Department to check the safety equipment?

“A. That’s not what I said. The Housing [Authority] has a contract with the Sheriffs Department to put units patrolling inside different housing projects at dates at their request. They did not ask us specifically to check for safety equipment. They asked for us to provide patrol unit in the presence in there [sic].

“Q. And the Housing [Authority] was — I guess you said they have some kind of contract with the County Sheriffs Department where they want you to come in and check for problems they have?

“A. They come in and ask us to make a presence and then patrol the area, yes, sir.

“Q. Okay. To prevent crime from happening?

“A. I don’t know. That’s not stated in there. I was just told to go in and put in a presence into R.V. Taylor.

“Q. Why do you think they would want a presence of law enforcement officers?

“A. I would assume that crime determent [sic] — deterrence would be one.

“Q. Okay.

“A. R.V. Taylor is used as a crossover street between Michigan Avenue and stuff. There’s a lot of pedestrians. I would think the traffic would be a severe problem there. We have a lot of people *165that speed. A lot of people use it as a cut-through. We have a lot of people on bicycles and stuff, so I would think traffic, crime deterrent.

“Q. So they wanted y’all to enforce the traffic laws on Michigan Avenue for pedestrians?

“A. You asked me what I thought they would want us for, and I would think traffic control, deter crime, or any type of crime, just a high presence.”

Jackson argues that this testimony, considered in conjunction with the contract between the housing authority and the sheriffs department, which uses the words police “presence,” indicates that the primary purpose of the safety checkpoint in this case was general law enforcement, a purpose that invalidates a “checkpoint stop.” “The Supreme Court has never upheld ... a police roadblock designed to promote general law enforcement purposes.” Galberth v. United States, 590 A.2d 990, 998 (D.C.Ct.App.1991). He analogizes his case to Hagood, supra, in which the Alabama Court of Criminal Appeals determined that, based on the testimony of the chief of police that he had ordered the driver’s license checkpoint because of “ ‘trouble’ — ‘fighting, [public] drunkenness] and disorderly [conduct]’ — at the Town Creek Apartments,” 628 So.2d at 1060, the checkpoint was for the purpose of “preventing criminal activity in general.” 628 So.2d at 1060. The Court of Criminal Appeals stated that “this general interest in law enforcement simply does not outweigh the liberty interests of those seized,” 628 So.2d at 1060, and that the “goal of preventing ‘trouble’ in the Town Creek Apartments could have been accomplished without intruding on the liberty rights of individual motorists simply by stationing a police officer in the parking lot of the apartments.” 628 So.2d at 1061. The Court of Criminal Appeals, therefore, held that the roadblock-type stop in Town Creek was an unconstitutional seizure.

There were other problems with the Ha-good checkpoint. When the officers waited “a couple of hours” at one location and found no traffic, 628 So.2d at 1058, they moved to another location. Two of the four officers testified that the “roadblocks were conducted upon the ‘mutual agreement’ of the four officers.” 628 So.2d at 1058. There were no formal guidelines, very few safety precautions at the location of the stop, and the officers had not been trained in how to conduct the stops. Therefore, in Hagood the evidence supporting the existence of an “objective and neutral plan” was lacking.

We have a very different situation in this case. Other than the inferential suspicion based on the word “presence” in Sgt. Cassidy’s testimony and the contract between the sheriffs department and the housing authority,3 Jackson presented no evidence to prove that this particular roadblock-type stop was for a general law-enforcement purpose. Therefore, we hold that Jackson has not sufficiently proven that the license checkpoint was a subterfuge for a general law-enforcement “checkpoint stop.”

Conclusion

We adopt the rationale used by the Alabama Court of Criminal Appeals in Cains, supra, for determining whether a roadblock-type stop is constitutional. Jackson has failed to show that the stop by the Mobile County Sheriffs Department in his case was for an invalid purpose, i.e., general law enforcement, as was the license checkpoint in Hagood, supra. Therefore, we affirm the judgment of the Court of Criminal Appeals.

AFFIRMED.

*166HOUSTON, SEE, BROWN, HARWOOD,* WOODALL, and STUART, JJ., concur.

LYONS, J., concurs specially.

JOHNSTONE, J., dissents.

LYONS, Justice

(concurring specially).

I concur in the main -opinion. I write specially to state that I am not persuaded that Jackson overcame the presumption of correctness that attaches to the trial court’s finding based on-ore tenus evidence that the roadblock-type stop conducted to check driver’s licenses was not a -subterfuge for a stop conducted for general law-enforcement purposes.

*650Mr. Justice White

delivered the opinion of the Court.

The question is whether it is an unreasonable seizure under the Fourth and Fourteenth Amendments to stop an automobile, being driven on a public highway, for the purpose of checking the driving license of the operator and the registration of the car, where there is neither probable cause to believe nor reasonable suspicion that the car is being driven contrary to the laws governing the operation of motor vehicles or that either the car or any of its occupants is subject to seizure or detention in connection with the violation of any other applicable law.

I

At 7:20 p. m. on November 30, 1976, a New Castle County, Del., patrolman in a police cruiser stopped the automobile occupied by respondent.1 The patrolman smelled marihuana smoke as he was walking toward the stopped vehicle, and he seized marihuana in plain view on the car floor. Respondent was subsequently indicted for illegal possession of a controlled substance. At a hearing on respondent's motion to suppress the marihuana seized as a result of the stop, the patrolman testified that prior to stopping the vehicle he had observed neither traffic or equipment violations nor any suspicious activity, and that he made the stop only in order to check the driver’s license and registration. The patrolman was not acting pursuant to any standards, guidelines, or procedures pertaining to document spot checks, promulgated by either his department or the State Attorney General. Characterizing the stop as “routine,” the patrolman explained, “I saw the car *651in the area and wasn’t answering any complaints, so I decided to pull them off.” App. A9. The trial court granted the motion to suppress, finding the stop and detention to have been wholly capricious and therefore violative of the Fourth Amendment.

The Delaware Supreme Court affirmed, noting first that “[t]he issue of the legal validity of systematic, roadblock-type stops of a number of vehicles for license and vehicle registration check is not now before the Court,” 382 A. 2d 1359, 1362 (1978) (emphasis in original). The court held that “a random stop of a motorist in the absence of specific articulable facts which justify the stop by indicating a reasonable suspicion that a violation of the law has occurred is constitutionally impermissible and violative of the Fourth and Fourteenth Amendments to the United States Constitution.” Id., at 1364. We granted certiorari to resolve the conflict between this decision, which is in accord with decisions in five other jurisdictions,2 and the contrary determination in six jurisdictions3 that the Fourth Amendment does not prohibit the kind of automobile stop that occurred here. 439 U. S. 816 (1978).

II

Because the Delaware Supreme Court held that the stop at issue not only violated the Federal Constitution but also *652was impermissible under Art. I, § 6, of the Delaware Constitution, it is urged that the judgment below was based on an independent and adequate state ground and that we therefore have no jurisdiction in this case. Fox Film Corp. v. Muller, 296 U. S. 207, 210 (1935). At least, it is suggested, the matter is sufficiently uncertain that we should remand for clarification as to the ground upon which the judgment rested. California v. Krivda, 409 U. S. 33, 35 (1972). Based on our reading of the opinion, however, we are satisfied that even if the State Constitution would have provided an adequate basis for the judgment, the Delaware Supreme Court did not intend to rest its decision independently on the State Constitution and that we have jurisdiction of this case.

As we understand the opinion below, Art I, § 6, of the Delaware Constitution will automatically be interpreted at least as broadly as the Fourth Amendment; 4 that is, every police practice authoritatively determined to be contrary to the Fourth and Fourteenth Amendments will, without further analysis, be held to be contrary to Art. I, § 6. This approach, which is consistent with previous opinions of the Delaware Supreme Court,5 was followed in this case. The court ana*653lyzed the various decisions interpreting the Federal Constitution, concluded that the Fourth Amendment foreclosed spot checks of automobiles, and summarily held that the State Constitution was therefore also infringed. This is one of those cases where “at the very least, the [state] court felt compelled by what it understood to be federal constitutional considerations to construe ... its own law in the manner it did.” Zacchini v. Scripps-Howard Broadcasting Co., 433 U. S. 562, 568 (1977). Had state law not been mentioned at all, there would be no question about our jurisdiction, even though the State Constitution might have provided an independent and adequate state ground. Ibid. The same result should follow here where the state constitutional holding depended upon the state court's view of the reach of the Fourth and Fourteenth Amendments. If the state court misapprehended federal law, “[i]t should be freed to decide . . . these suits according to its own local law.” Missouri ex rel. Southern R. Co. v. Mayfield, 340 U. S. 1, 5 (1950).

Ill

The Fourth and Fourteenth Amendments are implicated in this case because stopping an automobile and detaining its occupants constitute a “seizure” within the meaning of those Amendments, even though the purpose of the stop is limited and the resulting detention quite brief. United States v. Martinez-Fuerte, 428 U. S. 543, 556-558 (1976); United States v. Brignoni-Ponce, 422 U. S. 873, 878 (1975); cf. Terry v. Ohio, 392 U. S. 1, 16 (1968). The essential purpose of the proscriptions in the Fourth Amendment is to impose a stand*654ard of “reasonableness” 6 upon the exercise of discretion by government officials, including law enforcement agents, in order “ 'to safeguard the privacy and security of individuals against arbitrary invasions. . . ” Marshall v. Barlow’s, Inc., 436 U. S. 307, 312 (1978), quoting Camara v. Municipal Court, 387 U. S. 523, 528 (1967).7 Thus, the permissibility of a particular law enforcement practice is judged by balancing its intrusion on the individual’s Fourth Amendment interests against its promotion of legitimate governmental interests.8 Implemented in this manner, the reasonableness standard usually requires, at a minimum, that the facts upon which an intrusion is based be capable of measurement against “an objective standard,” 9 whether this be probable cause10 or a less stringent test.11 In those situations in which the balance of interests precludes insistence upon “some quantum *655of individualized suspicion,” 12 other safeguards are generally relied upon to assure that the individual’s reasonable expectation of privacy is not “subject to the discretion of the official in the field,” Camara v. Municipal Court, 387 U. S., at 532. See id., at 534-535; Marshall v. Barlow’s, Inc., supra, at 320-321; United States v. United States District Court, 407 U. S. 297, 322-323 (1972) (requiring warrants).

In this case, however, the State of Delaware urges that patrol officers be subject to no constraints in deciding which automobiles shall be stopped for a license and registration check because the State’s interest in discretionary spot checks as a means of ensuring the safety of its roadways outweighs the resulting intrusion on the privacy and security of the persons detained.

IV

We have only recently considered the legality of investigative stops of automobiles where the officers making the stop-have neither probable cause to believe nor reasonable suspicion that either the automobile or its occupants are subject to seizure under the applicable criminal laws. In United States v. Brignoni-Ponce, supra, Border Patrol agents conducting roving patrols in areas near the international border asserted statutory authority to stop at random any vehicle in order to determine whether it contained illegal aliens or was involved in smuggling operations. The practice was held to violate the Fourth Amendment, but the Court did not invalidate all warrantless automobile stops upon less than probable cause. Given “the importance of the governmental interest at stake, the minimal intrusion of a brief stop, and the absence of practical alternatives for policing the border,” 422 U. S., at 881, the Court analogized the roving-patrol stop to the on-the-street encounter addressed in Terry v. Ohio, supra, and held:

“Except at the border and its functional equivalents, officers on roving patrol may stop vehicles only if they are *656aware of specific articulable facts, together with rational inferences from those facts, that reasonably warrant suspicion that the vehicles contain aliens who may be illegally in the country.” 422 U. S., at 884 (footnote omitted).

Because “the nature of illegal alien trafile and the characteristics of smuggling operations tend to generate articulable grounds for identifying violators,” id., at 883, “a requirement of reasonable suspicion for stops allows the Government adequate means of guarding the public interest and also protects residents of the border areas from indiscriminate official interference.” Ibid.

The constitutionality of stops by Border Patrol agents was again before the Court in United States v. Martinez-Fuerte, supra, in which we addressed the permissibility of checkpoint operations. This practice involved slowing all oncoming traffic “to a virtual, if not a complete, halt,” 428 U. S., at 546, at a highway roadblock, and referring vehicles chosen at the discretion of Border Patrol agents to an area for secondary inspection. See id., at 546, 558. Recognizing that the governmental interest involved was the same as that furthered by roving-patrol stops, the Court nonetheless sustained the constitutionality of the Border Patrol’s checkpoint operations. The crucial distinction was the lesser intrusion upon the motorist’s Fourth Amendment interests:

“[The] objective intrusion- — the stop itself, the questioning, and the visual inspection- — also existed in roving-patrol stops. But we view checkpoint stops in a different light because the subjective intrusion — the generating of concern or even fright on the part of lawful travelers — is appreciably less in the case of a checkpoint stop.” Id., at 558.

Although not dispositive,13 these decisions undoubtedly pro*657vide guidance in balancing the public interest against the individual’s Fourth Amendment interests implicated by the practice of spot checks such as occurred in this case. We cannot agree that stopping or detaining a vehicle on an ordinary city street is less intrusive than a roving-patrol stop on a major highway and that it bears greater resemblance to a permissible stop and secondary detention at a checkpoint near the border. In this regard, we note that Brignoni-Ponce was not limited to roving-patrol stops on limited-access roads, but applied to any roving-patrol stop by Border Patrol agents on any type of roadway on less than reasonable suspicion. See 422 U. S., at 882-883; United States v. Ortiz, 422 U. S. 891, 894 (1975). We cannot assume that the physical and psychological intrusion visited upon the occupants of a vehicle by a random stop to check documents is of any less moment than that occasioned by a stop by border agents on roving patrol. Both of these stops generally entail law enforcement officers signaling a moving automobile to pull over to the side of the roadway, by means of a possibly unsettling show of authority. Both interfere with freedom of movement, are inconvenient, and consume time. Both may create substantial anxiety. For Fourth Amendment purposes, we also see insufficient resemblance between sporadic and random stops of individual vehicles making their way through city traffic and those stops occasioned by roadblocks where all vehicles are brought to a halt or to a near halt, and all are subjected to a show of the police power of the community. “At traffic checkpoints the motorist can see that other vehicles are being stopped, he can see visible signs of the officers’ authority, and he is much less likely to be frightened or annoyed by the intrusion.” Id., at 894-895, quoted in United States v. Martinez-Fuerte, 428 U. S., at 558.

*658y

But the State of Delaware urges that even if discretionary spot checks such as occurred in this case intrude upon motorists as much as or more than do the roving patrols held impermissible in Brignoni-Ponce, these stops are reasonable under the Fourth Amendment because the State’s interest in the practice as a means of promoting public safety upon its roads more than outweighs the intrusion entailed. Although the record discloses no statistics concerning the extent of the problem of lack of highway safety, in Delaware or in the Nation as a whole, we are aware of the danger to life14 and property posed by vehicular traffic and of the difficulties that even a cautious and an experienced driver may encounter. We agree that the States have a vital interest in ensuring that only those qualified to do so are permitted to operate motor vehicles, that these vehicles are fit for safe operation, and hence that licensing, registration, and vehicle inspection requirements are being observed. Automobile licenses are issued periodically to evidence that the drivers holding them are sufficiently familiar with the rules of the road and are physically qualified to operate a motor vehicle.15 The registration requirement and, more pointedly, the related annual inspection requirement in Delaware16 are designed to keep dangerous automobiles off the road. Unquestionably, these provisions, properly administered, are essential elements in a highway safety program. Furthermore, we note that the State of Delaware requires a minimum amount of insurance *659coverage as a condition to automobile registration,17 implementing its legitimate interest in seeing to it that its citizens have protection when involved in a motor vehicle accident.18

The question remains, however, whether in the service of these important ends the discretionary spot check is a sufficiently productive mechanism to justify the intrusion upon Fourth Amendment interests which such stops entail. On the record before us, that question must be answered in the negative. Given the alternative mechanisms available, both those in use and those that might be adopted, we are unconvinced that the incremental contribution to highway safety of the random spot check justifies the practice under the Fourth Amendment.

The foremost method of enforcing traffic and vehicle safety regulations, it must be recalled, is acting upon observed violations. Vehicle stops for traffic violations occur countless times each day; and on these occasions, licenses and registration papers are subject to inspection and drivers without them will be ascertained. Furthermore, drivers without licenses are presumably the less safe drivers whose propensities may well exhibit themselves.19 Absent some empirical data to the contrary, it must be assumed that finding an unlicensed driver among those who commit traffic violations is a much more likely event than finding an unlicensed driver by choosing randomly from the entire universe of drivers. If this were not so, licensing of drivers would hardly be an effective means of promoting roadway safety. It seems common sense that the *660percentage of all drivers on the road who are driving without a license is very small and that the number of licensed drivers who will be stopped in order to find one unlicensed operator will be large indeed. The contribution to highway safety made by discretionary stops selected from among drivers generally will therefore be marginal at best. Furthermore, and again absent something more than mere assertion to the contrary, we find it difficult to believe that the unlicensed driver would not be deterred by the possibility of being involved in a traffic violation or having some other experience calling for proof of his entitlement to drive but that he would be deterred by the possibility that he would be one of those chosen for a spot check. In terms of actually discovering unlicensed drivers or deterring them from driving, the spot check does not appear sufficiently productive to qualify as a reasonable law enforcement practice under the Fourth Amendment.

Much the same can be said about the safety aspects of automobiles as distinguished from drivers. Many violations of minimum vehicle-safety requirements are observable, and something can be done about them by the observing officer, directly and immediately. Furthermore, in Delaware, as elsewhere, vehicles must carry and display current license plates,20 which themselves evidence that the vehicle is properly registered;21 and, under Delaware law, to qualify for annual registration a vehicle must pass the annual safety inspection 22 and be properly insured.23 It does not appear, therefore, that a stop of a Delaware-registered vehicle is necessary in order to ascertain compliance with the State's registration requirements; and, because there is nothing to *661show that a significant percentage of automobiles from other States do not also require license plates indicating current registration, there is no basis for concluding that stopping even out-of-state cars for document checks substantially promotes the State’s interest.

The marginal contribution to roadway safety possibly resulting from a system of spot checks cannot justify subjecting, every occupant of every vehicle on the roads to a seizure— limited in magnitude compared to other intrusions but nonetheless constitutionally cognizable — at the unbridled discretion of law enforcement officials. To insist neither upon an appropriate factual basis for suspicion directed at a particular automobile nor upon some other substantial and objective standard or rule to govern the exercise of discretion “would invite intrusions upon constitutionally guaranteed rights based on nothing more substantial than inarticulate hunches . . . .” Terry v. Ohio, 392 U. S., at 22. By hypothesis, stopping apparently safe drivers is necessary only because the danger presented by some drivers is not observable at the time of the stop. When there is not probable cause to believe that a driver is violating any one of the multitude of applicable traffic and equipment regulations24 — or other articulable basis amounting to reasonable suspicion that the driver is unlicensed or his vehicle unregistered — we cannot conceive of any legitimate basis upon which a patrolman could decide that stopping a particular - driver for a spot check would be more productive than stopping any other driver. This kind of standardless and unconstrained discretion is the evil the Court has discerned when in previous cases it has insisted that the discretion of the official in the field be circumscribed, at least to some extent. Almeida-Sanchez v. United States, 413 U. S. 266, 270 (1973); Camara v. Municipal Court, 387 U. S., at 532-533.

*662VI

The “grave danger” of abuse of discretion, United States v. Martines-Fuerte, 428 U. S., at 559, does not disappear simply because the automobile is subject to state regulation resulting in numerous instances of police-citizen contact, Cady v. Dombrowski, 413 U. S. 433, 441 (1973). Only last Term we pointed out that “if the government intrudes . . . the privacy interest suffers whether the government’s motivation is to investigate violations of criminal laws or breaches of other statutory or regulatory standards.” Marshall v. Barlow’s, Inc., 436 U. S., at 312-313. There are certain “relatively unique circumstances,” id., at 313, in which consent to regulatory restrictions is presumptively concurrent with participation in the regulated enterprise. See United States v. Biswell, 406 U. S. 311 (1972) (federal regulation of firearms); Colonnade Catering Corp. v. United States, 397 U. S. 72 (1970) (federal regulation of liquor). Otherwise, regulatory inspections unaccompanied by any quantum of individualized, articulable suspicion must be undertaken pursuant to previously specified “neutral criteria.” Marshall v. Barlow’s, Inc., supra, at 323.

An individual operating or traveling in an automobile does not lose all reasonable expectation of privacy simply because the automobile and its use are subject to government regulation.25 Automobile travel is a basic, pervasive, and often necessary mode of transportation to and from one’s home, workplace, and leisure activities. Many people spend more hours each day traveling in cars than walking on the streets. Undoubtedly, many find a greater sense of security and privacy in traveling in an automobile than they do in exposing themselves by pedestrian or other modes of travel. Were the *663individual subject to unfettered governmental intrusion every time he entered an automobile, the security guaranteed by the Fourth Amendment would be seriously circumscribed. As Terry v. Ohio, supra, recognized, people are not shorn of all Fourth Amendment protection when they step from their homes onto the public sidewalks. Nor are they shorn of those interests when they step from the sidewalks into their automobiles. See Adams v. Williams, 407 U. S. 143, 146 (1972).

YII

Accordingly, we hold that except in those situations in which there is at least articulable and reasonable suspicion that a motorist is unlicensed or that an automobile is not registered, or that either the vehicle or an occupant is otherwise subject to seizure for violation of law, stopping an automobile and detaining the driver in order to check his driver’s license and the registration of the automobile are unreasonable under the Fourth Amendment. This holding does not preclude the State of Delaware or other States from developing methods for spot checks that involve less intrusion or that do not involve the unconstrained exercise of discretion.26 Questioning of all oncoming traffic at roadblock-type stops is one possible alternative. We hold only that persons in automobiles on public roadways may not for that reason alone have their travel and privacy interfered with at the unbridled discretion of police officers. The judgment below is affirmed.

So ordered.

MR. Justice Blackmun,

with whom Mr. Justice Powell joins,

concurring.

The Court, ante, this page, carefully protects from the reach of its decision other less intrusive spot checks “that do not in*664volve the unconstrained exercise of discretion.” The roadblock stop for all traffic is given as an example. I necessarily assume that the Court’s reservation also includes other not purely random stops (such as every 10th car to pass a given point) that equate with, but are less intrusive than, a 100% roadblock stop. And I would not regard the present case as a precedent that throws any constitutional shadow upon the necessarily somewhat individualized and perhaps largely random examinations by game wardens in the performance of their duties. In a situation of that type, it seems to me, the Court’s balancing process, and the value factors under consideration, would be quite different.

With this understanding, I join the Court’s opinion and its judgment.

Mr. Justice Rehnquist,

dissenting.

The Court holds, in successive sentences, that absent an articulable, reasonable suspicion of unlawful conduct, a motorist may not be subjected to a random license check, but that the States are free to develop “methods for spot checks that ... do not involve the unconstrained exercise of discretion,” such as “[questioning ... all oncoming traffic at roadblock-type stops . . . .” Ante, at 663. Because motorists, apparently like sheep, are much less likely to be “frightened” or “annoyed” when stopped en masse, a highway patrolman needs neither probable cause nor articulable suspicion to stop all motorists on a particular thoroughfare, but he cannot without articulable suspicion stop less than all motorists. The Court thus elevates the adage “misery loves company” to a novel role in Fourth Amendment jurisprudence. The rule becomes “curiouser and curiouser” as one attempts to follow the Court’s explanation for it.

As the Court correctly points out, people are not shorn of their Fourth Amendment protection when they step from their homes onto the public sidewalks or from the sidewalks into *665their automobiles. But a random license check of a motorist operating a vehicle on highways owned and maintained by the State is quite different from a random stop designed to uncover violations of laws that have nothing to do with motor vehicles.* No one questions that the State may require the licensing of those who drive on its highways and the registration of vehicles which are driven on those highways. If it may insist on these requirements, it obviously may take steps necessary to enforce compliance. The reasonableness of the enforcement measure chosen by the State is tested by weighing its intrusion on the motorists’ Fourth Amendment interests against its promotion of the State’s legitimate interests. E. g., United States v. Brignoni-Ponce, 422 U. S. 873, 878 (1975).

In executing this balancing process, the Court concludes that given the alternative mechanisms available, discretionary spot checks are not a “sufficiently productive mechanism” to safeguard the State’s admittedly “vital interest in ensuring that only those qualified to do so are permitted to operate motor vehicles, that these vehicles are fit for safe operation, and hence that licensing, registration, and vehicle inspection requirements are being observed.” Ante, at 659, 658. Foremost among the alternative methods of enforcing traffic and vehicle *666safety regulations, according to the Court, is acting upon observed violations, for “drivers without licenses are presumably the less safe drivers whose propensities may well exhibit themselves.” Ante, at 659. Noting that “finding an unlicensed driver among those who commit trafile violations is a much more likely event than finding an unlicensed driver by choosing randomly from the entire universe of drivers,” ibid., the Court concludes that the contribution to highway safety made by random stops would be marginal at best. The State’s primary interest, however, is in traffic safety, not in apprehending unlicensed motorists for the sake of apprehending unlicensed motorists. The whole point of enforcing motor vehicle safety regulations is to remove from the road the unlicensed driver before he demonstrates why he is unlicensed. The Court would apparently prefer that the State check licenses and vehicle registrations as the wreckage is being towed away.

Nor is the Court impressed with the deterrence rationale, finding it inconceivable that an unlicensed driver who is not deterred by the prospect of being involved in a traffic violation or other incident requiring him to produce a license would be deterred by the possibility of being subjected to a spot check. The Court arrives at its conclusion without the benefit of a shred of empirical data in this record suggesting that a system of random spot checks would fail to deter violators. In the absence of such evidence, the State’s determination that random stops would serve a deterrence function should stand.

On the other side of the balance, the Court advances only the most diaphanous of citizen interests. Indeed, the Court does not say that these interests can never be infringed by the State, just that the State must infringe them en masse rather than citizen by citizen. To comply with the Fourth Amendment, the State need only subject all citizens to the same “anxiety” and “inconvenien[ce]” to which it now subjects only a few.

*667For constitutional purposes, the action of an individual law enforcement officer is the action of the State itself, e, g., Ex parte Virginia, 100 U. S. 339, 346-347 (1880), and state acts are accompanied by a presumption of validity until shown otherwise. See, e. g., McDonald v. Board of Election, 394 U. S. 802 (1969). Although a system of discretionary stops could conceivably be abused, the record before us contains no showing that such abuse is probable or even likely. Nor is there evidence in the record that a system of random license checks would fail adequately to further the State’s interest in deterring and apprehending violators. Nevertheless, the Court concludes “[o]n the record before us” that the random spot check is not “a sufficiently productive mechanism to justify the intrusion upon Fourth Amendment interests which such stops entail.” Ante, at 659. I think that the Court’s approach reverses the presumption of constitutionality accorded acts of the States. The burden is not upon the State to demonstrate that its procedures are consistent with the Fourth Amendment, but upon respondent to demonstrate that they are not. “On this record” respondent has failed to make such a demonstration.

Neither the Court’s opinion, nor the opinion of the Supreme Court of Delaware, suggests that the random stop made in this case was carried out in a manner inconsistent with the Equal Protection Clause of the Fourteenth Amendment. Absent an equal protection violation, the fact that random stops may entail “a possibly unsettling show of authority,” ante, at 657, and “may create substantial anxiety,” ibid., seems an insufficient basis to distinguish for Fourth Amendment purposes between a roadblock stopping all cars and the random stop at issue here. Accordingly, I would reverse the judgment of the Supreme Court of Delaware.

Justice Rehnquist

announced the judgment of the Court and delivered an opinion, in which The Chief Justice, Justice White, and Justice O’Connor joined.

Respondent Clifford James Brown was convicted in the District Court of Tarrant County, Tex., for possession of heroin in violation of state law. The Texas Court of Criminal Appeals reversed his conviction, holding that certain evidence should have been suppressed because it was obtained in violation of the Fourth Amendment to the United States Constitution.1 617 S. W. 2d 196. That court rejected the *733State’s contention that the so-called “plain view” doctrine justified the police seizure. Because of apparent uncertainty concerning the scope and applicability of this doctrine, we granted certiorari, 457 U. S. 1116, and now reverse the judgment of the Court of Criminal Appeals.

On a summer evening in June 1979, Tom Maples, an officer of the Fort Worth police force, assisted in setting up a routine driver’s license checkpoint on East Allen Street in that city. Shortly before midnight Maples stopped an automobile driven by respondent Brown, who was alone. Standing alongside the driver’s window of Brown’s car, Maples asked him for his driver’s license. At roughly the same time, Maples shined his flashlight into the car and saw Brown withdraw his right hand from his right pants pocket. Caught between the two middle fingers of the hand was an opaque, green party balloon, knotted about one-half inch from the tip. Brown let the balloon fall to the seat beside his leg, and then reached across the passenger seat and opened the glove compartment.

*734Because of his previous experience in arrests for drug offenses, Maples testified that he was aware that narcotics frequently were packaged in balloons like the one in Brown’s hand. When he saw the balloon, Maples shifted his position in order to obtain a better view of the interior of the glove compartment. He noticed that it contained several small plastic vials, quantities of loose white powder, and an open bag of party balloons. After rummaging briefly through the glove compartment, Brown told Maples that he had no driver’s license in his possession. Maples then instructed him to get out of the car and stand at its rear. Brown complied, and, before following him to the rear of the car, Maples reached into the car and picked up the green balloon; there seemed to be a sort of powdery substance within the tied-off portion of the balloon.

Maples then displayed the balloon to a fellow officer who indicated that he “understood the situation.” The two officers then advised Brown that he was under arrest.2 They *735also conducted an on-the-scene inventory of Brown’s car, discovering several plastic bags containing a green leafy substance and a large bottle of milk sugar. These items, like the balloon, were seized by the officers. At the suppression hearing conducted by the District Court, a police department chemist testified that he had examined the substance in the balloon seized by Maples and determined that it was heroin. He also testified that narcotics frequently were packaged in ordinary party balloons.

The Court of Criminal Appeals, discussing the Fourth Amendment issue, observed that “ ‘plain view alone is never enough to justify the warrantless seizure of evidence.’ ” 617 S. W. 2d, at 200, quoting Coolidge v. New Hampshire, 403 U. S. 443, 468 (1971) (opinion of Stewart, J., joined by Douglas, Brennan, and Marshall, JJ.) It further concluded that “Officer Maples had to know that ‘incriminatory evidence was before him when he seized the balloon.’” 617 S. W. 2d, at 200 (emphasis supplied), quoting DeLao v. State, 550 S. W. 2d 289, 291 (Tex. Crim. App. 1977). On the State’s petition for rehearing, three judges dissented, stating their view that “[t]he issue turns on whether an officer, relying on years of practical experience and knowledge commonly accepted, has probable cause to seize the balloon in plain view.” 617 S. W. 2d, at 201.

Because the “plain view” doctrine generally is invoked in conjunction with other Fourth Amendment principles, such as those relating to warrants, probable cause, and search incident to arrest, we rehearse briefly these better understood principles of Fourth Amendment law. That Amendment secures the persons, houses, papers, and effects of the people against unreasonable searches and seizures, and requires the existence of probable cause before a warrant shall issue. Our cases hold that procedure by way of a warrant is preferred, although in a wide range of diverse situations we have recognized flexible, common-sense exceptions to this requirement. See, e. g., Warden v. Hayden, 387 U. S. 294 (1967) *736(hot pursuit); United States v. Jeffers, 342 U. S. 48, 51-52 (1951) (exigent circumstances); United States v. Ross, 456 U. S. 798 (1982) (automobile search); Chimel v. California, 395 U. S. 752 (1969), United States v. Robinson, 414 U. S. 218 (1973), and New York v. Belton, 453 U. S. 454 (1981) (search of person and surrounding area incident to arrest); Almeida-Sanchez v. United States, 413 U. S. 266 (1973) (search at border or “functional equivalent”); Zap v. United States, 328 U. S. 624, 630 (1946) (consent). We have also held to be permissible intrusions less severe than full-scale searches or seizures without the necessity of a warrant. See, e. g., Terry v. Ohio, 392 U. S. 1 (1968) (stop and frisk); United States v. Brignoni-Ponce, 422 U. S. 873 (1975) (seizure for questioning); Delaware v. Prouse, 440 U. S. 648 (1979) (roadblock). One frequently mentioned “exception to the warrant requirement,” Coolidge v. New Hampshire, supra, at 456, is the so-called “plain view” doctrine, relied upon by the State in this case.

While conceding that the green balloon seized by Officer Maples was clearly visible to him, the Court of Criminal Appeals held that the State might not avail itself of the “plain view” doctrine. That court said:

“For the plain view doctrine to apply, not only must the officer be legitimately in a position to view the object, but it must be immediately apparent to the police that they have evidence before them. This ‘immediately apparent’ aspect is central to the plain view exception and is here relied upon by appellant. [Citation omitted.] In this case then, Officer Maples had to know that ‘incriminatory evidence was before him when he seized the balloon.’” 617 S. W. 2d, at 200.

The Court of Criminal Appeals based its conclusion primarily on the plurality portion of the opinion of this Court in Coolidge v. New Hampshire, supra. In the Coolidge plurality’s view, the “plain view” doctrine permits the warrantless seizure by police of private possessions where three require*737ments are satisfied.3 First, the police officer must lawfully make an “initial intrusion” or otherwise properly be in a position from which he can view a particular area. Id., at 465-468. Second, the officer must discover incriminating evidence “inadvertently,” which is to say, he may not “know in advance the location of [certain] evidence and intend to seize it,” relying on the plain-view doctrine only as a pretext. Id., at 470. Finally, it must be “immediately apparent” to the police that the items they observe may be evidence of a crime, contraband, or otherwise subject to seizure. Id., at 466. While the lower courts generally have applied the Coolidge plurality’s discussion of “plain view,” it has never been expressly adopted by a majority of this Court. On the contrary, the plurality’s formulation was sharply criticized at the time, see, Coolidge v. New Hampshire, 403 U. S., at 506 (Black, J., dissenting); id., at 516-521 (White, J., dissenting). While not a binding precedent, as the considered opinion of four Members of this Court it should obviously be the point of reference for further discussion of the issue.

The Coolidge plurality observed: “it is important to keep in mind that, in the vast majority of cases, any evidence seized by the police will be in plain view, at least at the moment of seizure,” simply as “the normal concomitant of any search, legal or illegal.” Id., at 465. The question whether property in plain view of the police may be seized therefore must turn on the legality of the intrusion that enables them to perceive and physically seize the property in question. The Coolidge plurality, while following this approach to “plain *738view,” characterized it as an independent exception to the warrant requirement. At least from an analytical perspective, this description may be somewhat inaccurate. We recognized in Payton v. New, York, 445 U. S. 573, 587 (1980), the well-settled rule that “objects such as weapons or contraband found in a public place may be seized by the police without a warrant. The seizure of property in plain view involves no invasion of privacy and is presumptively reasonable, assuming that there is probable cause to associate the property with criminal activity.” A different situation is presented, however, when the property in open view is “‘situated on private premises to which access is not otherwise available for the seizing officer.’” Ibid., quoting G. M. Leasing Corp. v. United States, 429 U. S. 338, 354 (1977). As these cases indicate, “plain view” provides grounds for seizure of an item when an officer’s access to an object has some prior justification under the Fourth Amendment.4 “Plain view” is perhaps better understood, therefore, not as an independent “exception” to the Warrant *739Clause, but simply as an extension of whatever the prior justification for an officer’s “access to an object” may be.

The principle is grounded on the recognition that when a police officer has observed an object in “plain view,” the owner’s remaining interests in the object are merely those of possession and ownership, see Coolidge v. New Hampshire, supra, at 515 (White, J., dissenting). Likewise, it reflects the fact that requiring police to obtain a warrant once they have obtained a first-hand perception of contraband, stolen property, or incriminating evidence generally would be a “needless inconvenience,” 403 U. S., at 468, that might involve danger to the police and public. Ibid. We have said previously that “the permissibility of a particular law enforcement practice is judged by balancing its intrusion on . . . Fourth Amendment interests against its promotion of legitimate governmental interests.” Delaware v. Prouse, 440 U. S., at 654. In light of the private and governmental interests just outlined, our decisions have come to reflect the rule that if, while lawfully engaged in an activity in a particular place, police officers perceive a suspicious object, they may seize it immediately. See Marron v. United States, 275 U. S. 192 (1927); Go-Bart Importing Co. v. United States, 282 U. S. 344, 358 (1931); United States v. Lefkowitz, 285 U. S. 452, 465 (1932); Harris v. United States, 390 U. S. 234, 236 (1968); Frazier v. Cupp, 394 U. S. 731 (1969). This rule merely reflects an application of the Fourth Amendment’s central requirement of reasonableness to the law governing seizures of property.

Applying these principles, we conclude that Officer Maples properly seized the green balloon from Brown’s automobile. The Court of Criminal Appeals stated that it did not “question . . . the validity of the officer’s initial stop of appellant’s vehicle as a part of a license check,” 617 S. W. 2d, at 200, and we agree. Delaware v. Prouse, supra, at 654-655. It is likewise beyond dispute that Maples’ action in shining his *740flashlight to illuminate the interior of Brown’s car trenched upon no right secured to the latter by the Fourth Amendment. The Court said in United States v. Lee, 274 U. S. 559, 563 (1927): “[The] use of a searchlight is comparable to the use of a marine glass or a field glass. It is not prohibited by the Constitution.” Numerous other courts have agreed that the use of artificial means to illuminate a darkened area simply does not constitute a search, and thus triggers no Fourth Amendment protection.5

Likewise, the fact that Maples “changed [his] position” and “bent down at an angle so [he] could see what was inside” Brown’s car, App. 16, is irrelevant to Fourth Amendment analysis. The general public could peer into the interior of Brown’s automobile from any number of angles; there is no reason Maples should be precluded from observing as an officer what would be entirely visible to him as a private citizen. There is no legitimate expectation of privacy, Katz v. United States, 389 U. S. 347, 361 (1967) (Harlan, J., concurring); Smith v. Maryland, 442 U. S. 735, 739-745 (1979), shielding that portion of the interior of an automobile which may be viewed from outside the vehicle by either inquisitive passersby or diligent police officers. In short, the conduct that enabled Maples to observe the interior of Brown’s car and of his open glove compartment was not a search within the meaning of the Fourth Amendment.

*741Thus there can be no dispute here as to the presence of the first of the three requirements held necessary by the Coolidge plurality to invoke the “plain view” doctrine.6 But the Court of Criminal Appeals, as we have noted, felt the State’s case ran aground on the requirement that the incriminating nature of the items be “immediately apparent” to the police officer. To the Court of Criminal Appeals, this apparently meant that the officer must be possessed of near certainty as to the seizable nature of the items. Decisions by this Court since Coolidge indicate that the use of the phrase “immediately apparent” was very likely an unhappy choice of words, since it can be taken to imply that an unduly high degree of certainty as to the incriminatory character of evidence is necessary for an application of the “plain view” doctrine.

In Colorado v. Bannister, 449 U. S. 1, 3-4 (1980), we applied what was in substance the plain-view doctrine to an officer’s seizure of evidence from an automobile. Id., at 4, n. 4. The officer noticed that the occupants of the automobile matched a description of persons suspected of a theft and that auto parts in the open glove compartment of the car similarly resembled ones reported stolen. The Court held that these facts supplied the officer with “probable cause,” id., at 4, and therefore, that he could seize the incriminating items from the car without a warrant. Plainly, the Court did not view the “immediately apparent” language of Coolidge as establishing any requirement that a police officer “know” that certain items are contraband or evidence of a crime. Indeed, Colorado v. Bannister, supra, was merely an application of the rule, set forth in Payton v. New York, 445 U. S. 573 (1980), that “[t]he seizure of property in plain view involves no invasion of privacy and is presumptively reasonable, assuming that there is probable cause to associate the property *742 with criminal activity.” Id., at 587 (emphasis added). We think this statement of the rule from Payton, supra, requiring probable cause for seizure in the ordinary case,7 is consistent with the Fourth Amendment and we reaffirm it here.

As the Court frequently has remarked, probable cause is a flexible, common-sense standard. It merely requires that the facts available to the officer would “warrant a man of reasonable caution in the belief,” Carroll v. United States, 267 U. S. 182, 162 (1925), that certain items may be contraband or stolen property or useful as evidence of a crime; it does not demand any showing that such a belief be correct or more likely true than false. A “practical, nontechnical” probability that incriminating evidence is involved is all that is required. Brinegar v. United States, 338 U. S. 160, 176 (1949). Moreover, our observation in United States v. Cortez, 449 U. S. 411, 418 (1981), regarding “particularized suspicion,” is equally applicable to the probable-cause requirement:

“The process does not deal with hard certainties, but with probabilities. Long before the law of probabilities was articulated as such, practical people formulated certain common-sense conclusions about human behavior; jurors as factfinders are permitted to do the same — and so are law enforcement officers. Finally, the evidence thus collected must be seen and weighed not in terms of library analysis by scholars, but as understood by those versed in the field of law enforcement.”

With these considerations in mind it is plain that Officer Maples possessed probable cause to believe that the balloon in Brown’s hand contained an illicit substance. Maples testified that he was aware, both from his participation in previous narcotics arrests and from discussions with other officers,

*743that balloons tied in the manner of the one possessed by Brown were frequently used to carry narcotics. This testimony was corroborated by that of a police department chemist who noted that it was “common” for balloons to be used in packaging narcotics. In addition, Maples was able to observe the contents of the glove compartment of Brown’s car, which revealed further suggestions that Brown was engaged in activities that might involve possession of illicit substances. The fact that Maples could not see through the opaque fabric of the balloon is all but irrelevant: the distinctive character of the balloon itself spoke volumes as to its contents — particularly to the trained eye of the officer.

In addition to its statement that for seizure of objects in plain view to be justified the basis upon which they might be seized had to be “immediately apparent,” and the requirement that the initial intrusion be lawful, both of which requirements we hold were satisfied here, the Coolidge plurality also stated that the police must discover incriminating evidence “inadvertently,” which is to say, they may not “know in advance the location of [certain] evidence and intend to seize it,” relying on the plain-view doctrine only as a pretense. 430 U. S., at 470. Whatever may be the final disposition of the “inadvertence” element of “plain view,”8 it clearly was no bar to the seizure here. The circumstances of this meeting between Maples and Brown give no suggestion that the roadblock was a pretext whereby evidence of narcotics violation might be uncovered in “plain view” in the course of a check for driver’s licenses. Here, although the officers no doubt had an expectation that some of the cars they halted on East Allen Street — which was part of a “medium” area of narcotics traffic, App. 33 — would contain narcotics or para*744phernalia, there is no indication in the record that they had anything beyond this generalized expectation. Likewise, there is no indication that Maples had any reason to believe that any particular object would be in Brown’s glove compartment or elsewhere in his automobile. The “inadvertence” requirement of “plain view,” properly understood, was no bar to the seizure here.

Maples lawfully viewed the green balloon in the interior of Brown’s car, and had probable cause to believe that it was subject to seizure under the Fourth Amendment. The judgment of the Texas Court of Criminal Appeals is accordingly reversed, and the case is remanded for further proceedings.

It is so ordered.

Justice White,

concurring.

While joining Justice Rehnquist’s plurality opinion, I continue to disagree with the views of four Justices in Coolidge v. New Hampshire, 403 U. S. 443, 469 (1971), that plain-view seizures are valid only if the viewing is “inadvertent.” Nor does the Court purport to endorse that view in its opinions today.

Justice Powell,

with whom Justice Blackmun joins, concurring in the judgment.

I concur in the judgment, and also agree with much of the plurality’s opinion relating to the application in this case of the plain-view exception to the Warrant Clause. But I do not join the plurality’s opinion because it goes well beyond the application of the exception. As I read the opinion, it appears to accord less significance to the Warrant Clause of the Fourth Amendment than is justified by the language and purpose of that Amendment. In dissent in United States v. Rabinowitz, 339 U. S. 56 (1950), Justice Frankfurter wrote eloquently:

“One cannot wrench ‘unreasonable searches’ from the text and context and historic content of the Fourth *745Amendment. . . . When [that] Amendment outlawed 'unreasonable searches’ and then went on to define the very restricted authority that even a search warrant issued by a magistrate could give, the framers said with all the clarity of the gloss of history that a search is ‘unreasonable’ unless a warrant authorizes it, barring only exceptions justified by absolute necessity.” Id., at 70.

To be sure, the opinions of this Court in Warrant Clause cases have not always been consistent. They have reflected disagreement among Justices as to the extent to which the Clause defines the reasonableness standard of the Amendment. In one of my earliest opinions, United States v. United States District Court, 407 U. S. 297 (1972), I cited Justice Frankfurter’s Rabinowitz dissent in emphasizing the importance of the Warrant Clause. 407 U. S., at 316. Although I would not say that exceptions can be justified only by “absolute necessity,”1 I stated that they were “few in number and carefully delineated.” Id., at 318. This has continued to be my view, as expressed recently in Arkansas v. Sanders, 442 U. S. 753, 759 (1979). It is a view frequently repeated by this Court. See, e. g., United States v. Ross, 456 U. S. 798, 825 (1982); Mincey v. Arizona, 437 U. S. 385, 390 (1978) (unanimous decision); Vale v. Lousiana, 399 U. S. 30, 34 (1970); Katz v. United States, 389 U. S. 347, 357 (1967); Camara v. Municipal Court, 387 U. S. 523, 528-529 (1967); Jones v. United States, 357 U. S. 493, 499 (1958).

This case involves an application of the plain-view exception, first addressed at some length by the plurality portion of the opinion in Coolidge v. New Hampshire, 403 U. S. 443 (1971). The plurality today states that this opinion “has *746never been expressly adopted by a majority of this Court.” Ante, at 737. Whatever my view might have been when Coolidge was decided, I see no reason at this late date to imply criticism of its articulation of this exception. It has been accepted generally for over a decade.2 Moreover, it seems unnecessary to cast doubt on Coolidge in this case. Its plurality formulation is dispositive of the question before us.

Respondent Brown does not dispute that Officer Maples’ initial intrusion was lawful. Brown also concedes that the discovery of the tied-off balloon was inadvertent in that it was observed in the course of a lawful inspection of the front seat area of the automobile. If probable cause must be shown, as the Payton dicta suggest, see Payton v. New York, 445 U. S. 573, 587 (1980), I think it is clear that it existed here. Officer Maples testified that he previously had made an arrest in a case where narcotics were carried in tied-off balloons similar to the one at issue here. Other officers had told him of such cases. Even if it were not generally known that a balloon is a common container for carrying illegal narcotics, we have recognized that a law enforcement officer may rely on his training and experience to draw inferences and make deductions that might well elude an untrained person. United States v. Cortez, 449 U. S. 411, 418 (1981). We are not advised of any innocent item that is commonly carried in uninflated, tied-off balloons such as the one Officer Maples seized.

*747Accordingly, I concur in the judgment as it is consistent with principles established by our prior decisions.

Justice Stevens,

with whom Justice Brennan and Justice Marshall join, concurring in the judgment.

The Texas Court of Criminal Appeals held that the war-rantless seizure of respondent’s balloon could not be justified under the plain-view doctrine because incriminating evidence was not immediately apparent. This Court reverses, holding that even though the contents of the balloon were not visible to the officer, incriminating evidence was immediately apparent because he had probable cause to believe the balloon contained an illicit substance. I agree with the Court that contraband need not be visible in order for a plain-view seizure to be justified. I therefore concur in the conclusion that the Texas Court interpreted the Fourth Amendment more strictly than is required.

The plurality’s explanation of our disposition of this case is, however, incomplete. It gives inadequate consideration to our cases holding that a closed container may not be opened without a warrant, even when the container is in plain view and the officer has probable cause to believe contraband is concealed within. United States v. Chadwick, 433 U. S. 1 (1977); Arkansas v. Sanders, 442 U. S. 753 (1979); United States v. Ross, 456 U. S. 798, 811-812 (1982). Final determination of whether the trial court properly denied the suppression motion requires a more complete understanding of the plain-view doctrine, as well as the answer to a factual inquiry that remains open to the state court on remand.

Although our Fourth Amendment cases sometimes refer indiscriminately to searches and seizures, there are important differences between the two that are relevant to the plain-view doctrine. The Amendment protects two different interests of the citizen — the interest in retaining possession of property and the interest in maintaining personal privacy. A seizure threatens the former, a search the latter. As a matter of timing, a seizure is usually preceded by a search, *748but when a container is involved the converse is often true. Significantly, the two protected interests are not always present to the same extent; for example, the seizure of a locked suitcase does not necessarily compromise the secrecy of its contents, and the search of a stopped vehicle does not necessarily deprive its owner of possession.

An object may be considered to be “in plain view” if it can be seized without compromising any interest in privacy. Since seizure of such an object threatens only the interest in possession, circumstances diminishing that interest may justify exceptions to the Fourth Amendment’s usual requirements. Thus, if an item has been abandoned, neither Fourth Amendment interest is implicated, and neither probable cause nor a warrant is necessary to justify seizure. See, e. g., Abel v. United States, 362 U. S. 217, 241 (1960); cf. United States v. Lisk, 522 F. 2d 228, 230 (CA71975). And if an officer has probable cause to believe that a publicly situated item is associated with criminal activity, the interest in possession is outweighed by the risk that such an item might disappear or be put to its intended use before a warrant could be obtained. The officer may therefore seize it without a warrant. See G. M. Leasing Corp. v. United States, 429 U. S. 338, 354 (1975); Payton v. New York, 445 U. S. 573, 587 (1980). The “plain view” exception to the warrant requirement is easy to understand and to apply in cases in which no search is made and no intrusion on privacy occurs.

The Court’s more difficult plain-view cases, however, have regularly arisen in two contexts that link the seizure with a prior or subsequent search. The first is the situation in which an officer who is executing a valid search for one item seizes a different item. The Court has been sensitive to the danger inherent in such a situation that officers will enlarge a specific authorization, furnished by a warrant or an exigency, into the equivalent of a general warrant to rummage and seize at will. That danger is averted by strict attention to two of the core requirements of plain view: seizing the item must entail no significant additional invasion of privacy, and *749at the time of seizure the officer must have probable cause to connect the item with criminal behavior. See United States v. Lefkowitz, 285 U. S. 452, 465 (1932); cf. Coolidge v. New Hampshire, 403 U. S. 443, 465-466 (1971).

The second familiar context is the situation in which an officer comes upon a container in plain view and wants both to seize it and to examine its contents. In recent years, the Court has spoken at some length about the latter act, e. g., Ross, supra; Chadwick, supra; Sanders, supra, emphasizing the Fourth Amendment privacy values implicated whenever a container is opened. In this case, however, both the search of a container (the balloon) and the antecedent seizure are open to challenge.1 In that regard, it more closely resembles Coolidge, supra. 2 All of these cases, however, demonstrate that the constitutionality of a container search is not automatically determined by the constitutionality of the prior seizure. See Chadwick, 433 U. S., at 13-14, n. 8; Sanders, 442 U. S., at 761-762. Separate inquiries are necessary, taking into account the separate interests at stake.

If a movable container is in plain view, seizure does not implicate any privacy interests. Therefore, if there is probable cause to believe it contains contraband, the owner’s posses-sory interest in the container must yield to society’s interest in making sure that the contraband does not vanish during *750the time it would take to obtain a warrant. The item may be seized temporarily. It does not follow, however, that the container may be opened on the spot. Once the container is in custody, there is no risk that evidence will be destroyed. Some inconvenience to the officer is entailed by requiring him to obtain a warrant before opening the container, but that alone does not excuse the duty to go before a neutral magistrate. Johnson v. United States, 333 U. S. 10, 15 (1948); McDonald v. United States, 335 U. S. 451, 455 (1948). As Justice Powell emphasizes, ante, at 744-745, the Warrant Clause embodies our government’s historical commitment to bear the burden of inconvenience. Exigent circumstances must be shown before the Constitution will entrust an individual’s privacy to the judgment of a single police officer.

In this case, I have no doubt concerning the propriety of the officer’s warrantless seizure of the balloon. For the reasons stated by Justices Powell and Rehnquist, I agree that the police officer invaded no privacy interest in order to see the balloon, and that when he saw it he had probable cause to believe it contained drugs. But before the balloon’s contents could be used as evidence against the respondent, the State also had to justify opening it without a warrant.3 I can perceive two potential justifications. First, it is entirely possible that what the officer saw in the car’s glove compartment, coupled with his observation of respondent and the contents of his pockets, provided probable cause to believe that contraband was located somewhere in the car — and not merely in the one balloon at issue. If so, then under United States v. Ross, 456 U. S. 798 (1982), which was not decided until after the Texas Court of Criminal Appeals reviewed this case, it was permissible to examine the contents of any container in the car, including this balloon.

Alternatively, the balloon could be one of those rare single-purpose containers which “by their very nature cannot sup*751port any reasonable expectation of privacy because their contents can be inferred from their outward appearance.” Sanders, swpra, at 764-765, n. 13. Whereas a suitcase or a paper bag may contain an almost infinite variety of items, a balloon of this kind might be used only to transport drugs. Viewing it where he did could have given the officer a degree of certainty that is equivalent to the plain view of the heroin itself. If that be true, I would conclude that the plain-view doctrine supports the search as well as the seizure even though the contents of the balloon were not actually visible to the officer.4

This reasoning leads me to the conclusion that the Fourth Amendment would not require exclusion of the balloon’s contents in this case if, but only if, there was probable cause to search the entire vehicle or there was virtual certainty that the balloon contained a controlled substance.5 Neither of these fact-bound inquiries was made by the Texas courts, and neither should be made by this Court in the first instance. Moreover, it may be that on remand the Texas Court of Criminal Appeals will find those inquiries unnecessary because the respondent may have waived his right to demand them. See n. 3, supra. I therefore concur in the judgment.

Mr. Justice Powell

delivered the opinion of the Court.

This case raises questions as to the United States Border Patrol’s authority to stop automobiles in areas near the Mexican border. It differs from our decision in Almeida-Sanchez v. United States, 413 U. S. 266 (1973), in that the Border Patrol does not claim authority to search cars, but only to question the occupants about their citizenship and immigration status.

I

As part of its regular traffic-checking operations in southern California, the Border Patrol operates a fixed checkpoint on Interstate Highway 5 south of San Clemente. On the evening of March 11, 1973, the checkpoint was closed because of inclement weather, but two officers were observing northbound traffic from a patrol *875car parked at the side of the highway. The road was dark, and they were using the patrol car’s headlights to illuminate passing cars. They pursued respondent’s car and stopped it, saying later that their only reason for doing so was that its three occupants appeared to be of Mexican descent. The officers questioned respondent and his two passengers about their citizenship and learned that the passengers were aliens who had entered the country illegally. All three were then arrested, and respondent was charged with two counts of knowingly transporting illegal immigrants, a violation of § 274 (a) (2) of the Immigration and Nationality Act, 66 Stat. 228, 8 U. S. C. § 1324 (a)(2). At trial respondent moved to suppress the testimony of and about the two passengers, claiming that this evidence was the fruit of an illegal seizure. The trial court denied the motion, the aliens testified at trial, and respondent was convicted on both counts.

Respondent’s appeal was pending in the Court of Appeals for the Ninth Circuit when we announced our decision in Almeida-Sanchez v. United States, supra, holding that the Fourth Amendment prohibits the use of roving patrols to search vehicles, without a warrant or probable cause, at points removed from the border and its functional equivalents. The Court of Appeals, sitting en banc, held that the stop in this case more closely resembled a roving-patrol stop than a stop at a traffic checkpoint, and applied the principles of Almeida-Sanchez. 1 *876The court held that the Fourth Amendment, as interpreted in Almeida-Sanchez, forbids stopping a vehicle, even for the limited purpose of questioning its occupants, unless the officers have a “founded suspicion” that the occupants are aliens illegally in the country. The court refused to find that Mexican ancestry alone supported such a “founded suspicion” and held that respondent’s motion to suppress should have been granted.2 499 F. 2d 1109 (1974). We granted certiorari and set the case for oral argument with No. 73-2050, United States v. Ortiz, post, p. 891, and No. 73-6848, Bowen v. United States, post, p. 916. 419 U. S. 824 (1974).

The Government does not challenge the Court of Appeals’ factual conclusion that the stop of respondent’s car was a roving-patrol stop rather than a checkpoint stop. Brief for United States 8. Nor does it challenge the retroactive application of Almeida-Sanchez, supra, Brief for United States 9, or contend that the San Clemente checkpoint is the functional equivalent of the border. The only issue presented for decision is whether a roving patrol may stop a vehicle in an area near the border and question its occupants when the only ground for suspicion is that the occupants appear to be of Mexican ancestry. For the reasons that follow, we affirm the decision of the Court of Appeals.

II

The Government claims two sources of statutory au*877thority for stopping cars without warrants in the border areas. Section 287 (a)(1) of the Immigration and Nationality Act, 8 U. S. C. § 1357 (a)(1), authorizes any officer or employee of the Immigration and Naturalization Service (INS) without a warrant, “to interrogate any alien or person believed to be an alien as to his right to be or to remain in the United States.” There is no geographical limitation on this authority. The Government contends that, at least in the areas adjacent to the Mexican border, a person’s apparent Mexican ancestry alone justifies belief that he or she is an alien and satisfies the requirement of this statute. Section 287 (a)(3) of the Act, 8 U. S. C. § 1357 (a)(3), authorizes agents, without a warrant,

“within a reasonable distance from any external boundary of the United States, to board and search for aliens any vessel within the territorial waters of the United States and any railway car, aircraft, conveyance, or vehicle . . . .”

Under current regulations, this authority may be exercised anywhere within 100 miles of the border. 8 CFR § 287.1 (a) (1975). The Border Patrol interprets the statute as granting authority to stop moving vehicles and question the occupants about their citizenship, even when its officers have no reason to believe that the occupants are aliens or that other aliens may be concealed in the vehicle.3 But “no Act of Congress can authorize a violation of the Constitution,” AImeida-Sanchez, supra, at 272, *878and we must decide whether the Fourth Amendment allows such random vehicle stops in the border areas.

Ill

The Fourth Amendment applies to all seizures of the person, including seizures that involve only a brief detention short of traditional arrest. Davis v. Mississippi, 394 U. S. 721 (1969); Terry v. Ohio, 392 U. S. 1, 16-19 (1968). “[Wjhenever a police officer accosts an individual and restrains his freedom to walk away, he has 'seized’ that person,” id., at 16, and the Fourth Amendment requires that the seizure be “reasonable.” As with other categories of police action subject to Fourth Amendment constraints, the reasonableness of such seizures depends on a balance between the public interest and the individual’s right to personal security free from arbitrary interference by law officers. Id., at 20-21; Camara v. Municipal Court, 387 U. S. 523, 536-537 (1967).

The Government makes a convincing demonstration that the public interest demands effective measures to prevent the illegal entry of aliens at the Mexican border. Estimates of the number of illegal immigrants in the United States vary widely. A conservative estimate in 1972 produced a figure of about one million, but the INS now suggests there may be as many as 10 or 12 million aliens illegally in the country.4 Whatever the number, these aliens create significant economic and social problems, competing with citizens and legal resident *879aliens for jobs, and generating extra demand for social services. The aliens themselves are vulnerable to exploitation because they cannot complain of substandard working conditions without risking deportation. See generally Hearings on Illegal Aliens before Subcommittee No. 1 of the House Committee on the Judiciary, 92d Cong., 1st and 2d Sess., ser. 13, pts. 1-5 (1971-1972).

The Government has estimated that 85% of the aliens illegally in the country are from Mexico. United States v. Baca, 368 F. Supp. 398, 402 (SD Cal. 1973).5 The Mexican border is almost 2,000 miles long, and even a vastly reinforced Border Patrol would find it impossible to prevent illegal border crossings. Many aliens cross the Mexican border on foot, miles away from patrolled areas, and then purchase transportation from the border area to inland cities, where they find jobs and elude the immigration authorities. Others gain entry on valid temporary border-crossing permits, but then violate the conditions of their entry. Most of these aliens leave the border area in private vehicles, often assisted by professional “alien smugglers.” The Border Patrol’s traffic-checking operations are designed to prevent this inland movement. They succeed in apprehending some illegal entrants and smugglers, and they deter the movement of others by threatening apprehension and increasing the cost of illegal transportation.

Against this valid public interest we must weigh the interference with individual liberty that results when an officer stops an automobile and questions its occupants. *880The intrusion is modest. The Government tells us that a stop by a roving patrol “usually consumes no more than a minute.” Brief for United States 25. There is no search of the vehicle or its occupants, and the visual inspection is limited to those parts of the vehicle that can be seen by anyone standing alongside.6 According to the Government, “[a] 11 that is required of the vehicle’s occupants is a response to a brief question or two and possibly the production of a document evidencing a right to be in the United States.” Ibid.

Because of the limited nature of the intrusion, stops of this sort may be justified on facts that do not amount to the probable cause required for an arrest. In Terry v. Ohio, supra, the Court declined expressly to decide whether facts not amounting to probable cause could justify an “investigative 'seizure’ ” short of an arrest, 392 U. S., at 19 n. 16, but it approved a limited search — a pat-down for weapons — for the protection of an officer investigating suspicious behavior of persons he reasonably believed to be armed and dangerous. The Court approved such a search on facts that did not constitute probable cause to believe the suspects guilty of a crime, requiring only that “the police officer ... be able to point to specific and articulable facts which, taken together with rational inferences from those facts, reasonably warrant” a belief that his safety or that of others is in danger. Id., at 21; see id., at 27.

We elaborated on Terry in Adams v. Williams, 407 U. S. 143 (1972), holding that a policeman was justified *881in approaching the respondent to investigate a tip that he was carrying narcotics and a gun.

“The Fourth Amendment does not require a policeman who lacks the precise level of information necessary for probable cause to arrest to simply shrug his shoulders and allow a crime to occur or a criminal to escape. On the contrary, Terry recognizes that it may be the essence of good police work to adopt an intermediate response. ... A brief stop of a suspicious individual, in order to determine his identity or to maintain the status quo momentarily while obtaining more information, may be most reasonable in light of the facts known to the officer at the time.” Id,., at 145-146.

These cases together establish that in appropriate circumstances the Fourth Amendment allows a properly limited “search” or “seizure” on facts that do not constitute probable cause to arrest or to search for contraband or evidence of crime. In both Terry and Adams v. Williams the investigating officers had reasonable grounds to believe that the suspects were armed and that they might be dangerous. The limited searches and seizures in those cases were a valid method of protecting the public and preventing crime. In this ease as well, because of the importance of the governmental interest at stake, the minimal intrusion of a brief stop, and the absence of practical alternatives for policing the border, we hold that when an officer’s observations lead him reasonably to suspect that a particular vehicle may contain aliens who are illegally in the country, he may stop the car briefly and investigate the circumstances that provoke suspicion. As in Terry, the stop and inquiry must be “reasonably related in scope to the justification for their initiation.” 392 U. S., at 29. The officer may question the driver and passengers about their citizenship and *882immigration status, and he may ask them to explain suspicious circumstances, but any further detention or search must be based on consent or probable cause.

We are unwilling to let the Border Patrol dispense entirely with the requirement that officers must have a reasonable suspicion to justify roving-patrol stops.7 In the context of border area stops, the reasonableness requirement of the Fourth Amendment demands something more than the broad and unlimited discretion sought by the Government. Roads near the border carry not only aliens seeking to enter the country illegally, but a large volume of legitimate traffic as well. San Diego, with a metropolitan population of 1.4 million, is located on the border. Texas has two fairly large metropolitan areas directly on the border: El Paso, with a population of 360,000, and the Brownsville-McAllen area, with a combined population of 320,000. We are confident that substantially all of the traffic in these cities is lawful and that relatively few of their residents have any connection with the illegal entry and transportation of aliens. To approve roving-patrol stops of all vehicles in the border area, without any suspicion that a particular vehicle is carrying illegal immigrants, would subject the residents of these and other areas to potentially unlimited interference with their use of the highways, solely at the discretion of Border Patrol officers. The only formal limitation on that discretion appears to be the administrative regulation defining the term “reasonable distance” in § 287 (a) (3) to mean within 100 *883air miles from the border. 8 CFR §287.1 (a) (1975). Thus, if we approved the Government’s position in this case, Border Patrol officers could stop motorists at random for questioning, day or night, anywhere within 100 air miles of the 2,000-mile border, on a city street, a busy highway, or a desert road, without any reason to suspect that they have violated any law.

We are not convinced that the legitimate needs of law enforcement require this degree of interference with lawful traffic. As we discuss in Part IV, infra, the nature of illegal alien traffic and the characteristics of smuggling operations tend to generate articulable grounds for identifying violators. Consequently, a requirement of reasonable suspicion for stops allows the Government adequate means of guarding the public interest and also protects residents of the border areas from indiscriminate official interference. Under the circumstances, and even though the intrusion incident to a stop is modest, we conclude that it is not “reasonable” under the Fourth Amendment to make such stops on a random basis.8

The Government also contends that the public interest in enforcing conditions on legal alien entry justifies stopping persons who may be aliens for questioning about their citizenship and immigration status. Although we *884may assume for purposes of this case that the broad congressional power over immigration, see Kleindienst v. Mandel, 408 U. S. 753, 765-767 (1972), authorizes Congress to admit aliens on condition that they will submit to reasonable questioning about their right to be and remain in the country, this power cannot diminish the Fourth Amendment rights of citizens who may be mistaken for aliens. For the same reasons that the Fourth Amendment forbids stopping vehicles at random to inquire if they are carrying aliens who are illegally in the country, it also forbids stopping or detaining persons for questioning about their citizenship on less than a reasonable suspicion that they may be aliens.

IV

The effect of our decision is to limit exercise of the authority granted by both § 287 (a)(1) and § 287 (a) (3). Except at the border and its functional equivalents, officers on roving patrol may stop vehicles only if they are aware of specific articulable facts, together with rational inferences from those facts, that reasonably warrant suspicion that the vehicles contain aliens who may be illegally in the country.9

Any number of factors may be taken into account in deciding whether there is reasonable suspicion to stop a car in the border area. Officers may consider the characteristics of the area in which they encounter a vehicle. Its proximity to the border, the usual pat*885terns of traffic on the particular road, and previous experience with alien traffic are all relevant. See Carroll v. United States, 267 U. S. 132, 159-161 (1925); United States v. Jaime-Barrios, 494 F. 2d 455 (CA9), cert. denied, 417 U. S. 972 (1974).10 They also may consider information about recent illegal border crossings in the area. The driver’s behavior may be relevant, as erratic driving or obvious attempts to evade officers can support a reasonable suspicion. See United States v. Larios-Montes, 500 F. 2d 941 (CA9 1974); Duprez v. United States, 435 F. 2d 1276 (CA9 1970). Aspects of the vehicle itself may justify suspicion. For instance, officers say that certain station wagons, with large compartments for fold-down seats or spare tires, are frequently used for transporting concealed aliens. See United States v. Bugarin-Casas, 484 F. 2d 853 (CA9 1973), cert. denied, 414 U. S. 1136 (1974); United States v. Wright, 476 F. 2d 1027 (CA5 1973). The vehicle may appear to be heavily loaded, it may have an extraordinary number of passengers, or the officers may observe persons trying to hide. See United States v. Larios-Montes, supra. The Government also points out that trained officers can recognize the characteristic appearance of persons who live in Mexico, relying on such factors as the mode of dress and haircut. Reply Brief for United States 12-13, in United States v. Ortiz, post, p. 891. In all situations the officer is entitled to assess the facts in light of his experience in detecting illegal entry and smuggling. Terry v. Ohio, 392 U. S., at 27.

In this case the officers relied on a single factor to justify stopping respondent’s car: the apparent Mexican an*886cestry of the occupants.11 We cannot conclude that this furnished reasonable grounds to believe that the three occupants were aliens. At best the officers had only a fleeting glimpse of the persons in the moving car, illuminated by headlights. Even if they saw enough to think that the occupants were of Mexican descent, this factor alone would justify neither a reasonable belief that they were aliens, nor a reasonable belief that the car concealed other aliens who were illegally in the country. Large numbers of native-born and naturalized citizens have the physical characteristics identified with Mexican ancestry, and even in the border area a relatively small proportion of them are aliens.12 The likelihood that any given *887person of Mexican ancestry is an alien is high enough to make Mexican appearance a relevant factor, but standing alone it does not justify stopping all Mexican-Americans to ask if they are aliens.

The judgment of the Court of Appeals is

Affirmed.

[For opinion of The Chief Justice concurring in the judgment, see post, p. 899.]

[For opinion of Mr. Justice White concurring in the judgment, see post, p. 914.]

Mr. Justice Rehnquist,

concurring.

I join in the opinion of the Court. I think it quite important to point out, however, that that opinion, which is joined by a somewhat different majority than that which comprised the Almeida-Sanchez Court, is both by its terms and by its reasoning concerned only with the type of stop involved in this case. I think that just as travelers entering the country may be stopped and searched without probable cause and without founded suspicion, because of “national self protection reasonably requiring one entering the country to identify himself as entitled to come in, and his belongings as effects which may be lawfully brought in,” Carroll v. United States, 267 U. S. 132, 154 (1925), a strong case may be made for those charged with the enforcement of laws conditioning the right of vehicular use of a highway to likewise stop motorists using highways in order to determine whether they have met the qualifications prescribed by applicable law for such use. See Cady v. Dombrowski, 413 U. S. 433, 440-441 (1973); United States v. Biswell, 406 U. S. 311 (1972). I regard these and similar situations, such *888as agricultural inspections and highway roadblocks to apprehend known fugitives, as not in any way constitutionally suspect by reason of today’s decision.

Mr. Justice Douglas,

concurring in the judgment.

I join in the affirmance of the judgment. The stopping of respondent’s automobile solely because its occupants appeared to be of Mexican ancestry was a patent violation of the Fourth Amendment. I cannot agree, however, with the standard the Court adopts to measure the lawfulness of the officers’ action. The Court extends the “suspicion” test of Terry v. Ohio, 392 U. S. 1 (1968), to the stop of a moving automobile. I dissented from the adoption of the suspicion test in Terry, believing it an unjustified weakening of the Fourth Amendment’s protection of citizens from arbitrary interference by the police. I remarked then:

“The infringement on personal liberty of any 'seizure’ of a person can only be 'reasonable’ under the Fourth Amendment if we require the police to possess 'probable cause’ before they seize him. Only that line draws a meaningful distinction between an officer’s mere inkling and the presence of facts within the officer’s personal knowledge which would convince a reasonable man that the person seized has committed, is committing, or is about to commit a particular crime.” Id., at 38.

The fears I voiced in Terry about the weakening of the Fourth Amendment have regrettably been borne out by subsequent events. Hopes that the suspicion test might be employed only in the pursuit of violent crime — a limitation endorsed by some of its proponents* — have now been dashed, as it has been applied *889in narcotics investigations, in apprehension of “illegal” aliens, and indeed has come to be viewed as a legal construct for the regulation of a general investigatory police power. The suspicion test has been warmly embraced by law enforcement forces and vigorously employed in the cause of crime detection. In criminal cases we see those for whom the initial intrusion led to the discovery of some wrongdoing. But the nature of the test permits the police to interfere as well with a multitude of law-abiding citizens, whose only transgression may be a nonconformist appearance or attitude. As one commentator has remarked:

“ ‘Police power exercised without probable cause is arbitrary. To say that the police may accost citizens at their whim and may detain them upon reasonable suspicion is to say, in reality, that the police may both accost and detain citizens at their whim.1 ” Amsterdam, Perspectives on the Fourth Amendment, 58 Minn. L. Rev. 349, 395 (1974).

The uses to which the suspicion test has been put are illustrated in some of the cases cited in the Court’s opinion. In United States v. Wright, 476 F. 2d 1027 (CA5 1973), for example, immigration officers stopped a station wagon near the border because there was a spare tire in the back seat. The court held that the officers reasonably suspected that the spare wheel well had been freed in order to facilitate the concealment of aliens. In United States v. Bugarin-Casas, 484 F. 2d 853 (CA9 1973), the Border Patrol officers encountered a man driving alone in a station wagon which was “riding low”; stopping the car was held reasonable because the officers suspected that aliens might have been hidden beneath the floorboards. The vacationer whose car is weighted down with luggage will find no comfort in these decisions; nor will the many law-abiding citi*890zens who drive older vehicles that ride low because their suspension systems are old or in disrepair. The suspicion test has indeed brought a state of affairs where the police may stop citizens on the highway on the flimsiest of ■justifications.

The Court does, to be sure, disclaim approval of the particular decisions it cites applying the suspicion test. But by specifying factors to be considered without attempting to explain what combination is necessary to satisfy the test, the Court may actually induce the police to push its language beyond intended limits and to advance as a justification any of the enumerated factors even where its probative significance is negligible.

Ultimately the degree to which the suspicion test actually restrains the police will depend more upon what the Court does henceforth than upon what it says today. If my Brethren mean to give the suspicion test a new bite, I applaud the intention. But in view of the developments since the test was launched in Terry, I am not optimistic. This is the first decision to invalidate a stop on the basis of the suspicion standard. In fact, since Terry we have granted review of a case applying the test only once, in Adams v. Williams, 407 U. S. 143 (1972), where the Court found the standard satisfied by the tip from an informant whose credibility was not established and whose information was not shown to be based upon personal knowledge. If in the future the suspicion test is to provide any meaningful restraint of the police, its force must come from vigorous review of its applications, and not alone from the qualifying language of today’s opinion. For now, I remain unconvinced that the suspicion test offers significant protection of the “comprehensive right of personal liberty in the face of governmental intrusion,” Lopez v. United States, 373 U. S. 427, 455 (1963) (dissenting opinion), that is embodied in the Fourth Amendment.

*545Mr. Justice Powell

delivered the opinion of the Court.

These cases involve criminal prosecutions for offenses relating to the transportation of illegal Mexican aliens. Each defendant was arrested at a permanent checkpoint operated by the Border Patrol' away from the international border with Mexico, and each sought the exclusion of certain evidence on the ground that the operation of the checkpoint was incompatible with the Fourth Amendment. In each instance whether the Fourth Amendment was violated turns primarily on whether a vehicle may be stopped at a fixed checkpoint for brief questioning of its occupants even though there is no reason, to believe the particular vehicle contains illegal aliens. We reserved this question last Term in United States v. Ortiz, 422 U. S. 891, 897 n. 3 (1975). We hold today that such stops are consistent with the Fourth Amendment. We also hold that the operation of a fixed checkpoint need not be authorized in advance by a judicial warrant.

I

A

The respondents in No. 74 — 1560 are defendants in three separate prosecutions resulting from arrests made on three different occasions at the permanent immigration checkpoint on Interstate 5 near San Clemente, Cal. Interstate 5 is the principal highway between San Diego and Los Angeles, and the San Clemente checkpoint is 66 road miles north of the Mexican border. We previously have described the checkpoint as follows:

“ 'Approximately one mile south of the checkpoint is a large black on yellow sign with flashing yellow lights over the highway stating “ALL VEHICLES, STOP AHEAD, 1 MILE.” Three-quarters of a *546mile further north are two black on yellow signs suspended over the highway with flashing lights stating “WATCH FOR BRAKE LIGHTS.” At the checkpoint, which is also the location of a State of California weighing station, are two large signs with flashing red lights suspended over the highway. These signs each state “STOP HERE — U. S. OFFICERS.” Placed on the highway are a number of orange traffic cones funneling traffic into two lanes where a Border Patrol agent in full dress uniform, standing behind a white on red “STOP” sign checks traffic. Blocking traffic in the unused lanes are official U. S. Border Patrol vehicles with flashing red lights. In addition, there is a permanent building which houses the Border Patrol office and temporary detention facilities. There are also floodlights for nighttime operation.’ ” United States v. Ortiz, supra, at 893, quoting United States v. Baca, 368 F. Supp. 398, 410-411 (SD Cal. 1973).

The “point” agent standing between the two lanes of traffic visually screens all northbound vehicles, which the checkpoint brings to a virtual, if not a complete, halt.1 Most motorists are allowed to resume their progress without any oral inquiry or close visual examination. In a relatively small number of cases the “point” agent will conclude that further inquiry is in order. He directs these cars to a secondary inspection area, where their occupants are asked about their citizenship and immigration status. The Government informs us that at San *547Clemente the average length of an investigation in the secondary inspection area is three to five minutes. Brief for United States 53. A direction to stop in the secondary inspection area could be based on something suspicious about a particular car passing through the checkpoint, but the Government concedes that none of the three stops at issue in No. 74-1560 was based on any articulable suspicion. During the period when these stops were made, the checkpoint was operating under a magistrate’s “warrant of inspection,” which authorized the Border Patrol to conduct a routine-stop operation at the San Clemente location.2

We turn now to the particulars of the stops involved in No. 74-1560, and the procedural history of the case. Respondent Amado Martinez-Fuerte approached the checkpoint driving a vehicle containing two female passengers. The women were illegal Mexican aliens who had entered the United States at the San Ysidro port of entry by using false papers and rendezvoused with Martinez-Fuerte in San Diego to be transported northward. At the checkpoint their car was directed to the secondary inspection area. Martinez-Fuerte produced documents showing him to be a lawful resident alien, but his passengers admitted being present in the country unlawfully. He was charged, inter alia, with two counts of illegally transporting aliens in violation *548of 8 U. S. C. § 1324 (a)(2). He moved before trial to suppress all evidence stemming from the stop on the ground that the operation of the checkpoint was in violation of the Fourth Amendment.3 The motion to suppress was denied, and he was convicted on both counts after a jury trial.

Respondent Jose Jiminez-Garcia attempted to pass through the checkpoint while driving a car containing one passenger. He had picked the passenger up- by prearrangement in San Ysidro after the latter had been smuggled across the border. Questioning at the secondary inspection area revealed the illegal status of the passenger, and Jiminez-Garcia was charged in two counts with illegally transporting an alien, 8 U. S. C. § 1324 (a) (2), and conspiring to commit that offense, 18 U. S. C. § 371. His motion to suppress the evidence derived from the stop- was granted.

Respondents Raymond Guillen and Fernando Me-drano-Barragan approached the checkpoint with Guillen driving and Medrano-Barragan and his wife as passengers. Questioning at the secondary inspection area revealed that Medrano-Barragan and his wife were illegal aliens. A subsequent search of the car uncovered three other illegal aliens in the trunk. Medrano-Barragan had led the other aliens across the border at the beach near Tijuana, Mexico, where they rendezvoused with Guillen, a United States citizen. Guillen and Medrano-Barragan were jointly indicted on four counts of illegally trans*549porting aliens, 8 U. S. C. § 1324 (a)(2), four counts of inducing the illegal entry of aliens, § 1324 (a)(4), and one conspiracy count, 18 U. S. C. § 371. The District Court granted the defendants' motion to suppress.

Martinez-Fuerte appealed his conviction, and the Government appealed the granting of the motions to suppress in the respective prosecutions of Jiminez-Garcia and of Guillen and Medrano-Barragan.4 The Court of Appeals for the Ninth Circuit consolidated the three appeals, which presented the common question whether routine stops and interrogations at checkpoints are consistent with the Fourth Amendment.5 The Court of Appeals held, with one judge dissenting, that these stops violated the Fourth Amendment, concluding that a stop for inquiry is constitutional only if the Border Patrol reasonably suspects the presence of illegal aliens on the basis of articulable facts. It reversed Martinez-Fuerte’s conviction, and affirmed the orders to suppress in the other cases. 514 F. 2d 308 (1975). We reverse and remand.

B

Petitioner in No. 75-5387, Rodolfo Sifuentes, was arrested at the permanent immigration checkpoint on U. S. Highway 77 near Sarita, Tex. Highway 77 originates in Brownsville, and it is one of the two major highways running north from the lower Rio Grande valley. The Sarita checkpoint is about 90 miles north of Browns*550ville, and 65-90 miles from the nearest points of the Mexican border. The physical arrangement of the checkpoint resembles generally that at San Clemente, but the checkpoint is operated differently in that the officers customarily stop all northbound motorists for a brief inquiry. Motorists whom the officers recognize as local inhabitants, however, are waved through the checkpoint without inquiry. Unlike the San Clemente checkpoint the Sarita operation was conducted without a judicial warrant.

Sifuentes drove up to the checkpoint without any visible passengers. When an agent approached the vehicle, however, he observed four passengers, one in the front seat and the other three in the rear, slumped down in the seats. Questioning revealed that each passenger was an illegal alien, although Sifuentes was a United States citizen. The aliens had met Sifuentes in the United States, by prearrangement, after swimming across the Rio Grande.

Sifuentes was indicted on four counts of illegally transporting aliens. 8 U. S. C. § 1324 (a)(2). He moved on Fourth Amendment grounds to suppress the evidence derived from the stop. The motion was denied and he was convicted after a jury trial. Sifuentes renewed his Fourth Amendment argument on appeal, contending primarily that stops made without reason to believe a car is transporting aliens illegally are unconstitutional. The United States Court of Appeals for the Fifth Circuit affirmed the conviction, 517 F. 2d 1402 (1975), relying on its opinion in United States v. Santibanez, 517 F. 2d 922 (1975). There the Court of Appeals had ruled that routine checkpoint stops are consistent with the Fourth- Amendment. We affirm.6

*551II

The Courts of Appeals for the Ninth and the Fifth Circuits are in conflict on the constitutionality of a law enforcement technique considered, important by those charged with policing the Nation’s borders. Before turning to the constitutional question, we examine the context in which it arises.

A

It has been national policy for many years to limit immigration into the United States. Since July 1, 1968, the annual quota for immigrants from all independent countries of the Western Hemisphere, including Mexico, has been 120,000 persons. Act of Oct. 3, 1965, § 21 (e), 79 Stat. 921. Many more aliens than can be accommodated under the quota want to live and work in the United States. Consequently, large numbers of aliens seek illegally to enter or to remain in the United States. We noted last Term that “ [estimates of the number of illegal immigrants [already] in the United States vary widely. A conservative estimate in 1972 produced a figure of about one million, but the Immigration and Naturalization Service now suggests there may be as many as 10 or 12 million aliens illegally in the country.” United States v. Brignoni-Ponce, 422 U. S. 873, 878 (1975) (footnote omitted). It is estimated that 85% of the illegal immigrants are from Mexico, drawn by the fact that economic opportunities are significantly greater in the United States than they are in Mexico. United States v. Baca, 368 F. Supp., at 402.

*552Interdicting the flow of illegal entrants from Mexico poses formidable law enforcement problems. The principal problem arises from surreptitious entries. Id,., at 405. The United States shares a border with Mexico that is almost 2,000 miles long, and much of the border area is uninhabited desert or thinly populated arid land. Although the Border Patrol maintains personnel, electronic equipment, and fences along portions of the border, it remains relatively easy for individuals to enter the United States without detection. It also is possible for an alien to enter unlawfully at a port of entry by the use of falsified papers or to enter lawfully but violate restrictions of entry in an effort to remain in the country unlawfully.7 Once within the country, the aliens seek to travel inland to areas where employment is believed to be available, frequently meeting by prearrangement with friends or professional smugglers who transport them in private vehicles. United States v. Brignoni-Ponce, supra, at 879.

The Border Patrol conducts three kinds of inland traffic-checking operations in an effort to minimize illegal immigration. Permanent checkpoints, such as those at San Clemente and Sarita, are maintained at or near intersections of important roads leading away from the border. They operate on a coordinated basis designed to avoid circumvention by smugglers and others who transport the illegal aliens. Temporary checkpoints, which operate like permanent ones, occasionally are established in other strategic locations. Finally, roving patrols are maintained to supplement the checkpoint system. See Almeida-Sanchez v. United *553 States, 413 U. S. 266, 268 (1973).8 In fiscal 1973, 175,-511 deportable aliens were apprehended throughout the Nation by “line watch” agents stationed at the border itself. Traffic-checking operations in the interior apprehended approximately 55,300 more deportable aliens.9 Most of the traffic-checking apprehensions were at checkpoints, though precise figures are not available. United States v. Baca, supra, at 405, 407, and n. 2.

B

We are concerned here with permanent checkpoints, the locations of which are chosen on the basis of a number of factors. The Border Patrol believes that to assure effectiveness, a checkpoint must be (i) distant enough from the border to avoid interference with traffic in populated areas near the border, (ii) close to the confluence of two or more significant roads leading away from the border, (iii) situated in terrain that restricts vehicle passage around the checkpoint, (iv) on a stretch of highway compatible with safe operation, and (v) beyond the 25-mile zone in which “border passes,” see n. 7, supra, are valid. United States v. Baca, supra, at 406.

*554The record in No. 74-1560 provides a rather complete picture of the effectiveness of the San Clemente checkpoint. Approximately 10 million cars pass the checkpoint location each year, although the checkpoint actually is in operation only about 70% of the time.10 In calendar year 1973, approximately 17,000 illegal aliens were apprehended there. During an eight-day period in 1974 that included the arrests involved in No. 74^1560, roughly 146,000 vehicles passed through the checkpoint during 124% hours of operation. Of these, 820 vehicles were referred to the secondary inspection area, where Border Patrol agents found 725 deportable aliens in 171 vehicles. In all but two cases, the aliens were discovered without a conventional search of the vehicle. A similar rate of apprehensions throughout the year would have resulted in an annual total of over 33,000, although the Government contends that many illegal aliens pass through the checkpoint undetected. The record in No. 75-5387 does not provide comparable statistical information regarding the Sarita checkpoint. While it appears that fewer illegal aliens are apprehended there, it may be assumed that fewer pass by undetected, as every motorist is questioned.

Ill

The Fourth Amendment imposes limits on search-and-seizure powers in order to prevent arbitrary and oppressive interference by enforcement officials with the privacy and personal security of individuals. See United States v. Brignoni-Ponce, 422 U. S., at 878; United States v. Ortiz, 422 U. S., at 895; Camara v. Municipal Court, *555387 U. S. 523, 528 (1967). In delineating the constitutional safeguards applicable in particular contexts, the Court has weighed the public interest against the Fourth Amendment interest of the individual, United States v. Brignoni-Ponce, supra, at 878; Terry v. Ohio, 392 U. S. 1, 20-21 (1968), a process evident in our previous cases dealing with Border Patrol traffic-checking operations.

In Almeida-Sanchez v. United States, supra, the question was whether a roving-patrol unit constitutionally could search a vehicle for illegal aliens simply because it was in the general vicinity of the border. We recognized that important law enforcement interests were at stake but held that searches by roving patrols impinged so significantly on Fourth Amendment privacy interests that a search could be conducted without consent only if there was probable cause to believe that a car contained illegal aliens, at least in the absence of a judicial warrant authorizing random searches by roving patrols in a given area. Compare 413 U. S., at 273, with id., at 283-285 (Powell, J., concurring), and id., at 288 (White, J., dissenting). We held in United States v. Ortiz, supra, that the same limitations applied to vehicle searches conducted at a permanent checkpoint.

In United States v. Brignoni-Ponce, supra, however, we recognized that other traffic-checking practices involve a different balance of public and private interests and appropriately are subject to less stringent constitutional safeguards. The question was under what circumstances a roving patrol could stop motorists in the general area of the border for brief inquiry into their residence status. We found that the interference with Fourth Amendment interests involved in such a stop was “modest,” 422 U. S., at 880, while the inquiry served significant law enforcement needs. We therefore held that a roving-patrol stop need not be justified by probable *556cause and may be undertaken if the stopping officer is “aware of specific articulable facts, together with rational inferences from those facts, that reasonably warrant suspicion” that a vehicle contains illegal aliens. Id., at 884.11

IY

It is agreed that checkpoint stops are “seizures” within the meaning of the Fourth Amendment. The defendants contend primarily that the routine stopping of vehicles at a checkpoint is invalid because Brignoni-Ponce must be read as proscribing any stops in the absence of reasonable suspicion. Sifuentes alternatively contends in No. 75-5387 that routine checkpoint stops are permissible only when the practice has the advance judicial authorization of a warrant. There was a warrant authorizing the stops at San Clemente but none at Sarita. As we reach the issue of a warrant requirement only if reasonable suspicion is not required, we turn first to whether reasonable suspicion is a prerequisite to a valid stop, a question to be resolved by balancing the interests at stake.

A

Our previous cases have recognized that maintenance of a traffic-checking program in the interior is necessary because the flow of illegal aliens cannot be controlled effectively at the border. We note here only the sub-stantiality of the public interest in the practice of routine stops for inquiry at permanent checkpoints, a practice which the Government identifies as the most important of the traffic-checking operations. Brief for United States in No. 74-1560, pp. 19-20.12 These checkpoints *557are located on important highways; in their absence such highways would offer illegal aliens a quick and safe route into the interior. Routine checkpoint inquiries apprehend many smugglers and illegal aliens who succumb to the lure of such highways. And the prospect of such inquiries forces others onto less efficient roads that are less heavily traveled, slowing their movement and making them more vulnerable to detection by roving patrols. Cf. United States v. Brignoni-Ponce, 422 U. S., at 883-885.

A requirement that stops on major routes inland always be based on reasonable suspicion would be impractical because the flow of trafile tends to be too heavy to allow the particularized study of a given car that would enable it to be identified as a possible carrier of illegal aliens. In particular, such a requirement would largely eliminate any deterrent to the conduct of well-disguised smuggling operations, even though smugglers are known to use these highways regularly.

B

While the need to make routine checkpoint stops is great, the consequent intrusion on Fourth Amendment interests is quite limited. The stop does intrude to a limited extent on motorists’ right to “free passage with*558out interruption,’' Carroll v. United States, 267 U. S. 132, 154 (1925), and arguably on their right to personal security. But it involves only a brief detention of travelers during which

“ ‘[a] 11 that is required of the vehicle’s occupants is a response to a brief question or two and possibly the production of a document evidencing a right to be in the United States.’ ” United States v. Brignoni-Ponce, supra, at 880.

Neither the vehicle nor its occupants are searched, and visual inspection of the vehicle is limited to what can be seen without a search. This objective intrusion — the stop itself, the questioning, and the visual inspection— also existed in roving-patrol stops. But we view checkpoint stops in a different light because the subjective intrusion — the generating of concern or even fright on the part of lawful travelers — is appreciably less in the case of a checkpoint stop. In Ortiz, we noted:

“[T]he circumstances surrounding a checkpoint stop and search are far less intrusive than those attending a roving-patrol' stop. Roving patrols often operate at night on seldom-traveled roads, and their approach may frighten motorists. At traffic checkpoints the motorist can see that other vehicles are being stopped, he can see visible signs of the officers’ authority, and he is much less likely to be frightened or annoyed by the intrusion.” 422 U. S., at 894-895.

In Brignoni-Ponce, we recognized that Fourth Amendment analysis in this context also must take into account the overall degree of interference with legitimate traffic. 422 U. S., at 882-883. We concluded there that random roving-patrol stops could not be tolerated because they “would subject the residents of . . . [border] areas to *559potentially unlimited interference with their use of the highways, solely at the discretion of Border Patrol officers. . . . [They] could stop motorists at random for questioning, day or night, anywhere within 100 air miles of the 2,000-mile border, on a city street, a busy highway, or a desert road . . . Ibid. There also was a grave danger that such unreviewable discretion would be abused by some officers in the field. Ibid.

Routine checkpoint stops do not intrude similarly on the motoring public. First, the potential interference with legitimate traffic is minimal. Motorists using these highways are not taken by surprise as they know, or may obtain knowledge of, the location of the checkpoints and will not be stopped elsewhere. Second, checkpoint operations both appear to and actually involve less discretionary enforcement activity. The regularized manner in which established checkpoints are operated is visible evidence, reassuring to law-abiding motorists, that the stops are duly authorized and believed to serve the public interest. The location of a fixed checkpoint is not chosen by officers in the field, but by officials responsible for making overall decisions as to the most effective allocation of limited enforcement resources. We may assumg that such officials will be unlikely to locate a checkpoint where it bears arbitrarily or oppressively on motorists as a class. And since field officers may stop only those cars passing the checkpoint, there is less room for abusive or harassing stops of individuals than there was in the case of roving-patrol stops. Moreover, a claim that a particular exercise of discretion in locating or operating a checkpoint is unreasonable is subject to post-stop judicial review.13

*560The defendants arrested at the San Clemente checkpoint suggest that its operation involves a significant extra element of intrusiveness in that only a small percentage of cars are referred to the secondary inspection area, thereby “stigmatizing” those diverted and reducing the assurances provided by equal treatment of all motorists. We think defendants overstate the consequences. Referrals are made for the sole purpose of conducting a routine and limited inquiry into residence status that cannot feasibly be made of every motorist where the traffic is heavy. The objective intrusion of the stop and inquiry thus remains minimal. Selective referral may involve some annoyance, but it remains true that the stops should not be frightening or offensive because of their public and relatively routine nature. Moreover, selective referrals — rather than questioning the occupants of every car — tend to advance some Fourth Amendment interests by minimizing the intrusion on the general motoring public.

C

The defendants note correctly that to accommodate public and private interests some quantum of individualized suspicion is usually a prerequisite to a constitutional search or seizure.14 See Terry v. Ohio, 392 *561U. S., at 21, and n. 18. But the Fourth Amendment imposes no irreducible requirement of such suspicion. This is clear from Camara v. Municipal Court, 387 U. S. 523 (1967). See also Almeida-Sanchez v. United States, 413 U. S., at 283-285 (Powell, J., concurring); id., at 288 (White, J., dissenting); Colonnade Catering Corp. v. United States, 397 U. S. 72 (1970); United States v. Biswell, 406 U. S. 311 (1972); Carroll v. United States, 267 U. S., at 154. In Camara the Court required an “area” warrant to support the reasonableness of inspecting private residences within a particular area for building code violations, but recognized that “specific knowledge of the condition of the particular dwelling” was not required to enter any given residence. 387 U. S., at 538. In so holding, the Court examined the government interests advanced to justify such routine intrusions “upon the constitutionally protected interests of the private citizen,” id., at 534—535, and concluded that under the circumstances the government interests outweighed those of the private citizen.

We think the same conclusion is appropriate here, where we deal neither with searches nor with the sanctity ' of private dwellings, ordinarily afforded the most stringent Fourth Amendment protection. See, e. g., McDonald v. United States, 335 U. S. 451 (1948). As we have noted earlier, one’s expectation of privacy in an automobile and of freedom in its operation are significantly different from the traditional expectation of privacy and freedom in one’s residence. United States v. Ortiz, 422 U. S., at 896 n. 2; see Cardwell v. Lewis, 417 U. S. 583, 590-591 (1974) (plurality *562opinion). And the reasonableness of the procedures followed in making these checkpoint stops makes the resulting intrusion on the interests of motorists minimal. On the other hand, the purpose of the stops is legitimate and in the public interest, and the need for this enforcement technique is demonstrated by the records in the cases before us. Accordingly, we hold that the stops and questioning at issue may be made in the absence of any individualized suspicion at reasonably located checkpoints.15

*563We further believe that it is constitutional to refer motorists selectively to the secondary inspection area at the San Clemente checkpoint on the basis of criteria that would not sustain a roving-patrol stop. Thus, even if it be assumed that such referrals are made largely on the basis of apparent Mexican ancestry,16 we perceive no constitutional violation. Cf. United States v. Brignoni-Ponce, 422 U. S., at 885-887. As the intrusion here is sufficiently minimal that no particularized reason need exist to justify it, we think it follows that the Border Patrol *564officers must have wide discretion in selecting the motorists to be diverted for the brief questioning involved.17

y

Sifuentes’ alternative argument is that routine stops at a checkpoint are permissible only if a warrant has given judicial authorization to the particular checkpoint location and the practice of routine stops. A warrant requirement in these circumstances draws some support from Camara, where the Court held that, absent consent, an “area” warrant was required to make a building code inspection, even though the search could be conducted absent cause to believe that there were violations in the building searched.18

We do not think, however, that Camara is an apt *565model. It involved the search of private residences, for which a warrant traditionally has been required. See, e. g., McDonald v. United States, 335 U. S. 451 (1948). As developed more fully above, the strong Fourth Amendment interests that justify the warrant requirement in that context are absent here. The degree of intrusion upon privacy that may be occasioned by a search of a house hardly can be compared with the minor interference with privacy resulting from the mere stop for questioning as to residence. Moreover, the warrant requirement in Camara served specific Fourth Amendment interests to which a warrant requirement here would make little contribution. The Court there said:

“[W]hen [an] inspector [without a warrant] demands entry, the occupant has no way of knowing whether enforcement of the municipal code involved requires inspection of his premises, no way of knowing the lawful limits of the inspector’s power to search, and no way of knowing whether the inspector himself is acting under proper authorization.” 387 U. S., at 532.

A warrant provided assurance to the occupant on these scores. We believe that the visible manifestations of the field officers’ authority at a checkpoint provide substantially the same assurances in this case.

Other purposes served by the requirement of a warrant also are inapplicable here. One such purpose is to prevent hindsight from coloring the evaluation of the reasonableness of a search or seizure. Cf. United States v. Watson, 423 U. S. 411, 455-456, n. 22 (1976) (Marshall, J., dissenting). The reasonableness of checkpoint stops, however, turns on factors such as the location and method of operation of the checkpoint, factors that are not susceptible to the distortion of hindsight, and therefore will be open to post-stop review notwith*566standing the absence of a warrant. Another purpose for a warrant requirement is to substitute the judgment of the magistrate for that of the searching or seizing officer. United States v. United States District Court, 407 U. S. 297, 316-318 (1972). But the need for this is reduced when the decision to “seize” is not entirely in the hands of the officer in the field, and deference is to be given to the administrative decisions of higher ranking officials.

VI

In summary, we hold that stops for brief questioning routinely conducted at permanent checkpoints are consistent with the Fourth Amendment and need not be authorized by warrant.19 The principal protection of Fourth *567Amendment rights at checkpoints lies in appropriate limitations on the scope of the stop. See Terry v. Ohio, 392 U. S., at 24—27; United States v. Brignoni-Ponce, 422 U. S., at 881-882. We have held that checkpoint searches are constitutional only if justified by consent or probable cause to search. United States v. Ortiz, 422 U. S. 891 (1975). And our holding today is limited to the type of stops described in this opinion. “[A]ny further detention . . . must be based on consent or probable cause.” United States v. Brignoni-Ponce, supra, at 882. None of the defendants in these cases argues that the stopping officers exceeded these limitations. Consequently, we affirm the judgment of the Court of Appeals for the Fifth Circuit, which had affirmed the conviction of Sifuentes. We reverse the judgment of the Court of Appeals for the Ninth Circuit and remand the case with directions to affirm the conviction of Martinez-Fuerte and to remand the other cases to the District Court for further proceedings.

It is so ordered.

MR. Justice Brennan,

with whom Mr. Justice Marshall joins,

dissenting.

Today's decision is the ninth this Term marking the continuing evisceration of Fourth Amendment protections against unreasonable searches and seizures. Early in the Term, Texas v. White, 423 U. S. 67 (1975), permitted the warrantless search of an automobile in police custody despite the unreasonableness of the custody *568and opportunity to obtain a warrant. United States v. Watson, 423 U. S. 411 (1976), held that regardless of whether opportunity exists to obtain a warrant, an arrest in a public place for a previously committed felony never requires a warrant, a result certainly not fairly supported by either history or precedent. See id., at 433 (Marshall, J., dissenting). United States v. Santana, 427 U. S. 38 (1976), went further and approved the warrantless arrest for a felony of a person standing on the front porch of her residence. United States v. Miller, 425 U. S. 435 (1976), narrowed the Fourth Amendment’s protection of privacy by denying the existence of a protectible interest in the compilation of checks, deposit slips, and other records pertaining to an individual’s bank account. Stone v. Powell, ante, p. 465, precluded the assertion of Fourth Amendment claims in federal collateral relief proceedings. United States v. Janis, ante, p. 433, held that evidence unconstitutionally seized by a state officer is admissible in a civil proceeding by or against the United States. South Dakota v. Opperman, ante, p. 364, approved sweeping inventory searches of automobiles in police custody irrespective of the particular circumstances of the case. Finally, in Andresen v. Maryland, 427 U. S. 463 (1976), the Court, in practical effect, weakened the Fourth Amendment prohibition against general warrants.

Consistent with this purpose to debilitate Fourth Amendment protections, the Court’s decision today virtually empties the Amendment of its reasonableness requirement by holding that law enforcement officials manning fixed checkpoint stations who make standard-less seizures of persons do not violate the Amendment. This holding cannot be squared with this Court’s recent decisions in United States v. Ortiz, 422 U. S. 891 (1975); United States v. Brignoni-Ponce, 422 U. S. 873 (1975); *569and Almeida-Sanchez v. United States, 413 U. S. 266 (1973). I dissent.

While the requisite justification for permitting a search or seizure may vary in certain contexts, compare Beck v. Ohio, 379 U. S. 89 (1964), with Terry v. Ohio, 392 U. S. 1 (1968), and Camara v. Municipal Court, 387 U. S. 523 (1967), even in the exceptional situations permitting intrusions on less than probable cause, it has long been settled that justification must be measured by objective standards. Thus in the seminal decision justifying intrusions on less-than-probable cause, Terry v. Ohio, supra, the Court said:

"The scheme of the Fourth Amendment becomes meaningful only when it is assured that at some point the conduct of those charged with enforcing the laws can be subjected to the more detached, neutral scrutiny of a judge who must evaluate the reasonableness of a particular search or seizure in light of the particular circumstances. And in making that assessment it is imperative that the facts be judged against an objective standard .... Anything less would invite intrusions upon constitutionally guaranteed rights based on nothing more substantial than inarticulate hunches, a result this Court has consistently refused to sanction.” 392 U. S., at 21-22 (emphasis added, footnote omitted).

“This demand for specificity in the information upon which police action is predicated is the central teaching of this Court’s Fourth Amendment jurisprudence.” 392 U. S., at 21 n. 18.

Terry thus made clear what common sense teaches: Conduct, to be reasonable, must pass muster under objective standards applied to specific facts.

We are told today, however, that motorists without number may be individually stopped, questioned, visu*570ally inspected, and then further detained without even a showing of articulable suspicion, see ante, at 547, let alone the heretofore constitutional minimum of reasonable suspicion, a result that permits search and seizure to rest upon “nothing more substantial than inarticulate hunches.” This defacement of Fourth Amendment protections is arrived at by a balancing process that overwhelms the individual’s protection against unwarranted official intrusion by a governmental interest said to justify the search and seizure. But that method is only a convenient cover for condoning arbitrary official conduct, for the governmental interests relied on as warranting intrusion here are the same as those in Almeida-Sanchez and Ortiz, which required a showing of probable cause for roving-patrol and fixed checkpoint searches, and Brignoni-Ponce, which required at least a showing of reasonable suspicion based on specific articulable facts to justify roving-patrol stops. Absent some difference in the nature of the intrusion, the same minimal requirement should be imposed for checkpoint stops.

The Court assumes, and I certainly agree, that persons stopped at fixed checkpoints, whether or not referred to a secondary detention area, are “seized” within the meaning of the Fourth Amendment. Moreover, since the vehicle and its occupants are subjected to a “visual inspection,” the intrusion clearly exceeds mere physical restraint, for officers are able to see more in a stopped vehicle than in vehicles traveling at normal speeds down the highway. As the Court concedes, ante, at 558, the checkpoint stop involves essentially the same intrusions as a roving-patrol stop, yet the Court provides no principled basis for distinguishing checkpoint stops.

Certainly that basis is not provided in the Court’s reasoning that the subjective intrusion here is appreciably less than in the case of a stop by a roving patrol. *571 Brignoni-Ponce nowhere bases the requirement of reasonable suspicion upon the subjective nature of the intrusion. In any event, the subjective aspects of checkpoint stops, even if different from the subjective aspects of roving-patrol stops, just as much require some principled restraint on law enforcement conduct. The motorist whose conduct has been nothing but innocent— and this is overwhelmingly the case — surely resents his own detention and inspection. And checkpoints, unlike roving stops, detain thousands of motorists, a dragnet-like procedure offensive to the sensibilities of free citizens. Also, the delay occasioned by stopping hundreds of vehicles on a busy highway is particularly irritating.

In addition to overlooking these dimensions of subjective intrusion, the Court, without explanation, also ignores one major source of vexation. In abandoning any requirement of a minimum of reasonable suspicion, or even articulable suspicion, the Court in every practical sense renders meaningless, as applied to checkpoint stops, the Brignoni-Ponce holding that “standing alone [Mexican appearance] does not justify stopping all Mexican-Americans to ask if they are aliens.” 1 422 *572U. S., at 887. Since the objective is almost entirely the Mexican illegally in the country, checkpoint officials, uninhibited by any objective standards and therefore free to stop any or all motorists without explanation or excuse, wholly on whim, will perforce target motorists of Mexican appearance. The process will then inescapably discriminate against citizens of Mexican ancestry and Mexican aliens lawfully in this country for no other reason than that they unavoidably possess the same “suspicious” physical and grooming characteristics of illegal Mexican aliens.

Every American citizen of Mexican ancestry and every Mexican alien lawfully in this country must know after today’s decision that he travels the fixed checkpoint highways at the risk of being subjected not only to a stop, but also to detention and interrogation, both prolonged and to an extent far more than for non-Mexican appearing motorists. To be singled out for referral and to be detained and interrogated must be upsetting to any motorist. One wonders what actual experience supports my Brethren’s conclusion that referrals “should not be frightening or offensive because of their public and relatively routine nature.” Ante, at 560.2 In point of fact, refer*573rals, viewed in context, are not relatively routine; thousands are otherwise permitted to pass. But for the arbitrarily selected motorists who must suffer the delay and humiliation of detention and interrogation, the experience can obviously be upsetting.3 And that experience is particularly vexing for the motorist of Mexican ancestry who is selectively referred, knowing that the officers’ target is the Mexican alien. That deep resentment will be stirred by a sense of unfair discrimination is not difficult to foresee.4

*574In short, if a balancing process is required, the balance should be struck, as in Brignoni-Ponce, to require that Border Patrol officers act upon at least reasonable suspicion in making checkpoint stops. In any event, even if a different balance were struck, the Court cannot, without ignoring the Fourth Amendment requirement of reasonableness, justify wholly unguided seizures by officials manning the checkpoints. The Court argues, however, that practicalities necessitate otherwise: “A requirement that stops on major routes inland always be based on reasonable suspicion would be impractical because the flow of traffic tends to be too heavy to allow the particularized study of a given car that would enable it to be identified as a possible carrier of illegal aliens.” Ante, at 557.

As an initial matter, whatever force this argument may have, it cannot apply to the secondary detentions that occurred in No. 74-1560. Once a vehicle has been slowed and observed at a checkpoint, ample opportunity *575exists to formulate the reasonable suspicion which, if it actually exists, would, justify further detention. Indeed, though permitting roving stops based on reasonable suspicion, Brignoni-Ponce required that “any further detention or search must be based on [the greater showing of] consent or probable cause.” 422 U. S., at 882. The Court today, however, does not impose a requirement of even reasonable suspicion for these secondary stops.

The Court’s rationale is also not persuasive because several of the factors upon which officers may rely in establishing reasonable suspicion are readily ascertainable, regardless of the flow of traffic. For example, with checkpoint stops as with roving-patrol stops, “[a]spects of the vehicle itself may justify suspicion.” Id., at 885. Thus it is relevant that the vehicle is a certain type of station wagon, appears to be heavily loaded, contains an extraordinary number of persons, or contains persons trying to hide. See ibid. If such factors are satisfactory to permit the imposition of a reasonable-suspicion requirement in the more demanding circumstances of a roving patrol, where officers initially deal with a vehicle traveling, not at a crawl, but at highway speeds, they clearly should suffice in the circumstances of a checkpoint stop.

Finally, the Court’s argument fails for more basic reasons. There is no principle in the jurisprudence of fundamental rights which permits constitutional limitations to be dispensed with merely because they cannot be conveniently satisfied. Dispensing with reasonable suspicion as a prerequisite to stopping and inspecting motorists because the inconvenience of such a requirement would make it impossible to identify a given car as a possible carrier of aliens is no more justifiable than dispensing with probable cause as prerequisite to the search of an individual because the inconvenience of *576such a requirement would make it impossible to identify a given person in a high-crime area as a possible carrier of concealed weapons. “The needs of law enforcement stand in constant tension with the Constitution’s protections of the individual against certain exercises of official power. It is precisely the predictability of these pressures that counsels a resolute loyalty to constitutional safeguards.” Almeida-Sanchez v. United States, 413 U. S., at 273.

The Court also attempts to justify its approval of standardless conduct on the ground that checkpoint stops “involve less discretionary enforcement activity” than roving stops. Ante, at 559. This view is at odds with its later more revealing statement that “officers must have wide discretion in selecting the motorists to be diverted for the brief questioning involved.” Ante, at 564. Similarly unpersuasive is the statement that “since field officers may stop only those cars passing the checkpoint, there is less room for abusive or harassing stops of individuals than there was in the case of roving-patrol stops.” Ante, at 559.5 The Fourth Amendment stand*577ard of reasonableness admits of neither intrusion at the discretion of law enforcement personnel nor abusive or harassing stops, however infrequent. Action based merely on whatever may pique the curiosity of a particular officer is the antithesis of the objective standards requisite to reasonable conduct and to avoiding abuse and harassment. Such action, which the Court now permits, has expressly been condemned as contrary to basic Fourth Amendment principles. Certainly today's holding is far removed from the proposition emphatically affirmed in United States v. United States District Court, 407 U. S. 297, 317 (1972), that “those charged with . . . investigative and prosecutorial duty should not be the sole judges of when to utilize constitutionally sensitive means in pursuing their tasks. The historical judgment, which the Fourth Amendment accepts, is that unreviewed executive discretion may yield too readily to pressures to obtain incriminating evidence and overlook potential invasions of privacy . . . Indeed, it is far removed from the even more recent affirmation that “the central concern of the Fourth Amendment is to protect liberty and privacy from arbitrary and oppressive interference by government officials.” United States v. Ortiz, 422 U. S., at 895.6

*578The cornerstone of this society, indeed of any free society, is orderly procedure. The Constitution, as originally adopted, was therefore, in great measure, a procedural document. For the same reasons the drafters of the Bill of Rights largely placed their faith in procedural limitations on government action. The Fourth Amendment’s requirement that searches and seizures be reasonable enforces this fundamental understanding in erecting its buffer against the arbitrary treatment of citizens by government. But to permit, as the Court does today, police discretion to supplant the objectivity of reason and, thereby, expediency to reign in the place of order, is to undermine Fourth Amendment safeguards and threaten erosion of the cornerstone of our system of a government, for, as Mr. Justice Frankfurter reminded us, “[t]he history of American freedom is, in no small measure, the history of procedure.” Malinski v. New York, 324 U. S. 401, 414 (1945).

Mr. Justice Powell

delivered the opinion of the Court.

Border Patrol officers stopped respondent’s car for a routine immigration search at the traffic checkpoint' *892on Interstate Highway 5 at San Clemente, Cal., on November 12, 1973. They found three aliens concealed in the trunk, and respondent was convicted on three counts of knowingly transporting aliens who were in the country illegally. The Court of Appeals for the Ninth Circuit reversed the conviction in an unreported opinion, relying on dictum in its opinion in United States v. Bowen, 500 F. 2d 960 (CA9 1974), aff’d, post, p. 916, to the effect that our decision in Almeida-Sanchez v. United States, 413 U. S. 266 (1973), required probable cause for all vehicle searches in the border area, whether conducted by roving patrols or at traffic checkpoints. We granted certiorari. 419 U. S. 824 (1974).

Nothing in this record suggests that the Border Patrol officers had any special reason to suspect that respondent’s car was carrying concealed aliens. Nor does the Government contend that the San Clemente checkpoint is a functional equivalent of the border. Brief for United States 16. The only question for decision is whether vehicle searches at traffic checkpoints, like the roving-patrol search in Almeida-Sanchez, must be based on probable cause.

I

In Almeida-Sanchez we rejected the Government’s contention that the Nation’s strong interest in controlling immigration and the practical difficulties of policing the Mexican border combined to justify dispensing with both warrant and probable cause for vehicle searches by roving patrols near the border. The facts did not require us to decide whether the same rule would apply to traffic checkpoints, which differ from roving patrols in several important respects. 413 U. S., at 273; id., at 276 (Powell, J., concurring).

A consolidated proceeding on motions to suppress in this and similar cases produced an extensive factual *893record on the operation of traffic checkpoints in southern California. United States v. Baca, 368 F. Supp. 398 (SD Cal. 1973). The San Clemente checkpoint is 62 air miles and 66 road miles north of the Mexican border. It is on the principal highway between San Diego and Los Angeles, and over 10 million vehicles pass the checkpoint in a year. United States v. Martinez-Fuerte, 514 F. 2d 308, 312 (CA9 1975). The District Court in Baca described the checkpoint as follows:

“Approximately one mile south of the checkpoint is a large black on yellow sign with flashing yellow lights over the highway stating ‘ALL VEHICLES, STOP AHEAD, 1 MILE.’ Three-quarters of a mile further north are two black on yellow signs suspended over the highway with flashing lights stating ‘WATCH FOR BRAKE LIGHTS.' At the checkpoint, which is also the location of a State of California weighing station, are two large signs with flashing red lights suspended over the highway. These signs each state ‘STOP HERE — U. S. OFFICERS.' Placed on the highway are a number of orange traffic cones tunneling traffic into two lanes where a Border Patrol agent in full dress uniform, standing behind a white on red ‘STOP' sign checks traffic. Blocking traffic in the unused lanes are official U. S. Border Patrol vehicles with flashing red lights. In addition, there is a permanent building which houses the Border Patrol office and temporary detention facilities. There are also floodlights for nighttime operation.” 368 F. Supp., at 410-411.

The Border Patrol would prefer to keep this checkpoint in operation continuously, but bad weather, heavy traffic, and personnel shortages keep it closed about one-third of the time. When it is open, officers screen all northbound traffic. If anything about a vehicle or its *894occupants leads an officer to suspect that it may be carrying aliens, he will stop the car and ask the occupants about their citizenship. If the officer’s suspicion persists, or if the questioning enhances it, he will “inspect” portions of the car in which an alien might hide.1 Operations at other checkpoints are similar, although the traffic at some is light enough that officers can stop all vehicles for questioning and routinely inspect more of them.

The Government maintains that these characteristics justify dispensing with probable cause at traffic checkpoints despite the' Court’s holding in Almeida-Sanchez. It gives essentially two reasons for distinguishing that case. First, a checkpoint officer’s discretion in deciding which cars to search is limited by the location of the checkpoint. That location is determined by high-level Border Patrol officials, using criteria that include the degree of inconvenience to the public and the potential for safe operation, as well as the potential for detecting and deterring the illegal movement of aliens. By contrast, officers on roving patrol were theoretically free before Almeida-Sanchez to stop and search any car within 100 miles of the border. Second, the circumstances surrounding a checkpoint stop and search are far less intrusive than those attending a roving-patrol stop. Roving patrols often operate at night on seldom-traveled roads, and their approach may frighten motorists. At *895traffic checkpoints the motorist can see that other vehicles are being stopped, he can see visible signs of the officers’ authority, and he is much less likely to be frightened or annoyed by the intrusion.

These differences are relevant to the constitutional issue, since the central concern of the Fourth Amendment is to protect liberty and privacy from arbitrary and oppressive interference by government officials. Camara v. Municipal Court, 387 U. S. 523, 528 (1967); Schmerber v. California, 384 U. S. 757, 767 (1966). The Fourth Amendment’s requirement that searches and seizures be reasonable also may limit police use of unnecessarily frightening or offensive methods of surveillance and investigation. See, e. g., Terry v. Ohio, 392 U. S. 1, 16-17 (1968); Camara, supra, at 531; Schmerber, supra, at 771-772. While the differences between a roving patrol and a checkpoint would be significant in determining the propriety of the stop, which is considerably less intrusive than a search, Terry v. Ohio, supra, they do not appear to make any difference in the search itself. The greater regularity attending the stop does not mitigate the invasion of privacy that a search entails. Nor do checkpoint procedures significantly reduce the likelihood of embarrassment. Motorists whose cars are searched, unlike those who are only questioned, may not be reassured by seeing that the Border Patrol searches other cars as well. Where only a few are singled out for a search, as at San Clemente, motorists may find the searches especially offensive. See Note, Border Searches and the Fourth Amendment, 77 Yale L. J. 1007, 1012-1013 (1968).

Moreover, we are not persuaded that the checkpoint limits to any meaningful extent the officer’s discretion to select cars for search. The record in the consolidated proceeding indicates that only about 3% of the cars that *896pass the San Clemente checkpoint are stopped for either questioning or a search, 368 F. Supp., at 411. Throughout the system, fewer than 3% of the vehicles that passed through checkpoints in 1974 were searched, Brief for United States 29, and no checkpoint involved in Baca reported a search rate of more than 10% or 15%. 368 F. Supp., at 412-415. It is apparent from these figures that checkpoint officers exercise a substantial degree of discretion in deciding which cars to search. The Government maintains that they voluntarily exercise that discretion with restraint and search only vehicles that arouse their suspicion, and it insists the officers should be free of judicial oversight of any kind. Viewed realistically, this position would authorize the Border Patrol to search vehicles at random, for no officer ever would have to justify his decision to search a particular car.

This degree of discretion to search private automobiles is not consistent with the Fourth Amendment. A search, even of an automobile, is a substantial invasion of privacy.2 To protect that privacy from official arbitrariness, the Court always has regarded probable cause as the minimum requirement for a lawful search. Almeida-Sanchez, 413 U. S., at 269-270; Chambers v. Maroney, 399 U. S. 42, 51 (1970). We are not persuaded that the differences between roving patrols and traffic checkpoints justify dispensing in this case with the safeguards we required in Almeida-Sanchez. We therefore follow that decision and hold that at traffic checkpoints removed from the border and its functional equivalents, *897officers may not search private vehicles without consent or probable cause.3

The Government lists in its reply brief some of the factors on which officers have relied in deciding which cars to search. They include the number of persons in a vehicle, the appearance and behavior of the driver and passengers, their inability to speak English, the responses they give to officers’ questions, the nature of the vehicle, and indications that it may be heavily loaded. All of these factors properly may be taken into account in deciding whether there is probable cause to search a particular vehicle. In addition, as we note today in United States v. Brignoni-Ponce, ante, at 884-885, the officers are entitled to draw reasonable inferences from these facts in light of their knowledge of the area and their prior experience with aliens and smugglers. In this case, however, the officers advanced no special reasons for believing respondent’s vehicle contained *898aliens. The absence of probable cause makes the search invalid.

II

The Government also contends that even if AlmeidaSanchez applies to checkpoint searches, the Court of Appeals erred in voiding this search because it occurred after the date of decision in Almeida-Sanchez but before the Court of Appeals stated in United States v. Bowen, supra, that it would require probable cause for checkpoint searches. Examination of the Government’s brief in the Ninth Circuit indicates that it did not raise this question below. On the contrary, it represented to the court that the decision in Bowen would be “determinative of the issues in this case.” We therefore decline to consider this issue, which was raised for the first time in the petition for certiorari.

Affirmed.

Mr. Justice Rehnquist,

concurring.

I joined the dissent of my Brother White in Almeida-Sanchez v. United States, 413 U. S. 266 (1973), and recognize that the present decision is an extension of the unsound rule announced in that case. I nonetheless join the opinion of the Court, because a majority of the Court still adheres to Almeida-Sanchez and because I agree with the Court’s analysis of the significance of the Government’s proffered distinctions between roving and fixed-checkpoint searches.

I wish to stress, however, that the Court’s opinion is confined to full searches, and does not extend to fixed-checkpoint stops for the purpose of inquiring about citizenship. Such stops involve only a modest intrusion, are not likely to be frightening or significantly annoying, are regularized by the fixed situs, and effectively serve the important national interest in controlling illegal *899entry. I do not regard such stops as unreasonable under the Fourth Amendment, whether or not accompanied by “reasonable suspicion” that a particular vehicle is involved in immigration violations, cf. United States v. Brignoni-Ponce, ante, p. 873, and I do not understand today’s opinion to cast doubt upon their constitutionality.

Me. Chief Justice Burger,

with whom Mr. Justice Blackmun joins, concurring in the judgment.*

Like Mr. Justice White I can, at most, do no more than concur in the judgment. As the Fourth Amendment now has been interpreted by the Court it seems that the Immigration and Naturalization Service is powerless to stop the tide of illegal aliens — and dangerous drugs — that daily and freely crosses our 2,000-mile southern boundary.1 Perhaps these decisions will be seen in perspective as but another example of a society seemingly impotent to deal with massive lawlessness. In that sense history may view us as prisoners of our own traditional and appropriate concern for individual rights, unable — or unwilling — to apply the concept of reasonableness explicit in the Fourth Amendment in order to develop a rational accommodation between those rights and the literal safety of the country.

*900Given today’s decisions it would appear that, absent legislative action, nothing less than a massive force of guards could adequately protect our southern border.2 To establish hundreds of checkpoints with enlarged border forces so as to stop literally every car and pedestrian at every border checkpoint, however, would doubtless impede the flow of commerce and travel between this country and Mexico. Moreover, it is uncertain whether stringent penalties for employment of illegal aliens, and rigid requirements for proof of legal entry before employment, would help solve the problems, but those remedies have not been tried.

1 would hope that when we next deal with this problem we give greater weight to the reality that the Fourth Amendment prohibits only “unreasonable searches and seizures” and to the frequent admonition that reasonableness must take into account all the circumstances and balance the rights of the individual with the needs of society. See, e. g., Terry v. Ohio, 392 U. S. 1 (1968); Elkins v. United States, 364 U. S. 206 (1960); United States v. Biswell, 406 U. S. 311 (1972).

APPENDIX TO OPINION OF BURGER, C. J., CONCURRING IN THE JUDGMENT

Excerpt from Judge Turrentine’s opinion in United States v. Baca, 368 F. Supp. 398, 402-408 (SD Cal. 1973)

THE ILLEGAL ALIEN PROBLEM

The United States through legislative action has determined that it is in the best interest of the nation to limit the number of persons who can legally immigrate into the country in any given year. These controls *901reflect in part a Congressional intent to protect the American labor market from an influx of foreign labor. Karnuth v. United States, 279 U. S. 231 ... (1929); § 201 (a) of the Immigration and Nationality Act of 1952, 66 Stat. 163, as amended by the Act of October 3, 1965, 79 Stat. 911, 8 U. S. C. § 1151 (a).

Under this policy of limited admission, 385,685 new immigrants entered the United States legally during fiscal year 1972. Since July 1, 1968, the law has established an annual quota of 120,000 persons for the independent countries of the Western Hemisphere. Included within this quota are immigrants from the Republic of Mexico who in fiscal year 1972 totalled 64,040. 1972 Annual Report, Immigration and Naturalization Service, p. 2, 28.

Currently illegal aliens are in residence within the United States in numbers which, while not susceptible of exact measurement, are estimated to be in the vicinity of 800,000 to over one million. Department of Justice, Special Study Group on Illegal Immigrants from Mexico, A Program for Effective And Humane Action on Illegal Mexican Immigrants, 6 (1973), [hereinafter cited as Cramton Rpt.].

Of these illegal aliens, approximately 85 percent are citizens of Mexico. Cramton Rpt. at 6. They are industrious, proud and hard-working people who enter this country for the purpose of earning wages, accumulating savings, and returning or sending their savings home to Mexico.

Since 1970, the number of illegal Mexican aliens in the United States who have been apprehended has been growing at a rate in excess of 20 percent per year. Cramton Rpt. at 6.

The increasingly large numbers of Mexican nationals seeking to illegally enter this country reflects the sub*902stantial unemployment and underemployment in Mexico — fueled by one of the highest birth rates in the world. Moreover, Mexican employment statistics are not likely to improve dramatically since fully 45 percent of Mexico’s population is under 15 years of age and, therefore, will soon be attempting to enter the labor market.

Further prompting Mexican nationals to seek employment in the United States is the fact that there is a significant disparity in wage rates between this country and Mexico. In Mexicali and Tijuana, both Mexican cities bordering the Southern District and each with a population in excess of 400,000, the average daily wage is about $3.40 per day. The minimum wage is even lower for workers in the interior of Mexico. The average worker in Mexico, assuming he can find work, earns in a day as much as he can make in only a few hours in the United States.

In addition, it is estimated that the per capita income of the poorest 40 percent of the Mexican population, the strata most likely to leave their homeland in search of employment in the United States, is less than $150 per year.

The manpower needs of the United States generated by World War II resulted in many Mexicans being imported into this country and becoming familiar with employment opportunities and practices in the United States. See Diaz v. Kay-Dix Ranch, 9 Cal. App. 3d 588, 88 Cal. Rptr. 443 (1970).

The opportunities available to Mexican aliens have traditionally been in agriculture. While still true in many parts of the United States Southwest, in recent years the pattern has changed and more and more illegal aliens are obtaining employment in the service and manufacturing sectors of our economy. These aliens are increasingly found in virtually all regions of the country *903and in all segments of the economy. State Social Welfare Board, Issue: Aliens in California, 12 (1973) [Hereinafter cited as Aliens in California].

The nature of the change in employment opportunities available is demonstrated by one estimate that 250,000 illegal aliens are employed in Los Angeles County where agricultural opportunities are known to be limited. Hearings on Illegal Aliens Before Subcom. No. 1 of the House Comm, on the Judiciary, 92d Cong., 1st Sess., pt. 1, at 208 (1971) [Hereinafter cited as Hearings on Illegal Aliens].

Other estimates of the impact of illegal aliens in California suggest that in 1971, when 595,000 Californians were unemployed (7.4 percent of the State’s labor force), there were between 200,000 and 300,000 illegal aliens employed in California earning approximately $100 million in wages. Hearings on Illegal Aliens at 150.

Since the majority of Mexicans are unskilled or low skilled workers they tend to compete with Mexican-Americans, blacks, Indians, and other minority groups who, due to the declining percentage of jobs requiring low or no skills, are finding it increasingly difficult to obtain gainful employment. Cramton Rpt. at 12.

Illegal aliens compete for jobs with persons legally residing in the United States who are unskilled and uneducated and who form that very group which our society is trying to provide with a fair share of America’s prosperity.

In addition, illegal aliens tend to perpetuate poor economic conditions by frustrating unionization, especially in such occupations as farm work.

Illegal aliens pose a potential health hazard to the community since many seek work as nursemaids, food handlers, cooks, housekeepers, waiters, dishwashers, and grocery workers. Immigration and medical officials in *904Los Angeles, for example, have discovered that the illegal alien population in Los Angeles’ barrio is infected with a high incidence of typhoid, dysentery, tuberculosis, tapeworms, venereal disease and hepatitis. L. A. Times, Sept. 16, 1973, pt. II, at 1.

In some states illegal aliens abuse public assistance programs. In some instances entire families who entered the country illegally have been admitted to the welfare rolls. Aliens in California at 35, 43.

Another aspect of the problem created by illegal aliens is that employed aliens tend to send a substantial portion of their earnings to relatives or friends in Mexico. This outflow of United States dollars exacerbates our balance of payments problem to the extent of $1 billion a year. Hearings on Illegal Aliens, pt. 3 at 683.

The net effect of this silent invasion of illegal aliens from Mexico is suffering by the aliens who are frequently victims of extortion, violence and sharp practices, displacement of American citizens and legally residing aliens from the labor market, and irritation between two neighboring countries.

THE LAW ENFORCEMENT PROBLEM

Given that illegal aliens are a significant problem in American life, especially for those minority groups who are described as economically deprived, and that Congress has decreed that all but a relatively few aliens are to be permanently excluded, then we must analyze what law enforcement problems exist. In this regard, the following findings of fact are made:

The illegal alien problem is one found primarily in the Southwestern Region of the United States.

This problem along the Mexican-American border has existed for some time with the original responsibility for securing the integrity of the border being assigned to *905the U. S. Army, along with the Departments of Treasury and Labor, who had about 20,000 men assigned to the border between Brownsville, Texas, and San Diego, California, in 1920. National Geographic Magazine, “Along Our Side of the Mexican Border.” (July 1920).

Currently the burden of controlling the entry of aliens and stemming the flow of illegal aliens along the Mexican-American border is assigned to the INS.1

The border extends for almost 2,000 miles from the Gulf of Mexico to the Pacific Coast.

Along this border there were over 152 million legal entries at authorized ports of entry during fiscal 1972, of which over 91 million were made by aliens. Over 39 million of the legal entries were made at the three ports of entry in Southern California (Calexico, San Ysidro and Tecate) of which over 24 million were made by aliens. Immigration and Naturalization Service, 1972 Annual Report, 25.

Of these entries made by aliens, the large portion were made by visitors with official permission to enter the country who had been issued temporary “border passes” such as 1-186 cards (issued to residents of Mexico), which authorize the holder to travel within an area no further than 25 miles from the border and for a period of time not to exceed 72 hours. See 8 C. F. R. § 212.6.

These temporary border passes (1-186) are issued to simplify procedures needed for entry, and the issuing process recognizes the inter-relationship of contiguous communities along both sides of the border. Hearings on Illegal Aliens, pt. 1, 192.

In fiscal 1973 approximately 208,000 1-186 cards were issued and it is estimated that over two million such *906cards are currently in circulation. Hearings on Illegal Aliens, pt. 1, 173.

Within the INS, the U. S. Border Patrol, which was first established in 1924, has the primary function of preventing the illegal entry of aliens and the apprehension of those who have entered illegally and those who smuggle these illegal entrants.

The Border Patrol has approximately 1,700 agents, who are well-trained law enforcement officers, and of these about 80 percent are assigned along our southern border with Mexico.

A “deportable alien” is a person who has been found to be deportable by an immigration judge, or who admits his deportability upon questioning by official agents.

The number of deportable aliens apprehended by the Border Patrol (which makes the great majority of apprehensions) nationally has grown from 38,861 during fiscal 1963 to 498,123 in fiscal 1973; of this number 128,889 were found by Border Patrol agents working in the Chula Vista sector which includes 70 miles of the border in San Diego County, and 23,125 were located by agents in the El Centro sector which includes the Imperial County of California and 75 miles of the Mexican-American border.

The Border Patrol agents have the power to apprehend illegal aliens since by regulation the Attorney General has designated Border Patrol agents to be immigration officers and authorized them to exercise powers and duties as such officers [8 C. F. R. § 103.1 (i)]; immigration officers by statute § 101 (a) (17) of the Immigration and Nationality Act of 1952, 66 Stat. 163; as amended by the Act of October 3, 1973, 79 Stat. 911, 8 U. S. C. §1101 (a) (17), are empowered, without a warrant, to stop and interrogate any alien or person believed to be an alien as to his right to remain or to be in the United *907States. See Au Yi Lau v. I. N. S., 144 U. S. App. D. C. 147, 445 F. 2d 217 (1971), cert. denied, 404 U. S. 864 ....

Sec. 287 (a) (3) of the 1952 Immigration Act provides authority for an immigration officer within a reasonable distance from the border of the United States to board and search any conveyance or vehicle; “reasonable distance” as used in that section of the Act means within 100 air miles from any external boundary of the United States, 8 C. F. R. § 287.1 (b).

Immigration officers also are authorized to conduct inspection of aliens seeking admission or readmission to, or the privilege of passing through, the United States, and also are authorized and empowered to board and search any vehicle or like conveyance in which they believe aliens are being brought into the United States. Sec. 235 (a) of the 1952 Immigration Act, 8 U. S. C. § 1225 (a).

The deployment of Border Patrol agents along the border is intended to maximize the effectiveness of the limited number of personnel, with the first line of defense being called the “line watch.” The line watch consists of agents being placed immediately upon the physical boundary where experience has shown that large numbers of illegal aliens can be detected attempting entry. A large number of agents so assigned are primarily concerned with responding to sensor alarms (electronic detection equipment) which are located at strategic positions. These agents also respond to citizen complaints concerning the suspected presence of deportable aliens.

In fiscal 1973, there were 175,511 deportable aliens apprehended throughout the nation by agents assigned to the line watch, with 69,147 being apprehended in the Chula Yista sector and 5,908 in the El Centro sector.

While the Border Patrol would like to apprehend all *908deportable aliens right on the border by agents on the line, watch, inspections at regular points of entry are not infallible and illegal crossings at other than legal ports of entry are numerous and recurring. The maintenance of continuous patrol over the vast stretches of the border in Southern California is physically impossible, since the approximately 145 miles of boundary creates geographic barriers to effective patrol and man-made devices such as fences and electronic devices are in large part ineffective.

Increased manpower on line watch would not make that activity appreciably more effective as was demonstrated in 1969 during "Operation Intercept” when many more agents were stationed immediately on the border, and yet, the number of illegal aliens apprehended by agents operating inland was not significantly different from like periods when such additional manpower was not located at the boundary.

Once the aliens negotiate their way through the port of entry or, as is most common, walk across the border at a place other than an official port of entry, they find transportation inland either in public conveyances, or private vehicles with increasing numbers being transported by professional smugglers. A few have been known to walk some distance inland and have been apprehended after having walked as far north as Julian, California, which is over 60 miles from the border.

After crossing the line watch some illegal aliens seek employment in the Southern District, but the vast majority attempt to proceed to Los Angeles County and points north.

Once the illegal alien gets settled in a big city far away from the border it becomes very difficult to apprehend him, and therefore, the Border Patrol attempts to contain the illegal entrant within this district. Aliens in *909 California at 7. With this objective in mind, they have (pursuant to their statutory authority discussed above) established, since at least 1927, strategically located traffic inspection facilities, commonly referred to as checkpoints, on highways and roads, for the purpose of questioning vehicle occupants believed to be aliens, as to their right to be, or to remain, in the United States, and also to search such vehicles for illegal aliens. Immigration and Naturalization Service Border Patrol Handbook 9-1 (1972) [hereinafter cited as Handbook].

The primary objective of the checkpoints is to intercept vehicles or conveyances transporting illegal aliens, or nonresident aliens admitted with temporary border passing cards (1-186), with particular attention being paid to vehicles operated by smugglers or transporters destined for inland cities in violation of 8 U. S. C. § 1324.

The selection of the location of a checkpoint is determined by factors relevant to the interdiction or interception of deportable aliens who have succeeded in gaining entry in an unlawful manner or are proceeding beyond the immediate border area in violation of conditions of their admission as border crossers, 8 C. P. R. § 212.60. The primary factors in selecting a checkpoint site are:

1. A location on a highway just beyond the confluence of two or more roads from the border, in order to permit the checking of a large volume of traffic with a minimum number of officers. This also avoids the inconvenience of repeated checking of commuter or urban traffic which would occur if the sites were operated on the network of roads leading from and through the more populated areas near the border.

2. Terrain and topography that restrict passage of vehicles around the checkpoint, such as mountains, desert, and, as in the case of the San Clemente checkpoint, the Camp Pendleton Marine Base.

*9103. Safety factors: an unobstructed view of oncoming traffic, to provide a safe distance for slowing and stopping; parking space off the highway; power source to illuminate control signs and inspection area, and bypass capability for vehicles not requiring examination.

4. Due to the travel restrictions of the 1-186 nonresident border crosser to an area 25 miles from the border (unless issued additional documentation) the checkpoints, as a general rule, are located at a point beyond the 25 mile zone in order to control the unlawful movement inland of such visitors.

Strategic sites that meet the foregoing enumerated criteria are selected for “permanent checkpoints.” These are sites equipped to handle a large volume of traffic on what would be a 24-hour basis except in case of manpower shortage, poor weather, or where traffic becomes excessive causing a potential safety hazard. Handbook at 9-3.

Other traffic checkpoints, known as “temporary checkpoints” are maintained on roads where traffic is less frequent. The placement of these sites will be governed by the same safety factors as involved in permanent site placement and are usually located where the terrain allows an element of surprise. Operations at these temporary checkpoints are set up at irregular intervals and intermittently so as to confuse the potential violator. Handbook at 9-3.

When the checkpoints, whether permanent or temporary, are in operation, an officer standing at the “point” in full dress uniform on the highway will view the decelerating oncoming vehicles and their passengers, and will visually determine whether he has reason to believe the occupants of the vehicle are aliens (i. e., “breaks the pattern” of usual traffic). If so, the vehicle will be stopped (if the traffic at the checkpoint is heavy, as at *911the San Clemente checkpoint, the vehicle will be actually directed off the highway) for inquiries to be made by the agent. If the agent does not have reason to believe that the vehicle approaching the checkpoint is carrying aliens, he may exchange salutations, or merely wave the vehicle through the checkpoint.

If, after questioning the occupants, the agent then believes that illegal aliens may be secreted in the vehicle (because of a break in the “pattern” indicating the possibility of smuggling) he will inspect the vehicle by giving a cursory visual inspection of those areas of the vehicle not visible from the outside (i. e. trunk, interior portion of camper, etc.).

At the point of location of the sites now in regular use few aliens have reached the locale on foot, with 99 percent having entered a vehicle of one type or another. Approximately 12 percent of all apprehensions of deportable aliens throughout the nation are made at checkpoints.

In the United' States, during fiscal 1973, approximately 55,300 deportable aliens were apprehended by Border Patrol agents working traffic checking operations. In the Chula Vista sector the number for that period was 21,232, while in the El Centro sector the total was 3,825.2 During fiscal 1973, a total of 4,975 of the above were visitors apprehended at the checkpoints and a majority of these were those who were in violation of the terms of temporary border passes (Form 1-186).

The placement of the checkpoints and their operations are coordinated between the two sectors located in this *912district and with Border Patrol activities to the east in Arizona. In actual operation the checkpoints, be they “permanent” or “temporary,” have the same basic accouterments. Typically, about one-half mile to one mile south of the checkpoint is the first notification that the checkpoint is ahead. The notice is in the form of a black on yellow sign indicated “STOP AHEAD” which has floodlights for nighttime illumination, Handbook at 9-9. Next, about 200 yards from the checkpoint is another sign cautioning the traffic to slow down or to be careful; this sign usually has flashing yellow lights attached. For the fifty yards directly south of the checkpoint there are placed traffic cones evenly spaced along each side of the highway. The actual checkpoint has a sign indicating to the traffic to stop, with official Border Patrol vehicles parked on each side of the stop zone showing the official Border Patrol emblem and/or the designation U. S. OFFICERS. At this point the agents assigned at the “point,” in their official uniform, conduct checking and inspection operations. Beyond the checkpoint is usually a sign indicating “THANK YOU.”

While a large number of apprehensions are made at the checkpoints each year, as related above, the primary reason for their operation is that they effectively deter large numbers of aliens from illegally entering the country or violating the terms of any temporary crossing card they may have, because they form an effective obstacle and are located on all major routes north out of the border region.

The deterrence aspect of these traffic checkpoint operations is amply demonstrated by the fact that the illegal alien has to resort to the employment of professional smugglers to provide transportation around or through these checkpoints.

Some of these smuggling operations have developed *913into sophisticated and involved operations with the following general modus operandi:

1. Contact is made between the smuggler and the alien prior to the latter’s leaving Mexico.

2. The aliens then make entry on foot, with possibly the aid of a “guide,” or by use of temporary border passes. Then they enter vehicles approximately 2 or 20 miles inland after having passed through the Border Patrol’s line watch activities.

3. To get through the traffic checkpoint they might use a “drop house,” which acts as a staging area to keep the aliens awaiting inclement weather, or any event that might cause the checkpoint to close down temporarily. Or, they may use a “decoy” vehicle, which is a vehicle loaded with illegal aliens which it is anticipated will be stopped at the checkpoint and would therefore occupy the agents so that other vehicles could pass through without inspection. They even use “scout cars” to probe those roads where temporary checkpoints are maintained, so as to advise other vehicles whether it is safe to proceed.

4. The “load” vehicles themselves can be of any type of conveyance and the methods used to secrete aliens inside them are varied and often show some originality. Unfortunately, sometimes these are very dangerous to the aliens themselves. It has been reported, for example, that it is not at all unusual for an alien to die from asphyxiation while concealed in an automobile trunk or a tank car.

5. The cost of the transportation provided to the aliens is approximately $225 to $250 for each alien for the trip through the checkpoint on to the Los Angeles area. Since smuggling operations are almost exclusively “cash and carry” businesses and the average income among Mexican nationals who may wish to seek resi*914dence here illegally is quite small, this cost tends to act as a very significant deterrent in and of itself. The checkpoints are the major reason for such a high price and if they were discontinued for any length of time it would be one more encouragement to illegal immigration.

The deterrent impact of these checkpoints has been noted on several occasions when they, resumed operation unexpectedly and a great number of aliens were apprehended.

The evidence presented before this court clearly established that there is no reasonable or effective alternative method of detection and apprehension available to the Border Patrol in the absence of the checkpoints, for even a geometric increase in its personnel or line watch would not leave any control over those admitted as temporary visitors from Mexico.

Of the approximately half million illegal aliens apprehended in fiscal 1973, virtually none were prosecuted, unless they presented counterfeit or altered documents or aided in smuggling endeavors.

This district has only 3 percent of the total length of land borders, and yet fully 30 percent of all apprehensions of deportable aliens made in the United States are made within this district.

Mr. Justice White,

with whom Mr. Justice Black-mun joins, concurring in the judgment.*

Given Almeida-Sanchez v. United States, 413 U. S. 266 (1973), with which I disagreed but which is now authoritative, the results reached in these cases were largely foreordained. The Court purports to leave the question open, but it seems to me, my Brother Rehnquist *915notwithstanding, that under the Court’s opinions checkpoint investigative stops, without search, will be difficult to justify under the Fourth Amendment absent probable cause or reasonable suspicion. In any event, the Court has thus dismantled major parts of the apparatus by which the Nation has attempted to intercept millions of aliens who enter and remain illegally in this country.

The entire system, however, has been notably unsuccessful in deterring or stemming this heavy flow; and its costs, including added burdens on the courts, have been substantial. Perhaps the Judiciary should not strain to accommodate the requirements of the Fourth Amendment to the needs of a system which at best can demonstrate only minimal effectiveness as long as it is lawful for business firms and others to employ aliens who are illegally in the country. This problem, which ordinary law enforcement has not been able to solve, essentially poses questions of national policy and is chiefly the business of Congress and the Executive Branch rather than the courts.

I concur in the judgment in these two cases.

Justice O’Connor

delivered the opinion of the Court.

In Michigan Dept. of State Police v. Sitz, 496 U. S. 444 (1990), and United States v. Martinez-Fuerte, 428 U. S. 543 (1976), we held that brief, suspicionless seizures at highway checkpoints for the purposes of combating drunk driving and intercepting illegal immigrants were constitutional. We now consider the constitutionality of a highway checkpoint program whose primary purpose is the discovery and interdiction of illegal narcotics.

I

In August 1998, the city of Indianapolis began to operate vehicle checkpoints bn Indianapolis roads in an effort to interdict unlawful drugs. The city conducted six such roadblocks between August and November that year, stopping *351,161 vehicles and arresting 104 motorists. Fifty-five arrests were for drug-related crimes, while 49 were for offenses unrelated to drugs. Edmond v. Goldsmith, 183 F. 3d 659, 661 (CA7 1999). The overall “hit rate” of the program was thus approximately nine percent.

The parties stipulated to the facts concerning the operation of the checkpoints by the Indianapolis Police Department (IPD) for purposes of the preliminary injunction proceedings instituted below. At each checkpoint location, the police stop a predetermined number of vehicles. Approximately 30 officers are stationed at the checkpoint. Pursuant to written directives issued by the chief of police, at least one officer approaches the vehicle, advises the driver that he or she is being stopped briefly at a drug checkpoint, and asks the driver to produce a license and registration. The officer also looks for signs of impairment and conducts an open-view examination of the vehicle from the outside. A narcotics-detection dog walks around the outside of each stopped vehicle.

The directives instruct the officers that they may conduct a search only by consent or based on the appropriate quantum of particularized suspicion. The officers must conduct each stop in the same manner until particularized suspicion develops, and the officers have no discretion to stop any vehicle out of sequence. The city agreed in the stipulation to operate the checkpoints in such a way as to ensure that the total duration of each stop, absent reasonable suspicion or probable cause, would be five minutes or less.

The affidavit of Indianapolis Police Sergeant Marshall DePew, although it is technically outside the parties’ stipulation, provides further insight concerning the operation of the checkpoints. According to Sergeant DePew, checkpoint locations are selected weeks in advance based on such considerations as area crime statistics and traffic flow. The checkpoints are generally operated during daylight hours and are identified with lighted signs reading, “ ‘NARCOTICS *36CHECKPOINT_MILE AHEAD, NARCOTICS K-9 IN USE, BE PREPARED TO STOP.’” App. to Pet. for Cert. 57a. Once a group of cars has been stopped, other traffic proceeds without interruption until all the stopped cars have been processed or diverted for further processing. Sergeant DePew also stated that the average stop for a vehicle not subject to further processing lasts two to three minutes or less.

Respondents James Edmond and Joell Palmer were each stopped at a narcotics checkpoint in late September 1998. Respondents then filed a lawsuit on behalf of themselves and the class of all motorists who had been stopped or were subject to being stopped in the future at the Indianapolis drug checkpoints. Respondents claimed that the roadblocks violated the Fourth Amendment of the United States Constitution and the search and seizure provision of the Indiana Constitution. Respondents requested declaratory and in-junctive relief for the class, as well as damages and attorney’s fees for themselves.

Respondents then moved for a preliminary injunction. Although respondents alleged that the officers who stopped them did not follow the written directives, they agreed to the stipulation concerning the operation of the checkpoints for purposes of the preliminary injunction proceedings. The parties also stipulated to certification of the plaintiff class. The United States District Court for the Southern District ■ of Indiana agreed to class certification and denied the motion for a preliminary injunction, holding that the checkpoint program did not violate the Fourth Amendment. Edmond v. Goldsmith, 38 F. Supp. 2d 1016 (1998). A divided panel of the United States Court of Appeals for the Seventh Circuit reversed, holding that the checkpoints contravened the Fourth Amendment. 183 F. 3d 659 (1999). The panel denied rehearing. We granted certiorari, 528 U. S. 1153 (2000), and now affirm.

*37II

The Fourth Amendment requires that searches and seizures be reasonable. A search or seizure is ordinarily unreasonable in the absence of individualized suspicion of wrongdoing. Chandler v. Miller, 520 U. S. 305, 308 (1997). While such suspicion is not an “irreducible” component of reasonableness, Martinez-Fuerte, 428 U. S., at 561, we have recognized only limited circumstances in which the usual rule does not apply. For example, we have upheld certain regimes of suspicionless searches where the program was designed to serve “special needs, beyond the normal need for law enforcement.” See, e. g., Vernonia School Dist. 47J v. Acton, 515 U. S. 646 (1995) (random drug testing of studentathletes); Treasury Employees v. Von Raab, 489 U. S. 656 (1989) (drug tests for United States Customs Service employees seeking transfer or promotion to certain positions); Skinner v. Railway Labor Executives’ Assn., 489 U. S. 602 (1989) (drug and alcohol tests for railway employees involved in train accidents or found to be in violation of particular safety regulations). We have also allowed searches for certain administrative purposes without particularized suspicion of misconduct, provided that those searches are appropriately limited. See, e. g., New York v. Burger, 482 U. S. 691, 702-704 (1987) (warrantless administrative inspection of premises of “closely regulated” business); Michigan v. Tyler, 436 U. S. 499, 507-509, 511-512 (1978) (administrative inspection of fire-damaged premises to determine cause of blaze); Camara v. Municipal Court of City and County of San Francisco, 387 U. S. 523, 534-539 (1967) (administrative inspection to ensure compliance with city housing code).

We have alsoseizures of motorists at a fixed Border Patrol checkpoint designed to intercept illegal aliens, Martinez-Fuerte, supra, and at a sobriety checkpoint aimed at removing drunk drivers from the road, Michigan Dept. of State Police v. Sitz, 496 U. S. 444 (1990). In addition, in Delaware v. Prouse, 440 U. S. 648, 663 (1979), *38we suggested that a similar type of roadblock with the purpose of verifying drivers’ licenses and vehicle registrations would be permissible. In none of these cases, however, did we indicate approval of a checkpoint program whose primary purpose was to detect evidence of ordinary criminal wrongdoing.

In Martinez-Fuerte, we challenges to stops at two permanent immigration checkpoints located on major United States highways less than 100 miles from the Mexican border. We noted at the outset the particular context in which the constitutional question arose, describing in some detail the “formidable law enforcement problems” posed by the northbound tide of illegal entrants into the United States. 428 U. S., at 551-554. These problems had also been the focus of several earlier cases addressing the constitutionality of other Border Patrol traffic-checking operations. See United States v. Ortiz, 422 U. S. 891 (1975); United States v. Brignoni-Ponce, 422 U. S. 873 (1975); Almeida-Sanchez v. United States, 413 U. S. 266 (1973). In Martinez-Fuerte, we found that the balance tipped in favor of the Government’s interests in policing the Nation’s borders. 428 U. S., at 561-564. In so finding, we emphasized the difficulty of effectively containing illegal immigration at the border itself. Id., at 556. We also stressed the impracticality of the particularized study of a given car to discern whether it was transporting illegal aliens, as well as the relatively modest degree of intrusion entailed by the stops. Id., at 556-564.

Our subsequent cases specifically related to the need to police the border were a significant factor in our Martinez-Fuerte decision. For example, in United States v. Montoya de Hernandez, 473 U. S. 531, 538 (1985), we counted Martinez-Fuerte as one of a number of Fourth Amendment cases that “reflect longstanding concern for the protection of the integrity of the border.” Although the stops in Martinez-Fuerte did not occur at the *39border itself, the checkpoints were located near the border and served a border. control function made necessary by the difficulty of guarding the border’s entire length. See Martinez-Fuerte, supra, at 556.

In Sitz, we evaluated the constitutionality of a Michigan highway sobriety checkpoint program. The Sitz checkpoint involved brief, suspicionless stops of motorists so that police officers could detect signs of intoxication and remove impaired drivers from the road. 496 U. S., at 447-448. Motorists who exhibited signs of intoxication were diverted for a license and registration check and, if warranted, further sobriety tests. Id., at 447. This checkpoint program was clearly aimed at reducing the immediate hazard posed by the presence of drunk drivers on the highways, and there was an obvious connection between the imperative of highway safety and the law enforcement practice at issue. The gravity of the drunk driving problem and the magnitude of the State’s interest in getting drunk drivers off the road weighed heavily in our determination that the program was constitutional. See id., at 451.

In Prouse, we invalidated a discretionary, suspicionless stop for a spot check of a motorist’s driver’s license and vehicle registration. The officer’s conduct' in that case was unconstitutional primarily on account of his exercise of “stand-ardless and unconstrained discretion.” 440 U. S., at 661. We nonetheless acknowledged the States’ “vital interest in ensuring that only those qualified to do so are permitted to operate motor vehicles, that these vehicles are fit for safe operation, and hence that licensing, registration, and vehicle inspection requirements are being observed.” Id., at 658. Accordingly, we suggested that “[questioning of all oncoming traffic at roadblock-type stops” would be a lawful means of serving this interest in highway safety. Id., at 668.

We furtherwe considered the purposes of such a hypothetical roadblock to be distinct from a general purpose of investigating crime. The State prof*40fered the additional interests of “the apprehension of stolen motor vehicles and of drivers under the influence of alcohol or narcotics” in its effort to justify the discretionary spot check. Id,, at 659, n. 18. We attributed the entirety of the latter interest to the State’s interest in roadway safety. Ibid. We also noted that the interest in apprehending stolen vehicles may be partly subsumed by the interest in roadway safety. Ibid. We observed, however, that “[t]he remaining governmental interest in controlling automobile thefts is not distinguishable from the general interest in crime control.” Ibid. Not only does the common thread of highway safety thus run through Sitz and Prouse, but Prouse itself reveals a difference in the Fourth Amendment significance of highway safety interests and the general interest in crime control.

III

It is well established that a vehicle stop at a highway checkpoint effectuates a seizure within the meaning of the Fourth Amendment. See, e. g., Sitz, supra, at 450. The fact that officers walk a narcotics-detection dog around the exterior of each car at the Indianapolis checkpoints does not transform the seizure into a search. See United States v. Place, 462 U. S. 696, 707 (1983). Just as in Place, an exterior sniff of an automobile does not require entry into the car and is not designed to disclose any information other than the presence or absence of narcotics. See ibid. Like the dog sniff in Place, a sniff by a dog that simply walks around a car is “much less intrusive than a typical search.” Ibid. Cf. United States v. Turpin, 920 F. 2d 1377, 1385 (CA8 1990). Rather, what principally distinguishes these checkpoints from those we have previously approved is their primary purpose.

As petitioners gram unquestionably has the primary purpose of interdicting illegal narcotics. In their stipulation of facts, the parties repeatedly refer to the checkpoints as “drug checkpoints” and *41describe them as “being operated by the City of Indianapolis in an effort to interdict unlawful drugs in Indianapolis.” App. to Pet. for Cert. 51a-52a. In addition, the first document attached to the parties’ stipulation is entitled “DRUG CHECKPOINT CONTACT OFFICER DIRECTIVES BY ORDER OF THE CHIEF OF POLICE.” Id., at 53a. These directives instruct officers to “[a]dvise the citizen that they are being stopped briefly at a drug checkpoint.” Ibid. The second document attached to the stipulation is entitled “1998 Drug Road Blocks” and contains a statistical breakdown of information relating to the checkpoints conducted. Id., at 55a. Further, according to Sergeant DePew, the checkpoints are identified with lighted signs reading, “‘NARCOTICS CHECKPOINT _ MILE AHEAD, NARCOTICS K-9 IN USE, BE PREPARED TO STOP.’” Id., at 57a. Finally, both the District Court and the Court of Appeals recognized that the primary purpose of the roadblocks is the interdiction of narcotics. 38 F. Supp. 2d, at 1026 (noting that both parties “stress the primary purpose of the roadblocks as the interdiction of narcotics” and that “[t]he IPD has made it clear that the purpose for its checkpoints is to interdict narcotics traffic”); 183 F. 3d, at 665 (observing that “the City concedes that its proximate goal is to catch drug offenders”).

We have never approved a checkpoint program whose primary purpose was to detect evidence of ordinary criminal wrongdoing. Rather, our checkpoint cases have recognized only limited exceptions to the general rule that a seizure must be accompanied by some measure of individualized suspicion. We suggested in Prouse that we would not credit the “general interest in crime control” as justification for a regime of suspicionless stops. 440 U. S., at 659, n. 18. Consistent with this suggestion, each of the checkpoint programs that we have approved was designed primarily to serve purposes closely related to the problems of policing the border or the necessity of ensuring roadway safety. Because the *42primary purpose of the Indianapolis narcotics checkpoint program is to uncover evidence of ordinary criminal wrongdoing, the program contravenes the Fourth Amendment.

Petitioners propose ways detection purpose of the instant checkpoint program may instead resemble the primary purposes of the checkpoints in Sitz and Martinez-Fuerte. Petitioners state that the checkpoints in those cases had the same ultimate purpose of arresting those suspected of committing crimes. Brief for Petitioners 22. Securing the border and apprehending drunk drivers are, of course, law enforcement activities, and law enforcement officers employ arrests and criminal prosecutions in pursuit of these goals. See Sitz, 496 U. S., at 447, 450; Martinez-Fuerte, 428 U. S., at 545-550. If we were to rest the case at this high level of generality, there would be little check on the ability of the authorities to construct roadblocks for almost any conceivable law enforcement purpose. Without drawing the line at roadblocks designed primarily to serve the general interest in crime control, the Fourth Amendment would do little to prevent such intrusions from becoming a routine part of American life.

Petitioners also emphasize severe ture of the drug problem as justification for the checkpoint program. Brief for Petitioners 14-17, 31. There is no doubt that traffic in illegal narcotics creates social harms of the first magnitude. Cf. Von Raab, 489 U. S., at 668. The law enforcement problems that the drug trade creates likewise remain daunting and complex, particularly in light of the myriad forms of spin-off crime that it spawns. Cf. Montoya de Hernandez, 473 U. S., at 538. The same can be said of various other illegal activities, if only to a lesser degree. But the gravity of the threat alone cannot be dispositive of questions concerning what means law enforcement officers may employ to pursue a given purpose. Rather, in determining whether individualized suspicion is required, we must consider the nature of the interests threatened and their con-*43neetion to the particular law enforcement practices at issue. We are particularly reluctant to recognize exceptions to the general rule of individualized suspicion where governmental authorities primarily pursue their general crime control ends.

Nor can the narcotics-interdiction purpose of the checkpoints be rationalized in terms of a highway safety concern similar to that present in Sitz. The detection and punishment of almost any criminal offense serves broadly the safety of the community, and our streets would no doubt be safer but for the scourge of illegal drugs. Only with respect to a smaller class of offenses, however, is society confronted with the type of immediate, vehicle-bound threat to life and limb that the sobriety checkpoint in Sitz was designed to eliminate.

Petitioners also liken the anticontraband agenda of the Indianapolis checkpoints to the antismuggling purpose of the checkpoints in Martinez-Fuerte. Brief for Petitioners 15-16. Petitioners cite this Court’s conclusion in Martinez-Fuerte that the flow of traffic was too heavy to permit “particularized study of a given car that would enable it to be identified as a possible carrier of illegal aliens,” 428 U. S., at 557, and claim that this logic has even more force here. The problem with this argument is that the same logic prevails any time a vehicle is employed to conceal contraband or other evidence of a crime. This type of connection to the roadway is very different from the close connection to roadway safety that was present in Sitz and Prouse. Further, the Indianapolis checkpoints are far removed from the border context that was crucial in Martinez-Fuerte. While the difficulty of examining each passing car was an important factor in validating the law enforcement technique employed in Martinez-Fuerte, this factor alone cannot justify a regime of suspicionless searches or seizures. Rather, we must look more closely at the nature of the public interests that such a regime is designed principally to serve.

*44The primary purpose of the Indianapolis narcotics checkpoints is in the end to advance “the general interest in crime control,” Prouse, 440 U. S., at 659, n. 18. We decline to suspend the usual requirement of individualized suspicion where the police seek to employ a checkpoint primarily for the ordinary enterprise of investigating crimes. We cannot sanction stops justified only by the generalized and ever-present possibility that interrogation and inspection may reveal that any given motorist has committed some crime.

Of course, are enforcement checkpoint where the primary purpose would otherwise, but for some emergency, relate to ordinary crime control. For example, as the Court of Appeals noted, the Fourth Amendment would almost certainly permit an appropriately tailored roadblock set up to thwart an imminent terrorist attack or to catch a dangerous criminal who is likely to flee by way of a particular route. See 183 F. 3d, at 662-663. The exigencies created by these scenarios are far removed from the circumstances under which authorities might simply stop cars as a matter of course to see if there just happens to be a felon leaving the jurisdiction. While we do not limit the purposes that may justify a checkpoint program to any rigid set of categories, we decline to approve a program whose primary purpose is ultimately indistinguishable from the general interest in crime control.1

*45Petitioners argue that our prior cases preclude an inquiry into the purposes of the checkpoint program. For example, they cite Whren v. United States, 517 U. S. 806 (1996), and Bond v. United States, 529 U. S. 334 (2000), to support the proposition that “where the government articulates and pursues a legitimate interest for a suspicionless stop, courts should not look behind that interest to determine whether the government’s ‘primary purpose’ is valid.” Brief for Petitioners 34; see also id., at 9. These cases, however, do not control the instant situation.

In Whren, we held that an individual officer’s subjective intentions are irrelevant to the Fourth Amendment validity of a traffic stop that is justified objectively by probable cause to believe that a traffic violation has occurred. 517 U. S., at 810-813. We observed that our prior cases “foreclose any argument that the constitutional reasonableness of traffic stops depends on the actual motivations of the individual officers involved.” Id., at 813. In so holding, we expressly distinguished eases where we had addressed the validity of searches conducted in the absence of probable cause. See id., at 811-812 (distinguishing Florida v. Wells, 495 U. S. 1, 4 (1990) (stating that “an inventory search must not be a ruse for a general rummaging in order to discover incriminating evidence”), Colorado v. Bertine, 479 U. S. 367, 372 (1987) (suggesting that the absence of bad faith and the lack of a purely investigative purpose were relevant to the validity of an inventory search), and Burger, 482 U. S., at 716-717, n. 27 (observing that a valid administrative inspection conducted with neither a warrant nor probable cause did not appear to be a pretext for gathering evidence of violations of the penal laws)).

Whren therefore reinforces the principle that, while “[sjubjective intentions play no role in ordinary, probable-cause Fourth Amendment analysis,” 517 U. S., at 813, programmatic purposes may be relevant to the validity of Fourth Amendment intrusions undertaken pursuant to a *46general scheme without individualized suspicion. Accordingly, Whren does not preclude an inquiry into programmatic purpose in such contexts. Cf. Chandler v. Miller, 520 U. S. 305 (1997); Treasury Employees v. Von Raab, 489 U. S. 656 (1989); Burger, supra; Michigan v. Tyler, 436 U. S. 499 (1978); Camara v. Municipal Court of City and County of San Francisco, 387 U. S. 523 (1967). It likewise does not preclude an inquiry into programmatic purpose here.

Last we law enforcement officer violated a reasonable expectation of privacy in conducting a tactile examination of carry-on luggage in the overhead compartment of a bus. In doing so, we simply noted that the principle of Whren rendered the subjective intent of an officer irrelevant to this analysis. 529 U. S., at 338, n. 2. While, as petitioners correctly observe, the analytical rubric of Bond was not “ordinary, probable-cause Fourth Amendment analysis,” Whren, supra, at 813, nothing in Bond suggests that we would extend the principle of Whren to all situations where individualized suspicion was lacking. Rather, subjective intent was irrelevant in Bond because the inquiry that our precedents required focused on the objective effects of the actions of an individual officer. By contrast, our cases dealing with intrusions that occur pursuant to a general scheme absent individualized suspicion have often required an inquiry into purpose at the programmatic level.

Petitioners argue that the Indianapolis checkpoint program is justified by its lawful secondary purposes of keeping impaired motorists off the road and verifying licenses and registrations. Brief for Petitioners 31-34. If this were the case, however, law enforcement authorities would be able to establish checkpoints for virtually any purpose so long as they also included a license or sobriety check. For this reason, we examine the available evidence to determine the primary purpose of the checkpoint program. While we recognize the challenges inherent in a purpose inquiry, courts *47routinely engage in this enterprise in many areas of constitutional jurisprudence as a means of sifting abusive governmental conduct from that which is lawful. Cf. 183 F. 3d, at 665. As a result, a program driven by an impermissible purpose may be proscribed while a program impelled by licit purposes is permitted, even though the challenged conduct may be outwardly similar. While reasonableness under the Fourth Amendment is predominantly an objective inquiry, our special needs and administrative search cases demonstrate that purpose is often relevant when suspicionless intrusions pursuant to a general scheme are at issue.2

It goes saying that our holding today does nothing to alter the constitutional status of the sobriety and border checkpoints that we approved in Sitz and Martinez-Fuerte, or of the type of traffic checkpoint that we suggested would be lawful in Prouse. The constitutionality of such checkpoint programs still depends on a balancing of the competing interests at stake and the effectiveness of the program. See Sitz, 496 U. S., at 450-455; Martinez-Fuerte, 428 U. S., at 556-564. When law enforcement authorities pursue primarily general crime control purposes at checkpoints such as here, however, stops can only be justified by some quantum of individualized suspicion.

Our holding also does not affect the validity of border searches or searches at places like airports and government *48buildings, where the need for such measures to ensure public safety can be particularly acute. Nor does our opinion speak to other intrusions aimed primarily at purposes beyond the general interest in crime control. Our holding also does not impair the ability of police officers to act appropriately upon information that they properly learn during a checkpoint stop justified by a lawful primary purpose, even where such action may result in the arrest of a motorist for an offense unrelated to that purpose. Finally, we caution that the purpose inquiry in this context is to be conducted only at the programmatic level and is not an invitation to probe the minds of individual officers acting at the scene. Cf. Whren, supra.

Because the primary purpose point program is ultimately indistinguishable from the general interest in crime control, the checkpoints violate the Fourth Amendment. The judgment of the Court of Appeals is, accordingly, affirmed.

It is so ordered.

ChieF Justice Rehnquist,

with whom Justice Thomas joins, and with whom Justice Scalia joins as to Part I, dissenting.

The State’s use of a drug-sniffing dog, according to the Court’s holding, annuls what is otherwise plainly constitutional under our Fourth Amendment jurisprudence: brief, standardized, discretionless, roadblock seizures of automobiles, seizures which effectively serve a weighty state interest with only minimal intrusion on the privacy of their occupants. Because these seizures serve the State’s accepted and significant interests of preventing drunken driving and checking for driver’s licenses and vehicle registrations, and because there is nothing in the record to indicate that the addition of the dog sniff lengthens these otherwise legitimate seizures, I dissent.

*49I

As it is nowhere to be found m the Court’s opinion, I begin with blackletter roadblock seizure law. “The principal protection of Fourth Amendment rights at checkpoints lies in appropriate limitations on the scope of the stop.” United States v. Martinez-Fuerte, 428 U. S. 543, 566-567 (1976). Roadblock seizures are consistent with the Fourth Amendment if they are “carried out pursuant to a plan embodying explicit, neutral limitations on the conduct of individual officers.” Brown v. Texas, 443 U. S. 47, 51 (1979). Specifically, the constitutionality of a seizure turns upon “a weighing of the gravity of the public concerns served by the seizure, the degree to which the seizure advances the public interest, and the severity of the interference with individual liberty.” Id., at 50-51.

We first applied these principles in Martinez-Fuerte, supra, which approved highway checkpoints for detecting illegal aliens. In Martinez-Fuerte, we balanced the United States’ formidable interest in checking the flow of illegal immigrants against the limited “objective” and “subjective” intrusion on the motorists. The objective intrusion — the stop itself,1 the brief questioning of the occupants, and the visual inspection of the car — was considered “limited” because “[n]either the vehicle nor its occupants [were] searched.” Id., at 558. Likewise, the subjective intrusion, or the fear and surprise engendered in law-abiding motorists by the nature of the stop, was found to be minimal because the “regularized manner in which [the] established checkpoints [were] operated [was] visible evidence, reassuring to law-abiding motorists, that the stops [were] duly authorized and believed to serve the public interest.” Id., at 559. Indeed, the standardized operation of the roadblocks was viewed as *50markedly different from roving patrols, where the unbridled discretion of officers in the field could result in unlimited interference with motorists’ use of the highways. Cf. United States v. Brignoni-Ponce, 422 U. S. 873 (1975). And although the decision in Martinez-Fuerte did not turn on the checkpoints’ effectiveness, the record in one of the consolidated cases demonstrated that illegal aliens were found in 0.12 percent of the stopped vehicles. See 428 U. S., at 554.

In Michigan Dept. of State v. (1990), we upheld the State’s use of a highway sobriety checkpoint after applying the framework set out in Martinez-Fuerte, supra, and Brown v. Texas, supra. There, we recognized the gravity of the State’s interest in curbing drunken driving and found the objective intrusion of the approximately 25-second seizure to be “slight.” 496 U. S., at 451. Turning to the subjective intrusion, we noted that the checkpoint was selected pursuant to guidelines and was operated by uniformed officers. See id., at 453. Finally, we concluded that the program effectively furthered the State’s interest because the checkpoint resulted in the arrest of two drunk drivers, or 1.6 percent of the 126 drivers stopped. See id., at 455-456.

This case follows naturally from Martinez-Fuerte and Sitz. Petitioners acknowledge that the “primary purpose” of these roadblocks is to interdict illegal drugs, but this fact should not be controlling. Even accepting the Court’s conclusion that the checkpoints at issue in Martinez-Fuerte and Sitz were not primarily related to criminal law enforcement,2 the *51question whether a law enforcement purpose could support a roadblock seizure is not presented in this case. The District Court found that another “purpose of the checkpoints is to check driver’s licenses and vehicle registrations,” App. to Pet. for Cert. 44a, and the written directives state that the police officers are to “[l]ook for signs of impairment,” id., at 53a. The use of roadblocks to look for signs of impairment was validated by Sitz, and the use of roadblocks to check for driver’s licenses and vehicle registrations was expressly recognized in Delaware v. Prouse, 440 U. S. 648, 663 (1979).3 That the roadblocks serve these legitimate state interests cannot be seriously disputed, as the 49 people arrested for offenses unrelated to drugs can attest. Edmond v. Goldsmith, 183 F. 3d 659, 661 (CA7 1999). And it would be speculative to conclude — given the District Court’s findings, the written directives, and the actual arrests — that petitioners would not have operated these roadblocks but for the State’s interest in interdicting drugs.

Because of the valid reasons for conducting these roadblock seizures, it is constitutionally irrelevant that petitioners also hoped to interdict drugs. In Whren v. United States, 517 U. S. 806 (1996), we held that an officer’s subjective intent would not invalidate an otherwise objectively justifiable stop of an automobile. The reasonableness of an officer’s discretionary decision to stop an automobile, at issue in Whren, turns on whether there is probable cause to believe that a traffic violation has occurred. The reasonableness of highway checkpoints, at issue here, turns on whether they effectively serve a significant state interest with minimal intrusion on motorists. The stop in Whren was objectively reasonable because the police officers had witnessed traffic violations; so too the roadblocks here are objectively *52reasonable because they serve the substantial interests of preventing drunken driving and checking for driver’s licenses and vehicle registrations with minimal intrusion on motorists.

Once the constitutional requirements for a particular seizure are satisfied, the subjective expectations of those responsible for it, be it police officers or members of a city council, are irrelevant. Cf. Scott v. United States, 436 U. S. 128, 136 (1978) (“Subjective intent alone . . . does not make otherwise lawful conduct illegal or unconstitutional”). It is the objective effect of the State’s actions on the privacy of the individual that animates the Fourth Amendment. See Bond v. United States, 529 U. S. 334, 338, n. 2 (2000) (applying Wkren to determine if an officer’s conduct amounted to a “search” under the Fourth Amendment because “the issue is not his state of mind, but the objective effect of his actions”). Because the objective intrusion of a valid seizure does not turn upon anyone’s subjective thoughts, neither should our constitutional analysis.4

With these checkpoints serving ests, the remaining prongs of the Brown v. Texas balancing test are easily met. The seizure is objectively reasonable as it lasts, on average, two to three minutes and does not involve a search. App. to Pet. for Cert. 57a. The subjective intrusion is likewise limited as the checkpoints are clearly marked and operated by uniformed officers who are directed to stop every vehicle in the same manner. Ibid. The only difference between this case and Sitz is the presence of the dog. We have already held, however, that a “sniff test” by a trained narcotics dog is not a “search” within the meaning of the Fourth Amendment because it does not require physical intrusion of the object being sniffed and it does not ex*53pose anything other than the contraband items. United States v. Place, 462 U. S. 696, 706-707 (1983). And there is nothing in the record to indicate that the dog sniff lengthens the stop. Finally, the checkpoints’ success rate — 49 arrests for offenses unrelated to drugs — only confirms the State’s legitimate interests in preventing drunken driving and ensuring the proper licensing of drivers and registration of their vehicles. 183 F. 3d, at 661.5

These stops effectively serve the State’s legitimate interests; they are executed in a regularized and neutral manner; and they only minimally intrude upon the privacy of the motorists. They should therefore be constitutiorial.

II

The Court, unwilling to adopt the straightforward analysis that these precedents dictate, adds a new non-law-enforcement primary purpose test lifted from a distinct area of Fourth Amendment jurisprudence relating to the searches of homes and businesses. As discussed above, the question that the Court answers is not even posed in this case given the accepted reasons for the seizures. But more fundamentally, whatever sense a non-law-enforcement primary purpose test may make in the search setting, it is ill suited to brief roadblock seizures, where we have consistently looked at “the scope of the stop” in assessing a program’s constitutionality. Martinez-Fuerte, 428 U. S., at 567.

We haan to apply the non-law-enforcement primary purpose test that the Court now finds so indispensable. The respondents in Sitz argued that the Brown v. Texas balancing test was not the “proper method of analysis” with regards to roadblock seizures:

“Respondents argue that there must be a showing of some special governmental need ‘beyond the normal *54need’ for criminal law enforcement before a balancing analysis is appropriate, and that [the State] ha[s] demonstrated no such special need.

“But it is perfectly plain from a Employees v.] Von Raab[, 489 U. S. 656 (1989)], which cited and discussed with approval our earlier decision in United States v. Martinez-Fuerte, 428 U. S. 543 (1976), that it was in no way designed to repudiate our prior cases dealing with police stops of motorists on public highways. Martinez-Fuerte, supra, which utilized a balancing analysis in approving highway checkpoints for detecting illegal aliens, and Brown v. Texas, supra, are the relevant authorities here.” 496 U. S., at 449, 450.

Considerations of stare decisis aside, the “perfectly plain” reason for not incorporating the “special needs” test in our roadblock seizure cases is that seizures of automobiles “deal neither with searches nor with the sanctity of private dwellings, ordinarily afforded the most stringent Fourth Amendment protection.” Martinez-Fuerte, supra, at 561.

The “special hold certain suspicionless searches performed for reasons unrelated to law enforcement, is an exception to the general rule that a search must be based on individualized suspicion of wrongdoing. See, e. g., Skinner v. Railway Labor Executives’ Assn., 489 U. S. 602 (1989) (drug test search); Camara v. Municipal Court of City and County of San Francisco, 887 U. S. 523 (1967) (home administrative search). The doctrine permits intrusions into a person’s body and home, areas afforded the greatest Fourth Amendment protection. But there were no such intrusions here.

“[0]ne’s expectation of privacy in an automobile and of freedom in its operation are significantly different from the traditional expectation of privacy and freedom in one’s residence.” Martinez-Fuerte, supra, at 561. This is because “[a]utomobiles, unlike homes, are subjected to pervasive and continuing governmental regulation and controls.” South *55 Dakota v. Opperman, 428 U. S. 364, 368 (1976); see also New York v. Class, 475 U. S. 106, 113 (1986) (“[Ajutomobiles are justifiably the subject of pervasive regulation by the State”); Cardwell v. Lewis, 417 U. S. 583, 590 (1974) (“One has a lesser expectation of privacy in a motor vehicle because its function is transportation and it seldom serves as one’s residence or as the repository of personal effects”). The lowered expectation of privacy in one’s automobile is coupled with the limited nature of the intrusion: a brief, standardized, nonintru-sive seizure.6 The brief seizure of an automobile can hardly be compared to the intrusive search of the body or the home. Thus, just as the “special needs” inquiry serves to both define and limit the permissible scope of those searches, the Brown v. Texas balancing test serves to define and limit the permissible scope of automobile seizures.

Because limitations upon roadblock seizures, the Court’s newfound non-law-enforcement primary purpose test is both unnecessary to secure Fourth Amendment rights and bound to produce wide-ranging litigation over the “purpose” of any given seizure. Police designing highway roadblocks can never be sure of their validity, since a jury might later determine that a forbidden purpose exists. Roadblock stops identical to the one that we upheld in Sitz 10 years ago, or to the one that we upheld 24 years ago in Martinez-Fuerte, may now be challenged on the grounds that they have some concealed forbidden purpose.

Efforts on highways used by millions of motorists are obviously necessary to our society. The Court’s opinion today casts a shadow over what had been assumed, on the basis of stare decisis, to be a perfectly lawful activity. Conversely, if the Indianapolis police had assigned a different purpose to their activity here, but in no way changed what was done on the ground to individual *56motorists, it might well be valid. See ante, at 47, n. 2. The Court’s non-law-enforcement primary purpose test simply does not serve as a proxy for anything that the Fourth Amendment is, or should be, concerned about in the automobile seizure context.

Petitioners’ program complies with our decisions regarding roadblock seizures of automobiles, and the addition of a dog sniff does not add to the length or the intrusion of the stop. Because such stops are consistent with the Fourth Amendment, I would reverse the decision of the Court of Appeals.

Justice Thomas,

dissenting.

Taken together, our decisions in Michigan Dept. of State Police v. Sitz, 496 U. S. 444 (1990), and United States v. Martinez-Fuerte, 428 U. S. 643 (1976), stand for the proposition that suspicionless roadblock seizures are constitutionally permissible if conducted according to a plan that limits the discretion of the officers conducting the stops. I am not convinced that Sitz and Martinez-Fuerte were correctly decided. Indeed, I rather doubt that the Framers of the Fourth Amendment would have considered “reasonable” a program of indiscriminate stops of individuals not suspected of wrongdoing.

Respondents of Sitz and Martinez-Fuerte, and I am reluctant to consider such a step without the benefit of briefing and argument. For the reasons given by The Chief Justice, I believe that those cases compel upholding the program at issue here. I, therefore, join his opinion.

Justice Scalia

delivered the opinion of the Court.

The Student Athlete Drug Policy adopted by School District 47J in the town of Vernonia, Oregon, authorizes random urinalysis drug testing of students who participate in the District’s school athletics programs. We granted certiorari to decide whether this violates the Fourth and Fourteenth Amendments to the United States Constitution.

I

A

Petitioner Vernonia School District 47J (District) operates one high school and three grade schools in the logging community of Vernonia, Oregon. As elsewhere in small-town America, school sports play a prominent role in the town’s life, and student athletes are admired in their schools and in the community.

Drugs had not been a major problem in Vernonia schools. In the mid-to-late 1980’s, however, teachers and administrators observed a sharp increase in drug use. Students began to speak out about their attraction to the drug culture, and to boast that there was nothing the school could do about it. Along with more drugs came more disciplinary problems. *649Between 1988 and 1989 the number of disciplinary referrals in Vernonia schools rose to more than twice the number reported in the early 1980’s, and several students were suspended. Students became increasingly rude during class; outbursts of profane language became common.

Not only were student athletes included among the drug users but, as the District Court found, athletes were the leaders of the drug culture. 796 F. Supp. 1354, 1357 (Ore. 1992). This caused the District’s administrators particular concern, since drug use increases the risk of sports-related injury. Expert testimony at the trial confirmed the deleterious effects of drugs on motivation, memory, judgment, reaction, coordination, and performance. The high school football and wrestling coach witnessed a severe sternum injury suffered by a wrestler, and various omissions of safety procedures and misexecutions by football players, all attributable in his belief to the effects of drug use.

Initially, the District responded to the drug problem by offering special classes, speakers, and presentations designed to deter drug use. It even brought in a specially trained dog to detect drugs, but the drug problem persisted. According to the District Court:

“[T]he administration was at its wits end and ... a large segment of the student body, particularly those involved in interscholastic athletics, was in a state of rebellion. Disciplinary actions had reached ‘epidemic proportions.’ The coincidence of an almost three-fold increase in classroom disruptions and disciplinary reports along with the staff’s direct observations of students using drugs or glamorizing drug and alcohol use led the administration to the inescapable conclusion that the rebellion was being fueled by alcohol and drug abuse as well as the student’s misperceptions about the drug culture.” Ibid.

At that point, District officials began considering a drug-testing program. They held a parent “input night” to dis*650cuss the proposed Student Athlete Drug Policy (Policy), and the parents in attendance gave their unanimous approval. The school board approved the Policy for implementation in the fall of 1989. Its expressed purpose is to prevent student athletes from using drugs, to protect their health and safety, and to provide drug users with assistance programs.

B

The Policy applies to all students participating in interscholastic athletics. Students wishing to play sports must sign a form consenting to the testing and must obtain the written consent of their parents. Athletes are tested at the beginning of the season for their sport. In addition, once each week of the season the names of the athletes are placed in a “pool” from which a student, with the supervision of two adults, blindly draws the names of 10% of the athletes for random testing. Those selected are notified and tested that same day, if possible.

The student to be tested completes a specimen control form which bears an assigned number. Prescription medications that the student is taking must be identified by providing a copy of the prescription or a doctor’s authorization. The student then enters an empty locker room accompanied by an adult monitor of the same sex. Each boy selected produces a sample at a urinal, remaining fully clothed with his back to the monitor, who stands approximately 12 to 15 feet behind the student. Monitors may (though do not always) watch the student while he produces the sample, and they listen for normal sounds of urination. Girls produce samples in an enclosed bathroom stall, so that they can be heard but not observed. After the sample is produced, it is given to the monitor, who checks it for temperature and tampering and then transfers it to a vial.

The samples are sent to an independent laboratory, which routinely tests them for amphetamines, cocaine, and marijuana. Other drugs, such as LSD, may be screened at the *651request of the District, but the identity of a particular student does not determine which drugs will be tested. The laboratory’s procedures are 99.94% accurate. The District follows strict procedures regarding the chain of custody and access to test results. The laboratory does not know the identity of the students whose samples it tests. It is authorized to mail written test reports only to the superintendent and to provide test results to District personnel by telephone only after the requesting official recites a code confirming his authority. Only the superintendent, principals, vice-principals, and athletic directors have access to test results, and the results are not kept for more than one year.

If a sample tests positive, a second test is administered as soon as possible to confirm the result. If the second test is negative, no further action is taken. If the second test is positive, the athlete’s parents are notified, and the school principal convenes a meeting with the student and his parents, at which the student is given the option of (1) participating for six weeks in an assistance program that includes weekly urinalysis, or (2) suffering suspension from athletics for the remainder of the current season and the next athletic season. The student is then retested prior to the start of the next athletic season for which he or she is eligible. The Policy states that a second offense results in automatic imposition of option (2); a third offense in suspension for the remainder of the current season and the next two athletic seasons.

C

In the fall of 1991, respondent James Acton, then a seventh grader, signed up to play football at one of the District’s grade schools. He was denied participation, however, because he and his parents refused to sign the testing consent forms. The Actons filed suit, seeking declaratory and in-junctive relief from enforcement of the Policy on the grounds that it violated the Fourth and Fourteenth Amendments to the United States Constitution and Article I, § 9, of the Ore*652gon Constitution. After a bench trial, the District Court entered an order denying the claims on the merits and dismissing the action. 796 F. Supp., at 1355. The United States Court of Appeals for the Ninth Circuit reversed, holding that the Policy violated both the Fourth and Fourteenth Amendments and Article I, § 9, of the Oregon Constitution. 23 F. 3d 1514 (1994). We granted certiorari. 513 U. S. 1013 (1994).

II

The Fourth Amendment to the United States Constitution provides that the Federal Government shall not violate “[t]he right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures . . . .” We have held that the Fourteenth Amendment extends this constitutional guarantee to searches and seizures by state officers, Elkins v. United States, 364 U. S. 206, 213 (1960), including public school officials, New Jersey v. T L. O., 469 U. S. 325, 336-337 (1985). In Skinner v. Railway Labor Executives’ Assn., 489 U. S. 602, 617 (1989), we held that state-compelled collection and testing of urine, such as that required by the Policy, constitutes a “search” subject to the demands of the Fourth Amendment. See also Treasury Employees v. Von Raab, 489 U. S. 656, 665 (1989).

As the text of the Fourth Amendment indicates, the ultimate measure of the constitutionality of a governmental search is “reasonableness.” At least in a case such as this, where there was no clear practice, either approving or disapproving the type of search at issue, at the time the constitutional provision was enacted,1 whether a particular search meets the reasonableness standard “ ‘is judged by balancing *653its intrusion on the individual’s Fourth Amendment interests against its promotion of legitimate governmental interests.’” Skinner, supra, at 619 (quoting Delaware v. Prouse, 440 U. S. 648, 654 (1979)). Where a search is undertaken by law enforcement officials to discover evidence of criminal wrongdoing, this Court has said that reasonableness generally requires the obtaining of a judicial warrant, Skinner, supra, at 619. Warrants cannot be issued, of course, without the showing of probable cause required by the Warrant Clause. But a warrant is not required to establish the reasonableness of all government searches; and when a warrant is not required (and the Warrant Clause therefore not applicable), probable cause is not invariably required either. A search unsupported by probable cause can be constitutional, we have said, “when special needs, beyond the normal need for law enforcement, make the warrant and probable-cause requirement impracticable.” Griffin v. Wisconsin, 488 U. S. 868, 873 (1987) (internal quotation marks omitted).

We have found such “special needs” to exist in the public school context. There, the warrant requirement “would unduly interfere with the maintenance of the swift and informal disciplinary procedures [that are] needed,” and “strict adherence to the requirement that searches be based on probable cause” would undercut “the substantial need of teachers and administrators for freedom to maintain order in the schools.” T L. O., 469 U. S., at 340, 341. The school search we approved in T L. 0., while not based on probable cause, was based on individualized suspicion of wrongdoing. As we explicitly acknowledged, however, “‘the Fourth Amendment imposes no irreducible requirement of such suspicion,’ ” id., at 342, n. 8 (quoting United States v. Martinez-Fuerte, 428 U. S. 543, 560-561 (1976)). We have upheld sus-picionless searches and seizures to conduct drug testing of railroad personnel involved in train accidents, see Skinner, supra; to conduct random drug testing of federal customs officers who carry arms or are involved in drug interdiction, *654see Von Raab, supra; and to maintain automobile checkpoints looking for illegal immigrants and contraband, Martinez-Fuerte, supra, and drunk drivers, Michigan Dept. of State Police v. Sitz, 496 U. S. 444 (1990).

1 — 1 1 — 1

The first factor to be considered is the nature of the privacy interest upon which the search here at issue intrudes. The Fourth Amendment does not protect all subjective expectations of privacy, but only those that society recognizes as “legitimate.” T L. O., 469 U. S., at 338. What expectations are legitimate varies, of course, with context, id., at 337, depending, for example, upon whether the individual asserting the privacy interest is at home, at work, in a car, or in a public park. In addition, the legitimacy of certain privacy expectations vis-a-vis the State may depend upon the individual’s legal relationship with the State. For example, in Griffin, supra, we held that, although a “probationer’s home, like anyone else’s, is protected by the Fourth Amendment,” the supervisory relationship between probationer and State justifies “a degree of impingement upon [a probationer’s] privacy that would not be constitutional if applied to the public at large.” 483 U. S., at 873, 875. Central, in our view, to the present case is the fact that the subjects of the Policy are (1) children, who (2) have been committed to the temporary custody of the State as schoolmaster.

Traditionally at common law, and still today, unemanci-pated minors lack some of the most fundamental rights of self-determination — including even the right of liberty in its narrow sense, i. e., the right to come and go at will. They are subject, even as to their physical freedom, to the control of their parents or guardians. See 59 Am. Jur. 2d, Parent and Child §10 (1987). When parents place minor children in private schools for their education, the teachers and administrators of those schools stand in loco parentis over the children entrusted to them. In fact, the tutor or schoolmas*655ter is the very prototype of that status. As Blackstone describes it, a parent “may . . . delegate part of his parental authority, during his life, to the tutor or schoolmaster of his child; who is then in loco parentis, and has such a portion of the power of the parent committed to his charge, viz. that of restraint and correction, as may be necessary to answer the purposes for which he is employed.” 1 W. Blackstone, Commentaries on the Laws of England 441 (1769).

In I L. O. we rejected the notion that public schools, like private schools, exercise only parental power over their students, which of course is not subject to constitutional constraints. 469 U. S., at 336. Such a view of things, we said, “is not entirely ‘consonant with compulsory education laws/ ” ibid. (quoting Ingraham v. Wright, 430 U. S. 651, 662 (1977)), and is inconsistent with our prior decisions treating school officials as state actors for purposes of the Due Process and Free Speech Clauses, T L. O., supra, at 336. But while denying that the State’s power over schoolchildren is formally no more than the delegated power of their parents, T. L. O. did not deny, but indeed emphasized, that the nature of that power is custodial and tutelary, permitting a degree of supervision and control that could not be exercised over free adults. “[A] proper educational environment requires close supervision of schoolchildren, as well as the enforcement of rules against conduct that would be perfectly permissible if undertaken by an adult.” 469 U. S., at 339. While we do not, of course, suggest that public schools as a general matter have such a degree of control over children as to give rise to a constitutional “duty to protect,” see DeShaney v. Winnebago County Dept. of Social Servs., 489 U. S. 189, 200 (1989), we have acknowledged that for many purposes “school authorities ac[t] in loco parentis,” Bethel School Dist. No. 403 v. Fraser, 478 U. S. 675, 684 (1986), with the power and indeed the duty to “inculcate the habits and manners of civility,” id., at 681 (internal quotation marks omitted). Thus, while children assuredly do not “shed their constitutional *656rights ... at the schoolhouse gate,” Tinker v. Des Moines Independent Community School Dist., 393 U. S. 503, 506 (1969), the nature of those rights is what is appropriate for children in school. See, e. g., Goss v. Lopez, 419 U. S. 565, 581-582 (1975) (due process for a student challenging disciplinary suspension requires only that the teacher “informally discuss the alleged misconduct with the student minutes after it has occurred”); Fraser, supra, at 683 (“[I]t is a highly appropriate function of public school education to prohibit the use of vulgar and offensive terms in public discourse”); Hazelwood School Dist. v. Kuhlmeier, 484 U. S. 260, 273 (1988) (public school authorities may censor school-sponsored publications, so long as the censorship is “reasonably related to legitimate pedagogical concerns”); Ingraham, supra, at 682 (“Imposing additional administrative safeguards [upon corporal punishment]... would ... entail a significant intrusion into an area of primary educational responsibility”).

Fourth Amendment rights, no less than First and Fourteenth Amendment rights, are different in public schools than elsewhere; the “reasonableness” inquiry cannot disregard the schools’ custodial and tutelary responsibility for children. For their own good and that of their classmates, public school children are routinely required to submit to various physical examinations, and to be vaccinated against various diseases. According to the American Academy of Pediatrics, most public schools “provide vision and hearing screening and dental and dermatological checks. . . . Others also mandate scoliosis screening at appropriate grade levels.” Committee on School Health, American Academy of Pediatrics, School Health: A Guide for Health Professionals 2 (1987). In the 1991-1992 school year, all 50 States required public school students to be vaccinated against diphtheria, measles, rubella, and polio. U. S. Dept, of Health & Human Services, Public Health Service, Centers for Disease Control, State Immunization Requirements 1991-1992, p. 1. Particularly with regard to medical examinations and proce*657dures, therefore, “students within the school environment have a lesser expectation of privacy than members of the population generally.” I L. O., supra, at 348 (Powell, J., concurring).

Legitimate privacy expectations are even less with regard to student athletes. School sports are not for the bashful. They require “suiting up” before each practice or event, and showering and changing afterwards. Public school locker rooms, the usual sites for these activities, are not notable for the privacy they afford. The locker rooms in Vernonia are typical: No individual dressing rooms are provided; shower heads are lined up along a wall, unseparated by any sort of partition or curtain; not even all the toilet stalls have doors. As the United States Court of Appeals for the Seventh Circuit has noted, there is “an element of ‘communal undress’ inherent in athletic participation,” Schaill by Kross v. Tippecanoe County School Corp., 864 F. 2d 1309, 1318 (1988).

There is an additional respect in which school athletes have a reduced expectation of privacy. By choosing to “go out for the team,” they voluntarily subject themselves to a degree of regulation even higher than that imposed on students generally. In Vernonia’s public schools, they must submit to a preseason physical exam (James testified that his included the giving of a urine sample, App. 17), they must acquire adequate insurance coverage or sign an insurance waiver, maintain a minimum grade point average, and comply with any “rules of conduct, dress, training hours and related matters as may be established for each sport by the head coach and athletic director with the principal’s approval.” Record, Exh. 2, p. 30, ¶ 8. Somewhat like adults who choose to participate in a “closely regulated industry,” students who voluntarily participate in school athletics have reason to expect intrusions upon normal rights and privileges, including privacy. See Skinner, 489 U. S., at 627; United States v. Biswell, 406 U. S. 311, 316 (1972).

*658 >

Having considered the scope of the legitimate expectation of privacy at issue here, we turn next to the character of the intrusion that is complained of. We recognized in Skinner that collecting the samples for urinalysis intrudes upon “an excretory function traditionally shielded by great privacy.” 489 U. S., at 626. We noted, however, that the degree of intrusion depends upon the manner in which production of the urine sample is monitored. Ibid. Under the District’s Policy, male students produce samples at a urinal along a wall. They remain fully clothed and are only observed from behind, if at all. Female students produce samples in an enclosed stall, with a female monitor standing outside listening only for sounds of tampering. These conditions are nearly identical to those typically encountered in public restrooms, which men, women, and especially schoolchildren use daily. Under such conditions, the privacy interests compromised by the process of obtaining the urine sample are in our view negligible.

The other privacy-invasive aspect of urinalysis is, of course, the information it discloses concerning the state of the subject’s body, and the materials he has ingested. In this regard it is significant that the tests at issue here look only for drugs, and not for whether the student is, for example, epileptic, pregnant, or diabetic. See id., at 617. Moreover, the drugs for which the samples are screened are standard, and do not vary according to the identity of the student. And finally, the results of the tests are disclosed only to a limited class of school personnel who have a need to know; and they are not turned over to law enforcement authorities or used for any internal disciplinary function. 796 F. Supp., at 1364; see also 23 F. 3d, at 1521.2

*659Respondents argue, however, that the District’s Policy is in fact more intrusive than this suggests, because it requires the students, if they are to avoid sanctions for a falsely positive test, to identify in advance prescription medications they are taking. We agree that this raises some cause for concern. In Von Raab, we flagged as one of the salutary features of the Customs Service drug-testing program the fact that employees were not required to disclose medical information unless they tested positive, and, even then, the information was supplied to a licensed physician rather than to the Government employer. See Von Raab, 489 U. S., at 672-673, n. 2. On the other hand, we have never indicated that requiring advance disclosure of medications is per se unreasonable. Indeed, in Skinner we held that it was not “a significant invasion of privacy.” 489 U. S., at 626, n. 7. It can be argued that, in Skinner, the disclosure went only to the medical personnel taking the sample, and the Government personnel analyzing it, see id., at 609, but see id., at 610 (railroad personnel responsible for forwarding the sample, and presumably accompanying information, to the Government’s testing lab); and that disclosure to teachers and coaches — to persons who personally know the student — is a greater invasion of privacy. Assuming for the sake of argu*660ment that both those propositions are true, we do not believe they establish a difference that respondents are entitled to rely on here.

The General Authorization Form that respondents refused to sign, which refusal was the basis for James’s exclusion from the sports program, said only (in relevant part): “I . . . authorize the Vernonia School District to conduct a test on a urine specimen which I provide to test for drugs and/or alcohol use. I also authorize the release of information concerning the results of such a test to the Vernonia School District and to the parents and/or guardians of the student.” App. 10-11. While the practice of the District seems to have been to have a school official take medication information from the student at the time of the test, see id., at 29, 42, that practice is not set forth in, or required by, the Policy, which says simply: “Student athletes who . . . are or have been taking prescription medication must provide verification (either by a copy of the prescription or by doctor’s authorization) prior to being tested.” Id., at 8. It may well be that, if and when James was selected for random testing at a time that he was taking medication, the School District would have permitted him to provide the requested information in a confidential manner — for example, in a sealed envelope delivered to the testing lab. Nothing in the Policy contradicts that, and when respondents choose, in effect, to challenge the Policy on its face, we will not assume the worst. Accordingly, we reach the same conclusion as in Skinner: that the invasion of privacy was not significant.

V

Finally, we turn to consider the nature and immediacy of the governmental concern at issue here, and the efficacy of this means for meeting it. In both Skinner and Von Raab, we characterized the government interest motivating the search as “compelling.” Skinner, supra, at 628 (interest in preventing railway accidents); Von Raab, supra, at 670 (in*661terest in ensuring fitness of customs officials to interdict drugs and handle firearms). Relying on these cases, the District Court held that because the District’s program also called for drug testing in the absence of individualized suspicion, the District “must demonstrate a ‘compelling need’ for the program.” 796 F. Supp., at 1368. The Court of Appeals appears to have agreed with this view. See 23 F. 3d, at 1526. It is a mistake, however, to think that the phrase “compelling state interest,” in the Fourth Amendment context, describes a fixed, minimum quantum of governmental concern, so that one can dispose of a case by answering in isolation the question: Is there a compelling state interest here? Rather, the phrase describes an interest that appears important enough to justify the particular search at hand, in light of other factors that show the search to be relatively intrusive upon a genuine expectation of privacy. Whether that relatively high degree of government concern is necessary in this case or not, we think it is met.

That the nature of the concern is important — indeed, perhaps compelling — can hardly be doubted. Deterring drug use by our Nation’s schoolchildren is at least as important as enhancing efficient enforcement of the Nation’s laws against the importation of drugs, which was the governmental concern in Von Raab, supra, at 668, or deterring drug use by engineers and trainmen, which was the governmental concern in Skinner, supra, at 628. School years are the time when the physical, psychological, and addictive effects of drugs are most severe. “Maturing nervous systems are more critically impaired by intoxicants than mature ones are; childhood losses in learning are lifelong and profound”; “children grow chemically dependent more quickly than adults, and their record of recovery is depressingly poor.” Hawley, The Bumpy Road to Drug-Free Schools, 72 Phi Delta Kap-pan 310, 314 (1990). See also Estroff, Schwartz, & Hoff-mann, Adolescent Cocaine Abuse: Addictive Potential, Behavioral and Psychiatric Effects, 28 Clinical Pediatrics 550 *662(Dec. 1989); Kandel, Davies, Karus, & Yamaguchi, The Consequences in Young Adulthood of Adolescent Drug Involvement, 43 Arch. Gen. Psychiatry 746 (Aug. 1986). And of course the effects of a drug-infested school are visited not just upon the users, but upon the entire student body and faculty, as the educational process is disrupted. In the present case, moreover, the necessity for the State to act is magnified by the fact that this evil is being visited not just upon individuals at large, but upon children for whom it has undertaken a special responsibility of care and direction. Finally, it must not be lost sight of that this program is directed more narrowly to drug use by school athletes, where the risk of immediate physical harm to the drug user or those with whom he is playing his sport is particularly high. Apart from psychological effects, which include impairment of judgment, slow reaction time, and a lessening of the perception of pain, the particular drugs screened by the District’s Policy have been demonstrated to pose substantial physical risks to athletes. Amphetamines produce an “artificially induced heart rate increase, [peripheral vasoconstriction, [b]lood pressure increase, and [mjasking of the normal fatigue response,” making them a “very dangerous drug when used during exercise of any type.” Hawkins, Drugs and Other Ingesta: Effects on Athletic Performance, in H. Appenzeller, Managing Sports and Risk Management Strategies 90, 90-91 (1993). Marijuana causes “[ijrregular blood pressure responses during changes in body position,” “[Reduction in the oxygen-carrying capacity of the blood,” and “[ijnhibition of the normal sweating responses resulting in increased body temperature.” Id., at 94. Cocaine produces “[vjasocon-striction[,] [e]levated blood pressure,” and “[possible coronary artery spasms and myocardial infarction.” Ibid.

As for the immediacy of the District’s concerns: We are not inclined to question — indeed, we could not possibly find clearly erroneous — the District Court’s conclusion that “a large segment of the student body, particularly those in*663volved in interscholastic athletics, was in a state of rebellion,” that “[disciplinary actions had reached ‘epidemic proportions/” and that “the rebellion was being fueled by alcohol and drug abuse as well as by the student’s mispercep-tions about the drug culture.” 796 F. Supp., at 1357. That is an immediate crisis of greater proportions than existed in Skinner, where we upheld the Government’s drug-testing program based on findings of drug use by railroad employees nationwide, without proof that a problem existed on the particular railroads whose employees were subject to the test. See Skinner, 489 U. S., at 607. And of much greater proportions than existed in Von Raab, where there was no documented history of drug use by any customs officials. See Von Raab, 489 U. S., at 673; id., at 683 (Scalia, J., dissenting).

As to the efficacy of this means for addressing the problem: It seems to us self-evident that a drug problem largely fueled by the “role model” effect of athletes’ drug use, and of particular danger to athletes, is effectively addressed by making sure that athletes do not use drugs. Respondents argue that a “less intrusive means to the same end” was available, namely, “drug testing on suspicion of drug use.” Brief for Respondents 45-46. We have repeatedly refused to declare that only the “least intrusive” search practicable can be reasonable under the Fourth Amendment. Skinner, supra, at 629, n. 9 (collecting cases). Respondents’ alternative entails substantial difficulties — if it is indeed practicable at all. It may be impracticable, for one thing, simply because the parents who are willing to accept random drug testing for athletes are not willing to accept accusatory drug testing for all students, which transforms the process into a badge of shame. Respondents’ proposal brings the risk that teachers will impose testing arbitrarily upon troublesome but not drug-likely students. It generates the expense of defending lawsuits that charge such arbitrary imposition, or that simply demand greater process before accusatory drug

*664testing is imposed. And not least of all, it adds to the ever-expanding diversionary duties of schoolteachers the new function of spotting and bringing to account drug abuse, a task for which they are ill prepared, and which is not readily compatible with their vocation. Cf. Skinner, supra, at 628 (quoting 50 Fed. Reg. 31526 (1985)) (a drug impaired individual “will seldom display any outward ‘signs detectable by the lay person or, in many cases, even the physician’”); Goss, 419 U. S., at 594 (Powell, J., dissenting) (“There is an ongoing relationship, one in which the teacher must occupy many roles — educator, adviser, friend, and, at times, parent-substitute. It is rarely adversary in nature . . .”) (footnote omitted). In many respects, we think, testing based on “suspicion” of drug use would not be better, but worse.3

>

Taking into account all the factors we have considered above — the decreased expectation of privacy, the relative unobtrusiveness of the search, and the severity of the need met *665by the search — we conclude Vernonia’s Policy is reasonable and hence constitutional.

We caution against the assumption that suspicionless drug testing will readily pass constitutional muster in other contexts. The most significant element in this case is the first we discussed: that the Policy was undertaken in furtherance of the government’s responsibilities, under a public school system, as guardian and tutor of children entrusted to its care.4 Just as when the government conducts a search in its capacity as employer (a warrantless search of an absent employee’s desk to obtain an urgently needed file, for example), the relevant question is whether that intrusion upon privacy is one that a reasonable employer might engage in, see O’Connor v. Ortega, 480 U. S. 709 (1987); so also when the government acts as guardian and tutor the relevant question is whether the search is one that a reasonable guardian and tutor might undertake. Given the findings of need made by the District Court, we conclude that in the present case it is.

We may note that the primary guardians of Vernonia’s schoolchildren appear to agree. The record shows no objection to this districtwide program by any parents other than the couple before us here — even though, as we have described, a public meeting was held to obtain parents’ views. We find insufficient basis to contradict the judgment of Ver-nonia’s parents, its school board, and the District Court, as to what was reasonably in the interest of these children under the circumstances.

*666* * *

The Ninth Circuit held that Vernonia’s Policy not only violated the Fourth Amendment, but also, by reason of that violation, contravened Article I, § 9, of the Oregon Constitution. Our conclusion that the former holding was in error means that the latter holding rested on a flawed premise. We therefore vacate the judgment, and remand the case to the Court of Appeals for further proceedings consistent with this opinion.

It is so ordered.

Justice Ginsburg,

concurring.

The Court constantly observes that the School District’s drug-testing policy applies only to students who voluntarily participate in interscholastic athletics. Ante, at 650,657 (reduced privacy expectation and closer school regulation of student athletes), 662 (drug use by athletes risks immediate physical harm to users and those with whom they play). Correspondingly, the most severe sanction allowed under the District’s policy is suspension from extracurricular athletic programs. Ante, at 651. I comprehend the Court’s opinion as reserving the question whether the District, on no more than the showing made here, constitutionally could impose routine drug testing not only on those seeking to engage with others in team sports, but on all students required to attend school. Cf. United States v. Edwards, 498 F. 2d 496, 500 (CA2 1974) (Friendly, J.) (in contrast to search without notice and opportunity to avoid examination, airport search of passengers and luggage is avoidable “by choosing not to travel by air”) (internal quotation marks omitted).

Justice O’Connor,

with whom Justice Stevens and Justice Souter join,

dissenting.

The population of our Nation’s public schools, grades 7 through 12, numbers around 18 million. See U. S. Dept, of *667Education, National Center for Education Statistics, Digest of Education Statistics 58 (1994) (Table 43). By the reasoning of today’s decision, the millions of these students who participate in interscholastic sports, an overwhelming majority of whom have given school officials no reason whatsoever to suspect they use drugs at school, are open to an intrusive bodily search.

In justifying this result, the Court dispenses with a requirement of individualized suspicion on considered policy grounds. First, it explains that precisely because every student athlete is being tested, there is no concern that school officials might act arbitrarily in choosing whom to test. Second, a broad-based search regime, the Court reasons, dilutes the accusatory nature of the search. In making these policy arguments, of course, the Court sidesteps powerful, countervailing privacy concerns. Blanket searches, because they can involve “thousands or millions” of searches, “pos[e] a greater threat to liberty” than do suspicion-based ones, which “affec[t] one person at a time,” Illinois v. Krull, 480 U. S. 340, 365 (1987) (O’Connor, J., dissenting). Searches based on individualized suspicion also afford potential targets considerable control over whether they will, in fact, be searched because a person can avoid such a search by not acting in an objectively suspicious way. And given that the surest way to avoid acting suspiciously is to avoid the underlying wrongdoing, the costs of such a regime, one would think, are minimal.

But whether a blanket search is “better,” ante, at 664, than a regime based on individualized suspicion is not a debate in which we should engage. In my view, it is not open to judges or government officials to decide on policy grounds which is better and which is worse. For most of our constitutional history, mass, suspicionless searches have been generally considered per se unreasonable within the meaning of the Fourth Amendment. And we have allowed exceptions *668in recent years only where it has been clear that a suspicion-based regime would be ineffectual. Because that is not the case here, I dissent.

I

A

In Carroll v. United States, 267 U. S. 132 (1925), the Court explained that “[t]he Fourth Amendment does not denounce all searches or seizures, but only such as are unreasonable.” Id., at 147. Applying this standard, the Court first held that a search of a car was not unreasonable merely because it was warrantless; because obtaining a warrant is impractical for an easily movable object such as a car, the Court explained, a warrant is not required. The Court also held, however, that a warrantless car search was unreasonable unless supported by some level of individualized suspicion, namely, probable cause. Significantly, the Court did not base its conclusion on the express probable cause requirement contained in the Warrant Clause, which, as just noted, the Court found inapplicable. Rather, the Court rested its views on “what was deemed an unreasonable search and seizure when [the Fourth Amendment] was adopted” and “[what] will conserve public interests as well as the interests and rights of individual citizens.” Id., at 149. With respect to the “rights of individual citizens,” the Court eventually offered the simple yet powerful intuition that “those lawfully within the country, entitled to use the public highways, have a right to free passage without interruption or search unless there is known to a competent official authorized to search, probable cause for believing that their vehicles are carrying contraband or illegal merchandise.” Id., at 154.

More important for the purposes of this case, the Court clearly indicated that evenhanded treatment was no substitute for the individualized suspicion requirement:

“It would be intolerable and unreasonable if a prohibition agent were authorized to stop every automobile on *669the chance of finding liquor and thus subject all persons lawfully using the highways to the inconvenience and indignity of such a search.” Id., at 153-154.

The Carroll Court’s view that blanket searches are “intolerable and unreasonable” is well grounded in history. As recently confirmed in one of the most exhaustive analyses of the original meaning of the Fourth Amendment ever undertaken, see W. Cuddihy, The Fourth Amendment: Origins and Original Meaning (1990) (Ph.D. Dissertation at Claremont Graduate School) (hereinafter Cuddihy), what the Framers of the Fourth Amendment most strongly opposed, with limited exceptions wholly inapplicable here, were general searches — that is, searches by general warrant, by writ of assistance, by broad statute, or by any other similar authority. See id., at 1402, 1499, 1555; see also Clancy, The Role of Individualized Suspicion in Assessing the Reasonableness of Searches and Seizures, 25 Mem. St. U. L. Rev. 483, 528 (1994); Maclin, When the Cure for the Fourth Amendment Is Worse Than the Disease, 68 S. Cal. L. Rev. 1, 9-12 (1994); L. Levy, Original Intent and the Framers’ Constitution 221-246 (1988). Although, ironically, such warrants, writs, and statutes typically required individualized suspicion, see, e.g., Cuddihy 1140 (“Typical of the American warrants of 1761-76 was Starke’s ‘tobacco’ warrant, which commanded its bearer to ‘enter any suspected Houses’ ”) (emphasis added), such requirements were subjective and largely unenforceable. Accordingly, these various forms of authority led in practice to “virtually unrestrained,” and hence “general,” searches. J. Landynski, Search and Seizure and the Supreme Court 20 (1966). To be sure, the Fourth Amendment, in the Warrant Clause, prohibits by name only searches by general warrants. But that was only because the abuses of the general warrant were particularly vivid in the minds of the Framers’ generation, Cuddihy 1554-1560, and not because the Framers viewed other kinds of general searches as any less unreasonable. “Prohibition of the general warrant was part of a *670larger scheme to extinguish general searches categorically.” Id., at 1499.

More important, there is no indication in the historical materials that the Framers’ opposition to general searches stemmed solely from the fact that they allowed officials to single out individuals for arbitrary reasons, and thus that officials could render them reasonable simply by making sure to extend their search to every house in a given area or to every person in a given group. See Delaware v. Prouse, 440 U. S. 648, 664 (1979) (Rehnquist, J., dissenting) (referring to this as the “ ‘misery loves company’ ” theory of the Fourth Amendment). On the contrary, although general searches were typically arbitrary, they were not invariably so. Some general searches, for example, were of the arguably evenhanded “door-to-door” kind. Cuddihy 1091; see also id., at 377, 1502, 1557. Indeed, Cuddihy’s descriptions of a few blanket searches suggest they may have been considered more worrisome than the typical general search. See id., at 575 (“One type of warrant [between 1700 and 1760] went beyond a general search, in which the searcher entered and inspected suspicious places, by requiring him to search entire categories of places whether he suspected them or not”); id., at 478 (“During the exigencies of Queen Anne’s War, two colonies even authorized searches in 1706 that extended to entire geographic areas, not just to suspicious houses in a district, as conventional general warrants allowéd”).

Perhaps most telling of all, as reflected in the text of the Warrant Clause, the particular way the Framers chose to curb the abuses of general warrants — and by implication, all general searches — was not to impose a novel “evenhandedness” requirement; it was to retain the individualized suspicion requirement contained in the typical general warrant, but to make that requirement meaningful and enforceable, for instance, by raising the required level of individualized suspicion to objective probable cause. See U. S. Const., Arndt. 4. So, for example, when the same Congress that *671proposed the Fourth Amendment authorized duty collectors to search for concealed goods subject to import duties, specific warrants were required for searches on land; but even for searches at sea, where warrants were impractical and thus not required, Congress nonetheless limited officials to searching only those ships and vessels “in which [a collector] shall have reason to suspect any goods, wares or merchandise subject to duty shall be concealed.” The Collection Act of July 31, 1789, § 24, 1 Stat. 43 (emphasis added); see also Cuddihy 1490-1491 (“The Collection Act of 1789 was [the] most significant [of all early search statutes], for it identified the techniques of search and seizure that the framers of the amendment believed reasonable while they were framing it”). Not surprisingly, the Carroll Court relied on this statute and other subsequent ones like it in arriving at its views. See Carroll, 267 U. S., at 160-151, 154; cf. Clancy, supra, at 489 (“While the plain language of the Amendment does not mandate individualized suspicion as a necessary component of all searches and seizures, the historical record demonstrates that the framers believed that individualized suspicion was an inherent quality of reasonable searches and seizures”).

True, not all searches around the time the Fourth Amendment was adopted required individualized suspicion — although most did. A search incident to arrest was an obvious example of one that did not, see Cuddihy 1518, but even those searches shared the essential characteristics that distinguish suspicion-based searches from abusive general searches: they only “affec[t] one person at a time,” Krull, 480 U. S., at 365 (O’Connor, J., dissenting), and they are generally avoidable by refraining from wrongdoing. See supra, at 667. Protection of privacy, not evenhandedness, was then and is now the touchstone of the Fourth Amendment.

The view that mass, suspicionless searches, however evenhanded, are generally unreasonable remains inviolate in the criminal law enforcement context, see Ybarra v. Illinois, 444 *672U. S. 85 (1979) (invalidating evenhanded, nonaccusatory pat-down for weapons of all patrons in a tavern in which there was probable cause to think drug dealing was going on), at least where the search is more than minimally intrusive, see Michigan Dept. of State Police v. Sitz, 496 U. S. 444 (1990) (upholding the brief and easily avoidable detention, for purposes of observing signs of intoxication, of all motorists approaching a roadblock). It is worth noting in this regard that state-compelled, state-monitored collection and testing of urine, while perhaps not the most intrusive of searches, see, e. g., Bell v. Wolfish, 441 U. S. 520, 558-560 (1979) (visual body cavity searches), is still “particularly destructive of privacy and offensive to personal dignity.” Treasury Employees v. Von Raab, 489 U. S. 656, 680 (1989) (Scalia, J., dissenting); see also ante, at 658; Skinner v. Railway Labor Executives’ Assn., 489 U. S. 602, 617 (1989). We have not hesitated to treat monitored bowel movements as highly intrusive (even in the special border search context), compare United States v. Martinez-Fuerte, 428 U. S. 543 (1976) (brief interrogative stops of all motorists crossing certain border checkpoint reasonable without individualized suspicion), with United States v. Montoya de Hernandez, 473 U. S. 531 (1985) (monitored bowel movement of border crossers reasonable only upon reasonable suspicion of alimentary canal smuggling), and it is not easy to draw a distinction. See Fried, Privacy, 77 Yale L. J. 475, 487 (1968) (“[I]n our culture the excretory functions are shielded by more or less absolute privacy”). And certainly monitored urination combined with urine testing is more intrusive than some personal searches we have said trigger Fourth Amendment protections in the past. See, e. g., Cupp v. Murphy, 412 U. S. 291, 295 (1973) (Stewart, J.) (characterizing the scraping of dirt from under a person’s fingernails as a “ ‘severe, though brief, intrusion upon cherished personal security’ ”) (citation omitted). Finally, the collection and testing of urine is, of course, a search of a person, one of only four categories of suspect *673searches the Constitution mentions by name. See U. S. Const., Arndt. 4 (listing “persons, houses, papers, and effects”); cf. Cuddihy 835, 1518, 1552, n. 394 (indicating long history of outrage at personal searches before 1789).

Thus, it remains the law that the police cannot, say, subject to drug testing every person entering or leaving a certain drug-ridden neighborhood in order to find evidence of crime. 3 W. LaFave, Search and Seizure § 9.5(b), pp. 551-553 (2d ed. 1987) (hereinafter LaFave). And this is true even though it is hard to think of a more compelling government interest than the need to fight the scourge of drugs on our streets and in our neighborhoods. Nor could it be otherwise, for if being evenhanded were enough to justify evaluating a search regime under an open-ended balancing test, the Warrant Clause, which presupposes that there is some category of searches for which individualized suspicion is nonnegotiable, see 2 LaFave §4.1, at 118, would be a dead letter.

Outside the criminal context, however, in response to the exigencies of modern life, our cases have upheld several evenhanded blanket searches, including some that are more than minimally intrusive, after balancing the invasion of privacy against the government’s strong need. Most of these cases, of course, are distinguishable insofar as they involved searches either not of a personally intrusive nature, such as searches of closely regulated businesses, see, e. g., New York v. Burger, 482 U. S. 691, 699-703 (1987); cf. Cuddihy 1501 (“Even the states with the strongest constitutional restrictions on general searches had long exposed commercial establishments to warrantless inspection”), or arising in unique contexts such as prisons, see, e. g., Wolfish, supra, at 558-560 (visual body cavity searches of prisoners following contact visits); cf. Cuddihy 1516-1519, 1552-1553 (indicating that searches incident to arrest and prisoner searches were the only common personal searches at time of founding). This certainly explains why Justice Scalia, in his dissent in our recent Von Raab decision, found it significant that “[u]ntil *674today this Court had upheld a bodily search separate from arrest and without individualized suspicion of wrongdoing only with respect to prison inmates, relying upon the uniquely dangerous nature of that environment.” Von Raab, supra, at 680 (citation omitted).

In any event, in many of the cases that can be distinguished on the grounds suggested above and, more important, in all of the cases that cannot, see, e. g., Skinner, supra (blanket drug testing scheme); Von Raab, supra (same); cf. Camara v. Municipal Court of City and County of San Francisco, 387 U. S. 523 (1967) (area-wide searches of private residences), we upheld the suspicionless search only after first recognizing the Fourth Amendment’s longstanding preference for a suspicion-based search regime, and then pointing to sound reasons why such a regime would likely be ineffectual under the unusual circumstances presented. In Skinner, for example, we stated outright that “ ‘some quantum of individualized suspicion’ ” is “usually required” under the Fourth Amendment, Skinner, supra, at 624, quoting Martinez-Fuerte, supra, at 560, and we built the requirement into the test we announced: “In limited circumstances, where the privacy interests implicated by the search are minimal, and where an important governmental interest furthered by the intrusion would be placed in jeopardy by a requirement of individualized suspicion, a search may be reasonable despite the absence of such suspicion,” 489 U. S., at 624 (emphasis added). The obvious negative implication of this reasoning is that, if such an individualized suspicion requirement would not place the government’s objectives in jeopardy, the requirement should not be forsaken. See also Von Raab, supra, at 665-666.

Accordingly, we upheld the suspicionless regime at issue in Skinner on the firm understanding that a requirement of individualized suspicion for testing train operators for drug or alcohol impairment following serious train accidents would be unworkable because “the scene of a serious rail *675accident is chaotic.” Skinner, 489 U. S., at 631. (Of course, it could be plausibly argued that the fact that testing occurred only after train operators were involved in serious train accidents amounted to an individualized suspicion requirement in all but name, in light of the record evidence of a strong link between serious train accidents and drug and alcohol use.) We have performed a similar inquiry in the other cases as well. See Von Raab, 489 U. S., at 674 (suspicion requirement for searches of customs officials for drug impairment impractical because “not feasible to subject [such] employees and their work product to the kind of day-to-day scrutiny that is the norm in more traditional office environments”); Camara, supra, at 537 (suspicion requirement for searches of homes for safety code violations impractical because conditions such as “faulty wiring” not observable from outside of house); see also Wolfish, 441 U. S., at 559-560, n. 40 (suspicion requirement for searches of prisoners for smuggling following contact visits impractical because observation necessary to gain suspicion would cause “obvious disruption of the confidentiality and intimacy that these visits are intended to afford”); Martinez-Fuerte, 428 U. S., at 557 (“A requirement that stops on major routes inland always be based on reasonable suspicion would be impractical because the flow of traffic tends to be too heavy to allow the particularized study of a given car that would enable it to be identified as a possible carrier of illegal aliens”); United States v. Edwards, 498 F. 2d 496, 500 (CA2 1974) (Friendly, J.) (suspicion-based searches of airport passengers’ carry-on luggage impractical because of the great number of plane travelers and “conceded inapplicability” of the profile method of detecting hijackers).

Moreover, an individualized suspicion requirement was often impractical in these cases because they involved situations in which even one undetected instance of wrongdoing could have injurious consequences for a great number of people. See, e. g., Camara, supra, at 535 (even one safety code *676violation can cause “fires and epidemics [that] ravage large urban areas”); Skinner, supra, at 628 (even one drug- or alcohol-impaired train operator can lead to the “disastrous consequences” of a train wreck, such as “great human loss”); Von Raab, supra, at 670, 674, 677 (even one customs official caught up in drugs can, by virtue of impairment, susceptibility to bribes, or indifference, result in the noninterdiction of a “sizable drug shipmen[t],” which eventually injures the lives of thousands, or to a breach of “national security”); Edwards, supra, at 600 (even one hijacked airplane can destroy “ ‘hundreds of human lives and millions of dollars of property’ ”) (citation omitted).

B

The instant case stands in marked contrast. One searches today’s majority opinion in vain for recognition that history and precedent establish that individualized suspicion is “usually required” under the Fourth Amendment (regardless of whether a warrant and probable cause are also required) and that, in the area of intrusive personal searches, the only recognized exception is for situations in which a suspicion-based scheme would be likely ineffectual. See supra, at 674-675 and this page. Far from acknowledging anything special about individualized suspicion, the Court treats a suspicion-based regime as if it were just any run-of-the-mill, less intrusive alternative — that is, an alternative that officials may bypass if the lesser intrusion, in their reasonable estimation, is outweighed by policy concerns unrelated to practicability.

As an initial matter, I have serious doubts whether the Court is right that the District reasonably found that the lesser intrusion of a suspicion-based testing program outweighed its genuine concerns for the adversarial nature of such a program, and for its abuses. See ante, at 663-664. For one thing, there are significant safeguards against abuses. The fear that a suspicion-based regime will lead to the testing of “troublesome but not drug-likely” students, *677ante, at 663, for example, ignores that the required level of suspicion in the school context is objectively reasonable suspicion. In this respect, the facts of our decision in New Jersey v. I L. O., 469 U. S. 325 (1985), should be reassuring. There, we found reasonable suspicion to search a ninth-grade girl’s purse for cigarettes after a teacher caught the girl smoking in the bathroom with a companion who admitted it. See id., at 328, 345-346. Moreover, any distress arising from what turns out to be a false accusation can be minimized by keeping the entire process confidential.

For another thing, the District’s concern for the adversarial nature of a suspicion-based regime (which appears to extend even to those who are rightly accused) seems to ignore the fact that such a regime would not exist in a vacuum. Schools already have adversarial, disciplinary schemes that require teachers and administrators in many areas besides drug use to investigate student wrongdoing (often by means of accusatory searches); to make determinations about whether the wrongdoing occurred; and to impose punishment. To such a scheme, suspicion-based drug testing would be only a minor addition. The District’s own elaborate disciplinary scheme is reflected in its handbook, which, among other things, lists the following disciplinary “problem areas” carrying serious sanctions: “DEFIANCE OF AUTHORITY,” “DISORDERLY OR DISRUPTIVE CONDUCT INCLUDING FOUL LANGUAGE,” “AUTOMOBILE USE OR MISUSE,” “FORGERY OR LYING,” “GAMBLING,” “THEFT,” “TOBACCO,” “MISCHIEF,” “VANDALISM,” “RECKLESSLY ENDANGERING,” “MENACING OR HARASSMENT,” “ASSAULT,” “FIGHTING,” “WEAPONS,” “EXTORTION,” “EXPLOSIVE DEVICES,” and “ARSON.” Record, Exh. 2, p. 11; see also id., at 20-21 (listing rules regulating dress and grooming, public displays of affection, and the wearing of hats inside); cf. id., at 8 (“RESPONSIBILITIES OF SCHOOLS” include “To develop and distribute to parents and students reasonable rules *678and regulations governing student behavior and attendance” and “To provide fair and reasonable standards of conduct and to enforce those standards through appropriate disciplinary action”). The high number of disciplinary referrals in the record in this case illustrates the District’s robust scheme in action.

In addition to overstating its concerns with a suspicion-based program, the District seems to have understated the extent to which such a program is less intrusive of students’ privacy. By invading the privacy of a few students rather than many (nationwide, of thousands rather than millions), and by giving potential search targets substantial control over whether they will, in fact, be searched, a suspicion-based scheme is significantly less intrusive.

In any event, whether the Court is right that the District reasonably weighed the lesser intrusion of a suspicion-based scheme against its policy concerns is beside the point. As stated, a suspicion-based search regime is not just any less intrusive alternative; the individualized suspicion requirement has a legal pedigree as old as the Fourth Amendment itself, and it may not be easily cast aside in the name of policy concerns. It may only be forsaken, our cases in the personal search context have established, if a suspicion-based regime would likely be ineffectual.

But having misconstrued the fundamental role of the individualized suspicion requirement in Fourth Amendment analysis, the Court never seriously engages the practicality of such a requirement in the instant case. And that failure is crucial because nowhere is it less clear that an individualized suspicion requirement would be ineffectual than in the school context. In most schools, the entire pool of potential search targets — students—is under constant supervision by teachers and administrators and coaches, be it in classrooms, hallways, or locker rooms. See T. L. O., 469 U. S., at 339 (“[A] proper educational environment requires close supervision of schoolchildren”).

*679The record here indicates that the Vernonia schools are no exception. The great irony of this case is that most (though not all) of the evidence the District introduced to justify its suspicionless drug testing program consisted of first- or second-hand stories of particular, identifiable students acting in ways that plainly gave rise to reasonable suspicion of in-school drug use — and thus that would have justified a drug-related search under our T. L. O. decision. See id., at 340-342 (warrant and probable cause not required for school searches; reasonable suspicion sufficient). Small groups of students, for example, were observed by a teacher “passing joints back and forth” across the street at a restaurant before school and during school hours. Tr. 67 (Apr. 29,1992). Another group was caught skipping school and using drugs at one of the students’ houses. See id., at 93-94. Several students actually admitted their drug use to school officials (some of them being caught with marijuana pipes). See id., at 24. One student presented himself to his teacher as “clearly obviously inebriated” and had to be sent home. Jd., at 68. Still another was observed dancing and singing at the top of his voice in the back of the classroom; when the teacher asked what was going on, he replied, “Well, I’m just high on life.” Id., at 89-90. To take a final example, on a certain road trip, the school wrestling coach smelled marijuana smoke in a motel room occupied by four wrestlers, see id., at 110-112, an observation that (after some questioning) would probably have given him reasonable suspicion to test one or all of them. Cf. 4 LaFave § 10.11(b), at 169 (“[I]n most instances the evidence of wrongdoing prompting teachers or principals to conduct searches is sufficiently detailed and specific to meet the traditional probable cause test”).

In light of all this evidence of drug use by particular students, there is a substantial basis for concluding that a vigorous regime of suspicion-based testing (for which the District appears already to have rules in place, see Record, Exh. 2, at 14, 17) would have gone a long way toward solving Ver-*680nonia’s school drug problem while preserving the Fourth Amendment rights of James Acton and others like him. And were there any doubt about such a conclusion, it is removed by indications in the record that suspicion-based testing could have been supplemented by an equally vigorous campaign to have Vernonia’s parents encourage their children to submit to the District’s voluntary drug testing program. See id., at 32 (describing the voluntary program); ante, at 665 (noting widespread parental support for drug testing). In these circumstances, the Fourth Amendment dictates that a mass, suspicionless search regime is categorically unreasonable.

I recognize that a suspicion-based scheme, even where reasonably effective in controlling in-school drug use, may not be as effective as a mass, suspicionless testing regime. In one sense, that is obviously true — -just as it is obviously true that suspicion-based law enforcement is not as effective as mass, suspicionless enforcement might be. “But there is nothing new in the realization” that Fourth Amendment protections come with a price. Arizona v. Hicks, 480 U. S. 321, 329 (1987). Indeed, the price we pay is higher in the criminal context, given that police do not closely observe the entire class of potential search targets (all citizens in the area) and must ordinarily adhere to the rigid requirements of a warrant and probable cause.

The principal counterargument to all this, central to the Court’s opinion, is that the Fourth Amendment is more lenient with respect to school searches. That is no doubt correct, for, as the Court explains, ante, at 655-656, schools have traditionally had special guardianlike responsibilities for children that necessitate a degree of constitutional leeway. This principle explains the considerable Fourth Amendment leeway we gave school officials in I L. O. In that case, we held that children at school do not enjoy two of the Fourth Amendment's traditional categorical protections against unreasonable searches and seizures: the warrant requirement *681and the probable cause requirement. See T L. O., 469 U. S., at 337-343. And this was true even though the same children enjoy such protections “in a nonschool setting.” Id., at 348 (Powell, J., concurring).

The instant case, however, asks whether the Fourth Amendment is even more lenient than that, i. e., whether it is so lenient that students may be deprived of the Fourth Amendment’s only remaining, and most basic, categorical protection: its strong preference for an individualized suspicion requirement, with its accompanying antipathy toward personally intrusive, blanket searches of mostly innocent people. It is not at all clear that people in prison lack this categorical protection, see Wolfish, 441 U. S., at 558-560 (upholding certain suspicionless searches of prison inmates); but cf. supra, at 675 (indicating why suspicion requirement was impractical in Wolfisk), and we have said “[w]e are not yet ready to hold that the schools and the prisons need be equated for purposes of the Fourth Amendment.” T L. O., supra, at 338-339. Thus, if we are to mean what we often proclaim — that students do not “shed their constitutional rights ... at the schoolhouse gate,” Tinker v. Des Moines Independent Community School Dist., 393 U. S. 503, 506 (1969) — the answer must plainly be no.1

*682For the contrary position, the Court relies on cases such as T L. O., Ingraham v. Wright, 430 U. S. 651 (1977), and Goss v. Lopez, 419 U. S. 565 (1975). See ante, at 655-656. But I find the Court’s reliance on these cases ironic. If anything, they affirm that schools have substantial constitutional leeway in carrying out their traditional mission of responding to particularized wrongdoing. See T. L. O., supra (leeway in investigating particularized wrongdoing); Ingraham, supra (leeway in punishing particularized wrongdoing); Goss, supra (leeway in choosing procedures by which particularized wrongdoing is punished).

By contrast, intrusive, blanket searches of schoolchildren, most of whom are innocent, for evidence of serious wrongdoing are not part of any traditional school function of which I am aware. Indeed, many schools, like many parents, prefer to trust their children unless given reason to do otherwise. As James Acton’s father said on the witness stand, “[suspi-cionless testing] sends a message to children that are trying to be responsible citizens . . . that they have to prove that they’re innocent..., and I think that kind of sets a bad tone for citizenship.” Tr. 9 (Apr. 29, 1992).

I find unpersuasive the Court’s reliance, ante, at 656-657, on the widespread practice of physical examinations and vaccinations, which are both blanket searches of a sort. Of course, for these practices to have any Fourth Amendment significance, the Court has to assume that these physical exams and vaccinations are typically “required” to a similar extent that urine testing and collection is required in the instant case, i. e., that they are required regardless of parental *683objection and that some meaningful sanction attaches to the failure to submit. In any event, without forming any particular view of such searches, it is worth noting that a suspicion requirement for vaccinations is not merely impractical; it is nonsensical, for vaccinations are not searches for anything in particular and so there is nothing about which to be suspicious. Nor is this saying anything new; it is the same theory on which, in part, we have repeatedly upheld certain inventory searches. See, e. g., South Dakota v. Opperman, 428 U. S. 364, 370, n. 5 (1976) (“The probable-cause approach is unhelpful when analysis centers upon the reasonableness of routine administrative caretaking functions”). As for physical examinations, the practicability of a suspicion requirement is highly doubtful because the conditions for which these physical exams ordinarily search, such as latent heart conditions, do not manifest themselves in observable behavior the way school drug use does. See supra, at 679-680.

It might also be noted that physical exams (and of course vaccinations) are not searches for conditions that reflect wrongdoing on the part of the student, and so are wholly nonaccusatory and have no consequences that can be regarded as punitive. These facts may explain the absence of Fourth Amendment challenges to such searches. By contrast, although I agree with the Court that the accusatory nature of the District’s testing program is diluted by making it a blanket one, any testing program that searches for conditions plainly reflecting serious wrongdoing can never be made wholly nonaccusatory from the student’s perspective, the motives for the program notwithstanding; and for the same reason, the substantial consequences that can flow from a positive test, such as suspension from sports, are invariably — and quite reasonably — understood as punishment. The best proof that the District’s testing program is to some extent accusatory can be found in James Acton’s own explanation on the witness stand as to why he did not want to submit to drug testing: “Because I feel that they have no *684reason to think I was taking drugs.” Tr. 13 (Apr. 29, 1992). It is hard to think of a manner of explanation that resonates more intensely in our Fourth Amendment tradition than this.

II

I do not believe that suspicionless drug testing is justified on these facts. But even if I agreed that some such testing were reasonable here, I see two other Fourth Amendment flaws in the District’s program.2 First, and most serious, there is virtually no evidence in the record of a drug problem at the Washington Grade School, which includes the seventh and eighth grades, and which Acton attended when this litigation began. This is not surprising, given that, of the four witnesses who testified to drug-related incidents, three were teachers and/or coaches at the high school, see Tr. 65; id., at 86; id., at 99, and the fourth, though the principal of the grade school at the time of the litigation, had been employed as principal of the high school during the years leading up to (and beyond) the implementation of the drug testing policy. See id., at 17. The only evidence of a grade school drug problem that my review of the record uncovered is a “guarantee” by the late-arriving grade school principal that “our problems we’ve had in ’88 and ’89 didn’t start at the high school level. They started in the elementary school.” Id., at 43. But I would hope that a single assertion of this sort would not serve as an adequate basis on which to uphold mass, suspicionless drug testing of two entire grades of student athletes — in Vernonia and, by the Court’s reasoning, in other school districts as well. Perhaps there is a drug problem at the grade school, but one would not know it from this *685record. At the least, then, I would insist that the parties and the District Court address this issue on remand.

Second, even as to the high school, I find unreasonable the school’s choice of student athletes as the class to subject to suspicionless testing — a choice that appears to have been driven more by a belief in what would pass constitutional muster, see id., at 45-47 (indicating that the original program was targeted at students involved in any extracurricular activity), than by a belief in what was required to meet the District’s principal disciplinary concern. Reading the full record in this case, as well as the District Court’s authoritative summary of it, 796 F. Supp. 1354, 1356-1357 (Ore. 1992), it seems quite obvious that the true driving force behind the District’s adoption of its drug testing program was the need to combat the rise in drug-related disorder and disruption in its classrooms and around campus. I mean no criticism of the strength of that interest. On the contrary, where the record demonstrates the existence of such a problem, that interest seems self-evidently compelling. “Without first establishing discipline and maintaining order, teachers cannot begin to educate their students.” I L. O., 469 U. S., at 350 (Powell, J., concurring). And the record in this case surely demonstrates there was a drug-related discipline problem in Vernonia of “‘epidemic proportions.’” 796 F. Supp., at 1357. The evidence of a drug-related sports injury problem at Vernonia, by contrast, was considerably weaker.

On this record, then, it seems to me that the far more reasonable choice would have been to focus on the class of students found to have violated published school rules against severe disruption in class and around campus, see Record, Exh. 2, at 9,11 — disruption that had a strong nexus to drug use, as the District established at trial. Such a choice would share two of the virtues of a suspicion-based regime: testing dramatically fewer students, tens as against hundreds, and giving students control, through their behav*686ior, over the likelihood that they would be tested. Moreover, there would be a reduced concern for the accusatory nature of the search, because the Court’s feared “badge of shame,” ante, at 663, would already exist, due to the antecedent accusation and finding of severe disruption. In a lesser known aspect of Skinner, we upheld an analogous testing scheme with little hesitation. See Skinner, 489 U. S., at 611 (describing “ ‘Authorization to Test for Cause’ ” scheme, according to which train operators would be tested “in the event of certain specific rule violations, including noncompliance with a signal and excessive speeding”).

III

It cannot be too often stated that the greatest threats to our constitutional freedoms come in times of crisis. But we must also stay mindful that not all government responses to such times are hysterical overreactions; some crises are quite real, and when they are, they serve precisely as the compelling state interest that we have said may justify a measured intrusion on constitutional rights. The only way for judges to mediate these conflicting impulses is to do what they should do anyway: stay close to the record in each case that appears before them, and make their judgments based on that alone. Having reviewed the record here, I cannot avoid the conclusion that the District’s suspicionless policy of testing all student athletes sweeps too broadly, and too imprecisely, to be reasonable under the Fourth Amendment.

Justice Thomas

delivered the opinion of the Court.

The Student Activities Drug Testing Policy implemented by the Board of Education of Independent School District No. 92 of Pottawatomie County (School District) requires all students who participate in competitive extracurricular activities to submit to drug testing. Because this Policy reasonably serves the School District’s important interest in detecting and preventing drug use among its students, we hold that it is constitutional.

*826HH

The city of Tecumseh, Oklahoma, is a rural community located approximately 40 miles southeast of Oklahoma City. The School District administers all Tecumseh public schools. In the fall of 1998, the School District adopted the Student Activities Drug Testing Policy (Policy), which requires all middle and high school students to consent to drug testing in order to participate in any extracurricular activity. In practice, the Policy has been applied only to competitive extracurricular activities sanctioned by the Oklahoma Secondary Schools Activities Association, such as the Academic Team, Future Farmers of America, Future Homemakers of America, band, choir, pom pon, cheerleading, and athletics. Under the Policy, students are required to take a drug test before participating in an extracurricular activity, must submit to random drug testing while participating in that activity, and must agree to be tested at any time upon reasonable suspicion. The urinalysis tests are designed to detect only the use of illegal drugs, including amphetamines, marijuana, cocaine, opiates, and barbituates, not medical conditions or the presence of authorized prescription medications.

At the time of their suit, both respondents attended Tecumseh High School. Respondent Lindsay Earls was a member of the show choir, the marching band, the Academic Team, and the National Honor Society. Respondent Daniel James sought to participate in the Academic Team.1 Together with their parents, Earls and James brought a Rev. *827Stat. § 1979, 42 U. S. C. § 1983, action against the School District, challenging the Policy both on its face and as applied to their participation in extracurricular activities.2 They alleged that the Policy violates the Fourth Amendment as incorporated by the Fourteenth Amendment and requested in-junctive and declarative relief. They also argued that the School District failed to identify a special need for testing students who participate in extracurricular activities, and that the “Drug Testing Policy neither addresses a proven problem nor promises to bring any benefit to students or the school.” App. 9.

Applying the principles articulated in Vernonia School Dist. 47J v. Acton, 515 U. S. 646 (1995), in which we upheld the suspicionless drug testing of school athletes, the United States District Court for the Western District of Oklahoma rejected respondents’ claim that the Policy was unconstitutional and granted summary judgment to the School District. The court noted that “special needs” exist in the public school context and that, although the School District did “not show a drug problem of epidemic proportions,” there was a history of drug abuse starting in 1970 that presented “legitimate cause for concern.” 115 F. Supp. 2d 1281, 1287 (2000). The District Court also held that the Policy was effective because “[i]t can scarcely be disputed that the drug problem among the student body is effectively addressed by making sure that the large number of students participating in competitive, extracurricular activities do not use drugs.” Id., at 1295.

The United States Court of Appeals for the Tenth Circuit reversed, holding that the Policy violated the Fourth Amendment. The Court of Appeals agreed with the District Court that the Policy must be evaluated in the “unique environment of the school setting,” but reached a different conclu*828sion as to the Policy’s constitutionality. 242 F. 3d 1264, 1270 (2001). Before imposing a suspicionless drug testing program, the Court of Appeals concluded that a school “must demonstrate that there is some identifiable drug abuse problem among a sufficient number of those subject to the testing, such that testing that group of students will actually redress its drug problem.” Id., at 1278. The Court of Appeals then held that because the School District failed to demonstrate such a problem existed among Tecumseh students participating in competitive extracurricular activities, the Policy was unconstitutional. We granted certiorari, 534 U. S. 1015 (2001), and now reverse.

II

The Fourth Amendment to the United States Constitution protects “[t]he right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures.” Searches by public school officials, such as the collection of urine samples, implicate Fourth Amendment interests. See Vernonia, supra, at 652; cf. New Jersey v. T. L. O., 469 U. S. 325, 334 (1985). We must therefore review the School District’s Policy for “reasonableness,” which is the touchstone of the constitutionality of a governmental search.

In the criminal context, reasonableness usually requires a showing of probable cause. See, e. g., Skinner v. Railway Labor Executives’ Assn., 489 U. S. 602, 619 (1989). The probable-cause standard, however, “is peculiarly related to criminal investigations” and may be unsuited to determining the reasonableness of administrative searches where the “Government seeks to prevent the development of hazardous conditions.” Treasury Employees v. Von Raab, 489 U. S. 656, 667-668 (1989) (internal quotation marks and citations omitted) (collecting eases). The Court has also held that a warrant and finding of probable cause are unnecessary in the public school context because such requirements “ ‘would unduly interfere with the maintenance of the swift and infor*829mal disciplinary procedures [that are] needed.’ ” Vernonia, supra, at 653 (quoting T L. O., supra, at 340-341).

Given that the School District’s Policy is not in any way related to the conduct of criminal investigations, see Part II-B, infra, respondents do not contend that the School District requires probable cause before testing students for drug use. Respondents instead argue that drug testing must be based at least on some level of individualized suspicion. See Brief for Respondents 12-14. It is true that we generally determine the reasonableness of a search by balancing the nature of the intrusion on the individual’s privacy against the promotion of legitimate governmental interests. See Delaware v. Prouse, 440 U. S. 648, 654 (1979). But we have long held that “the Fourth Amendment imposes no irreducible requirement of [individualized] suspicion.” United States v. Martinez-Fuerte, 428 U. S. 543, 561 (1976). “[I]n certain limited circumstances, the Government’s need to discover such latent or hidden conditions, or to prevent their development, is sufficiently compelling to justify the intrusion on privacy entailed by conducting such searches without any measure of individualized suspicion.” Von Raab, supra, at 668; see also Skinner, supra, at 624. Therefore, in the context of safety and administrative regulations, a search unsupported by probable cause may be reasonable “when 'special needs, beyond the normal need for law enforcement, make the warrant and probable-cause requirement impracticable.’” Griffin v. Wisconsin, 483 U. S. 868, 873 (1987) (quoting T. L. O., supra, at 351 (Blackmun, J., concurring in judgment)); see also Vernonia, supra, at 653; Skinner, supra, at 619.

Significantly, this Court has previously held that “special needs” inhere in the public school context. See Vernonia, supra, at 653; T. L. O., supra, at 339-340. While schoolchildren do not shed their constitutional rights when they enter the schoolhouse, see Tinker v. Des Moines Independent Community School Dist., 393 U. S. 503, 506 (1969), “Fourth *830Amendment rights . . . are different in public schools than elsewhere; the ‘reasonableness’ inquiry cannot disregard the schools’ custodial and tutelary responsibility for children.” Vernonia, 515 U. S., at 656. In particular, a finding of individualized suspicion may not be necessary when a school conducts drug testing.

In Vernonia, this Court held that the suspicionless drug testing of athletes was constitutional. The Court, however, did not simply authorize all school drug testing, but rather conducted a fact-specific balancing of the intrusion on the children’s Fourth Amendment rights against the promotion of legitimate governmental interests. See id., at 652-653. Applying the principles of Vernonia to the somewhat different facts of this case, we conclude that Tecumseh’s Policy is also constitutional.

A

We first consider the nature of the privacy interest allegedly compromised by the drug testing. See id., at 654. As in Vernonia, the context of the public school environment serves as the backdrop for the analysis of the privacy interest at stake and the reasonableness of the drug testing policy in general. See ibid. (“Central... is the fact that the subjects of the Policy are (1) children, who (2) have been committed to the temporary custody of the State as schoolmaster”); see also id., at 665 (“The most significant element in this case is the first we discussed: that the Policy was undertaken in furtherance of the government’s responsibilities, under a public school system, as guardian and tutor of children entrusted to its care”); ibid. (“[W]hen the government acts as guardian and tutor the relevant question is whether the search is one that a reasonable guardian and tutor might undertake”).

A student’s privacy interest is limited in a public school environment where the State is responsible for maintaining discipline, health, and safety. Schoolchildren are routinely required to submit to physical examinations and vaccinations *831against disease. See id., at 656. Securing order in the school environment sometimes requires that students be subjected to greater controls than those appropriate for adults. See T. L. O., 469 U. S., at 350 (Powell, J., concurring) (“Without first establishing discipline and maintaining order, teachers cannot begin to educate their students. And apart from education, the school has the obligation to protect pupils from mistreatment by other children, and also to protect teachers themselves from violence by the few students whose conduct in recent years has prompted national concern”).

Respondents argue that because children participating in nonathletic extracurricular activities are not subject to regular physicals and communal undress, they have a stronger expectation of privacy than the athletes tested in Vernonia. See Brief for Respondents 18-20. This distinction, however, was not essential to our decision in Vernonia, which depended primarily upon the school’s custodial responsibility and authority.3

In any event, students who participate in competitive extracurricular activities voluntarily subject themselves to many of the same intrusions on their privacy as do athletes.4 *832Some of these clubs and activities require occasional off-campus travel and communal undress. All of them have their own rules and requirements for participating students that do not apply to the student body as a whole. 115 F. Supp. 2d, at 1289-1290. For example, each of the competitive extracurricular activities governed by the Policy must abide by the rules of the Oklahoma Secondary Schools Activities Association, and a faculty sponsor monitors the students for compliance with the various rules dictated by the clubs and activities. See id., at 1290. This regulation of extracurricular activities further diminishes the expectation of privacy among schoolchildren. Cf. Vernonia, supra, at 657 (“Somewhat like adults who choose to participate in a closely regulated industry, students who voluntarily participate in school athletics have reason to expect intrusions upon normal rights and privileges, including privacy” (internal quotation marks omitted)). We therefore conclude that the students affected by this Policy have a limited expectation of privacy.

B

Next, we consider the character of the intrusion imposed by the Policy. See Vernonia, supra, at 658. Urination is “an excretory function traditionally shielded by great privacy.” Skinner, 489 U. S., at 626. But the “degree of intrusion” on one’s privacy caused by collecting a urine sample “depends upon the manner in which production of the urine sample is monitored.” Vernonia, supra, at 658.

Under the Policy, a faculty monitor waits outside the closed restroom stall for the student to produce a sample and must “listen for the normal sounds of urination in order to guard against tampered specimens and to insure an accurate chain of custody.” App. 199. The monitor then pours the sample into two bottles that are sealed and placed into a mailing pouch along with a consent form signed by the student. This procedure is virtually identical to that reviewed in Vernonia, except that it additionally protects privacy by *833allowing male students to produce their samples behind a closed stall. Given that we considered the method of collection in Vernonia a “negligible” intrusion, 515 U. S., at 658, the method here is even less problematic.

In addition, the Policy clearly requires that the test results be kept in confidential files separate from a student’s other educational records and released to school personnel only on a “need to know” basis. Respondents nonetheless contend that the intrusion on students’ privacy is significant because the Policy fails to protect effectively against the disclosure of confidential information and, specifically, that the school “has been careless in protecting that information: for example, the Choir teacher looked at students’ prescription drug lists and left them where other students could see them.” Brief for Respondents 24. But the choir teacher is someone with a “need to know,” because during off-campus trips she needs to know what medications are taken by her students. Even before the Policy was enacted the choir teacher had access to this information. See App. 132. In any event, there is no allegation that any other student did see such information. This one example of alleged carelessness hardly increases the character of the intrusion.

Moreover, the test results are not turned over to any law enforcement authority. Nor do the test results here lead to the imposition of discipline or have any academic consequences. Cf. Vernonia, supra, at 658, and n. 2. Rather, the only consequence of a failed drug test is to limit the student’s privilege of participating in extracurricular activities. Indeed, a student may test positive for drugs twice and still be allowed to participate in extracurricular activities. After the first positive test, the school contacts the student’s parent or guardian for a meeting. The student may continue to participate in the activity if within five days of the meeting the student shows proof of receiving drug counseling and submits to a second drug test in two weeks. For the second positive test, the student is suspended from participation in *834all extracurricular activities for 14 days, must complete four hours of substance abuse counseling, and must submit to monthly drug tests. Only after a third positive test will the student be suspended from participating in any extracurricular activity for the remainder of the school year, or 88 school days, whichever is longer. See App. 201-202.

Given the minimally intrusive nature of the sample collection and the limited uses to which the test results are put, we conclude that the invasion of students’ privacy is not significant.

C

Finally, this Court must consider the nature and immediacy of the government’s concerns and the efficacy of the Policy in meeting them. See Vernonia, 515 U. S., at 660. This Court has already articulated in detail the importance of the governmental concern in preventing drug use by schoolchildren. See id., at 661-662. The drug abuse problem among our Nation’s youth has hardly abated since Vernonia was decided in 1995. In fact, evidence suggests that it has only grown worse.5 As in Vernonia, “the necessity for the State to act is magnified by the fact that this evil is being visited not just upon individuals at large, but upon children for whom it has undertaken a special responsibility of care and direction.” Id., at 662. The health and safety risks identified in Vernonia apply with equal force to Tecumseh’s children. Indeed, the nationwide drug epidemic makes the war against drugs a pressing concern in every school.

Additionally, the School District in this case has presented specific evidence of drug use at Tecumseh schools. Teachers testified that they had seen students who appeared to be *835under the influence of drugs and that they had heard students speaking-openly about using drugs. See, e. g., App. 72 (deposition of Dean Rogers); id., at 115 (deposition of Sheila Evans). A drug dog found marijuana cigarettes near the school parking lot. Police officers once found drugs or drug paraphernalia in a car driven by a Future Farmers of America member. And the school board president reported that people in the community were calling the board to discuss the ‘‘drug situation.” See 115 F. Supp. 2d, at 1285-1286. We decline to second-guess the finding of the District Court that “[viewing the evidence as a whole, it cannot be reasonably disputed that the [School District] was faced with a ‘drug problem’ when it adopted the Policy.” Id., at 1287.

Respondents consider the proffered evidence insufficient and argue that there is no “real and immediate interest” to justify a policy of drug testing nonathletes. Brief for Respondents 32. We have recognized, however, that “[a] demonstrated problem of drug abuse . . . [is] not in all cases necessary to the validity of a testing regime,” but that some showing does “shore up an assertion of special need for a suspieionless general search program.” Chandler v. Miller, 520 U. S. 305, 319 (1997). The School District has provided sufficient evidence to shore up the need for its drug testing program.

Furthermore, this Court has not required a particularized or pervasive drug problem before allowing the government to conduct suspicionless drug testing. For instance, in Von Raab the Court upheld the drug testing of customs officials on a purely preventive basis, without any documented history of drug use by such officials. See 489 U. S., at 673. In response to the lack of evidence relating to drug use, the Court noted generally that “drug abuse is one of the most serious problems confronting our society today,” and that programs to prevent and detect drug use among customs officials could not be deemed unreasonable. Id., at 674; cf. Skinner, 489 U. S., at 607, and n. 1 (noting nationwide *836studies that identified on-the-job alcohol and drug use by railroad employees). Likewise, the need to prevent and deter the substantial harm of childhood drug use provides the necessary immediacy for a school testing policy. Indeed, it would make little sense to require a school district to wait for a substantial portion of its students to begin using drugs before it was allowed to institute a drug testing program designed to deter drug use.

Given the nationwide epidemic of drug use, and the evidence of increased drug use in Tecumseh schools, it was entirely reasonable for the School District to enact this particular drug testing policy. We reject the Court of Appeals’ novel test that “any district seeking to impose a random sus-picionless drug testing policy as a condition to participation in a school activity must demonstrate that there is some identifiable drug abuse problem among a sufficient number of those subject to the testing, such that testing that group of students will actually redress its drug problem.” 242 F. 3d, at 1278. Among other problems, it would be difficult to administer such a test. As we cannot articulate a threshold level of drug use that would suffice to justify a drug testing program for schoolchildren, we refuse to fashion what would in effect be a constitutional quantum of drug use necessary to show a “drug problem.”

Respondents also argue that the testing of nonathletes does not implicate any safety concerns, and that safety is a “crucial factor” in applying the special needs framework. Brief for Respondents 25-27. They contend that there must be “surpassing safety interests,” Skinner, supra, at 634, or “extraordinary safety and national security hazards,” Von Raab, supra, at 674, in order to override the usual protections of the Fourth Amendment. See Brief for Respondents 25-26. Respondents are correct that safety factors into the special needs analysis, but the safety interest furthered by drug testing is undoubtedly substantial for all children, athletes and nonathletes alike. We know all too well that drug *837use carries a variety of health risks for children, including death from overdose.

We also reject respondents’ argument that drug testing must presumptively be based upon an individualized reasonable suspicion of wrongdoing because such a testing regime would be less intrusive. See id., at 12-16. In this context, the Fourth Amendment does not require a finding of individualized suspicion, see supra, at 829, and we decline to impose such a requirement on schools attempting to prevent and detect drug use by students. Moreover, we question whether testing based on individualized suspicion in fact would be less intrusive. Such a regime would place an additional burden on public school teachers who are already tasked with the difficult job of maintaining order and discipline. A program of individualized suspicion might unfairly target members of unpopular groups. The fear of lawsuits resulting from such targeted searches may chill enforcement of the program, rendering it ineffective in combating drug use. See Vernonia, 515 U. S., at 668-664 (offering similar reasons for why “testing based on ‘suspicion’ of drug use would not be better, but worse”). In any case, this Court has repeatedly stated that reasonableness under the Fourth Amendment does not require employing the least intrusive means, because “[t]he logic of such elaborate less-restrictive-alternative arguments could raise insuperable barriers to the exercise of virtually all search-and-seizure powers.” Martinez-Fuerte, 428 U. S., at 556-557, n. 12; see also Skinner, supra, at 624 (“[A] showing of individualized suspicion is not a constitutional floor, below which a search must be presumed unreasonable”).

Finally, we find that testing students who participate in extracurricular activities is a reasonably effective means of addressing the School District’s legitimate concerns in preventing, deterring, and detecting drug use. While in Ver-nonia there might have been a closer fit between the testing of athletes and the trial court’s finding that the drug problem *838was “fueled by the ‘role model’ effect of athletes’ drug use,” such a finding was not essential to the holding. 515 U. S., at 663; cf. id., at 684-685 (O’Connor, J., dissenting) (questioning the extent of the drug problem, especially as applied to athletes). Vernonia did not require the school to test the group of students most likely to use drugs, but rather considered the constitutionality of the program in the context of the public school’s custodial responsibilities. Evaluating the Policy in this context, we conclude that the drug testing of Tecumseh students who participate in extracurricular activities effectively serves the School District’s interest in protecting the safety and health of its students.

HH l-H l — H

Within the limits of the Fourth Amendment, local school boards must assess the desirability of drug testing schoolchildren. In upholding the constitutionality of the Policy, we express no opinion as to its wisdom. Rather, we hold only that Tecumseh’s Policy is a reasonable means of furthering the School District’s important interest in preventing and deterring drug use among its schoolchildren. Accordingly, we reverse the judgment of the Court of Appeals.

It is so ordered.

Justice Breyer,

concurring.

I agree with the Court that Vernonia School Dist. 47J v. Acton, 515 U. S. 646 (1995), governs this case and requires reversal of the Tenth Circuit’s decision. The school’s drug testing program addresses a serious national problem by focusing upon demand, avoiding the use of criminal or disciplinary sanctions, and relying upon professional counseling and treatment. See App. 201-202. In my view, this program does not violate the Fourth Amendment’s prohibition of “unreasonable searches and seizures.” I reach this conclusion primarily for the reasons given by the Court, but I would *839emphasize several underlying considerations, which I understand to be consistent with the Court’s opinion.

I

In respect to the school’s need for the drug testing program, I would emphasize the following: First, the drug problem in our Nation’s schools is serious in terms of size, the kinds of drugs being used, and the consequences of that use both for our children and the rest of us. See, e. g., White House Nat. Drug Control Strategy 25 (Feb. 2002) (drug abuse leads annually to about 20,000 deaths, $160 billion in economic costs); Department of Health and Human Services, L. Johnston et al., Monitoring the Future: National Results on Adolescent Drug Use, Overview of Key Findings 5 (2001) (Monitoring the Future) (more than one-third of all students have used illegal drugs before completing the eighth grade; more than half before completing high school); ibid, (about 30% of all students use drugs other than marijuana prior to completing high school (emphasis added)); National Center on Addiction and Substance Abuse, Malignant Neglect: Substance Abuse and America’s Schools 15 (Sept. 2001) (Malignant Neglect) (early use leads to later drug dependence); Nat. Drug Control Strategy, supra, at 1 (same).

Second, the government’s emphasis upon supply side interdiction apparently has not reduced teenage use in recent years. Compare R. Perl, CRS Issue Brief for Congress, Drug Control: International Policy and Options CRS-1 (Dec. 12, 2001) (supply side programs account for 66% of the federal drug control budget), with Partnership for a Drug-Free America, 2001 Partnership Attitude Tracking Study: Key Findings 1 (showing increase in teenage drug use in early 1990’s, peak in 1997, holding steady thereafter); 2000-2001 PRIDE National Summary: Alcohol, Tobacco, Illicit Drugs, Violence and Related Behaviors, Grades 6 thru 12 (Jul. 16, 2002), http://www.pridesurveys.com/main/supportfiles/ natsum00.pdf, p. 15 (slight rise in high school drug use in *8402000-2001); Monitoring the Future, Table 1 (lifetime prevalence of drug use increasing over last 10 years).

Third, public school systems must find effective ways to deal with this problem. Today’s public expects its schools not simply to teach the fundamentals, but “to shoulder the burden of feeding students breakfast and lunch, offering before and after school child care services, and providing medical and psychological services,” all in a school environment that is safe and encourages learning. Brief for National School Boards Association et al. as Amici Curiae 3-4. See also Bethel School Dist. No. 403 v. Fraser, 478 U. S. 675, 681 (1986) (Schools “ ‘prepare pupils for citizenship in the Republic [and] inculcate the habits and manners of civility as values in themselves conductive to happiness and as indispensable to the practice of self-government in the community and the nation’ ”) (quoting C. Beard & M. Beard, New Basic History of the United States 228 (1968)). The law itself recognizes these responsibilities with the phrase in loco parentis — a phrase that draws its legal force primarily from the needs of younger students (who here are necessarily grouped together with older high school students) and which reflects, not that a child or adolescent lacks an interest in privacy, but that a child’s or adolescent’s school-related privacy interest, when compared to the privacy interests of an adult, has different dimensions. Cf. Vernonia, supra, at 654-655. A public school system that fails adequately to carry out its responsibilities may well see parents send their children to private or parochial school instead — with help from the State. See Zelman v. Simmons-Harris, ante, p. 639.

Fourth, the program at issue here seeks to discourage demand for drugs by changing the school’s environment in order to combat the single most important factor leading schoolchildren to take drugs, namely, peer pressure. Malignant Neglect 4 (students “whose friends use illicit drugs are more than 10 times likelier to use illicit drugs than those whose friends do not”). It offers the adolescent a nonthreat*841ening reason to decline his friend’s drug-use invitations, namely, that he intends to play baseball, participate in debate, join the band, or engage in any one of half a dozen useful, interesting, and important activities.

II

In respect to the privacy-related burden that the drug testing program imposes upon students, I would emphasize the following: First, not everyone would agree with this Court’s characterization of the privacy-related significance of urine sampling as “‘negligible.’” Ante, at 833 (quoting Vernonia, 515 U. S., at 658). Some find the procedure no more intrusive than a routine medical examination, but others are seriously embarrassed by the need to provide a urine sample with someone listening “outside the closed restroom stall,” ante, at 832. When trying to resolve this kind of close question involving the interpretation of constitutional values, I believe it important that the school board provided an opportunity for the airing of these differences at public meetings designed to give the entire community “the opportunity to be able to participate” in developing the drug policy. App. 87. The board used this democratic, participatory process to uncover and to resolve differences, giving weight to the fact that the process, in this instance, revealed little, if any, objection to the proposed testing program.

Second, the testing program avoids subjecting the entire school to testing. And it preserves an option for a conscientious objector. He can refuse testing while paying a price (nonparticipation) that is serious, but less severe than expulsion from the school.

Third, a contrary reading of the Constitution, as requiring “individualized suspicion” in this public school context, could well lead schools to push the boundaries of “individualized suspicion” to its outer limits, using subjective criteria that may “unfairly target members of impopular groups,” ante, at 837, or leave those whose behavior is slightly abnormal *842stigmatized in the minds of others. See Belsky, Random vs. Suspicion-Based Drug Testing in the Public Schools — A Surprising Civil Liberties Dilemma, 27 Okla. City U. L. Rev. 1, 20-21 (forthcoming 2002) (listing court-approved factors justifying suspicion-based drug testing, including tiredness, overactivity, quietness, boisterousness, sloppiness, excessive meticulousness, and tardiness). If so, direct application of the Fourth Amendment’s prohibition against “unreasonable searches and seizures” will further that Amendment’s liberty-protecting objectives at least to the same extent as application of the mediating “individualized suspicion” test, where, as here, the testing program is neither criminal nor disciplinary in nature.

* * *

I cannot know whether the school’s drug testing program will work. But, in my view, the Constitution does not prohibit the effort. Emphasizing the considerations I have mentioned, along with others to which the Court refers, I conclude that the school’s drug testing program, constitutionally speaking, is not “unreasonable.” And I join the Court’s opinion.

Justice O’Connor,

with whom Justice Souter joins, dissenting.

I dissented in Vernonia School Dist. 47J v. Acton, 515 U. S. 646 (1995), and continue to believe that case was wrongly decided. Because Vernonia is now this Court’s precedent, and because I agree that petitioners’ program fails even under the balancing approach adopted in that case, I join Justice Ginsburg’s dissent.

Justice Ginsburg,

with whom Justice Stevens, Justice O’Connor, and Justice Souter join, dissenting.

Seven years ago, in Vernonia School Dist. 47J v. Acton, 515 U. S. 646 (1995), this Court determined that a school *843district’s policy of randomly testing the urine of its student athletes for illicit drugs did not violate the Fourth Amendment. In so ruling, the Court emphasized that drug use “increase[d] the risk of sports-related injury” and that Ver-nonia’s athletes were the “leaders” of an aggressive local “drug culture” that had reached “‘epidemic proportions.’” Id., at 649. Today, the Court relies upon Vernonia to permit a school district with a drug problem its superintendent repeatedly described as “not. . . major,” see App. 180, 186, 191, to test the urine of an academic team member solely by reason of her participation in a nonathletic, competitive extracurricular activity — participation associated with neither special dangers from, nor particular predilections for, drug use.

“[T]he legality of a search of a student,” this Court has instructed, “should depend simply on the reasonableness, under all the circumstances, of the search.” New Jersey v. T. L. O., 469 U. S. 325, 341 (1985). Although “ ‘special needs’ inhere in the public school context,” see ante, at 829 (quoting Vernonia, 515 U. S., at 653), those needs are not so expansive or malleable as to render reasonable any program of student drug testing a school district elects to install. The particular testing program upheld today is not reasonable; it is capricious, even perverse: Petitioners’ policy targets for testing a student population least likely to be at risk from illicit drugs and their damaging effects. I therefore dissent.

1 — <

A

A search unsupported by probable cause nevertheless may be consistent with the Fourth Amendment “when special needs, beyond the normal need for law enforcement, make the warrant and probable-cause requirement impracticable.” Griffin v. Wisconsin, 483 U. S. 868, 873 (1987) (internal quotation marks omitted). In Vernonia, this Court made clear that “such ‘special needs’ . . . exist in the public school con*844text.” 515 U. S., at 653 (quoting Griffin, 483 U. S., at 873). The Court observed:

“[Wjhile children assuredly do not ‘shed their constitutional rights ... at the schoolhouse gate,’ Tinker v. Des Moines Independent Community School Dist., 393 U. S. 503, 506 (1969), the nature of those rights is what is appropriate for children in school.... Fourth Amendment rights, no less than First and Fourteenth Amendment rights, are different in public schools than elsewhere; the ‘reasonableness’ inquiry cannot disregard the schools’ custodial and tutelary responsibility for children.” 515 U. S., at 655-656 (other citations omitted).

The Vernonia Court concluded that a public school district facing a disruptive and explosive drug abuse problem sparked by members of its athletic teams had “special needs” that justified suspicionless testing of district athletes as a condition of their athletic participation.

This case presents circumstances dispositively different from those of Vernonia. True, as the Court stresses, Tecumseh students participating in competitive extracurricular activities other than athletics share two relevant characteristics with the athletes of Vernonia. First, both groups attend public schools. “[0]ur decision in Vernonia,” the Court states, “depended primarily upon the school’s custodial responsibility and authority.” Ante, at 831; see also ante, at 840 (Breyer, J., concurring) (school districts act in loco parentis). Concern for student health and safety is basic to the school’s caretaking, and it is undeniable that “drug use carries a variety of health risks for children, including death from overdose.” Ante, at 836-837 (majority opinion).

Those risks, however, are present for all schoolchildren. Vernonia cannot be read to endorse invasive and suspicion-less drug testing of all students upon any evidence of drug use, solely because drugs jeopardize the life and health of those who use them. Many children, like many adults, en*845gage in dangerous activities on their own time; that the children are enrolled in school scarcely allows government to monitor all such activities. If a student has a reasonable subjective expectation of privacy in the personal items she brings to school, see T. L. O., 469 U. S., at 338-339, surely she has a similar expectation regarding the chemical composition of her urine. Had the Vernonia Court agreed that public school attendance, in and of itself, permitted the State to test each student’s blood or urine for drugs, the opinion in Vernonia could have saved many words. See, e. g., 515 U. S., at 662 (“[I]t must not be lost sight of that [the Vernonia School District] program is directed ... to drug use by school athletes, where the risk of immediate physical harm to the drug user or those with whom he is playing his sport is particularly high.”).

The second commonality to which the Court points is the voluntary character of both interscholastic athletics and other competitive extracurricular activities. “By choosing to ‘go out for the team,’ [school athletes] voluntarily subject themselves to a degree of regulation even higher than that imposed on students generally.” Id., at 657. Comparably, the Court today observes, “students who participate in competitive extracurricular activities voluntarily subject themselves to” additional rules not applicable to other students. Ante, at 831.

The comparison is enlightening. While extracurricular activities are “voluntary” in the sense that they are not required for graduation, they are part of the school’s educational program; for that reason, the petitioner (hereinafter School District) is justified in expending public resources to ■ make them available. Participation in such activities is a key component of school life, essential in reality for students applying to college, and, for all participants, a significant contributor to the breadth and quality of the educational experience. See Brief for Respondents 6; Brief for American Academy of Pediatrics et al. as Amici Curiae 8-9. Students *846“volunteer” for extracurricular pursuits in the same way they might volunteer for honors classes: They subject themselves to additional requirements, but they do so in order to take full advantage of the education offered them. Cf. Lee v. Weisman, 505 U. S. 577, 595 (1992) (“Attendance may not be required by official decree, yet it is apparent that a student is not free to absent herself from the graduation exercise in any real sense of the term ‘voluntary,’ for absence would require forfeiture of those intangible benefits which have motivated the student through youth and all her high school years.”).

Voluntary participation in athletics has a distinctly different dimension: Schools regulate student athletes discretely because competitive school sports by their nature require communal undress and, more important, expose students to physical risks that schools have a duty to mitigate. For the very reason that schools cannot offer a program of competitive athletics without intimately affecting the privacy of students, Vernonia reasonably analogized school athletes to “adults who choose to participate in a closely regulated industry.” 515 U. S., at 657 (internal quotation marks omitted). Industries fall within the closely regulated category when the nature of their activities requires substantial government oversight. See, e. g., United States v. Biswell, 406 U. S. 311, 815-316 (1972). Interscholastic athletics similarly require close safety and health regulation; a school’s choir, band, and academic team do not.

In short, Vernonia applied, it did not repudiate, the principle that “the legality of a search of a student should depend simply on the reasonableness, under all the circumstances, of the search.” T. L. O., 469 U. S., at 341 (emphasis added). Enrollment in a public school, and election to participate in school activities beyond the bare minimum that the curriculum requires, are indeed factors relevant to reasonableness, but they do not on their own justify intrusive, suspicionless searches. Vernonia, accordingly, did not rest upon these *847factors; instead, the Court performed what today’s majority aptly describes as a “fact-specific balancing,” ante, at 830. Balancing of that order, applied to the facts now before the Court, should yield a result other than the one the Court announces today.

B

Vernonia initially considered “the nature of the privacy interest upon which the search [there] at issue intrude[d].” 515 U. S., at 654. The Court emphasized that student athletes’ expectations of privacy are necessarily attenuated:

“Legitimate privacy expectations are even less with regard to student athletes. School sports are not for the bashful. They require ‘suiting up’ before each practice or event, and showering and changing afterwards. Public school locker rooms, the usual sites for these activities, are not notable for the privacy they afford. The locker rooms in Vernonia are typical: No individual dressing rooms are provided; shower heads are lined up along a wall, unseparated by any sort of partition or curtain; not even all the toilet stalls have doors. . . . [T]here is an element of communal undress inherent in athletic participation.” Id., at 657 (internal quotation marks omitted).

Competitive extracurricular activities other than athletics, however, serve students of all manner: the modest and shy along with the bold and uninhibited. Activities of the kind plaintiff-respondent Lindsay Earls pursued — choir, show choir, marching band, and academic team — afford opportunities to gain self-assurance, to “come to know faculty members in a less formal setting than the typical classroom,” and to acquire “positive social supports and networks [that] play a critical role in periods of heightened stress.” Brief for American Academy of Pediatrics et al. as Amici Curiae 13.

On “occasional out-of-town trips,” students like Lindsay Earls “must sleep together in communal settings and use *848communal bathrooms.” 242 F. 3d 1264, 1275 (CA10 2001). But those situations are hardly equivalent to the routine communal undress associated with athletics; the School District itself admits that when such trips occur, “public-like restroom facilities,” which presumably include enclosed stalls, are ordinarily available for changing, and that “more modest students” find other ways to maintain their privacy. Brief for Petitioners 34.1

After describing school athletes’ reduced expectation of privacy, the Vernonia Court turned to “the character of the intrusion . . . complained of.” 515 U. S., at 658. Observing that students produce urine samples in a bathroom stall with a coach or teacher outside, Vernonia typed the privacy interests compromised by the process of obtaining samples “negligible.” Ibid. As to the required pretest disclosure of prescription medications taken, the Court assumed that “the School District would have permitted [a student] to provide the requested information in a confidential manner — for example, in a sealed envelope delivered to the testing lab.” Id., at 660. On that assumption, the Court concluded that Vernonia’s athletes faced no significant invasion of privacy.

In this case, however, Lindsay Earls and her parents allege that the School District handled personal information collected under the policy carelessly, with little regard for its confidentiality. Information about students’ prescription drug use, they assert, was routinely viewed by Lindsay’s choir teacher, who left files containing the information unlocked and unsealed, where others, including students, could see them; and test results were given out to all activity sponsors whether or not they had a clear “need to know.” See *849Brief for Respondents 6, 24; App. 105-106, 131. But see id., at 199 (policy requires that “[t]he medication list shall be submitted to the lab in a sealed and confidential envelope and shall not be viewed by district employees”).

In granting summary judgment to the School District, the District Court observed that the District’s “[pjolicy expressly provides for confidentiality of test results, and the Court must assume that the confidentiality provisions will be honored.” 115 F. Supp. 2d 1281, 1293 (WD Okla. 2000). The assumption is unwarranted. Unlike Vernonia, where the District Court held a bench trial before ruling in the School District’s favor, this case was decided by the District Court on summary judgment. At that stage, doubtful matters should not have been resolved in favor of the judgment seeker. See United States v. Diebold, Inc., 369 U. S. 654, 655 (1962) (per curiam) (“On summary judgment the inferences to be drawn from the underlying facts contained in [affidavits, attached exhibits, and depositions] must be viewed in the light most favorable to the party opposing the motion.”); see also 10A C. Wright, A. Miller, & M. Kane, Federal Practice and Procedure § 2716, pp. 274-277 (3d ed. 1998).

Finally, the “nature and immediacy of the governmental concern,” Vernonia, 515 U. S., at 660, faced by the Vernonia School District dwarfed that confronting Tecumseh administrators. Vernonia initiated its drug testing policy in response to an alarming situation: “[A] large segment of the student body, particularly those involved in interscholastic athletics, was in a state of rebellion ... fueled by alcohol and drug abuse as well as the student[s’] misperceptions about the drug culture.” Id., at 649 (internal quotation marks omitted). Tecumseh, by contrast, repeatedly reported to the Federal Government during the period leading up to the adoption of the policy that “types of drugs [other than alcohol and tobacco] including controlled dangerous substances, are present [in the schools] but have not identified themselves as major problems at this time.” 1998-1999 Tecum*850seh School’s Application for Funds under the Safe and Drug-Free Schools and Communities Program, reprinted at App. 191; accord, 1996-1997 Application, reprinted at App. 186; 1995-1996 Application, reprinted at App. 180.2 As the Tenth Circuit observed, “without a demonstrated drug abuse problem among the group being tested, the efficacy of the District’s solution to its perceived problem is . . . greatly diminished.” 242 F. 3d, at 1277.

The School District cites Treasury Employees v. Von Raab, 489 U. S. 656, 673-674 (1989), in which this Court permitted random drug testing of customs agents absent “any perceived drug problem among Customs employees,” given that “drug abuse is one of the most serious problems confronting our society today.” See also Skinner v. Railway Labor Executives’ Assn., 489 U. S. 602, 607, and n. 1 (1989) (upholding random drug and alcohol testing of railway employees based upon industry-wide, rather than railway-specific, evidence of drug and alcohol problems). The tests in Von Raab and Railway Labor Executives, however, were installed to avoid enormous risks to the lives and limbs of others, not dominantly in response to the health risks to users invariably present in any case of drug use. See Von Raab, 489 U. S., at 674 (drug use by customs agents involved in drug interdiction creates “extraordinary safety and national security hazards”); Railway Labor Executives, 489 U. S., at 628 (railway operators “discharge duties fraught with such risks of injury to others that even a momentary lapse of attention can have disastrous consequences”); see *851also Chandler v. Miller, 520 U. S. 305, 321 (1997) (“Von Raab must be read in its unique context”).

Not only did the Vernonia and Tecumseh districts confront drug problems of distinctly different magnitudes, they also chose different solutions: Vernonia limited its policy to athletes; Tecumseh indiscriminately subjected to testing all participants in competitive extracurricular activities. Urging that “the safety interest furthered by drug testing is undoubtedly substantial for all children, athletes and nonath-letes alike,” ante, at 836, the Court cuts out an element essential to the Vernonia judgment. Citing medical literature on the effects of combining illicit drug use with physical exertion, the Vernonia Court emphasized that “the particular drugs screened by [Vernonia’s] Policy have been demonstrated to pose substantial physical risks to athletes.” 515 U. S., at 662; see also id., at 666 (Ginsburg, J., concurring) (Vernonia limited to “those seeking to engage with others in team sports”). We have since confirmed that these special risks were necessary to our decision in Vernonia. See Chandler, 520 U. S., at 317 (Vernonia “emphasized the importance of deterring drug use by schoolchildren and the risk of injury a drug-using student athlete cast on himself and those engaged with him on the playing field”); see also Ferguson v. Charleston, 532 U. S. 67, 87 (2001) (Kennedy, J., concurring) (Vernonia’s policy had goal of “ ‘[djeterring drug use by our Nation’s schoolchildren,’ and particularly by student-athletes, because ‘the risk of immediate physical harm to the drug user or those with whom he is playing his sport is particularly high’ ”) (quoting Vernonia, 515 U. S., at 661-662).

At the margins, of course, no policy of random drug testing is perfectly tailored to the harms it seeks to address. The School District cites the dangers faced by members of the band, who must “perform extremely precise routines with heavy equipment and instruments in close proximity to other students,” and by Future Farmers of America, who *852“are required to individually control and restrain animals as large as 1500 pounds.” Brief for Petitioners 43. For its part, the United States acknowledges that “the linebacker faces a greater risk of serious injury if he takes the field under the influence of drugs than the drummer in the halftime band,” but parries that “the risk of injury to a student who is under the influence of drugs while playing golf, cross country, or volleyball (sports covered by the policy in Ver-nonia) is scarcely any greater than the risk of injury to a student... handling a 1500-pound steer (as [Future Farmers of America] members do) or working with cutlery or other sharp instruments (as [Future Homemakers of America] members do).” Brief for United States as Amicus Curiae 18. One can demur to the Government’s view of the risks drug use poses to golfers, cf. PGA TOUR, Inc. v. Martin, 532 U. S. 661, 687 (2001) (“golf is a low intensity activity”), for golfers were surely as marginal among the linebackers, sprinters, and basketball players targeted for testing in Ver-nonia as steer-handlers are among the choristers, musicians, and academic-team members subject to urinalysis in Tecumseh.3 Notwithstanding nightmarish images of out-of-control flatware, livestock run amok, and colliding tubas disturbing the peace and quiet of Tecumseh, the great majority of students the School District seeks to test in truth are engaged in activities that are not safety sensitive to an unusual degree. There is a difference between imperfect tailoring and no tailoring at all.

The Vernonia district, in sum, had two good reasons for testing athletes: Sports team members faced special health risks and they “were the leaders of the drug culture.” Vernonia, 515 U. S., at 649. No similar reason, and no other tenable justification, explains Teeumseh’s decision to target *853for testing all participants in every competitive extracurricular activity. See Chandler, 520 U. S., at 319 (drug testing candidates for office held incompatible with Fourth Amendment because program was “not well designed to identify candidates who violate antidrug laws”).

Nationwide, students who participate in extracurricular activities are significantly less likely to develop substance abuse problems than are their less-involved peers. See, e. g., N. Zill, C. Nord, & L. Loomis, Adolescent Time Use, Risky Behavior, and Outcomes 52 (1995) (tenth graders “who reported spending no time in school-sponsored activities were ... 49 percent more likely to have used drugs” than those who spent 1-4 hours per week in such activities). Even if students might be deterred from drug use in order to preserve their extracurricular eligibility, it is at least as likely that other students might forgo their extracurricular involvement in order to avoid detection of their drug use. Tecumseh’s policy thus falls short doubly if deterrence is its aim: It invades the privacy of students who need deterrence least, and risks steering students at greatest risk for substance abuse away from extracurricular involvement that potentially may palliate drug problems.4

To summarize, this case resembles Vernonia only in that the School Districts in both cases conditioned engagement in activities outside the obligatory curriculum on random subjection to urinalysis. The defining characteristics of the two programs, however, are entirely dissimilar. The Vernonia district sought to test a subpopulation of students distinguished by their reduced expectation of privacy, their special *854susceptibility to drug-related injury, and their heavy involvement with drug use. The Tecumseh district seeks to test a much larger population associated with none of these factors. It does so, moreover, without carefully safeguarding student confidentiality and without regard to the program’s untoward effects. A program so sweeping is not sheltered by Vemonia; its unreasonable reach renders it impermissible under the Fourth Amendment.

II

In Chandler, this Court inspected “Georgias requirement that candidates for state office pass a drug test”; we held that the requirement “d[id] not fit within the closely guarded category of constitutionally permissible suspicion-less searches.” 520 U. S., at 309. Georgia’s testing prescription, the record showed, responded to no “concrete danger,” id., at 319, was supported by no evidence of a particular problem, and targeted a group not involved in “high-risk, safety-sensitive tasks,” id., at 321-322. We concluded:

“What is left, after close review of Georgia’s scheme, is the image the State seeks to project. By requiring candidates for public office to submit to drug testing, Georgia displays its commitment to the struggle against drug abuse.... The need revealed, in short, is symbolic, not ‘special,’ as that term draws meaning from our case law.” Ibid.

Close review of Tecumseh’s policy compels a similar conclusion. That policy was not shown to advance the “‘special needs’ [existing] in the public school context [to maintain]... swift and informal disciplinary procedures ... [and] order in the schools,” Vernonia, 515 U. S.,.at 653 (internal quotation marks omitted). See supra, at 846-848, 849-853. What is left is the School District’s undoubted purpose to heighten awareness of its abhorrence of, and strong stand against, drug abuse. But the desire to augment eommunica*855tion of this message does not trump the right of persons— even of children within the schoolhouse gate — to be “secure in their persons . . . against unreasonable searches and seizures.” U. S. Const., Arndt. 4.

In Chandler, the Court referred to a pathmarking dissenting opinion in which “Justice Brandéis recognized the importance of teaching by example: ‘Our Government is the potent, the omnipresent teacher. For good or for ill, it teaches the whole people by its example.’ ” 520 U. S., at 322 (quoting Olmstead v. United States, 277 U. S. 438, 485 (1928)). That wisdom should guide decisionmakers in the instant case: The government is nowhere more a teacher than when it runs a public school.

It is a sad irony that the petitioning School District seeks to justify its edict here by trumpeting “the schools’ custodial and tutelary responsibility for children.” Vernonia, 515 U. S., at 656. In regulating an athletic program or endeavoring to combat an exploding drug epidemic, a school’s custodial obligations may permit searches that would otherwise unacceptably abridge students’ rights. When custodial duties are not ascendant, however, schools’ tutelary obligations to their students require them to “teach by example” by avoiding symbolic measures that diminish constitutional protections. “That [schools] are educating the young for citizenship is reason for scrupulous protection of Constitutional freedoms of the individual, if we are not to strangle the free mind at its source and teach youth to discount important principles of our government as mere platitudes.” West Virginia Bd. of Ed. v. Barnette, 319 U. S. 624, 637 (1943).

* * *

For the reasons stated, I would affirm the judgment of the Tenth Circuit declaring the testing policy at issue unconstitutional.

Justice White

delivered the opinion of the Court.

We granted certiorari in this case to examine the appropriateness of the exclusionary rule as a remedy for searches carried out in violation of the Fourth Amendment by public school authorities. Our consideration of the proper application of the Fourth Amendment to the public schools, however, has led us to conclude that the search that gave rise to *328the case now before us did not violate the Fourth Amendment. Accordingly, we here address only the questions of the proper standard for assessing the legality of searches conducted by public school officials and the application of that standard to the facts of this case.

I

On March 7, 1980, a teacher at Piscataway High School in Middlesex County, N. J., discovered two girls smoking in a lavatory. One of the two girls was the respondent T. L. 0., who at that time was a 14-year-old high school freshman. Because smoking in the lavatory was a violation of a school rule, the teacher took the two girls to the Principal’s office, where they met with Assistant Vice Principal Theodore Choplick. In response to questioning by Mr. Choplick, T. L. O.’s companion admitted that she had violated the rule. T. L. 0., however, denied that she had been smoking in the lavatory and claimed that she did not smoke at all.

Mr. Choplick asked T. L. O. to come into his private office and demanded to see her purse. Opening the purse, he found a pack of cigarettes, which he removed from the purse and held before T. L. O. as he accused her of having lied to him. As he reached into the purse for the cigarettes, Mr. Choplick also noticed a package of cigarette rolling papers. In his experience, possession of rolling papers by high school students was closely associated with the use of marihuana. Suspecting that a closer examination of the purse might yield further evidence of drug use, Mr. Choplick proceeded to search the purse thoroughly. The search revealed a smáll amount of marihuana, a pipe, a number of empty plastic bags, a substantial quantity of money in one-dollar bills, an index card that appeared to be a list of students who owed T. L. O. money, and two letters that implicated T. L. O. in marihuana dealing.

Mr. Choplick notified T. L. O.’s mother and the police, and turned the evidence of drug dealing over to the police. At *329the request of the police, T. L. O.’s mother took her daughter to police headquarters, where T. L. O. confessed that she had been selling marihuana at the high school. On the basis of the confession and the evidence seized by Mr. Choplick, the State brought delinquency charges against T. L. O. in the Juvenile and Domestic Relations Court of Middlesex County.1 Contending that Mr. Choplick’s search of her purse violated the Fourth Amendment, T. L. O. moved to suppress the evidence found in her purse as well as her confession, which, she argued, was tainted by the allegedly unlawful search. The Juvenile Court denied the motion to suppress. State ex rel. T. L. O., 178 N. J. Super. 329, 428 A. 2d 1327 (1980). Although the court concluded that the Fourth Amendment did apply to searches carried out by school officials, it held that

“a school official may properly conduct a search of a student’s person if the official has a reasonable suspicion that a crime has been or is in the process of being committed, or reasonable cause to believe that the search is necessary to maintain school discipline or enforce school policies.” Id., at 341, 428 A. 2d, at 1333 (emphasis in original).

Applying this standard, the court concluded that the search conducted by Mr. Choplick was a reasonable one. The initial decision to open the purse was justified by Mr. Choplick’s well-founded suspicion that T. L. O. had violated the rule forbidding smoking in the lavatory. Once the purse *330was open, evidence of marihuana violations was in plain view, and Mr. Choplick was entitled to conduct a thorough search to determine the nature and extent of T. L. O.’s drug-related activities. Id., at 343, 428 A. 2d, at 1334. Having denied the motion to suppress, the court on March 23, 1981, found T. L. O. to be a delinquent and on January 8, 1982, sentenced her to a year’s probation.

On appeal from the final judgment of the Juvenile Court, a divided Appellate Division affirmed the trial court’s finding that there had been no Fourth Amendment violation, but vacated the adjudication of delinquency and remanded for a determination whether T. L. O. had knowingly and voluntarily waived her Fifth Amendment rights before confessing. State ex rel. T. L. O., 185 N. J. Super. 279, 448 A. 2d 493 (1982). T. L. O. appealed the Fourth Amendment ruling, and the Supreme Court of New Jersey reversed the judgment of the Appellate Division and ordered the suppression of the evidence found in T. L. O.’s purse. State ex rel. T. L. O., 94 N. J. 331, 463 A. 2d 934 (1983).

The New Jersey Supreme Court agreed with the lower courts that the Fourth Amendment applies to searches conducted by school officials. The court also rejected the State of New Jersey’s argument that the exclusionary rule should not be employed to prevent the use in juvenile proceedings of evidence unlawfully seized by school officials. Declining to consider whether applying the rule to the fruits of searches by school officials would have any deterrent value, the court held simply that the precedents of this Court establish that “if an official search violates constitutional rights, the evidence is not admissible in criminal proceedings.” Id., at 341, 463 A. 2d, at 939 (footnote omitted).

With respect to the question of the legality of the search before it, the court agreed with the Juvenile Court that a warrantless search by a school official does not violate the Fourth Amendment so long as the official “has reasonable grounds to believe that a student possesses evidence of illegal *331activity or activity that would interfere with school discipline and order.” Id., at 346, 463 A. 2d, at 941-942. However, the court, with two justices dissenting, sharply disagreed with the Juvenile Court’s conclusion that the search of the purse was reasonable. According to the majority, the contents of T. L. O.’s purse had no bearing on the accusation against T. L. 0., for possession of cigarettes (as opposed to smoking them in the lavatory) did not violate school rules, and a mere desire for evidence that would impeach T. L. O.’s claim that she did not smoke cigarettes could not justify the search. Moreover, even if a reasonable suspicion that T. L. O. had cigarettes in her purse would justify a search, Mr. Choplick had no such suspicion, as no one had furnished him with any specific information that there were cigarettes in the purse. Finally, leaving aside the question whether Mr. Choplick was justified in opening the purse, the court held that the evidence of drug use that he saw inside did not justify the extensive “rummaging” through T. L. O.’s papers and effects that followed. Id., at 347, 463 A. 2d, at 942-943.

We granted the State of New Jersey’s petition for certio-rari. 464 U. S. 991 (1983). Although the State had argued in the Supreme Court of New Jersey that the search of T. L. O.’s purse did not violate the Fourth Amendment, the petition for certiorari raised only the question whether the exclusionary rule should operate to bar consideration in juvenile delinquency proceedings of evidence unlawfully seized by a school official without the involvement of law enforcement officers. When this case was first argued last Term, the State conceded for the purpose of argument that the standard devised by the New Jersey Supreme Court for determining the legality of school searches was appropriate and that the court had correctly applied that standard; the State contended only that the remedial purposes of the exclusionary rule were not well served by applying it to searches conducted by public authorities not primarily engaged in law enforcement.

*332Although we originally granted certiorari to decide the issue of the appropriate remedy in juvenile court proceedings for unlawful school searches, our doubts regarding the wisdom of deciding that question in isolation from the broader question of what limits, if any, the Fourth Amendment places on the activities of school authorities prompted us to order reargument on that question.2 Having heard argument on *333the legality of the search of T. L. O.’s purse, we are satisfied that the search did not violate the Fourth Amendment.3

II

In determining whether the search at issue in this case violated the Fourth Amendment, we are faced initially with the question whether that Amendment’s prohibition on unreasonable searches and seizures applies to searches conducted by public school officials. We hold that it does.

*334It is now beyond dispute that “the Federal Constitution, by virtue of the Fourteenth Amendment, prohibits unreasonable searches and seizures by state officers.” Elkins v. United States, 364 U. S. 206, 213 (1960); accord, Mapp v. Ohio, 367 U. S. 643 (1961); Wolf v. Colorado, 338 U. S. 25 (1949). Equally indisputable is the proposition that the Fourteenth Amendment protects the rights of students against encroachment by public school officials:

“The Fourteenth Amendment, as now applied to the States, protects the citizen against the State itself and all of its creatures — Boards of Education not excepted. These have, of course, important, delicate, and highly discretionary functions, but none that they may not perform within the limits of the Bill of Rights. That they are educating the young for citizenship is reason for scrupulous protection of Constitutional freedoms of the individual, if we are not to strangle the free mind at its source and teach youth to discount important principles of our government as mere platitudes.” West Virginia State Bd. of Ed. v. Barnette, 319 U. S. 624, 637 (1943).

These two propositions — that the Fourth Amendment applies to the States through the Fourteenth Amendment, and that the actions of public school officials are subject to the limits placed on state action by the Fourteenth Amendment — might appear sufficient to answer the suggestion that the Fourth Amendment does not proscribe unreasonable searches by school officials. On reargument, however, the State of New Jersey has argued that the history of the Fourth Amendment indicates that the Amendment was intended to regulate only searches and seizures carried out by law enforcement officers; accordingly, although public school officials are concededly state agents for purposes of the Fourteenth Amendment, the Fourth Amendment creates no rights enforceable against them.4

*335It may well be true that the evil toward which the Fourth Amendment was primarily directed was the resurrection of the pre-Revolutionary practice of using general warrants or “writs of assistance” to authorize searches for contraband by officers of the Crown. See United States v. Chadwick, 433 U. S. 1, 7-8 (1977); Boyd v. United States, 116 U. S. 616, 624-629 (1886). But this Court has never limited the Amendment’s prohibition on unreasonable searches and seizures to operations conducted by the police. Rather, the Court has long spoken of the Fourth Amendment’s strictures as restraints imposed upon “governmental action” — that is, “upon the activities of sovereign authority.” Burdeau v. McDowell, 256 U. S. 465, 475 (1921). Accordingly, we have held the Fourth Amendment applicable to the activities of civil as well as criminal authorities: building inspectors, see Camara v. Municipal Court, 387 U. S. 523, 528 (1967), Occupational Safety and Health Act inspectors, see Marshall v. Barlow’s, Inc., 436 U. S. 307, 312-313 (1978), and even firemen entering privately owned premises to battle a fire, see Michigan v. Tyler, 436 U. S. 499, 506 (1978), are all subject to the restraints imposed by the Fourth Amendment. As we observed in Camara v. Municipal Court, supra, “[t]he basic purpose of this Amendment, as recognized in countless decisions of this Court, is to safeguard the privacy and security of individuals against arbitrary invasions by governmental officials.” 387 U. S., at 528. Because the individual’s interest in privacy and personal security “suffers whether the government’s motivation is to investigate violations of criminal laws or breaches of other statutory or regulatory standards,” Marshall v. Barlow’s, Inc., supra, at 312-313, it would be “anomalous to say that the individual and his private property are fully protected by the Fourth Amendment only when the individual is suspected of criminal behavior.” Camara v. Municipal Court, supra, at 530.

*336Notwithstanding the general applicability of the Fourth Amendment to the activities of civil authorities, a few courts have concluded that school officials are exempt from the dictates of the Fourth Amendment by virtue of the special nature of their authority over schoolchildren. See, e. g., R. C. M. v. State, 660 S. W. 2d 552 (Tex. App. 1983). Teachers and school administrators, it is said, act in loco parentis in their dealings with students: their authority is that of the parent, not the State, and is therefore not subject to the limits of the Fourth Amendment. Ibid.

Such reasoning is in tension with contemporary reality and the teachings of this Court. We have held school officials subject to the commands of the First Amendment, see Tinker v. Des Moines Independent Community School District, 393 U. S. 503 (1969), and the Due Process Clause of the Fourteenth Amendment, see Goss v. Lopez, 419 U. S. 565 (1975). If school authorities are state actors for purposes of the constitutional guarantees of freedom of expression and due process, it is difficult to understand why they should be deemed to be exercising parental rather than public authority when conducting searches of their students. More generally, the Court has recognized that “the concept of parental delegation” as a source of school authority is not entirely “consonant with compulsory education laws.” Ingraham v. Wright, 430 U. S. 651, 662 (1977). Today’s public school officials do not merely exercise authority voluntarily conferred on them by individual parents; rather, they act in furtherance of publicly mandated educational and disciplinary policies. See, e. g., the opinion in State ex rel. T. L. O., 94 N. J., at 343, 463 A. 2d, at 934, 940, describing the New Jersey statutes regulating school disciplinary policies and establishing the authority of school officials over their students. In carrying out searches and other disciplinary functions pursuant to such policies, school officials act as representatives of the State, not merely as surrogates for the parents, and they *337cannot claim the parents’ immunity from the strictures of the Fourth Amendment.

Ill

To hold that the Fourth Amendment applies to searches conducted by school authorities is only to begin the inquiry into the standards governing such searches. Although the underlying command of the Fourth Amendment is always that searches and seizures be reasonable, what is reasonable depends on the context within which a search takes place. The determination of the standard of reasonableness governing any specific class of searches requires “balancing the need to search against the invasion which the search entails.” Camara v. Municipal Court, supra, at 536-537. On one side of the balance are arrayed the individual’s legitimate expectations of privacy and personal security; on the other, the government’s need for effective methods to deal with breaches of public order.

We have recognized that even a limited search of the person is a substantial invasion of privacy. Terry v. Ohio, 392 U. S. 1, 24-25 (1967). We have also recognized that searches of closed items of personal luggage are intrusions on protected privacy interests, for “the Fourth Amendment pro-' vides protection to the owner of every container that conceals" its contents from plain view.” United States v. Ross, 456 U. S. 798, 822-823 (1982). A search of a child’s person or of' a closed purse or other bag carried on her person,5 no less *338than a similar search carried out on an adult, is undoubtedly a severe violation of subjective expectations of privacy.

. Of course, the Fourth Amendment does not protect subjective expectations of privacy that are unreasonable or otherwise “illegitimate.” See, e. g., Hudson v. Palmer, 468 U. S. 517 (1984); Rawlings v. Kentucky, 448 U. S. 98 (1980). To receive the protection of the Fourth Amendment, an expectation of privacy must be one that society is “prepared to recognize as legitimate.” Hudson v. Palmer, supra, at 526. The State of New Jersey has argued that because of the pervasive supervision to which children in the schools are necessarily subject, a child has virtually no legitimate expectation of privacy in articles of personal property “unnecessarily” carried into a school. This argument has two factual premises: (1) the fundamental incompatibility of expectations of privacy with the maintenance of a sound educational environment; and (2) the minimal interest of the child in bringing any items of personal property into the school. Both premises are severely flawed.

Although this Court may take notice of the difficulty of maintaining discipline in the public schools today, the situation is not so dire that students in the schools may claim no legitimate expectations of privacy. We have recently recognized that the need to maintain order in a prison is such that prisoners retain no legitimate expectations of privacy in their cells, but it goes almost without saying that “[tjhe prisoner and the schoolchild stand in wholly different circumstances, separated by the harsh facts of criminal conviction and incarceration.” Ingraham v. Wright, supra, at 669. We are not *339yet ready to hold that the schools and the prisons need be equated for purposes of the Fourth Amendment.

Nor does the State’s suggestion that children have no legitimate need to bring personal property into the schools seem well anchored in reality. Students at a minimum must bring to school not only the supplies needed for their studies, but also keys, money, and the necessaries of personal hygiene and grooming. In addition, students may carry on their persons or in purses or wallets such nondisruptive yet highly personal items as photographs, letters, and diaries. Finally, students may have perfectly legitimate reasons to carry with them articles of property needed in connection with extracurricular or recreational activities. In short, schoolchildren may find it necessary to carry with them a variety of legitimate, noncontraband items, and there is no reason to conclude that they have necessarily waived all rights to privacy in such items merely by bringing them onto school grounds.

Against the child’s interest in privacy must be set the substantial interest of teachers and administrators in maintaining discipline in the classroom and on school grounds. Maintaining order in the classroom has never been easy, but in recent years, school disorder has often taken particularly ugly forms: drug use and violent crime in the schools have become major social problems. See generally 1 NIE, U. S. Dept, of Health, Education and Welfare, Violent Schools— Safe Schools: The Safe School Study Report to the Congress (1978). Even in schools that have been spared the most severe disciplinary problems, the preservation of order and a proper educational environment requires close supervision of schoolchildren, as well as the enforcement of rules against conduct that would be perfectly permissible if undertaken by an adult. “Events calling for discipline are frequent occurrences and sometimes require immediate, effective action.” Goss v. Lopez, 419 U. S., at 580. Accordingly, we have rec*340ognized that maintaining security and order in the schools requires a certain degree of flexibility in school disciplinary procedures, and we have respected the value of preserving the informality of the student-teacher relationship. See id., at 582-583; Ingraham v. Wright, 430 U. S., at 680-682.

How, then, should we strike the balance between the schoolchild’s legitimate expectations of privacy and the school’s equally legitimate need to maintain an environment in which learning can take place? It is evident that the school setting requires some easing of the restrictions to which searches by public authorities are ordinarily subject. The warrant requirement, in particular, is unsuited to the school environment: requiring a teacher to obtain a warrant before searching a child suspected of an infraction of school rules (or of the criminal law) would unduly interfere with the maintenance of the swift and informal disciplinary procedures needed in the schools. Just as we have in other cases dispensed with the warrant requirement when “the burden of obtaining a warrant is likely to frustrate the governmental purpose behind the search,” Camara v. Municipal Court, 387 U. S., at 532-533, we hold today that school officials need not obtain a warrant before searching a student who is under their authority.

The school setting also requires some modification of the level of suspicion of illicit activity needed to justify a search. Ordinarily, a search — even one that may permissibly be carried out without a warrant — must be based upon “probable cause” to believe that a violation of the law has occurred. See, e. g., Almeida-Sanchez v. United States, 413 U. S. 266, 273 (1973); Sibron v. New York, 392 U. S. 40, 62-66 (1968). However, “probable cause” is not an irreducible requirement of a valid search. The fundamental command of the Fourth Amendment is that searches and seizures be reasonable, and although “both the concept of probable cause and the requirement of a warrant bear on the reasonableness of a search, . . . in certain limited circumstances neither is required.” Almeida-Sanchez v. United States, supra, at 277 (Powell, *341J., concurring). Thus, we have in a number of cases recognized the legality of searches and seizures based on suspicions that, although “reasonable,” do not rise to the level of probable cause. See, e. g., Terry v. Ohio, 392 U. S. 1 (1968); United States v. Brignoni-Ponce, 422 U. S. 873, 881 (1975); Delaware v. Prouse, 440 U. S. 648, 654-655 (1979); United States v. Martinez-Fuerte, 428 U. S. 543 (1976); cf. Camara v. Municipal Court, supra, at 534-539. Where a careful balancing of governmental and private interests suggests that the public interest is best served by a Fourth Amendment standard of reasonableness that stops short of probable cause, we have not hesitated to adopt such a standard.

We join the majority of courts that have examined this issue6 in concluding that the accommodation of the privacy interests of schoolchildren with the substantial need of teachers and administrators for freedom to maintain order in the schools does not require strict adherence to the requirement that searches be based on probable cause to believe that the subject of the search has violated or is violating the law. Rather, the legality of a search of a student should depend simply on the reasonableness, under all the circumstances, of the search. Determining the reasonableness of any search involves a twofold inquiry: first, one must consider “whether the . . . action was justified at its inception,” Terry v. Ohio, 392 U. S., at 20; second, one must determine whether the search as actually conducted “was reasonably related in scope to the circumstances which justified the interference in the first place,” ibid. Under ordinary circumstances, a search of a student by a teacher or other school official7 will be *342“justified at its inception” when there are reasonable grounds for suspecting that the search will turn up evidence that the student has violated or is violating either the law or the rules of the school.8 Such a search will be permissible in its scope when the measures adopted are reasonably related to the objectives of the search and not excessively intrusive in light of the age and sex of the student and the nature of the infraction.9

This standard will, we trust, neither unduly burden the efforts of school authorities to maintain order in their schools *343nor authorize unrestrained intrusions upon the privacy of schoolchildren. By focusing attention on the question of reasonableness, the standard will spare teachers and school administrators the necessity of schooling themselves in the niceties of probable cause and permit them to regulate their conduct according to the dictates of reason and common sense. At the same time, the reasonableness standard should ensure that the interests of students will be invaded no more than is necessary to achieve the legitimate end of preserving order in the schools.

IV

There remains the question of the legality of the search in this case. We recognize that the “reasonable grounds” standard applied by the New Jersey Supreme Court in its consideration of this question is not substantially different from the standard that we have adopted today. Nonetheless, we believe that the New Jersey court’s application of that standard to strike down the search of T. L. O.’s purse reflects a somewhat crabbed notion of reasonableness. Our review of the facts surrounding the search leads us to conclude that the search was in no sense unreasonable for Fourth Amendment purposes.10

The incident that gave rise to this case actually involved two separate searches, with the first — the search for cigarettes — providing the suspicion that gave rise to the sec*344ond — the search for marihuana. Although it is the fruits of the second search that are at issue here, the validity of the search for marihuana must depend on the reasonableness of the initial search for cigarettes, as there would have been no reason to suspect that T. L. O. possessed marihuana had the first search not taken place. Accordingly, it is to the search for cigarettes that we first turn our attention.

The New Jersey Supreme Court pointed to two grounds for its holding that the search for cigarettes was unreasonable. First, the court observed that possession of cigarettes was not in itself illegal or a violation of school rules. Because the contents of T. L. O.’s purse would therefore have “no direct bearing on the infraction” of which she was accused (smoking in a lavatory where smoking was prohibited), there was no reason to search her purse.11 Second, even assuming that a search of T. L. O.’s purse might under some circumstances be reasonable in light of the accusation made against T. L. 0., the New Jersey court concluded that Mr. Choplick in this particular case had no reasonable grounds to suspect that T. L. O. had cigarettes in her purse. At best, accord*345ing to the court, Mr. Chopliek had “a good hunch.” 94 N. J., at 347, 463 A. 2d, at 942.

Both these conclusions are implausible. T. L. O. had been accused of smoking, and had denied the accusation in the strongest possible terms when she stated that she did not smoke at all. Surely it cannot be said that under these circumstances, T. L. O.’s possession of cigarettes would be irrelevant to the charges against her or to her response to those charges. T. L. O.’s possession of cigarettes, once it was discovered, would both corroborate the report that she had been smoking and undermine the credibility of her defense to the charge of smoking. To be sure, the discovery of the cigarettes would not prove that T. L. O. had been smoking in the lavatory; nor would it, strictly speaking, necessarily be inconsistent with her claim that she did not smoke at all. But it is universally recognized that evidence, to be relevant to an inquiry, need not conclusively prove the ultimate fact in issue, but only have “any tendency to make the existence of any fact that is of consequence to the determination of the action more probable or less probable than it would be without the evidence.” Fed. Rule Evid. 401. The relevance of T. L. O.’s possession of cigarettes to the question whether she had been smoking and to the credibility of her denial that she smoked supplied the necessary “nexus” between the item searched for and the infraction under investigation. See Warden v. Hayden, 387 U. S. 294, 306-307 (1967). Thus, if Mr. Chopliek in fact had a reasonable suspicion that T. L. O. had cigarettes in her purse, the search was justified despite the fact that the cigarettes, if found, would constitute “mere evidence” of a violation. Ibid.

Of course, the New Jersey Supreme Court also held that Mr. Chopliek had no reasonable suspicion that the purse would contain cigarettes. This conclusion is puzzling. A teacher had reported that T. L. O. was smoking in the lavatory. Certainly this report gave Mr. Chopliek reason to suspect that T. L. O. was carrying cigarettes with her; and *346if she did have cigarettes, her purse was the obvious place in which to find them. Mr. Choplick’s suspicion that there were cigarettes in the purse was not an “inchoate and un-particularized suspicion or ‘hunch,’” Terry v. Ohio, 392 U. S., at 27; rather, it was the sort of “common-sense conclusio[n] about human behavior” upon which “practical people” — including government officials — are entitled to rely. United States v. Cortez, 449 U. S. 411, 418 (1981). Of course, even if the teacher’s report were true, T. L. O. might not have had a pack of cigarettes with her; she might have borrowed a cigarette from someone else or have been sharing a cigarette with another student. But the requirement of reasonable suspicion is not a requirement of absolute certainty: “sufficient probability, not certainty, is the touchstone of reasonableness under the Fourth Amendment. ...” Hill v. California, 401 U. S. 797, 804 (1971). Because the hypothesis that T. L. O. was carrying cigarettes in her purse was itself not unreasonable, it is irrelevant that other hypotheses were also consistent with the teacher’s accusation. Accordingly, it cannot be said that Mr. Choplick acted unreasonably when he examined T. L. O.’s purse to see if it contained cigarettes.12

*347Our conclusion that Mr. Choplick’s decision to open T. L. O.’s purse was reasonable brings us to the question of the further search for marihuana once the pack of cigarettes was located. The suspicion upon which the search for marihuana was founded was provided when Mr. Choplick observed a package of rolling papers in the purse as he removed the pack of cigarettes. Although T. L. O. does not dispute the reasonableness of Mr. Choplick’s belief that the rolling papers indicated the presence of marihuana, she does contend that the scope of the search Mr. Choplick conducted exceeded permissible bounds when he seized and read certain letters that implicated T. L. O. in drug dealing. This argument, too, is unpersuasive. The discovery of the rolling papers concededly gave rise to a reasonable suspicion that T. L. O. was carrying marihuana as well as cigarettes in her purse. This suspicion justified further exploration of T. L. O.’s purse, which turned up more evidence of drug-related activities: a pipe, a number of plastic bags of the type commonly used to store marihuana, a small quantity of marihuana, and a fairly substantial amount of money. Under these circumstances, it was not unreasonable to extend the search to a separate zippered compartment of the purse; and when a search of that compartment revealed an index card containing a list of “people who owe me money” as well as two letters, the inference that T. L. O. was involved in marihuana trafficking was substantial enough to justify Mr. Choplick in examining the letters to determine whether they contained any further evidence. In short, we cannot conclude that the search for marihuana was unreasonable in any respect.

Because the search resulting in the discovery of the evidence of marihuana dealing by T. L. O. was reasonable, the New Jersey Supreme Court’s decision to exclude that evi*348dence from T. L. O.’s juvenile delinquency proceedings on Fourth Amendment grounds was erroneous. Accordingly, the judgment of the Supreme Court of New Jersey is

Reversed.

Justice Powell,

with whom Justice O’Connor joins,

concurring.

I agree with the Court’s decision, and generally with its opinion. I would place greater emphasis, however, on the special characteristics of elementary and secondary schools that make it unnecessary to afford students the same constitutional protections granted adults and juveniles in a nonschool setting.

In any realistic sense, students within the school environment have a lesser expectation of privacy than members of the population generally. They spend the school hours in close association with each other, both in the classroom and during recreation periods. The students in a particular class often know each other and their teachers quite well. Of necessity, teachers have a degree of familiarity with, and authority over, their students that is unparalleled except perhaps in the relationship between parent and child. It is simply unrealistic to think that students have the same subjective expectation of privacy as the population generally. But for purposes of deciding this case, I can assume that children in school — no less than adults — have privacy interests that society is prepared to recognize as legitimate.

However one may characterize their privacy expectations, students properly are afforded some constitutional protections. In an often quoted statement, the Court said that students do not “shed their constitutional rights ... at the schoolhouse gate.” Tinker v. Des Moines Independent Community School District, 393 U. S. 503, 506 (1969). The Court also has “emphasized the need for affirming the comprehensive authority of the states and of school officials . . . *349to prescribe and control conduct in the schools.” Id., at 507. See also Epperson v. Arkansas, 393 U. S. 97, 104 (1968). The Court has balanced the interests of the student against the school officials’ need to maintain discipline by recognizing qualitative differences between the constitutional remedies to which students and adults are entitled.

In Goss v. Lopez, 419 U. S. 565 (1975), the Court recognized a constitutional right to due process, and yet was careful to limit the exercise of this right by a student who challenged a disciplinary suspension. The only process found to be “due” was notice and a hearing described as “rudimentary”; it amounted to no more than “the disciplinarian . . . informally discussing] the alleged misconduct with the student minutes after it has occurred.” Id., at 581-582. In Ingraham v. Wright, 430 U. S. 651 (1977), we declined to extend the Eighth Amendment to prohibit the use of corporal punishment of schoolchildren as authorized by Florida law. We emphasized in that opinion that familiar constraints in the school, and also in the community, provide substantial protection against the violation of constitutional rights by school authorities. “[A]t the end of the school day, the child is invariably free to return home. Even while at school, the child brings with him the support of family and friends and is rarely apart from teachers and other pupils who may witness and protest any instances of mistreatment.” Id., at 670. The Ingraham Court further pointed out that the “openness of the public school and its supervision by the community afford significant safeguards” against the violation of constitutional rights. Ibid.

The special relationship between teacher and student also distinguishes the setting within which schoolchildren operate. Law enforcement officers function as adversaries of criminal suspects. These officers have the responsibility to investigate criminal activity, to locate and arrest those who violate our laws, and to facilitate the charging and bringing of such persons to trial. Rarely does this type of adversarial *350relationship exist between school authorities and pupils.1 Instead,'there is a commonality of interests between teachers and their pupils. The attitude of the typical teacher is one of personal responsibility for the student’s welfare as well as for his education.

The primary duty of school officials and teachers, as the Court states, is the education and training of young people. A State has a compelling interest in assuring that the schools meet this responsibility. Without first establishing discipline and maintaining order, teachers cannot begin to educate their students. And apart from education, the school has the obligation to protect pupils from mistreatment by other children, and also to protect teachers themselves from violence by the few students whose conduct in recent years has prompted national concern. For me, it would be unreasonable and at odds with history to argue that the full panoply of constitutional rules applies with the same force and effect in the schoolhouse as it does in the enforcement of criminal laws.2

In sum, although I join the Court’s opinion and its holding,3 my emphasis is somewhat different.

*351Justice Blackmun,

concurring in the judgment.

I join the judgment of the Court and agree with much that is said in its opinion. I write separately, however, because I believe the Court omits a crucial step in its analysis of whether a school search must be based upon probable cause. The Court correctly states that we have recognized limited exceptions to the probable-cause requirement “[w]here a careful balancing of governmental and private interests suggests that the public interest is best served” by a lesser standard. Ante, at 341. I believe that we have used such a balancing test, rather than strictly applying the Fourth Amendment’s Warrant and Probable-Cause Clause, only when we were confronted with “a special law enforcement need for greater flexibility.” Florida v. Royer, 460 U. S. 491, 514 (1983) (Blackmun, J., dissenting). I pointed out in United States v. Place, 462 U. S. 696 (1983):

“While the Fourth Amendment speaks in terms of freedom from unreasonable [searches], the Amendment does not leave the reasonableness of most [searches] to the judgment of courts or government officers; the Framers of the Amendment balanced the interests involved and decided that a [search] is reasonable only if supported by a judicial warrant based on probable cause. See Texas v. Brown, 460 U. S. 730, 744-745 (1983) (Powell, J., concurring); United States v. Rabinomtz, 339 U. S. 56, 70 (1950) (Frankfurter, J., dissenting).” Id., at 722 (opinion concurring in judgment).

See also Dunaway v. New York, 442 U. S. 200, 213-214 (1979); United States v. United States District Court, 407 U. S. 297, 315-316 (1972). Only in those exceptional circumstances in which special needs, beyond the normal need for law enforcement, make the warrant and probable-cause requirement impracticable, is a court entitled to substitute its balancing of interests for that of the Framers.

*352Thus, for example, in determining that police can conduct a limited “stop and frisk” upon less than probable cause, this Court relied upon the fact that “as a practical matter” the stop and frisk could not be subjected to a warrant and probable-cause requirement, because a law enforcement officer must be able to take immediate steps to assure himself that the person he has stopped to question is not armed with a weapon that could be used against him. Terry v. Ohio, 392 U. S. 1, 20-21, 23-24 (1968). Similarly, this Court’s holding that a roving Border Patrol may stop a car and briefly question its occupants upon less than probable cause was based in part upon “the absence of practical alternatives for policing the border.” United States v. Brignoni-Ponce, 422 U. S. 873, 881 (1975). See also Michigan v. Long, 463 U. S. 1032, 1049, n. 14 (1983); United States v. Martinez-Fuerte, 428 U. S. 543, 557 (1976); Camara v. Municipal Court, 387 U. S. 523, 537 (1967).

The Court’s implication that the balancing test is the rule rather than the exception is troubling for me because it is unnecessary in this case. The elementary and secondary school setting presents a special need for flexibility justifying a departure from the balance struck by the Framers. As Justice Powell notes, “[without first establishing discipline and maintaining order, teachers cannot begin to educate their students.” Ante, at 350. Maintaining order in the classroom can be a difficult task. A single teacher often must watch over a large number of students, and, as any parent knows, children at certain ages are inclined to test the outer boundaries of acceptable conduct and to imitate the misbehavior of a peer if that misbehavior is not dealt with quickly. Every adult remembers from his own schooldays the havoc a water pistol or peashooter can wreak until it is taken away. Thus, the Court has recognized that “[ejvents calling for discipline are frequent occurrences and sometimes require immediate, effective action.” Goss v. Lopez, 419 U. S. 565, 580 (1975). Indeed, because drug use and possession of weapons have become increasingly common *353among young people, an immediate response frequently is required not just to maintain an environment conducive to learning, but to protect the very safety of students and school personnel.

Such immediate action obviously would not be possible if a teacher were required to secure a warrant before searching a student. Nor would it be possible if a teacher could not conduct a necessary search until the teacher thought there was probable cause for the search. A teacher has neither the training nor the day-to-day experience in the complexities of probable cause that a law enforcement officer possesses, and is ill-equipped to make a quick judgment about the existence of probable cause. The time required for a teacher to ask the questions or make the observations that are necessary to turn reasonable grounds into probable cause is time during which the teacher, and other students, are diverted from the essential task of education. A teacher’s focus is, and should be, on teaching and helping students, rather than on developing evidence against a particular troublemaker.

Education “is perhaps the most important function” of government, Brown v. Board of Education, 347 U. S. 483, 493 (1954), and government has a heightened obligation to safeguard students whom it compels to attend school. The special need for an immediate response to behavior that threatens either the safety of schoolchildren and teachers or the educational process itself justifies the Court in excepting school searches from the warrant and probable-cause requirement, and in applying a standard determined by balancing the relevant interests. I agree with the standard the Court has announced, and with its application of the standard to the facts of this case. I therefore concur in its judgment.

Justice Brennan,

with whom Justice Marshall joins,

concurring in part and dissenting in part.

I fully agree with Part II of the Court’s opinion. Teachers, like all other government officials, must conform their *354conduct to the Fourth Amendment’s protections of personal privacy and personal security. As Justice Stevens points out, post, at 373-374, 385-386, this principle is of particular importance when applied to schoolteachers, for children learn as much by example as by exposition. It would be incongruous and futile to charge teachers with the task of embuing their students with an understanding of our system of constitutional democracy, while at the same time immunizing those same teachers from the need to respect constitutional protections. See Board of Education v. Pico, 457 U. S. 853, 864-865 (1982) (plurality opinion); West Virginia State Board of Education v. Barnette, 319 U. S. 624, 637 (1943).

I do not, however, otherwise join the Court’s opinion. Today’s decision sanctions school officials to conduct full-scale searches on a “reasonableness” standard whose only definite content is that it is not the same test as the “probable cause” standard found in the text of the Fourth Amendment. In adopting this unclear, unprecedented, and unnecessary departure from generally applicable Fourth Amendment standards, the Court carves out a broad exception to standards that this Court has developed over years of considering Fourth Amendment problems. Its decision is supported neither by precedent nor even by a fair application of the “balancing test” it proclaims in this very opinion.

I

Three basic principles underly this Court’s Fourth Amendment jurisprudence. First, warrantless searches are per se unreasonable, subject only to a few specifically delineated and well-recognized exceptions. See, e. g., Katz v. United States, 389 U. S. 347, 357 (1967); accord, Welsh v. Wisconsin, 466 U. S. 740, 748-749 (1984); United States v. Place, 462 U. S. 696, 701 (1983); Steagald v. United States, 451 U. S. 204, 211-212 (1981); Mincey v. Arizona, 437 U. S. 385 (1978); Terry v. Ohio, 392 U. S. 1, 20 (1968); Johnson v. United States, 333 U. S. 10, 13-14 (1948). Second, full-scale searches — whether conducted in accordance with the war*355rant requirement or pursuant to one of its exceptions — are “reasonable” in Fourth Amendment terms only on a showing of probable cause to believe that a crime has been committed and that evidence of the crime will be found in the place to be searched. Beck v. Ohio, 379 U. S. 89, 91 (1964); Wong Sun v. United States, 371 U. S. 471, 479 (1963); Brinegar v. United States, 338 U. S. 160, 175-176 (1949). Third, categories of intrusions that are substantially less intrusive than full-scale searches or seizures may be justifiable in accordance with a balancing test even absent a warrant or probable cause, provided that the balancing test used gives sufficient weight to the privacy interests that will be infringed. Dunaway v. New York, 442 U. S. 200, 210 (1979); Terry v. Ohio, supra.

Assistant Vice Principal Choplick’s thorough excavation of T. L. O.’s purse was undoubtedly a serious intrusion on her privacy. Unlike the searches in Terry v. Ohio, supra, or Adams v. Williams, 407 U. S. 143 (1972), the search at issue here encompassed a detailed and minute examination of respondent’s pocketbook, in which the contents of private papers and letters were thoroughly scrutinized.1 Wisely, neither petitioner nor the Court today attempts to justify the search of T. L. O.’s pocketbook as a minimally intrusive search in the Terry line. To be faithful to the Court’s settled doctrine, the inquiry therefore must focus on the warrant and probable-cause requirements.

A

I agree that schoolteachers or principals, when not acting as agents of law enforcement authorities, generally may conduct a search of their students’ belongings without first *356obtaining a warrant. To agree with the Court on this point is to say that school searches may justifiably be held to that extent to constitute an exception to the Fourth Amendment’s warrant requirement. Such an exception, however, is not to be justified, as the Court apparently holds, by assessing net social value through application of an unguided “balancing test” in which “the individual’s legitimate expectations of privacy and personal security” are weighed against “the government’s need for effective methods to deal with breaches of public order.” Ante, at 337. The Warrant Clause is something more than an exhortation to this Court to maximize social welfare as we see fit. It requires that the authorities must obtain a warrant before conducting a full-scale search. The undifferentiated governmental interest in law enforcement is insufficient to justify an exception to the warrant requirement. Rather, some special governmental interest beyond the need merely to apprehend lawbreakers is necessary to justify a categorical exception to the warrant requirement. For the most part, special governmental needs sufficient to override the warrant requirement flow from “exigency” — that is, from the press of time that makes obtaining a warrant either impossible or hopelessly infeasible. See United States v. Place, supra, at 701-702; Mincey v. Arizona, supra, at 393-394; Johnson v. United States, supra, at 15. Only after finding an extraordinary governmental interest of this kind do we — or ought we — engage in a balancing test to determine if a warrant should nonetheless be required.2

*357To require a showing of some extraordinary governmental interest before dispensing with the warrant requirement is not to undervalue society’s need to apprehend violators of the criminal law. To be sure, forcing law enforcement personnel to obtain a warrant before engaging in a search will predictably deter the police from conducting some searches that they would otherwise like to conduct. But this is not an unintended result of the Fourth Amendment’s protection of privacy; rather, it is the very purpose for which the Amendment was thought necessary. Only where the governmental interests at stake exceed those implicated in any ordinary law enforcement context — that is, only where there is some extraordinary governmental interest involved — is it legitimate to engage in a balancing test to determine whether a warrant is indeed necessary.

In this case, such extraordinary governmental interests do exist and are sufficient to justify an exception to the warrant requirement. Students are necessarily confined for most of the schoolday in close proximity to each other and to the school staff. I agree with the Court that we can take judicial notice of the serious problems of drugs and violence that plague our schools. As Justice Blackmun notes, teachers must not merely “maintain an environment conducive to learning” among children who “are inclined to test the outer boundaries of acceptable conduct,” but must also “protect the very safety of students and school personnel.” Ante, at 352-353. A teacher or principal could neither carry out essential teaching functions nor adequately protect students’ safety if required to wait for a warrant before conducting a necessary search.

B

I emphatically disagree with the Court’s decision to east aside the constitutional probable-cause standard when assessing the constitutional validity of a schoolhouse search. The Court’s decision jettisons the probable-cause standard— the only standard that finds support in the text of the Fourth *358Amendment — on the basis of its Rohrschach-like “balancing test.” Use of such a “balancing test” to determine the standard for evaluating the validity of a full-scale search represents a sizable innovation in Fourth Amendment analysis. This innovation finds support neither in precedent nor policy and portends a dangerous weakening of the purpose of the Fourth Amendment to protect the privacy and security of our citizens. Moreover, even if this Court’s historic understanding of the Fourth Amendment were mistaken and a balancing test of some kind were appropriate, any such test that gave adequate weight to the privacy and security interests protected by the Fourth Amendment would not reach the preordained result the Court's conclusory analysis reaches today. Therefore, because I believe that the balancing test used by the Court today is flawed both in its inception and in its execution, I respectfully dissent.

1

An unbroken line of cases in this Court have held that probable cause is a prerequisite for a full-scale search. In Carroll v. United States, 267 U. S. 132, 149 (1925), the Court held that “[o]n reason and authority the true rule is that if the search and seizure . . . are made upon probable cause .. . the search and seizure are valid.” Under our past decisions probable cause — which exists where “the facts and circumstances within [the officials’] knowledge and of which they had reasonably trustworthy information [are] sufficient in themselves to warrant a man of reasonable caution in the belief” that a criminal offense had occurred and the evidence would be found in the suspected place, id., at 162 — is the constitutional minimum for justifying a full-scale search, regardless of whether it is conducted pursuant to a warrant or, as in Carroll, within one of the exceptions to the warrant requirement. Henry v. United States, 361 U. S. 98, 104 (1959) (Carroll “merely relaxed the requirements for a warrant on grounds of practicality,” but “did not dispense *359with the need for probable cause”); accord, Chambers v. Maroney, 399 U. S. 42, 51 (1970) (“In enforcing the Fourth Amendment’s prohibition against unreasonable searches and seizures, the Court has insisted upon probable cause as a minimum requirement for a reasonable search permitted by the Constitution”).3

Our holdings that probable cause is a prerequisite to a full-scale search are based on the relationship between the two Clauses of the Fourth Amendment. The first Clause (“The right of the people to be secure in their persons, houses, papers and effects, against unreasonable searches and seizures, shall not be violated . . .”) states the purpose of the Amendment and its coverage. The second Clause (“. . . and no Warrants shall issue but upon probable cause . . .”) gives content to the word “unreasonable” in the first Clause. “For all but . . . narrowly defined intrusions, the requisite ‘balancing’ has been performed in centuries of precedent and is embodied in the principle that seizures are ‘reasonable’ only if supported by probable cause.” Dunaway v. New York, 442 U. S., at 214.

I therefore fully agree with the Court that “the underlying command of the Fourth Amendment is always that searches and seizures be reasonable.” Ante, at 337. But this “underlying command” is not directly interpreted in each category of cases by some amorphous “balancing test.” Rather, the provisions of the Warrant Clause — a warrant and probable cause — provide the yardstick against which official searches *360and seizures are to be measured. The Fourth Amendment neither requires nor authorizes the conceptual free-for-all that ensues when an unguided balancing test is used to assess specific categories of searches. If the search in question is more than a minimally intrusive Terry stop, the constitutional probable-cause standard determines its validity.

To be sure, the Court recognizes that probable cause “ordinarily” is required to justify a full-scale search and that the existence of probable cause “bears on” the validity of the search. Ante, at 340-341. Yet the Court fails to cite any case in which a full-scale intrusion upon privacy interests has been justified on less than probable cause. The line of cases begun by Terry v. Ohio, 392 U. S. 1 (1968), provides no support, for they applied a balancing test only in the context of minimally intrusive searches that served crucial law enforcement interests. The search in Terry itself, for instance, was a “limited search of the outer clothing.” Id., at 30. The type of border stop at issue in United States v. Brignoni-Ponce, 422 U. S. 873, 880 (1975), usually “consume[d] no more than a minute”; the Court explicitly noted that “any further detention . . . must be based on consent or probable cause.” Id., at 882. See also United States v. Hensley, ante, at 224 (momentary stop); United States v. Place, 462 U. S., at 706-707 (brief detention of luggage for canine “sniff”); Pennsylvania v. Mimms, 434 U. S. 106 (1977) (per curiam) (brief frisk after stop for traffic violation); United States v. Martinez-Fuerte, 428 U. S. 543, 560 (1976) (characterizing intrusion as “minimal”); Adams v. Williams, 407 U. S. 143 (1972) (stop and frisk). In short, all of these cases involved “‘seizures’ so substantially less intrusive than arrests that the general rule requiring probable cause to make Fourth Amendment ‘seizures’ reasonable could be replaced by a balancing test.” Dunaway, supra, at 210.

Nor do the “administrative search” cases provide any comfort for the Court. In Camara v. Municipal Court, 387 U. S. 523 (1967), the Court held that the probable-cause standard governed even administrative searches. Although *361the Camara Court recognized that probable-cause standards themselves may have to be somewhat modified to take into account the special nature of administrative searches, the Court did so only after noting that “because [housing code] inspections are neither personal in nature nor aimed at the discovery of evidence of crime, they involve a relatively limited invasion of the urban citizen’s privacy.” Id., at 537. Subsequent administrative search cases have similarly recognized that such searches intrude upon areas whose owners harbor a significantly decreased expectation of privacy, see, e. g., Donovan v. Dewey, 452 U. S. 594, 598-599 (1981), thus circumscribing the injury to Fourth Amendment interests caused by the search.

Considerations of the deepest significance for the freedom of our citizens counsel strict adherence to the principle that no search may be conducted where the official is not in possession of probable cause — that is, where the official does not know of “facts and circumstances [that] warrant a prudent man in believing that the offense has been committed.” Henry v. United States, 361 U. S., at 102; see also id., at 100-101 (discussing history of probable-cause standard). The Fourth Amendment was designed not merely to protect against official intrusions whose social utility was less as measured by some “balancing test” than its intrusion on individual privacy; it was designed in addition to grant the individual a zone of privacy whose protections could be breached only where the “reasonable” requirements of the probable-cause standard were met. Moved by whatever momentary evil has aroused their fears, officials — perhaps even supported by a majority of citizens — may be tempted to conduct searches that sacrifice the liberty of each citizen to assuage the perceived evil.4 But the Fourth Amendment *362rests on the principle that a true balance between the individual and society depends on the recognition of “the right to be let alone — the most comprehensive of rights and the right most valued by civilized men.” Olmstead v. United States, 277 U. S. 438, 478 (1928) (Brandéis, J., dissenting). That right protects the privacy and security of the individual unless the authorities can cross a specific threshold of need, designated by the term “probable cause.” I cannot agree with the Court’s assertions today that a “balancing test” can replace the constitutional threshold with one that is more convenient for those enforcing the laws but less protective of the citizens’ liberty; the Fourth Amendment’s protections should not be defaced by “a balancing process that overwhelms the individual’s protection against unwarranted official intrusion by a governmental interest said to justify the search and seizure.” United States v. Martinez-Fuerte, supra, at 570 (Brennan, J., dissenting).

2

I thus do not accept the majority’s premise that “[t]o hold that the Fourth Amendment applies to searches conducted by school authorities is only to begin the inquiry into the standards governing such searches.” Ante, at 337. For me, the finding that the Fourth Amendment applies, coupled with the observation that what is at issue is a full-scale search, is the end of the inquiry. But even if I believed that a “balancing test” appropriately replaces the judgment of the Framers of the Fourth Amendment, I would nonetheless object to the cursory and shortsighted “test” that the Court employs to justify its predictable weakening of Fourth Amendment protections. In particular, the test employed by the Court vastly overstates the social costs that a probable-cause standard entails and, though it plausibly articulates the serious privacy interests at stake, inexplicably fails to accord them adequate weight in striking the balance.

*363The Court begins to articulate its “balancing test” by-observing that “the government’s need for effective methods to deal with breaches of public order” is to be weighed on one side of the balance. Ibid. Of course, this is not correct. It is not the government’s need for effective enforcement methods that should weigh in the balance, for ordinary Fourth Amendment standards — including probable cause— may well permit methods for maintaining the public order that are perfectly effective. If that were the case, the governmental interest in having effective standards would carry no weight at all as a justification for departing from the probable-cause standard. Rather, it is the costs of applying probable cause as opposed to applying some lesser standard that should be weighed on the government’s side.5

In order to tote up the costs of applying the probable-cause standard, it is thus necessary first to take into account the nature and content of that standard, and the likelihood that it would hamper achievement of the goal — vital not just to “teachers and administrators,” see ante, at 339 — of maintaining an effective educational setting in the public schools. The seminal statement concerning the nature of the probable-cause standard is found in Carroll v. United States, 267 U. S. 132 (1925). Carroll held that law enforcement authorities have probable cause to search where “the facts and circumstances within their knowledge and of which they had reasonably trustworthy information [are] sufficient in themselves to *364warrant a man of reasonable caution in the belief” that a criminal offense had occurred. Id., at 162. In Brinegar v. United States, 338 U. S. 160 (1949), the Court amplified this requirement, holding that probable cause depends upon “the factual and practical considerations of everyday life on which reasonable and prudent men, not legal technicians, act.” Id., at 175.

Two Terms ago, in Illinois v. Gates, 462 U. S. 213 (1983), this Court expounded at some length its view of the probable-cause standard. Among the adjectives used to describe the standard were “practical,” “fluid,” “flexible,” “easily applied,” and “nontechnical.” See id., at 232, 236, 239. The probable-cause standard was to be seen as a “common-sense” test whose application depended on an evaluation of the “totality of the circumstances.” Id., at 238.

Ignoring what Gates took such great pains to emphasize, the Court today holds that a new “reasonableness” standard is appropriate because it “will spare teachers and school administrators the necessity of schooling themselves in the niceties of probable cause and permit them to regulate their conduct according to the dictates of reason and common sense.” Ante, at 343. I had never thought that our pre-Gates understanding of probable cause defied either reason or common sense. But after Gates, I would have thought that there could be no doubt that this “nontechnical,” “practical,” and “easily applied” concept was eminently serviceable in a context like a school, where teachers require the flexibility to respond quickly and decisively to emergencies.

A consideration of the likely operation of the probable-cause standard reinforces this conclusion. Discussing the issue of school searches, Professor LaFave has noted that the cases that have reached the appellate courts “strongly suggest that in most instances the evidence of wrongdoing prompting teachers or principals to conduct searches is sufficiently detailed and specific to meet the traditional probable cause test.” 3 W. LaFave, Search and Seizure § 10.11, *365pp. 459-460 (1978).6 The problems that have caused this Court difficulty in interpreting the probable-cause standard have largely involved informants, see, e. g., Illinois v. Gates, supra; Spinelli v. United States, 393 U. S. 410 (1969); Aguilar v. Texas, 378 U. S. 108 (1964); Draper v. United States, 358 U. S. 307 (1959). However, three factors make it likely that problems involving informants will not make it difficult for teachers and school administrators to make probable-cause decisions. This Court’s decision in Gates applying a “totality of the circumstances” test to determine whether an informant’s tip can constitute probable cause renders the test easy for teachers to apply. The fact that students and teachers interact daily in the school building makes it more likely that teachers will get to know students who supply information; the problem of informants who remain anonymous even to the teachers — and who are therefore unavailable for verification or further questioning — is unlikely to arise. Finally, teachers can observe the behavior of students under suspicion to corroborate any doubtful tips they do receive.

As compared with the relative ease with which teachers can apply the probable-cause standard, the amorphous “reasonableness under all the circumstances” standard freshly coined by the Court today will likely spawn increased litigation and greater uncertainty among teachers and administrators. Of course, as this Court should know, an essential purpose of developing and articulating legal norms is to enable individuals to conform their conduct to those norms. A school system conscientiously attempting to obey the Fourth Amendment’s dictates under a probable-cause standard could, for example, consult decisions and other legal materials and prepare a booklet expounding the rough outlines of the concept. Such a booklet could be distributed to *366teachers to provide them with guidance as to when a search may be lawfully conducted. I cannot but believe that the same school system faced with interpreting what is permitted under the Court’s new “reasonableness” standard would be hopelessly adrift as to when a search may be permissible. The sad result of this uncertainty may well be that some teachers will be reluctant to conduct searches that are fully permissible and even necessary under the constitutional probable-cause standard, while others may intrude arbitrarily and unjustifiably on the privacy of students.7

One further point should be taken into account when considering the desirability of replacing the constitutional probable-cause standard. The question facing the Court is not whether the probable-cause standard should be replaced by a test of “reasonableness under all the circumstances.” Rather, it is whether traditional Fourth Amendment standards should recede before the Court’s new standard. Thus, although the Court today paints with a broad brush and holds its undefined “reasonableness” standard applicable to all school searches, I would approach the question with considerably more reserve. I would not think it necessary to develop a single standard to govern all school searches, any more *367than traditional Fourth Amendment law applies even the probable-cause standard to all searches and seizures. For instance, just as police officers may conduct a brief stop and frisk on something less than probable cause, so too should teachers be permitted the same flexibility. A teacher or administrator who had reasonable suspicion that a student was carrying a gun would no doubt have authority under ordinary Fourth Amendment doctrine to conduct a limited search of the student to determine whether the threat was genuine. The “costs” of applying the traditional probable-cause standard must therefore be discounted by the fact that, where additional flexibility is necessary and where the intrusion is minor, traditional Fourth Amendment jurisprudence itself displaces probable cause when it determines the validity of a search.

A legitimate balancing test whose function was something more substantial than reaching a predetermined conclusion acceptable to this Court’s impressions of what authority teachers need would therefore reach rather a different result than that reached by the Court today. On one side of the balance would be the costs of applying traditional Fourth Amendment standards — the “practical” and “flexible” probable-cause standard where a full-scale intrusion is sought, a lesser standard in situations where the intrusion is much less severe and the need for greater authority compelling. Whatever costs were toted up on this side would have to be discounted by the costs of applying an unprecedented and ill-defined “reasonableness under all the circumstances” test that will leave teachers and administrators uncertain as to their authority and will encourage excessive fact-based litigation.

On the other side of the balance would be the serious privacy interests of the student, interests that the Court admirably articulates in its opinion, ante, at 337-339, but which the Court’s new ambiguous standard places in serious jeopardy. I have no doubt that a fair assessment of the two *368sides of the balance would necessarily reach the same conclusion that, as I have argued above, the Fourth Amendment’s language compels — that school searches like that conducted in this case are valid only if supported by probable cause.

I — { 1 — I

Applying the constitutional probable-cause standard to the facts of this case, I would find that Mr. Choplick’s search violated T. L. O.’s Fourth Amendment rights. After escorting T. L. O. into his private office, Mr. Choplick demanded to see her purse. He then opened the purse to find evidence of whether she had been smoking in the bathroom. When he opened the purse, he discovered the pack of cigarettes. At this point, his search for evidence of the smoking violation was complete.

Mr. Choplick then noticed, below the cigarettes, a pack of cigarette rolling papers. Believing that such papers were “associated,” see ante, at 328, with the use of marihuana, he proceeded to conduct a detailed examination of the contents of her purse, in which he found some marihuana, a pipe, some money, an index card, and some private letters indicating that T. L. O. had sold marihuana to other students. The State sought to introduce this latter material in evidence at a criminal proceeding, and the issue before the Court is whether it should have been suppressed.

On my view of the case, we need not decide whether the initial search conducted by Mr. Choplick — the search for evidence of the smoking violation that was completed when Mr. Choplick found the pack of cigarettes — was valid. For Mr. Choplick at that point did not have probable cause to continue to rummage through T. L. O.’s purse. Mr. Choplick’s suspicion of marihuana possession at this time was based solely on the presence of the package of cigarette papers. The mere presence without more of such a staple item of commerce is insufficient to warrant a person of reasonable caution in inferring both that T. L. O. had violated the law *369by possessing marihuana and that evidence of that violation would be found in her purse. Just as a police officer could not obtain a warrant to search a home based solely on his claim that he had seen a package of cigarette papers in that home, Mr. Choplick was not entitled to search possibly the most private possessions of T. L. O. based on the mere presence of a package of cigarette papers. Therefore, the fruits of this illegal search must be excluded and the judgment of the New Jersey Supreme Court affirmed.

h-H H — H

In the past several Terms, this Court has produced a succession of Fourth Amendment opinions in which “balancing tests” have been applied to resolve various questions concerning the proper scope of official searches. The Court has begun to apply a “balancing test” to determine whether a particular category of searches intrudes upon expectations of privacy that merit Fourth Amendment protection. See Hudson v. Palmer, 468 U. S. 517, 527 (1984) (“Determining whether an expectation of privacy is ‘legitimate’ or ‘reasonable’ necessarily entails a balancing of interests”). It applies a “balancing test” to determine whether a warrant is necessary to conduct a search. See ante, at 340; United States v. Martinez-Fuerte, 428 U. S., at 564-566. In today’s opinion, it employs a “balancing test” to determine what standard should govern the constitutionality of a given category of searches. See ante, at 340-341. Should a search turn out to be unreasonable after application of all of these “balancing tests,” the Court then applies an additional “balancing test” to decide whether the evidence resulting from the search must be excluded. See United States v. Leon, 468 U. S. 897 (1984).

All of these “balancing tests” amount to brief nods by the Court in the direction of a neutral utilitarian calculus while the Court in fact engages in an unanalyzed exercise of judicial will. Perhaps this doctrinally destructive nihilism is merely *370a convenient umbrella under which a majority that cannot agree on a genuine rationale can conceal its differences. Compare ante, p. 327 (White, J., delivering the opinion of the Court), with ante, p. 348 (Powell, J., joined by O’Connor, J., concurring), and ante, p. 351 (Blackmun, J., concurring in judgment). And it may be that the real force underlying today’s decision is the belief that the Court purports to reject — the belief that the unique role served by the schools justifies an exception to the Fourth Amendment on their behalf. If so, the methodology of today’s decision may turn out to have as little influence in future cases as will its result, and the Court’s departure from traditional Fourth Amendment doctrine will be confined to the schools.

On my view, the presence of the word “unreasonable” in the text of the Fourth Amendment does not grant a shifting majority of this Court the authority to answer all Fourth Amendment questions by consulting its momentary vision of the social good. Full-scale searches unaccompanied by probable cause violate the Fourth Amendment. I do not pretend that our traditional Fourth Amendment doctrine automatically answers all of the difficult legal questions that occasionally arise. I do contend, however, that this Court has an obligation to provide some coherent framework to resolve such questions on the basis of more than a conclusory recitation of the results of a “balancing test.” The Fourth Amendment itself supplies that framework and, because the Court today fails to heed its message, I must respectfully dissent.

Justice Stevens,

with whom Justice Marshall joins, and with whom Justice Brennan joins as to Part I,

concurring in part and dissenting in part.

Assistant Vice Principal Choplick searched T. L. O.’s purse for evidence that she was smoking in the girls’ restroom. Because T. L. O.’s suspected misconduct was not illegal and did not pose a serious threat to school discipline, the New Jersey Supreme Court held that Choplick’s search *371of her purse was an unreasonable invasion of her privacy and that the evidence which he seized could not be used against her in criminal proceedings. The New Jersey court’s holding was a careful response to the case it was required to decide.

The State of New Jersey sought review in this Court, first arguing that the exclusionary rule is wholly inapplicable to searches conducted by school officials, and then contending that the Fourth Amendment itself provides no protection at all to the student’s privacy. The Court has accepted neither of these frontal assaults on the Fourth Amendment. It has, however, seized upon this “no smoking” case to announce “the proper standard” that should govern searches by school officials who are confronted with disciplinary problems far more severe than smoking in the restroom. Although I join Part II of the Court’s opinion, I continue to believe that the Court has unnecessarily and inappropriately reached out to decide a constitutional question. See 468 U. S. 1214 (1984) (Stevens, J., dissenting from reargument order). More importantly, I fear that the concerns that motivated the Court’s activism have produced a holding that will permit school administrators to search students suspected of violating only the most trivial school regulations and guidelines for behavior.

I

The question the Court decides today — whether Mr. Chop-lick’s search of T. L. O.’s purse violated the Fourth Amendment — was not raised by the State’s petition for writ of certiorari. That petition only raised one question: “Whether the Fourth Amendment’s exclusionary rule applies to searches made by public school officials and teachers in school.”1 The State quite properly declined to submit the former question because “[it] did not wish to present what might appear to be solely a factual dispute to this Court.”2 *372Since this Court has twice had the threshold question argued, I believe that it should expressly consider the merits of the New Jersey Supreme Court’s ruling that the exclusionary rule applies.

The New Jersey Supreme Court’s holding on this question is plainly correct. As the state court noted, this case does not involve the use of evidence in a school disciplinary proceeding; the juvenile proceedings brought against T. L. O. involved a charge that would have been a criminal offense if committed by an adult.3 Accordingly, the exclusionary rule issue decided by that court and later presented to this Court concerned only the use in a criminal proceeding of evidence obtained in a search conducted by a public school administrator.

Having confined the issue to the law enforcement context, the New Jersey court then reasoned that this Court’s cases have made it quite clear that the exclusionary rule is equally applicable “whether the public official who illegally obtained the evidence was a municipal inspector, See v. Seattle 387 U. S. 541 [1967]; Camara [v. Municipal Court,] 387 U. S. 523 [1967]; a firefighter, Michigan v. Tyler, 436 U. S. 499, 506 [1978]; or a school administrator or law enforcement official.”4 It correctly concluded “that if an official search violates constitutional rights, the evidence is not admissible in criminal proceedings.”5

When a defendant in a criminal proceeding alleges that she was the victim of an illegal search by a school administrator, the application of the exclusionary rule is a simple corollary of the principle that “all evidence obtained by searches and seizures in violation of the Constitution is, by that same authority, inadmissible in a state court.” Mapp v. Ohio, 367 U. S. 643, 655 (1961). The practical basis for this principle is, in part, its deterrent effect, see id., at 656, and as a general *373matter it is tolerably clear to me, as it has been to the Court, that the existence of an exclusionary remedy does deter the authorities from violating the Fourth Amendment by sharply reducing their incentive to do so.6 In the case of evidence obtained in school searches, the “overall educative effect”7 of the exclusionary rule adds important symbolic force to this utilitarian judgment.

Justice Brandéis was both a great student and a great teacher. It was he who wrote:

“Our Government is the potent, the omnipresent teacher. For good or for ill, it teaches the whole people by its example. Crime is contagious. If the Government becomes a lawbreaker, it breeds contempt for. law; it invites every man to become a law unto himself; it invites anarchy.” Olmstead v. United States, 277 U. S. 438, 485 (1928) (dissenting opinion).

Those of us who revere the flag and the ideals for which it stands believe in the power of symbols. We cannot ignore that rules of law also have a symbolic power that may vastly exceed their utility.

Schools are places where we inculcate the values essential to the meaningful exercise of rights and responsibilities by a self-governing citizenry.8 If the Nation’s students can be convicted through the use of arbitrary methods destructive of personal liberty, they cannot help but feel that they have *374been dealt with unfairly.9 The application of the exclusionary rule in criminal proceedings arising from illegal school searches makes an important statement to young people that “our society attaches serious consequences to a violation of constitutional rights,”10 and that this is a principle of “liberty and justice for all.”11

Thus, the simple and correct answer to the question presented by the State’s petition for certiorari would have required affirmance of a state court’s judgment suppressing evidence. That result would have been dramatically out of character for a Court that not only grants prosecutors relief from suppression orders with distressing regularity,12 but *375also is prone to rely on grounds not advanced by the parties in order to protect evidence from exclusion.13 In characteristic disregard of the doctrine of judicial restraint, the Court avoided that result in this case by ordering reargument and directing the parties to address a constitutional question that the parties, with good reason, had not asked the Court to decide. Because judicial activism undermines the Court’s power to perform its central mission in a legitimate way, I dissented from the reargument order. See 468 U. S. 1214 (1984). I have not modified the views expressed in that dissent, but since the majority has brought the question before us, I shall explain why I believe the Court has misapplied the standard of reasonableness embodied in the Fourth Amendment.

HH H-t

The search of a young woman’s purse by a school administrator is a serious invasion of her legitimate expectations of privacy. A purse “is a common repository for one’s personal effects and therefore is inevitably associated with the expectation of privacy.” Arkansas v. Sanders, 442 U. S. 753, 762 (1979). Although such expectations must sometimes yield to the legitimate requirements of government, in assessing the constitutionality of a warrantless search, our decision must be guided by the language of the Fourth Amendment: “The right of the people to be secure in their persons, houses, *376papers and effects, against unreasonable searches and seizures, shall not be violated . . . In order to evaluate the reasonableness of such searches, “it is necessary ‘first to focus upon the governmental interest which allegedly justifies official intrusion upon the constitutionally protected interests of the private citizen/ for there is ‘no ready test for determining reasonableness other than by balancing the need to search [or seize] against the invasion which the search [or seizure] entails.’” Terry v. Ohio, 392 U. S. 1, 20-21 (1968) (quoting Camara v. Municipal Court, 387 U. S. 523, 528, 534-537, (1967)).14

The “limited search for weapons” in Terry was justified by the “immediate interest of the police officer in taking steps to assure himself that the person with whom he is dealing is not armed with a weapon that could unexpectedly and fatally be used against him.” 392 U. S., at 23, 25. When viewed from the institutional perspective, “the substantial need of teachers and administrators for freedom to maintain order in the schools,” ante, at 341 (majority opinion), is no less acute. Violent, unlawful, or seriously disruptive conduct is fundamentally inconsistent with the principal function of teaching institutions which is to educate young people and prepare them for citizenship.15 When such conduct occurs amidst a sizable group of impressionable young people, it creates an explosive atmosphere that requires a prompt and effective response.

Thus, warrantless searches of students by school administrators are reasonable when undertaken for those purposes. *377But the majority’s statement of the standard for evaluating the reasonableness of such searches is not suitably adapted to that end. The majority holds that “a search of a student by a teacher or other school official will be ‘justified at its inception’ when there are reasonable grounds for suspecting that the search will turn up evidence that the student has violated or is violating either the law or the rules of the school” Ante, at 341-342. This standard will permit teachers and school administrators to search students when they suspect that the search will reveal evidence of even the most trivial school regulation or precatory guideline for student behavior. The Court’s standard for deciding whether a search is justified “at its inception” treats all violations of the rules of the school as though they were fungible. For the Court, a search for curlers and sunglasses in order to enforce the school dress code16 is apparently just as important as a search for evidence of heroin addiction or violent gang activity.

The majority, however, does not contend that school administrators have a compelling need to search students in *378order.to achieve optimum enforcement of minor school regulations.17 To the contrary, when minor violations are involved, there is every indication that the informal school disciplinary process, with only minimum requirements of due process,18 can function effectively without the power to search for enough evidence to prove a criminal case. In arguing that teachers and school administrators need the power to search students based on a lessened standard, the United States as amicus curiae relies heavily on empirical evidence of a contemporary crisis of violence and unlawful behavior that is seriously undermining the process of education in American schools.19 A standard better attuned to this concern would permit teachers and school administrators to search a student when they have reason to believe that the search will uncover evidence that the student is violating the law or engaging in conduct that is seriously disruptive of school order, or the educational process.

This standard is properly directed at “[t]he sole justification for the [warrantless] search.”20 In addition, a standard *379that varies the extent of the permissible intrusion with the gravity of the suspected offense is also more consistent with common-law experience and this Court’s precedent. Criminal law has traditionally recognized a distinction between essentially regulatory offenses and serious violations of the peace, and graduated the response of the criminal justice system depending on the character of the violation.21 The application of a similar distinction in evaluating the reasonableness of warrantless searches and seizures “is not a novel idea.” Welsh v. Wisconsin, 466 U. S. 740, 750 (1984).22

In Welsh, police officers arrived at the scene of a traffic accident and obtained information indicating that the driver of the automobile involved was guilty of a first offense of *380driving while intoxicated — a civil violation with a maximum fine of $200. The driver had left the scene of the accident, and the officers followed the suspect to his home where they arrested him without a warrant. Absent exigent circumstances, the warrantless invasion of the home was a clear violation of Payton v. New York, 445 U. S. 573 (1980). In holding that the warrantless arrest for the “noncriminal, traffic offense” in Welsh was unconstitutional, the Court noted that “application of the exigent-circumstances exception in the context of a home entry should rarely be sanctioned when there is probable cause to believe that only a minor offense . . . has been committed.” 466 U. S., at 753.

. . . The logic of distinguishing between minor and serious offenses in evaluating the reasonableness of school searches is almost too clear for argument. In order to justify the serious intrusion on the persons and privacy of young people that New Jersey asks this Court to approve, the State must identify “some real immediate and serious consequences.” McDonald v. United States, 335 U. S. 451, 460 (1948) (Jackson, J., concurring, joined by Frankfurter, J.).23 While school administrators have entirely legitimate reasons for adopting school regulations and guidelines for student behavior, the authorization of searches to enforce them “displays a shocking lack of all sense of proportion.” Id., 459.24

*381The majority offers weak deference to these principles of balance and decency by announcing that school searches will only be reasonable in scope “when the measures adopted are reasonably related to the objectives of the search and not excessively intrusive in light of the age and sex of the student and the nature of the infraction” Ante, at 342 (emphasis added). The majority offers no explanation why a two-part standard is necessary to evaluate the reasonableness of the ordinary school search. Significantly, in the balance of its opinion the Court pretermits any discussion of the nature of T. L. O.’s infraction of the “no smoking” rule.

The “rider” to the Court’s standard for evaluating the reasonableness of the initial intrusion apparently is the Court’s perception that its standard is overly generous and does not, by itself, achieve a fair balance between the administrator’s right to search and the student’s reasonable expectations of privacy. The Court’s standard for evaluating the “scope” of reasonable school searches is obviously designed to prohibit physically intrusive searches of students by persons of the opposite sex for relatively minor offenses. The Court’s effort to establish a standard that is, at once, clear enough to allow searches to be upheld in nearly every case, and flexible enough to prohibit obviously unreasonable intrusions of young adults’ privacy only creates uncertainty in the extent of its resolve to prohibit the latter. Moreover, the majority’s application of its standard in this case — to permit a male administrator to rummage through the purse of a female high school student in order to obtain evidence that she was smok*382ing in a bathroom — raises grave doubts in my mind whether its effort will be effective.25 Unlike the Court, I believe the nature of the suspected infraction is a matter of first importance in deciding whether any invasion of privacy is permissible.

Ill

The Court embraces the standard applied by the New Jersey Supreme Court as equivalent to-its own, and then deprecates the state court’s application of the standard as reflecting “a somewhat crabbed notion of reasonableness.” Ante, at 343. There is no mystery, however, in the state court’s finding that the search in this case was unconstitutional; the decision below was not based on a manipulation of reasonable suspicion, but on the trivial character of the activity that promoted the official search. The New Jersey Supreme Court wrote:

“We are satisfied that when a school official has reasonable grounds to believe that a student possesses evidence of illegal activity or activity that would interfere with school discipline and order, the school official has the right to conduct a reasonable search for such evidence.

“In determining whether the school official has reasonable grounds, courts should consider The child’s age, history, and school record, the prevalence and seriousness of the problem in the school to which the search was *383directed, the exigency to make the search without delay, and the probative value and reliability of the information used as a justification for the search.’”26

The emphasized language in the state court’s opinion focuses on the character of the rule infraction that is to be the object of the search.

In the view of the state court, there is a quite obvious and material difference between a search for evidence relating to violent or disruptive activity, and a search for evidence of a smoking rule violation. This distinction does not imply that a no-smoking rule is a matter of minor importance. Rather, like a rule that prohibits a student from being tardy, its occasional violation in a context that poses no threat of disrupting school order and discipline offers no reason to believe that an immediate search is necessary to avoid unlawful conduct, violence, or a serious impairment of the educational process.

A correct understanding of the New Jersey court’s standard explains why that court concluded in T. L. O.’s case that “the assistant principal did not have reasonable grounds to believe that the student was concealing in her purse evidence of criminal activity or evidence of activity that would seriously interfere with school discipline or order.”27 The importance of the nature of the rule infraction to the New Jersey Supreme Court’s holding is evident from its brief explanation of the principal basis for its decision:

“A student has an expectation of privacy in the contents of her purse. Mere possession of cigarettes did not violate school rule or policy, since the school allowed smoking in designated areas. The contents of the handbag had no direct bearing on the infraction.

“The assistant principal’s desire, legal in itself, to gather evidence to impeach the student’s credibility at a *384hearing on the disciplinary infraction does not validate the search.”28

Like the New Jersey Supreme Court, I would view this case differently if the Assistant Vice Principal had reason to believe T. L. O.’s purse contained evidence of criminal activity, or of an activity that would seriously disrupt school discipline. There was, however, absolutely no basis for any such assumption — not even a “hunch.”

In this case, Mr. Choplick overreacted to what appeared to be nothing more than a minor infraction — a rule prohibiting smoking in the bathroom of the freshmen’s and sophomores’ building.29 It is, of course, true that he actually found evidence of serious wrongdoing by T. L. 0., but no one claims that the prior search may be justified by his unexpected discovery. As far as the smoking infraction is concerned, the search for cigarettes merely tended to corroborate a teacher’s eyewitness account of T. L. O.’s violation of a minor regulation designed to channel student smoking behavior into designated locations. Because this conduct was neither unlawful nor significantly disruptive of school order or the educational process, the invasion of privacy associated with the forcible opening of T. L. O.’s purse was entirely unjustified at its inception.

A review of the sampling of school search cases relied on by the Court demonstrates how different this case is from those *385in which there was indeed a valid justification for intruding on a student’s privacy. In most of them the student was suspected of a criminal violation;30 in the remainder either violence or substantial disruption of school order or the integrity of the academic process was at stake.31 New involved matters as trivial as the no-smoking rule violated by T. L. O.32 The rule the Court adopts today is so open-ended that it may make the Fourth Amendment virtually meaningless in the school context. Although I agree that school administrators must have broad latitude to maintain order and discipline in our classrooms, that authority is not unlimited.

> I — I

The schoolroom is the first opportunity most citizens have to experience the power of government. Through it passes every citizen and public official, from schoolteachers to *386policemen and prison guards. The values they learn there, they take with them in life. One of our most cherished ideals is the one contained in the Fourth Amendment: that the government may not intrude on the personal privacy of its citizens without a warrant or compelling circumstance. The Court’s decision today is a curious moral for the Nation’s youth. Although the search of T. L. O.’s purse does not trouble today’s majority, I submit that we are not dealing with “matters relatively trivial to the welfare of the Nation. There are village tyrants as well as village Hampdens, but none who acts under color of law is beyond reach of the Constitution.” West Virginia State Board of Education v. Barnette, 319 U. S. 624, 638 (1943).

I respectfully dissent.

*606Justice Kennedy

delivered the opinion of the Court.

The Federal Railroad Safety Act of 1970 authorizes the Secretary of Transportation to “prescribe, as necessary, appropriate rules, regulations, orders, and standards for all areas of railroad safety.” 84 Stat. 971, 45 U. S. C. § 431(a). Finding that alcohol and drug abuse by railroad employees poses a serious threat to safety, the Federal Railroad Administration (FRA) has promulgated regulations that mandate blood and urine tests of employees who are involved in certain train accidents. The FRA also has adopted regulations that do not require, but do authorize, railroads to administer breath and urine tests to employees who violate certain safety rules. The question presented by this case is whether these regulations violate the Fourth Amendment.

I

A

The problem of alcohol use on American railroads is as old as the industry itself, and efforts to deter it by carrier rules began at least a century ago. For many years, railroads have prohibited operating employees from possessing alcohol or being intoxicated while on duty and from consuming alcoholic beverages while subject to being called for duty. More recently, these proscriptions have been expanded to forbid possession or use of certain drugs. These restrictions are *607embodied in “Rule G,” an industry-wide operating rule promulgated by the Association of American Railroads, and are enforced, in various formulations, by virtually every railroad in the country. The customary sanction for Rule G violations is dismissal.

In July 1983, the FRA expressed concern that these industry efforts were not adequate to curb alcohol and drug abuse by railroad employees. The FRA pointed to evidence indicating that on-the-job intoxication was a significant problem in the railroad industry.1 The FRA also found, after a review of accident investigation reports, that from 1972 to 1983 “the nation’s railroads experienced at least 21 significant train accidents involving alcohol or drug use as a probable cause or contributing factor,” and that these accidents “resulted in 25 fatalities, 61 non-fatal injuries, and property damage estimated at $19 million (approximately $27 million in 1982 dollars).” 48 Fed. Reg. 30726 (1983). The FRA further identified “an additional 17 fatalities to operating employees working on or around rail rolling stock that involved alcohol or drugs as a contributing factor.” Ibid. In light of these problems, the FRA solicited comments from interested parties on a various regulatory approaches to the problems of alcohol and drug abuse throughout the Nation’s railroad system.

Comments submitted in response to this request indicated that railroads were able to detect a relatively small number of Rule G violations, owing, primarily, to their practice of *608relying on observation by supervisors and co-workers to enforce the rule. 49 Fed. Reg. 24266-24267 (1984). At the same time, “industry participants . . . confirmed that alcohol and drug use [did] occur on the railroads with unacceptable frequency,” and available information from all sources “suggested] that the problem included] ‘pockets’ of drinking and drug use involving multiple crew members (before and during work), sporadic cases of individuals reporting to work impaired, and repeated drinking and drug use by individual employees who are chemically or psychologically dependent on those substances.” Id., at 24253-24254. “Even without the benefit of regular post-accident testing,” the FRA “identified 34 fatalities, 66 injuries and over $28 million in property damage (in 1983 dollars) that resulted from the errors of alcohol and drug-impaired employees in 45 train accidents and train incidents during the period 1975 through 1983.” Id., at 24254. Some of these accidents resulted in the release of hazardous materials and, in one case, the ensuing pollution required the evacuation of an entire Louisiana community. Id., at 24254, 24259. In view of the obvious safety hazards of drug and alcohol use by railroad employees, the FRA announced in June 1984 its intention to promulgate federal regulations on the subject.

B

After reviewing further comments from representatives of the railroad industry, labor groups, and the general public, the FRA, in 1985, promulgated regulations addressing the problem of alcohol and drugs on the railroads. The final regulations apply to employees assigned to perform service subject to the Hours of Service Act, ch. 2939, 34 Stat. 1415, as amended, 45 U. S. C. § 61 et seq. The regulations prohibit covered employees from using or possessing alcohol or any controlled substance. 49 CFR §219.101(a)(1) (1987). The regulations further prohibit those employees from reporting for covered service while under the influence of, or *609impaired by, alcohol, while having a blood alcohol concentration of 0.04 or more, or while under the influence of, or impaired by, any controlled substance. §219.101(a)(2). The regulations do not restrict, however, a railroad’s authority to impose an absolute prohibition on the presence of alcohol or any drug in the body fluids of persons in its employ, §219.101(c), and, accordingly, they do not “replace Rule G or render it unenforceable.” 50 Fed. Reg. 31538 (1985).

To the extent pertinent here, two subparts of the regulations relate to testing. Subpart C, which is entitled “Post-Accident Toxicological Testing,” is mandatory. It provides that railroads “shall take all practicable steps to assure that all covered employees of the railroad directly involved . . . provide blood and urine samples for toxicological testing by FRA,” § 219.203(a), upon the occurrence of certain specified events. Toxicological testing is required following a “major train accident,” which is defined as any train accident that involves (i) a fatality, (ii) the release of hazardous material accompanied by an evacuation or a reportable injury, or (iii) damage to railroad property of $500,000 or more. §219.201 (a)(1). The railroad has the further duty of collecting blood and urine samples for testing after an “impact accident,” which is defined as a collision that results in a reportable injury, or in damage to railroad property of $50,000 or more. § 219.201(a)(2). Finally, the railroad is also obligated to test after “[a]ny train incident that involves a fatality to any on-duty railroad employee.” §219.201(a)(3).

After occurrence of an event which activates its duty to test, the railroad must transport all crew members and other covered employees directly involved in the accident or incident to an independent medical facility, where both blood and urine samples must be obtained from each employee.2 After *610the samples have been collected, the railroad is required to ship them by prepaid air freight to the FRA laboratory for analysis. § 219.205(d). There, the samples are analyzed using “state-of-the-art equipment and techniques” to detect and measure alcohol and drugs.3 The FRA proposes to place primary reliance on analysis of blood samples, as blood is “the only available body fluid . . . that can provide a clear indication not only of the presence of alcohol and drugs but also their current impairment effects.” 49 Fed. Reg. 24291 (1984). Urine samples are also necessary, however, because drug traces remain in the urine longer than in blood, and in some cases it will not be possible to transport employees to a medical facility before the time it takes for certain drugs to be eliminated from the bloodstream. In those instances, a “positive urine test, taken with specific information on the pattern of elimination for the particular drug and other information on the behavior of the employee and the circumstances of the accident, may be crucial to the determination of” the cause of an accident. Ibid.

The regulations require that the FRA notify employees of the results of the tests and afford them an opportunity to respond in writing before preparation of any final investigative report. See § 219.211(a)(2). Employees who refuse to provide required blood or urine samples may not perform cov*611ered service for nine months, but they are entitled to a hearing concerning their refusal to take the test. §219.213.

Subpart D of the regulations, which is entitled “Authorization to Test for Cause,” is permissive. It authorizes railroads to require covered employees to submit to breath or urine tests in certain circumstances not addressed by Sub-part C. Breath or urine tests, or both, may be ordered (1) after a reportable accident or incident, where a supervisor has a “reasonable suspicion” that an employee’s acts or omissions contributed to the occurrence or severity of the accident or incident, § 219.301(b)(2); or (2) in the event of certain specific rule violations, including noncompliance with a signal and excessive speeding, § 219.301(b)(3). A railroad also may require breath tests where a supervisor has a “reasonable suspicion” that an employee is under the influence of alcohol, based upon specific, personal observations concerning the appearance, behavior, speech, or body odors of the employee. § 219.301(b)(1). Where impairment is suspected, a railroad, in addition, may require urine tests, but only if two supervisors make the appropriate determination, §219.301(c)(2)(i), and, where the supervisors suspect impairment due to a substance other than alcohol, at least one of those supervisors must have received specialized training in detecting the signs of drug intoxication, §219.301(c)(2)(ii).

Subpart D further provides that whenever the results of either breath or urine tests are intended for use in a disciplinary proceeding, the employee must be given the opportunity to provide a blood sample for analysis at an independent medical facility. § 219.303(c). If an employee declines to give a blood sample, the railroad may presume impairment, absent persuasive evidence to the contrary, from a positive showing of controlled substance residues in the urine. The railroad must, however, provide detailed notice of this presumption to its employees, and advise them of their right to provide a contemporaneous blood sample. As in the case of samples procured under Subpart C, the regulations set forth *612procedures for the collection of samples, and require that samples “be analyzed by a method that is reliable within known tolerances.” §219.307(b).

C

Respondents, the Railway Labor Executives’ Association and various of its member labor organizations, brought the instant suit in the United States District Court for the Northern District of California, seeking to enjoin the FRA’s regulations on various statutory and constitutional grounds. In a ruling from the bench, the District Court granted summary judgment in petitioners’ favor. The court concluded that railroad employees “have a valid interest in the integrity of their own bodies” that deserved protection under the Fourth Amendment. App. to Pet. for Cert. 53a. The court held, however, that this interest was outweighed by the competing “public and governmental interest in the . . . promotion of . . . railway safety, safety for employees, and safety for the general public that is involved with the transportation. ” Id., at 52a. The District Court found respondents’ other constitutional and statutory arguments meritless.

A divided panel of the Court of Appeals for the Ninth Circuit reversed. Railway Labor Executives’ Assn. v. Burnley, 839 F. 2d 575 (1988). The court held, first, that tests mandated by a railroad in reliance on the authority conferred by Subpart D involve sufficient Government action to implicate the Fourth Amendment, and that the breath, blood, and urine tests contemplated by the FRA regulations are Fourth Amendment searches. The court also “agre[ed] that the exigencies of testing for the presence of alcohol and drugs in blood, urine or breath require prompt action which precludes obtaining a warrant.” Id., at 583. The court further held that “accommodation of railroad employees’ privacy interest with the significant safety concerns of the government does not require adherence to a probable cause requirement,” and, accordingly, that the legality of the searches contemplated by *613the FRA regulations depends on their reasonableness under all the circumstances. Id., at 587.

The court concluded, however, that particularized suspicion is essential to a finding that toxicological testing of railroad employees is reasonable. Ibid. A requirement of individualized suspicion, the court stated, would impose “no insuperable burden on the government,” id., at 588, and would ensure that the tests are confined to the detection of current impairment, rather than to the discovery of “the metabolites of various drugs, which are not evidence of current intoxication and may remain in the body for days or weeks after the ingestion of the drug.” Id., at 588-589. Except for the provisions authorizing breath and urine tests on a “reasonable suspicion” of drug or alcohol impairment, 49 CFR §§219.301(b)(1) and (c)(2) (1987), the FRA regulations did not require a showing of individualized suspicion, and, accordingly, the court invalidated them.

Judge Alarcon dissented. He criticized the majority for “failing] to engage in [a] balancing of interests” and for focusing instead “solely on the degree of impairment of the workers’ privacy interests.” 839 F. 2d, at 597. The dissent would have held that “the government’s compelling need to assure railroad safety by controlling drug use among railway personnel outweighs the need to protect privacy interests.” Id., at 596.

We granted the federal parties’ petition for a writ of certio-rari, 486 U. S. 1042 (1988), to consider whether the regulations invalidated by the Court of Appeals violate the Fourth Amendment. We now reverse.

II

The Fourth Amendment provides that “[t]he right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated . . . The Amendment guarantees the privacy, dignity, and security of persons against certain ar*614bitrary and invasive acts by officers of the Government or those acting at their direction. Camara v. Municipal Court of San Francisco, 387 U. S. 523, 528 (1967). See also Delaware v. Prouse, 440 U. S. 648, 653-654 (1979); United States v. Martinez-Fuerte, 428 U. S. 543, 554 (1976). Before we consider whether the tests in question are reasonable under the Fourth Amendment, we must inquire whether the tests are attributable to the Government or its agents, and whether they amount to searches or seizures. We turn to those matters.

A

Although the Fourth Amendment does not apply to a search or seizure, even an arbitrary one, effected by a private party on his own initiative, the Amendment protects against such intrusions if the private party acted as an instrument or agent of the Government. See United States v. Jacobsen, 466 U. S. 109, 113-114 (1984); Coolidge v. New Hampshire, 403 U. S. 443, 487 (1971). See also Burdeau v. McDowell, 256 U. S. 465, 475 (1921). A railroad that complies with the provisions of Subpart C of the regulations does so by compulsion of sovereign authority, and the lawfulness of its acts is controlled by the Fourth Amendment. Petitioners contend, however, that the Fourth Amendment is not implicated by Subpart D of the regulations, as nothing in Sub-part D compels any testing by private railroads.

We are unwilling to conclude, in the context of this facial challenge, that breath and urine tests required by private railroads in reliance on Subpart D will not implicate the Fourth Amendment. Whether a private party should be deemed an agent or instrument of the Government for Fourth Amendment purposes necessarily turns on the degree of the Government’s participation in the private party’s activities, cf. Lustig v. United States, 338 U. S. 74, 78-79 (1949) (plurality opinion); Byars v. United States, 273 U. S. 28, 32-33 (1927), a question that can only be resolved “in light of all the circumstances,” Coolidge v. New Hampshire, supra, *615at 487. The fact that the Government has not compelled a private party to perform a search does not, by itself, establish that the search is a private one. Here, specific features of the regulations combine to convince us that the Government did more than adopt a passive position toward the underlying private conduct.

The regulations, including those in Subpart D, pre-empt state laws, rules, or regulations covering the same subject matter, 49 CFR §219.13(a) (1987), and are intended to supersede “any provision of a collective bargaining agreement, or arbitration award construing such an agreement,” 50 Fed. Reg. 31552 (1985). They also confer upon the FRA the right to receive certain biological samples and test results procured by railroads pursuant to Subpart D. §219.11(c). In addition, a railroad may not divest itself of, or otherwise compromise by contract, the authority conferred by Subpart D. As the FRA explained, such “authority ... is conferred for the purpose of promoting the public safety, and a railroad may not shackle itself in a way inconsistent with its duty to promote the public safety.” 50 Fed. Reg. 31552 (1985). Nor is a covered employee free to decline his employer’s request to submit to breath or urine tests under the conditions set forth in Subpart D. See § 219.11(b). An employee who refuses to submit to the tests must be withdrawn from covered service. See 4 App. to Field Manual 18.

In light of these provisions, we are unwilling to accept petitioners’ submission that tests conducted by private railroads in reliance on Subpart D will be primarily the result of private initiative. The Government has removed all legal barriers to the testing authorized by Subpart D, and indeed has made plain not only its strong preference for testing, but also its desire to share the fruits of such intrusions. In addition, it has mandated that the railroads not bargain away the authority to perform tests granted by Subpart D. These are clear indices of the Government’s encouragement, endorse*616ment, and participation, and suffice to implicate the Fourth Amendment.

B

Our precedents teach that where, as here, the Government seeks to obtain physical evidence from a person, the Fourth Amendment may be relevant at several levels. See, e. g., United States v. Dionisio, 410 U. S. 1, 8 (1973). The initial detention necessary to procure the evidence may be a seizure of the person, Cupp v. Murphy, 412 U. S. 291, 294-295 (1973); Davis v. Mississippi, 394 U. S. 721, 726-727 (1969), if the detention amounts to a meaningful interference with his freedom of movement. INS v. Delgado, 466 U. S. 210, 215 (1984); United States v. Jacobsen, supra, at 113, n. 5. Obtaining and examining the evidence may also be a search, see Cupp v. Murphy, supra, at 295; United States v. Dionisio, supra, at 8, 13-14, if doing so infringes an expectation of privacy that society is prepared to recognize as reasonable, see, e. g., California v. Greenwood, 486 U. S. 35, 43 (1988); United States v. Jacobsen, supra, at 113.

We have long recognized that a “compelled intrusio[n] into the body for blood to be analyzed for alcohol content” must be deemed a Fourth Amendment search. See Schmerber v. California, 384 U. S. 757, 767-768 (1966). See also Winston v. Lee, 470 U. S. 753, 760 (1985). In light of our society’s concern for the security of one’s person, see, e. g., Terry v. Ohio, 392 U. S. 1, 9 (1968), it is obvious that this physical intrusion, penetrating beneath the skin, infringes an expectation of privacy that society is prepared to recognize as reasonable. The ensuing chemical analysis of the sample to obtain physiological data is a further invasion of the tested employee’s privacy interests. Cf. Arizona v. Hicks, 480 U. S. 321, 324-325 (1987). Much the same is true of the breath-testing procedures required under Subpart D of the regulations. Subjecting a person to a breathalyzer test, which generally requires the production of alveolar or “deep lung” breath for chemical analysis, see, e. g., California v. *617 Trombetta, 467 U. S. 479, 481 (1984), implicates similar concerns about bodily integrity and, like the blood-alcohol test we considered in Schmerber, should also be deemed a search, see 1 W. LaFave, Search and Seizure § 2.6(a), p. 463 (1987). See also Burnett v. Anchorage, 806 F. 2d 1447, 1449 (CA9 1986); Shoemaker v. Handel, 795 F. 2d 1136, 1141 (CA3), cert. denied, 479 U. S. 986 (1986).

Unlike the blood-testing procedure at issue in Schmerber, the procedures prescribed by the FRA regulations for collecting and testing urine samples do not entail a surgical intrusion into the body. It is not disputed, however, that chemical analysis of urine, like that of blood, can reveal a host of private medical facts about an employee, including whether he or she is epileptic, pregnant, or diabetic. Nor can it be disputed that the process of collecting the sample to be tested, which may in some cases involve visual or aural monitoring of the act of urination, itself implicates privacy interests. As the Court of Appeals for the Fifth Circuit has stated:

“There are few activities in our society more personal or private than the passing of urine. Most people describe it by euphemisms if they talk about it at all. It is a function traditionally performed without public observation; indeed, its performance in public is generally prohibited by law as well as social custom.” National Treasury Employees Union v. Von Raab, 816 F. 2d 170, 175 (1987).

Because it is clear that the collection and testing of urine intrudes upon expectations of privacy that society has long recognized as reasonable, the Federal Courts of Appeals have concluded unanimously, and we agree, that these intrusions must be deemed searches under the Fourth Amendment.4

*618In view of our conclusion that the collection and subsequent analysis of the requisite biological samples must be deemed Fourth Amendment searches, we need not characterize the employer’s antecedent interference with the employee’s freedom of movement as an independent Fourth Amendment seizure. As our precedents indicate, not every governmental interference with an individuál’s freedom of movement raises such constitutional concerns that there is a seizure of the person. See United States v. Dionisio, supra, at 9-11 (grand jury subpoena, though enforceable by contempt, does not effect a seizure of the person); United States v. Mara, 410 U. S. 19, 21 (1973) (same). For present purposes, it suffices to note that any limitation on an employee’s freedom of movement that is necessary to obtain the blood, urine, or breath samples contemplated by the regulations must be considered in assessing the intrusiveness of the searches effected by the Government’s testing program. Cf. United States v. Place, 462 U. S. 696, 707-709 (1983).

I — f t — I I — !

A

To hold that the Fourth Amendment is applicable to the drug and alcohol testing prescribed by the FRA regulations *619is only to begin the inquiry into the standards governing such intrusions. O’Connor v. Ortega, 480 U. S. 709, 719 (1987) (plurality opinion); New Jersey v. T. L. O., 469 U. S. 325, 337 (1985). For the Fourth Amendment does not proscribe all searches and seizures, but only those that are unreasonable. United States v. Sharpe, 470 U. S. 675, 682 (1985); Schmerber v. California, 384 U. S., at 768. What is reasonable, of course, “depends on all of the circumstances surrounding the search or seizure and the nature of the search or seizure itself.” United States v. Montoya de Hernandez, 473 U. S. 531, 537 (1985). Thus, the permissibility of a particular practice “is judged by balancing its intrusion on the individual’s Fourth Amendment interests against its promotion of legitimate governmental interests.” Delaware v. Prouse, 440 U. S., at 654; United States v. Martinez-Fuerte, 428 U. S. 543 (1976).

In most criminal cases, we strike this balance in favor of the procedures described by the Warrant Clause of the Fourth Amendment. See United States v. Place, supra, at 701, and n. 2; United States v. United States District Court, 407 U. S. 297, 315 (1972). Except in certain well-defined circumstances, a search or seizure in such a case is not reasonable unless it is accomplished pursuant to a judicial warrant issued upon probable cause. See, e. g., Payton v. New York, 445 U. S. 573, 586 (1980); Mincey v. Arizona, 437 U. S. 385, 390 (1978). We have recognized exceptions to this rule, however, “when ‘special needs, beyond the normal need for law enforcement, make the warrant and probable-cause requirement impracticable.’” Griffin v. Wisconsin, 483 U. S. 868, 873 (1987), quoting New Jersey v. T. L. O., supra, at 351 (Blackmun, J., concurring in judgment). When faced with such special needs, we have not hesitated to balance the governmental and privacy interests to assess the practicality of the warrant and probable-cause requirements in the particular context. See, e. g., Griffin v. Wisconsin, supra, at 873 (search of probationer’s home); New York v. *620 Burger, 482 U. S. 691, 699-703 (1987) (search of premises of certain highly regulated businesses); O’Connor v. Ortega, supra, at 721-725 (work-related searches of employees’ desks and offices); New Jersey v. T. L. O., supra, at 337-342 (search of student’s property by school officials); Bell v. Wolfish, 441 U. S. 520, 558-560 (1979) (body cavity searches of prison inmates).

The Government’s interest in regulating the conduct of railroad employees to ensure safety, like its supervision of probationers or regulated industries, or its operation of a government office, school, or prison, “likewise presents ‘special needs’ beyond normal law enforcement that may justify departures from the usual warrant and probable-cause requirements.” Griffin v. Wisconsin, supra, at 873-874. The hours of service employees covered by the FRA regulations include persons engaged in handling orders concerning train movements, operating crews, and those engaged in the maintenance and repair of signal systems. 50 Fed. Reg. 31511 (1985). It is undisputed that these and other covered employees are engaged in safety-sensitive tasks. The FRA so found, and respondents conceded the point at oral argument. Tr. of Oral Arg. 46-47. As we have recognized, the whole premise of the Hours of Service Act is that “[t]he length of hours of service has direct relation to the efficiency of the human agencies upon which protection [of] life and property necessarily depends.” Baltimore & Ohio R. Co. v. ICC, 221 U. S. 612, 619 (1911). See also Atchison, T. & S. F. R. Co. v. United States, 244 U. S. 336, 342 (1917) (“[I]t must be remembered that the purpose of the act was to prevent the dangers which must necessarily arise to the employee and to the public from continuing men in a dangerous and hazardous business for periods so long as to render them unfit to give that service which is essential to the protection of themselves and those entrusted to their care”).

The FRA has prescribed toxicological tests, not to assist in the prosecution of employees, but rather “to prevent acci*621dents and casualties in railroad operations that result from impairment of employees by alcohol or drugs.” 49 CFR §219.1(a) (1987).5 This governmental interest in ensuring the safety of the traveling public and of the employees themselves plainly justifies prohibiting covered employees from using alcohol or drugs on duty, or while subject to being called for duty. This interest also “require[s] and justifies] the exercise of supervision to assure that the restrictions are in fact observed.” Griffin v. Wisconsin, supra, at 875. The question that remains, then, is whether the Government’s need to monitor compliance with these restrictions justifies the privacy intrusions at issue absent a warrant or individualized suspicion.

B

An essential purpose of a warrant requirement is to protect privacy interests by assuring citizens subject to a search *622or seizure that such intrusions are not the random or arbitrary acts of government agents. A warrant assures the citizen that the intrusion is authorized by law, and that it is narrowly limited in its objectives and scope. See, e. g., New York v. Burger, supra, at 703; United States v. Chadwick, 433 U. S. 1, 9 (1977); Camara v. Municipal Court of San Francisco, 387 U. S., at 532. A warrant also provides the detached scrutiny of a neutral magistrate, and thus ensures an objective determination whether an intrusion is justified in any given case. See United States v. Chadwick, supra, at 9. In the present context, however, a warrant would do little to further these aims. Both the circumstances justifying toxicological testing and the permissible limits of such intrusions are defined narrowly and specifically in the regulations that authorize them, and doubtless are well known to covered employees. Cf. United States v. Biswell, 406 U. S. 311, 316 (1972). Indeed, in light of the standardized nature of the tests and the minimal discretion vested in those charged with administering the program, there are virtually no facts for a neutral magistrate to evaluate. Cf. Colorado v. Bertine, 479 U. S. 367, 376 (1987) (Blackmun, J., concurring).6

*623We have recognized, moreover, that the government’s interest in dispensing with the warrant requirement is at its strongest when, as here, “the burden of obtaining a warrant is likely to frustrate the governmental purpose behind the search.” Camara v. Municipal Court of San Francisco, supra, at 533. See also New Jersey v. T. L. O., 469 U. S., at 340; Donovan v. Dewey, 452 U. S. 594, 603 (1981). As the FRA recognized, alcohol and other drugs are eliminated from the bloodstream at a constant rate, see 49 Fed. Reg. 24291 (1984), and blood and breath samples taken to measure whether these substances were in the bloodstream when a triggering event occurred must be obtained as soon as possible. See Schmerber v. California, 384 U. S., at 770-771. Although the metabolites of some drugs remain in the urine for longer periods of time and may enable the FRA to estimate whether the employee was impaired by those drugs at the time of a covered accident, incident, or rule violation, 49 Fed. Reg. 24291 (1984), the delay necessary to procure a warrant nevertheless may result in the destruction of valuable evidence.

The Government’s need to rely on private railroads to set the testing process in motion also indicates that insistence on a warrant requirement would impede the achievement of the Government’s objective. Railroad supervisors, like school officials, see New Jersey v. T. L. O., supra, at 339-340, and hospital administrators, see O’Connor v. Ortega, 480 U. S., at 722, are not in the business of investigating violations of the criminal laws or enforcing administrative codes, and otherwise have little occasion to become familiar with the intricacies of this Court’s Fourth Amendment jurisprudence. “Imposing unwieldy warrant procedures . . . upon supervi*624sors, who would otherwise have no reason to be familiar with such procedures, is simply unreasonable.” Ibid.

In sum, imposing a warrant requirement in the present context would add little to the assurances of certainty and regularity already afforded by the regulations, while significantly hindering, and in many cases frustrating, the objectives of the Government’s testing program. We do not believe that a warrant is essential to render the intrusions here at issue reasonable under the Fourth Amendment.

C

Our cases indicate that even a search that may be performed without a warrant must be based, as a general matter, on probable cause to believe that the person to be searched has violated the law. See New Jersey v. T. L. O., supra, at 340. When the balance of interests precludes insistence on a showing of probable cause, we have usually required “some quantum of individualized suspicion” before concluding that a search is reasonable. See, e. g., United States v. Martinez-Fuerte, 428 U. S., at 560. We made it clear, however, that a showing of individualized suspicion is not a constitutional floor, below which a search must be presumed unreasonable. Id., at 561. In limited circumstances, where the privacy interests implicated by the search are minimal, and where an important governmental interest furthered by the intrusion would be placed in jeopardy by a requirement of individualized suspicion, a search may be reasonable despite the absence of such suspicion. We believe this is true of the intrusions in question here.

By and large, intrusions on privacy under the FRA regulations are limited. To the extent transportation and like restrictions are necessary to procure the requisite blood, breath, and urine samples for testing, this interference alone is minimal given the employment context in which it takes place. Ordinarily, an employee consents to significant restrictions in his freedom of movement where necessary for *625his employment, and few are free to come and go as they please during working hours. See, e. g., INS v. Delgado, 466 U. S., at 218. Any additional interference with a railroad employee’s freedom of movement that occurs in the time it takes to procure a blood, breath, or urine sample for testing cannot, by itself, be said to infringe significant privacy interests.

Our decision in Schmerber v. California, supra, indicates that the same is true of the blood tests required by the FRA regulations. In that case, we held that a State could direct that a blood sample be withdrawn from a motorist suspected of driving while intoxicated, despite his refusal to consent to the intrusion. We noted that the test was performed in a reasonable manner, as the motorist’s “blood was taken by a physician in a hospital environment according to accepted medical practices.” Id., at 771. We said also that the intrusion occasioned by a blood test is not significant, since such “tests are a commonplace in these days of periodic physical examinations and experience with them teaches that the quantity of blood extracted is minimal, and that for most people the procedure involves virtually no risk, trauma, or pain.” Ibid. Schmerber thus confirmed “society’s judgment that blood tests do not constitute an unduly extensive imposition on an individual’s privacy and bodily integrity.” Winston v. Lee, 470 U. S., at 762. See also South Dakota v. Neville, 459 U. S. 553, 563 (1983) (“The simple blood-alcohol test is . . . safe, painless, and commonplace”); Breithaupt v. Abram, 352 U. S. 432, 436 (1957) (“The blood test procedure has become routine in our everyday life”).

The breath tests authorized by Subpart D of the regulations are even less intrusive than the blood tests prescribed by Subpart C. Unlike blood tests, breath tests do not require piercing the skin and may be conducted safely outside a hospital environment and with a minimum of inconvenience or embarrassment. Further, breath tests reveal the level of alcohol in the employee’s bloodstream and nothing more. *626Like the blood-testing procedures mandated by Subpart C, which can be used only to ascertain the presence of alcohol or controlled substances in the bloodstream, breath tests reveal no other facts in which the employee has a substantial privacy interest. Cf. United States v. Jacobsen, 466 U. S., at 123; United States v. Place, 462 U. S., at 707. In all the circumstances, we cannot conclude that the administration of a breath test implicates significant privacy concerns.

A more difficult question is presented by urine tests. Like breath tests, urine tests are not invasive of the body and, under the regulations, may not be used as an occasion for inquiring into private facts unrelated to alcohol or drug use.7 We recognize, however, that the procedures for collecting the necessary samples, which require employees to perform an excretory function traditionally shielded by great privacy, raise concerns not implicated by blood or breath tests. While we would not characterize these additional privacy concerns as minimal in most contexts, we note that the regulations endeavor to reduce the intrusiveness of the collection process. The regulations do not require that samples be furnished under the direct observation of a monitor, despite the desirability of such a procedure to ensure the integrity of the sample. See 50 Fed. Reg. 31555 (1985). See also Field Manual B-15, D-l. The sample is also collected in a medical environment, by personnel unrelated to the railroad *627employer, and is thus not unlike similar procedures encountered often in the context of a regular physical examination.

More importantly, the expectations of privacy of covered employees are diminished by reason of their participation in an industry that is regulated pervasively to ensure safety, a goal dependent, in substantial part, on the health and fitness of covered employees. This relation between safety and employee fitness was recognized by Congress when it enacted the Hours of Service Act in 1907, Baltimore & Ohio R. Co. v. ICC, 221 U. S., at 619, and also when it authorized the Secretary to “test. . . railroad facilities, equipment, rolling stock, operations, or persons, as he deems necessary to carry out the provisions” of the Federal Railroad Safety Act of 1970. 45 U. S. C. § 437(a) (emphasis added). It has also been recognized by state governments,8 and has long been reflected in industry practice, as evidenced by the industry’s promulgation and enforcement of Rule G. Indeed, the FRA found, and the Court of Appeals acknowledged, see 839 F. 2d, at 585, that “most railroads require periodic physical examinations for train and engine employees and certain other employees.” 49 Fed. Reg. 24278 (1984). See also Railway Labor Executives Assn. v. Norfolk & Western R. Co., 833 F. 2d 700, 705-706 (CA7 1987); Brotherhood of Maintenance of *628 Way Employees, Lodge 16 v. Burlington Northern R. Co., 802 F. 2d 1016, 1024 (CA8 1986).

We do not suggest, of course, that the interest in bodily security enjoyed by those employed in a regulated industry must always be considered minimal. Here, however, the covered employees have long been a principal focus of regulatory concern. As the dissenting judge below noted: “The reason is obvious. An idle locomotive, sitting in the roundhouse, is harmless. It becomes lethal when operated negligently by persons who are under the influence of alcohol or drugs.” 839 F. 2d, at 593. Though some of the privacy interests implicated by the toxicological testing at issue reasonably might be viewed as significant in other contexts, logic and history show that a diminished expectation of privacy attaches to information relating to the physical condition of covered employees and to this reasonable means of procuring such information. We conclude, therefore, that the testing procedures contemplated by Subparts C and D pose only limited threats to the justifiable expectations of privacy of covered employees.

By contrast, the Government interest in testing without a showing of individualized suspicion is compelling. Employees subject to the tests discharge duties fraught with such risks of injury to others that even a momentary lapse of attention can have disastrous consequences. Much like persons who have routine access to dangerous nuclear power facilities, see, e. g., Rushton v. Nebraska Public Power Dist., 844 F. 2d 562, 566 (CA8 1988); Alverado v. Washington Public Power Supply System, 111 Wash. 2d 424, 436, 759 P. 2d 427, 433-434 (1988), cert. pending, No. 88-645, employees who are subject to testing under the FRA regulations can cause great human loss before any signs of impairment become noticeable to supervisors or others. An impaired employee, the FRA found, will seldom display any outward “signs detectable by the lay person or, in many cases, even the physician.” 50 Fed. Reg. 31526 (1985). This view finds *629ample support in the railroad industry’s experience with Rule G, and in the judgment of the courts that have examined analogous testing schemes. See, e. g., Brotherhood of Maintenance Way Employees, Lodge 16 v. Burlington Northern R. Co., supra, at 1020. Indeed, while respondents posit that impaired employees might be detected without alcohol or drug testing,9 the premise of respondents’ lawsuit is that even the occurrence of a major calamity will not give rise to a suspicion of impairment with respect to any particular employee.

While no procedure can identify all impaired employees with ease and perfect accuracy, the FRA regulations supply an effective means of deterring employees engaged in safety-sensitive tasks from using controlled substances or alcohol in the first place. 50 Fed. Reg. 31541 (1985). The railroad industry’s experience with Rule G persuasively shows, and common sense confirms, that the customary dismissal sanc*630tion that threatens employees who use drugs or alcohol while on duty cannot serve as an effective deterrent unless violators know that they are likely to be discovered. By ensuring that employees in safety-sensitive positions know they will be tested upon the occurrence of a triggering event, the timing of which no employee can predict with certainty, the regulations significantly increase the deterrent effect of the administrative penalties associated with the prohibited conduct, cf. Griffin v. Wisconsin, 483 U. S., at 876, concomitantly increasing the likelihood that employees will forgo using drugs or alcohol while subject to being called for duty.

The testing procedures contemplated by Subpart C also help railroads obtain invaluable information about the causes of major accidents, see 50 Fed. Reg. 31541 (1985), and to take appropriate measures to safeguard the general public. Cf. Michigan v. Tyler, 436 U. S. 499, 510 (1978) (noting that prompt investigation of the causes of a fire may uncover continuing dangers and thereby prevent the fire’s recurrence); Michigan v. Clifford, 464 U. S. 287, 308 (1984) (Rehnquist, J., dissenting) (same). Positive test results would point toward drug or alcohol impairment on the part of members of the crew as a possible cause of an accident, and may help to establish whether a particular accident, otherwise not drug related, was made worse by the inability of impaired employees to respond appropriately. Negative test results would likewise furnish invaluable clues, for eliminating drug impairment as a potential cause or contributing factor would help establish the significance of equipment failure, inadequate training, or other potential causes, and suggest a more thorough examination of these alternatives. Tests performed following the rule violations specified in Subpart D likewise can provide valuable information respecting the causes of those transgressions, which the FRA found to involve “the potential for a serious train accident or grave personal injury, or both.” 50 Fed. Reg. 31553 (1985).

*631A requirement of particularized suspicion of drug or alcohol use would seriously impede an employer’s ability to obtain this information, despite its obvious importance. Experience confirms the FRA’s judgment that the scene of a serious rail accident is chaotic. Investigators who arrive at the scene shortly after a major accident has occurred may find it difficult to determine which members of a train crew contributed to its occurrence. Obtaining evidence that might give rise to the suspicion that a particular employee is impaired, a difficult endeavor in the best of circumstances, is most impracticable in the aftermath of a serious accident. While events following the rule violations that activate the testing authority of Subpart D may be less chaotic, objective indicia of impairment are absent in these instances as well. Indeed, any attempt to gather evidence relating to the possible impairment of particular employees likely would result in the loss or deterioration of the evidence furnished by the tests. Cf. Michigan v. Clifford, supra, at 293, n. 4 (plurality opinion); Michigan v. Tyler, supra, at 510. It would be unrealistic, and inimical to the Government’s goal of ensuring safety in rail transportation, to require a showing of individualized suspicion in these circumstances.

Without quarreling with the importance of these governmental interests, the Court of Appeals concluded that the postaccident testing regulations were unreasonable because “[b]lood and urine tests intended to establish drug use other than alcohol. . . cannot measure current drug intoxication or degree of impairment.” 839 F. 2d, at 588. The court based its conclusion on its reading of certain academic journals that indicate that the testing of urine can disclose only drug metabolites, which “may remain in the body for days or weeks after the ingestion of the drug.” Id., at 589. We find this analysis flawed for several reasons.

As we emphasized in New Jersey v. T. L. O., “it is universally recognized that evidence, to be relevant to an inquiry, need not conclusively prove the ultimate fact in issue, but *632only have ‘any tendency to make the existence of any fact that is of consequence to the determination [of the point in issue] more probable or less probable than it would be without the evidence.’” 469 U. S., at 345, quoting Fed. Rule Evid. 401. Even if urine test results disclosed nothing more specific than the recent use of controlled substances by a covered employee, this information would provide the basis for further investigative work designed to determine whether the employee used drugs at the relevant times. See Field Manual B-4. The record makes clear, for example, that a positive test result, coupled with known information concerning the pattern of elimination for the particular drug and information that may be gathered from other sources about the employee’s activities, may allow the FRA to reach an informed judgment as to how a particular accident occurred. See supra, at 609-610.

More importantly, the Court of Appeals overlooked the FRA’s policy of placing principal reliance on the results of blood tests, which unquestionably can identify very recent drug use, see, e. g., 49 Fed. Reg. 24291 (1984), while relying on urine tests as a secondary source of information designed to guard against the possibility that certain drugs will be eliminated from the bloodstream before a blood sample can be obtained. The court also failed to recognize that the FRA regulations are designed not only to discern impairment but also to deter it. Because the record indicates that blood and urine tests, taken together, are highly effective means of ascertaining on-the-job impairment and of deterring the use of drugs by railroad employees, we believe the Court of Appeals erred in concluding that the postaccident testing regulations are not reasonably related to the Government objectives that support them.10

*633We conclude that the compelling Government interests served by the FRA’s regulations would be significantly hindered if railroads were required to point to specific facts giving rise to a reasonable suspicion of impairment before testing a given employee. In view of our conclusion that, on the present record, the toxicological testing contemplated by the regulations is not an undue infringement on the justifiable expectations of privacy of covered employees, the Government’s compelling interests outweigh privacy concerns.

IV

The possession of unlawful drugs is a criminal offense that the Government may punish, but it is a separate and far more dangerous wrong to perform certain sensitive tasks while under the influence of those substances. Performing those tasks while impaired by alcohol is, of course, equally dangerous, though consumption of alcohol is legal in most other contexts. The Government may take all necessary and reasonable regulatory steps to prevent or deter that hazardous conduct, and since the gravamen of the evil is performing certain functions while concealing the substance in the body, it may be necessary, as in the case before us, to examine the body or its fluids to accomplish the regulatory purpose. The necessity to perform that regulatory function with respect to railroad employees engaged in safety-sensitive tasks, and the reasonableness of the system for doing so, have been established in this case.

Alcohol and drug tests conducted in reliance on the authority of Subpart D cannot be viewed as private action outside the reach of the Fourth Amendment. Because the testing procedures mandated or authorized by Subparts C and D ef-*634feet searches of the person, they must meet the Fourth Amendment’s reasonableness requirement. In light of the limited discretion exercised by the railroad employers under the regulations, the surpassing safety interests served by toxicological tests in this context, and the diminished expectation of privacy that attaches to information pertaining to the fitness of covered employees, we believe that it is reasonable to conduct such tests in the absence of a warrant or reasonable suspicion that any particular employee may be impaired. We hold that the alcohol and drug tests contemplated by Subparts C and D of the FRA’s regulations are reasonable within the meaning of the Fourth Amendment. The judgment of the Court of Appeals is accordingly reversed.

It is so ordered.

Justice Stevens,

concurring in part and concurring in the judgment.

In my opinion the public interest in determining the causes of serious railroad accidents adequately supports the validity of the challenged regulations. I am not persuaded, however, that the interest in deterring the use of alcohol or drugs is either necessary or sufficient to justify the searches authorized by these regulations.

I think it a dubious proposition that the regulations significantly deter the use of alcohol and drugs by hours of service employees. Most people — and I would think most railroad employees as well — do not go to work with the expectation that they may be involved in a major accident, particularly one causing such catastrophic results as loss of life or the release of hazardous material requiring an evacuation. Moreover, even if they are conscious of the possibilities that such an accident might occur and that alcohol or drug use might be a contributing factor, if the risk of serious personal injury does not deter their use of these substances, it seems highly unlikely that the additional threat of loss of employment would have any effect on their behavior.

*635For this reason, I do not join the portions of Part III of the Court’s opinion that rely on a deterrence rationale; I do, however, join the balance of the opinion and the Court’s judgment.

Justice Marshall,

with whom Justice Brennan joins, dissenting.

The issue in this case is not whether declaring a war on illegal drugs is good public policy. The importance of ridding our society of such drugs is, by now, apparent to all. Rather, the issue here is whether the Government’s deployment in that war of a particularly Draconian weapon — the compulsory collection and chemical testing of railroad workers’ blood and urine — comports with the Fourth Amendment. Precisely because the need for action against the drug scourge is manifest, the need for vigilance against unconstitutional excess is great. History teaches that grave threats to liberty often come in times of urgency, when constitutional rights seem too extravagant to endure. The World War II relocation-camp cases, Hirabayashi v. United States, 320 U. S. 81 (1943); Korematsu v. United States, 323 U. S. 214 (1944), and the Red scare and McCarthy-era internal subversion cases, Schenck v. United States, 249 U. S. 47 (1919); Dennis v. United States, 341 U. S. 494 (1951), are only the most extreme reminders that when we allow fundamental freedoms to be sacrificed in the name of real or perceived exigency, we invariably come to regret it.

In permitting the Government to force entire railroad crews to submit to invasive blood and urine tests, even when it lacks any evidence of drug or alcohol use or other wrongdoing, the majority today joins those shortsighted courts which have allowed basic constitutional rights to fall prey to momentary emergencies. The majority holds that the need of the Federal Railroad Administration (FRA) to deter and diagnose train accidents outweighs any “minimal” intrusions on personal dignity and privacy posed by mass toxicological testing of persons who have given no indication whatsoever of *636impairment. Ante, at 624. In reaching this result, the majority ignores the text and doctrinal history of the Fourth Amendment, which require that highly intrusive searches of this type be based on probable cause, not on the evanescent cost-benefit calculations of agencies or judges. But the majority errs even under its own utilitarian standards, trivializing the raw intrusiveness of, and overlooking serious conceptual and operational flaws in, the FRA’s testing program. These flaws cast grave doubts on whether that program, though born of good intentions, will do more than ineffectually symbolize the Government’s opposition to drug use.

The majority purports to limit its decision to postaccident testing of workers in “safety-sensitive” jobs, ante, at 620, much as it limits its holding in the companion case to the testing of transferees to jobs involving drug interdiction or the use of firearms. Treasury Employees v. Von Raab, post, at 664. But the damage done to the Fourth Amendment is not so easily cabined. The majority’s acceptance of dragnet blood and urine testing ensures that the first, and worst, casualty of the war on drugs will be the precious liberties of our citizens. I therefore dissent.

I

The Court today takes its longest step yet toward reading the probable-cause requirement out of the Fourth Amendment. For the fourth time in as many years, a majority holds that a “‘special nee[d], beyond the normal need for law enforcement,’” makes the “‘requirement’” of probable cause “‘impracticable.’” Ante, at 619 (citations omitted). With the recognition of “[t]he Government’s interest in regulating the conduct of railroad employees to ensure safety” as such a need, ante, at 620, the Court has now permitted “special needs” to displace constitutional text in each of the four categories of searches enumerated in the Fourth Amendment: searches of “persons,” ante, at 613-614; “houses,” Griffin v. Wisconsin, 483 U. S. 868 (1987); “papers,” O’Connor v. Or *637 tega, 480 U. S. 709 (1987); and “effects,” New Jersey v. T. L. O., 469 U. S. 325 (1985).

The process by which a constitutional “requirement” can be dispensed with as “impracticable” is an elusive one to me. The Fourth Amendment provides that “[t]he right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated; and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.” The majority’s recitation of the Amendment, remarkably, leaves off after the word “violated,” ante, at 613, but the remainder of the Amendment — the Warrant Clause — is not so easily excised. As this Court has long recognized, the Framers intended the provisions of that Clause — a warrant and probable cause — to “provide the yardstick against which official searches and seizures are to be measured.” T. L. O., supra, at 359-360 (opinion of Brennan, J.). Without the content which those provisions give to the Fourth Amendment’s overarching command that searches and seizures be “reasonable,” the Amendment lies virtually devoid of meaning, subject to whatever content shifting judicial majorities, concerned about the problems of the day, choose to give to that supple term. See Dunaway v. New York, 442 U. S. 200, 213 (1979) (“[T]he protections intended by the Framers could all too easily disappear in the consideration and balancing of the multifarious circumstances presented by different cases”). Constitutional requirements like probable cause are not fair-weather friends, present when advantageous, conveniently absent when “special needs” make them seem not.

Until recently, an unbroken line of cases had recognized probable cause as an indispensable prerequisite for a full-scale search, regardless of whether such a search was conducted pursuant to a warrant or under one of the recognized exceptions to the warrant requirement. T. L. O., supra, at 358 *638and 359, n. 3 (opinion of Brennan, J.); see also Chambers v. Maroney, 399 U. S. 42, 51 (1970). Only where the government action in question had a “substantially less intrusive” impact on privacy, Dunaway, 442 U. S., at 210, and thus clearly fell short of a full-scale search, did we relax the probable-cause standard. Id., at 214 (“For all but those narrowly defined intrusions, the requisite ‘balancing’ ... is embodied in the principle that seizures are ‘reasonable’ only if supported by probable cause”); see also T. L. O., supra, at 360 (opinion of Brennan, J.). Even in this class of cases, we almost always required the government to show some individualized suspicion to justify the search.1 The few searches which we upheld in the absence of individualized justification were routinized, fleeting, and nonintrusive encounters conducted pursuant to regulatory programs which entailed no contact with the person.2

*639In the four years since this Court, in T. L. O., first began recognizing “special needs” exceptions to the Fourth Amendment, the clarity of Fourth Amendment doctrine has been badly distorted, as the Court has eclipsed the probable-cause requirement in a patchwork quilt of settings: public school principals’ searches of students’ belongings, T. L. O.; public employers’ searches of employees’ desks, O’Connor; and probation officers’ searches of probationers’ homes, Griffin, 3 Tellingly, each time the Court has found that “special needs” counseled ignoring the literal requirements of the Fourth Amendment for such full-scale searches in favor of a formless and unguided “reasonableness” balancing inquiry, it has concluded that the search in question satisfied that test. I have joined dissenting opinions in each of these cases, protesting the “jettison[ing of] . . . the only standard that finds support in the text of the Fourth Amendment” and predicting that the majority’s “Rohrsehach-like ‘balancing test’” portended “a dangerous weakening of the purpose of the Fourth Amendment to protect the privacy and security of our citizens.” T. L. O., supra, at 357-358 (opinion of Brennan, J.).

The majority’s decision today bears out that prophecy. After determining that the Fourth Amendment applies to the FRA’s testing regime, the majority embarks on an extended inquiry into whether that regime is “reasonable,” an inquiry in which it balances “‘all of the circumstances surrounding the search or seizure and the nature of the search or seizure itself.’” Ante, at 619, quoting United States v. Montoya de *640 Hernandez, 473 U. S. 531, 537 (1985). The result is “special needs” balancing analysis’ deepest incursion yet into the core protections of the Fourth Amendment. Until today, it was conceivable that, when a government search was aimed at a person and not simply the person’s possessions, balancing analysis had no place. No longer: with nary a word of explanation or acknowledgment of the novelty of its approach, the majority extends the “special needs” framework to a regulation involving compulsory blood withdrawal and urinary excretion, and chemical testing of the bodily fluids collected through these procedures. And until today, it was conceivable that a prerequisite for surviving “special needs” analysis was the existence of individualized suspicion. No longer: in contrast to the searches in T. L. O., O’Connor, and Griffin, which were supported by individualized evidence suggesting the culpability of the persons whose property was searched,4 the regulatory regime upheld today requires the postaccident collection and testing of the blood and urine of all covered employees — even if every member of this group gives every indication of sobriety and attentiveness.

In widening the “special needs” exception to probable cause to authorize searches of the human body unsupported by any evidence of wrongdoing, the majority today completes the process begun in T. L. O. of eliminating altogether the probable-cause requirement for civil searches — those undertaken for reasons “beyond the normal need for law enforcement.” Ante, at 619 (citations omitted). In its place, the majority substitutes a manipulable balancing inquiry under which, upon the mere assertion of a “special need,” even the deepest dignitary and privacy interests become vul*641nerable to governmental incursion. See ibid, (distinguishing criminal from civil searches). By its terms, however, the Fourth Amendment — unlike the Fifth and Sixth — does not confine its protections to either criminal or civil actions. Instead, it protects generally “[t]he right of the people to be secure.”5

The fact is that the malleable “special needs” balancing approach can be justified only on the basis of the policy results it allows the majority to reach. The majority’s concern with the railroad safety problems caused by drug and alcohol abuse is laudable; its cavalier disregard for the text of the Constitution is not. There is no drug exception to the Constitution, any more than there is a communism exception or an exception for other real or imagined sources of domestic unrest. Coolidge v. New Hampshire, 403 U. S. 443, 455 (1971). Because abandoning the explicit protections of the Fourth Amendment seriously imperils “the right to be let alone — the most comprehensive of rights and the right most valued by civilized men,” Olmstead v. United States, 277 U. S. 438, 478 (1928) (Brandeis, J., dissenting), I reject the majority’s “special needs” rationale as unprincipled and dangerous.

II

The proper way to evaluate the FRA’s testing regime is to use the same analytic framework which we have traditionally used to appraise Fourth Amendment claims involving full-scale searches, at least until the recent “special needs” cases. Under that framework, we inquire, serially, whether a *642search has taken place, see, e. g., Katz v. United States, 389 U. S. 347, 350-353 (1967); whether the search was based on a valid warrant or undertaken pursuant to a recognized exception to the warrant requirement, see, e. g., Welsh v. Wisconsin, 466 U. S. 740, 748-750 (1984); whether the search was based on probable cause or validly based on lesser suspicion because it was minimally intrusive, see, e. g., Dunaway, 442 U. S., at 208-210; and, finally, whether the search was conducted in a reasonable manner, see, e. g., Winston v. Lee, 470 U. S. 753, 763-766 (1985). See also T. L. O., 469 U. S., at 354-355 (opinion of Brennan, J.) (summarizing analytic framework).

The majority’s threshold determination that “covered” railroad employees have been searched under the FRA’s testing program is certainly correct. Ante, at 616-618. Who among us is not prepared to consider reasonable a person’s expectation of privacy with respect to the extraction of his blood, the collection of his urine, or the chemical testing of these fluids? United States v. Jacobsen, 466 U. S. 109, 113 (1984).6 The majority’s ensuing conclusion that the warrant requirement may be dispensed with, however, conveniently overlooks the fact that there are three distinct searches at issue. Although the importance of collecting blood and urine samples before drug or alcohol metabolites disappear justifies waiving the warrant requirement for those two searches under the narrow “exigent circumstances” exception, see Schmerber v. California, 384 U. S. 757, 770 (1966) (“[T]he delay necessary to obtain a warrant. . . threatens] ‘the destruction of evidence’ ”), no such exigency prevents railroad officials from securing a warrant before chemically testing the samples they obtain. Blood and urine do not spoil if *643properly collected and preserved, and there is no reason to doubt the ability of railroad officials to grasp the relatively simple procedure of obtaining a warrant authorizing, where appropriate, chemical analysis of the extracted fluids. It is therefore wholly unjustified to dispense with the warrant requirement for this final search. See Chimel v. California, 395 U. S. 752, 761-764 (1969) (exigency exception permits warrantless searches only to the extent that exigency exists).

It is the probable-cause requirement, however, that the FRA’s testing regime most egregiously violates, a fact which explains the majority’s ready acceptance and expansion of the countertextual “special needs” exception. By any measure, the FRA’s highly intrusive collection and testing procedures qualify as full-scale personal searches. Under our precedents, a showing of probable cause is therefore clearly required. But even if these searches were viewed as entailing only minimal intrusions on the order, say, of a police stop- and-frisk, the FRA’s program would still fail to pass constitutional muster, for we have, without exception, demanded that even minimally intrusive searches of the person be founded on individualized suspicion. See supra, at 638, and n. 1. The federal parties concede it does not satisfy this standard. Brief for Federal Parties 18. Only if one construes the FRA’s collection and testing procedures as akin to the routinized and fleeting regulatory interactions which we have permitted in the absence of individualized suspicion, see n. 2, supra, might these procedures survive constitutional scrutiny. Presumably for this reason, the majority likens this case to United States v. Martinez-Fuerte, 428 U. S. 543 (1976), which upheld brief automobile stops, at the border to ascertain the validity of motorists’ residence in the United States. Ante, at 624. CaseTaw and common sense reveal both the bankruptcy of this absurd analogy and the constitutional imperative of adhering to the textual standard of probable cause to evaluate the FRA’s multifarious full-scale searches.

*644Compelling a person to submit to the piercing of his skin by a hypodermic needle so that his blood may be extracted significantly intrudes on the “personal privacy and dignity against unwarranted intrusion by the State” against which the Fourth Amendment protects. Schmerber, supra, at 767. As we emphasized in Terry v. Ohio, 392 U. S. 1, 24-25 (1968), “Even a limited search of the outer clothing . . . constitutes a severe, though brief, intrusion upon cherished personal security, and it must surely be an annoying, frightening, and perhaps humiliating experience.” We have similarly described the taking of a suspect’s fingernail scrapings as a “ ‘severe, though brief, intrusion upon cherished personal security.’” Cupp v. Murphy, 412 U. S. 291, 295 (1973) (quoting Terry, supra, at 24-25, and upholding this procedure upon a showing of probable cause). The government-compelled withdrawal of blood, involving as it does the added aspect of physical invasion, is surely no less an intrusion. The surrender of blood on demand is, furthermore, hardly a quotidian occurrence. Cf. Martinez-Fuerte, supra, at 557 (routine stops involve “quite limited” intrusion).

In recognition of the intrusiveness of this procedure, we specifically required in Schmerber that police have evidence of a drunken-driving suspect’s impairment before forcing him to endure a blood test:

“The interests in human dignity and privacy which the Fourth Amendment protects forbid any such intrusions on the mere chance that desired evidence might be obtained. In the absence of a clear indication that in fact such evidence will be found, these fundamental human interests require law officers to suffer the risk that such evidence may disappear . . . .” 384 U. S., at 769-770.

Schmerber strongly suggested that the “clear indication” needed to justify a compulsory blood test amounted to a showing of probable cause, which “plainly” existed in that case. Id., at 768. Although subsequent cases interpreting Schmerber have differed over whether a showing of individ*645ualized suspicion would have sufficed, compare Winston, 470 U. S., at 760 (Schmerber “noted the importance of probable cause”), with Montoya de Hernandez, 473 U. S., at 540 (Schmerber “indicate[d] the necessity for particularized suspicion”), by any reading, Schmerber clearly forbade compulsory blood tests on any lesser showing than individualized suspicion. Exactly why a blood test which, if conducted on one person, requires a showing of at least individualized suspicion may, if conducted on many persons, be based on no showing whatsoever, the majority does not — and cannot — explain.7

Compelling a person to produce a urine sample on demand also intrudes deeply on privacy and bodily integrity. Urination is among the most private of activities. It is generally forbidden in public, eschewed as a matter of conversation, and performed in places designed to preserve this tradition of *646personal seclusion. Cf. Martinez-Fuerte, 428 U. S., at 560 (border-stop questioning involves no more than “some annoyance” and is neither “frightening” nor “offensive”). The FRA, however, gives scant regard to personal privacy, for its Field Manual instructs supervisors monitoring urination that railroad workers must provide urine samples “under direct observation by the physician/technician.” Federal Railroad Administration, United States Dept, of Transportation, Field Manual: Control of Alcohol and Drug Use in Railroad Operations D-5 (1986) (emphasis added).8 That the privacy interests offended by compulsory and supervised urine collection are profound is the overwhelming judgment of the lower courts and commentators. As Professor — later Solicitor General — Charles Fried has written:

“[I]n our culture the excretory functions are shielded by more or less absolute privacy, so much so that situations in which this privacy is violated are experienced as extremely distressing, as detracting from one’s dignity and self esteem.” Privacy, 77 Yale L. J. 475, 487 (1968).9

The majority’s characterization of the privacy interests implicated by urine collection as “minimal,” ante, at 624, is noth*647ing short of startling. This characterization is, furthermore, belied by the majority’s own prior explanation of why compulsory urination constitutes a search for the purposes of the Fourth Amendment:

“ ‘There are few activities in our society more personal or private than the passing of urine. Most people describe it by euphemisms if they talk about it at all. It is a function traditionally performed without public observation; indeed, its performance in public is generally prohibited by law as well as social custom.’” Ante, at 617, quoting National Treasury Employees Union v. Von Raab, 816 F. 2d 170, 175 (CA5 1987).

The fact that the majority can invoke this powerful passage in the context of deciding that a search has occurred, and then ignore it in deciding that the privacy interests this search implicates are “minimal,” underscores the shameless manipulability of its balancing approach.

Finally, the chemical analysis the FRA performs upon the blood and urine samples implicates strong privacy interests apart from those intruded upon by the collection of bodily fluids. Technological advances have made it possible to uncover, through analysis of chemical compounds in these fluids, not only drug or alcohol use, but also medical disorders such as epilepsy, diabetes, and clinical depression. Cf. Martinez-Fuerte, supra, at 558, quoting United States v. Brignoni-Ponce, 422 U. S. 873, 880 (1975) (checkpoint inquiry involves only “ ‘a brief question or two’ ” about motorist’s residence). As the Court of Appeals for the District of Columbia Circuit has observed: “[S]uch tests may provide Government officials with a periscope through which they can peer into an individual’s behavior in her private life, even in her own home.” Jones v. McKenzie, 266 U. S. App. D. C. 85, 89, 833 F. 2d 335, 339 (1987); see also Capua v. Plainfield, 643 F. Supp. 1507, 1511 (NJ 1986) (urine testing is “form of surveillance” which “reports on a person’s off-duty activities just as surely as someone had been present and *648watching”)- The FRA’s requirement that workers disclose the medications they have taken during the 30 days prior to chemical testing further impinges upon the confidentiality customarily attending personal health secrets.

By any reading of our precedents, the intrusiveness of these three searches demands that they — like other full-scale searches — be justified by probable cause. It is no answer to suggest, as does the majority, that railroad workers have relinquished the protection afforded them by this Fourth Amendment requirement, either by “participating] in an industry that is regulated pervasively to ensure safety” or by undergoing periodic fitness tests pursuant to state law or to collective-bargaining agreements. Ante, at 627.

Our decisions in the regulatory search area refute the suggestion that the heavy regulation of the railroad industry eclipses workers’ rights under the Fourth Amendment to insist upon a showing of probable cause when their bodily fluids are being extracted. This line of cases has exclusively involved searches of employer property, with respect to which “[c]ertain industries have such a history of government oversight that no reasonable expectation of privacy could exist for a proprietor over the stock of such an enterprise.” Marshall v. Barlow’s, Inc., 436 U. S. 307, 313 (1978) (emphasis added; citation omitted), quoted in New York v. Burger, 482 U. S. 691, 700 (1987). Never have we intimated that regulatory searches reduce employees’ rights of privacy in their persons. See Camara v. Municipal Court of San Francisco, 387 U. S. 523, 537 (1967) (“[T]he inspections are [not] personal in nature”); cf. Donovan v. Dewey, 452 U. S. 594, 598-599 (1981); Marshall, supra, at 313. As the Court pointed out in O’Con-nor, individuals do not lose Fourth Amendment rights at the workplace gate, 480 U. S., at 716-718; see also Oliver v. United States, 466 U. S. 170, 178, n. 8 (1984), any more than they relinquish these rights at the schoolhouse door, T. L. O., 469 U. S., at 333, or the hotel room threshold, Hoff a v. United States, 385 U. S. 293, 301 (1966). These rights mean *649little indeed if, having passed through these portals, an individual may remain subject to a suspicionless search of his person justified solely on the grounds that the government already is permitted to conduct a search of the inanimate contents of the surrounding area. In holding that searches of persons may fall within the category of regulatory searches permitted in the absence of probable cause or even individualized suspicion, the majority sets a dangerous and ill-conceived precedent.

The majority’s suggestion that railroad workers’ privacy is only minimally invaded by the collection and testing of their bodily fluids because they undergo periodic fitness tests, ante, at 624-625, is equally baseless. As an initial matter, even if participation in these fitness tests did render “minimal” an employee’s “interest in bodily security,” ante, at 628, such minimally intrusive searches of the person require, under our precedents, a justificatory showing of individualized suspicion. See supra, at 637. More fundamentally, railroad employees are not routinely required to submit to blood or urine tests to gain or to maintain employment, and railroad employers do not ordinarily have access to employees’ blood or urine, and certainly not for the purpose of ascertaining drug or alcohol usage. That railroad employees sometimes undergo tests of eyesight, hearing, skill, intelligence, and agility, ante, at 627, n. 8, hardly prepares them for Government demands to submit to the extraction of blood, to excrete under supervision, or to have these bodily fluids tested for the physiological and psychological secrets they may contain. Surely employees who release basic information about their financial and personal history so that employers may ascertain their “ethical fitness” do not, by so doing, relinquish their expectations of privacy with respect to their personal letters and diaries, revealing though these papers may be of their character.

I recognize that invalidating the full-scale searches involved in the FRA’s testing regime for failure to comport with the Fourth Amendment’s command of probable cause *650may hinder the Government’s attempts to make rail transit as safe as humanly possible. But constitutional rights have their consequences, and one is that efforts to maximize the public welfare, no matter how well intentioned, must always be pursued within constitutional boundaries. Were the police freed from the constraints of the Fourth Amendment for just one day to seek out evidence of criminal wrongdoing, the resulting convictions and incarcerations would probably prevent thousands of fatalities. Our refusal to tolerate this specter reflects our shared belief that even beneficent governmental power — whether exercised to save money, save lives, or make the trains run on time — must always yield to “a resolute loyalty to constitutional safeguards.” Almeida-Sanchez v. United States, 413 U. S. 266, 273 (1973). The Constitution demands no less loyalty here.

I — I K — I hH

Even accepting the majority’s view that the FRA s collection and testing program is appropriately analyzed under a multifactor balancing test, and not under the literal terms of the Fourth Amendment, I would still find the program invalid. The benefits of suspicionless blood and urine testing are far outstripped by the costs imposed on personal liberty by such sweeping searches. Only by erroneously deriding as “minimal” the privacy and dignity interests at stake, and by uncritically inflating the likely efficacy of the FRA’s testing program, does the majority strike a different balance.

For the reasons stated above, I find nothing minimal about the intrusion on individual liberty that occurs whenever the Government forcibly draws and analyzes a person’s blood and urine. Several aspects of the FRA’s testing program exacerbate the intrusiveness of these procedures. Most strikingly, the agency’s regulations not only do not forbid, but, in fact, appear to invite criminal prosecutors to obtain the blood and urine samples drawn by the FRA and use them as the basis of criminal investigations and trials. See 49 CFR *651§ 219.211(d) (1987) (“Each sample . . . may be made available to ... a party in litigation upon service of appropriate compulsory process on the custodian of the sample . . .”). This is an unprecedented invitation, leaving open the possibility of criminal prosecutions based on suspicionless searches of the human body. Cf. Treasury Employees, post, at 666 (Customs Service drug-testing program prohibits use of test results in criminal prosecutions); Camara, 387 U. S., at 537.

Tobe sure, the majority acknowledges, in passing, the possibility of criminal prosecutions, ante, at 621, n. 5-, but it refuses to factor this possibility into its Fourth Amendment balancing process, stating that “the record does not disclose that [49 CFR § 219.211(d) (1987)] was intended to be, or actually has been, so used.” Ibid. This demurrer is highly disingenuous. The federal parties concede that they find “no prohibition on the release of FRA testing results to prosecutors.” Brief for Federal Parties 10, n. 15. The absence of prosecutions to date — which is likely due to the fact that the FRA’s regulations have been held invalid for much of their brief history — hardly proves that prosecutors will not avail themselves of the FRA’s invitation in the future. If the majority really views the impact of FRA testing on privacy interests as minimal even if these tests generate criminal prosecutions, it should say so. If the prospect of prosecutions would lead the majority to reassess the validity of the testing program with prosecutions as part of the balance, it should say so, too, or condition its approval of that program on the nonrelease of test results to prosecutors. In ducking this important issue, the majority gravely disserves both the values served by the Fourth Amendment and the rights of those persons whom the FRA searches. Furthermore, the majority’s refusal to restrict the release of test results casts considerable doubt on the conceptual basis of its decision— that the “special need” of railway safety is one “beyond the *652normal need for law enforcement.” Ante, at 619 (citations omitted).10

The majority also overlooks needlessly intrusive aspects of the testing process itself. Although the FRA requires the collection and testing of both blood and urine, the agency concedes that mandatory urine tests — unlike blood tests — do not measure current impairment and therefore cannot differentiate on-duty impairment from prior drug or alcohol use which has ceased to affect the user’s behavior. See 49 CFR § 219.309(2) (1987) (urine test may reveal use of drugs or alcohol as much as 60 days prior to sampling). Given that the FRA’s stated goal is to ascertain current impairment, and not to identify persons who have used substances in their spare time sufficiently in advance of their railroad duties to pose no risk of on-duty impairment, §219.101(a), mandatory urine testing seems wholly excessive. At the very least, the FRA could limit its use of urinalysis to confirming findings of current impairment suggested by a person’s blood tests. The additional invasion caused by automatically testing urine as well as blood hardly ensures that privacy interests “will be invaded no more than is necessary.” T. L. O., 469 U. S., at 343.

The majority’s trivialization of the intrusions on worker privacy posed by the FRA’s testing program is matched at the other extreme by its blind acceptance of the Government’s assertion that testing will “dete[r] employees engaged in safety-sensitive tasks from using controlled substances or alcohol,” and “help railroads obtain invaluable information *653about the causes of major accidents.” Ante, at 629, 630. With respect, first, to deterrence, it is simply implausible that testing employees after major accidents occur, 49 CFR § 219.201(a)(1) (1987), will appreciably discourage them from using drugs or alcohol. As Justice Stevens observes in his concurring opinion:

“Most people — and I would think most railroad employees as well — do not go to work with the expectation that they may be involved in a major accident, particularly one causing such catastrophic results as loss of life or the release of hazardous material requiring an evacuation. Moreover, even if they are conscious of the possibilities that such an accident might occur and that alcohol or drug use might be a contributing factor, if the risk of serious personal injury does not deter their use of these substances, it seems highly unlikely that the additional threat of loss of employment would have any effect on their behavior.” Ante, at 634.

Under the majority’s deterrence rationale, people who skip school or work to spend a sunny day at the zoo will not taunt the lions because their truancy or absenteeism might be discovered in the event they are mauled. It is, of course, the fear of the accident, not the fear of a postaccident revelation, that deters. The majority’s credulous acceptance of the FRA’s deterrence rationale is made all the more suspect by the agency’s failure to introduce, in an otherwise ample administrative record, any studies explaining or supporting its theory of accident deterrence.

The poverty of the majority’s deterrence rationale leaves the Government’s interest in diagnosing the causes of major accidents as the sole remaining justification for the FRA’s testing program. I do not denigrate this interest, but it seems a slender thread from which to hang such an intrusive program, particularly given that the knowledge that one or more workers were impaired at the time of an accident falls far short of proving that substance abuse caused or exacer*654bated that accident. See 839 F. 2d 575, 587 (CA9 1988). Some corroborative evidence is needed: witness or co-worker accounts of a worker’s misfeasance, or at least indications that the cause of the accident was within a worker’s area of responsibility. Such particularized facts are, of course, the very essence of the individualized suspicion requirement which the respondent railroad workers urge, and which the Court of Appeals found to “pos[e] no insuperable burden on the government.” Id., at 588. Furthermore, reliance on the importance of diagnosing the causes of an accident as a critical basis for upholding the FRA’s testing plan is especially hard to square with our frequent admonition that the interest in ascertaining the causes of a criminal episode does not justify departure from the Fourth Amendment’s requirements. “[T]his Court has never sustained a search upon the sole ground that officers reasonably expected to find evidence of a particular crime . . . .” Katz, 389 U. S., at 356. Nor should it here.

IV

In his first dissenting opinion as a Member of this Court, Oliver Wendell Holmes observed:

“Great cases, like hard cases, make bad law. For great cases are called great, not by reason of their real importance in shaping the law of the future, but because of some accident of immediate overwhelming interest which appeals to the feelings and distorts the judgment. These immediate interests exercise a kind of hydraulic pressure which makes what previously was clear seem doubtful, and before which even well settled principles of law will bend.” Northern Securities Co. v. United States, 193 U. S. 197, 400-401 (1904).

A majority of this Court, swept away by society’s obsession with stopping the scourge of illegal drugs, today succumbs to the popular pressures described by Justice Holmes. In upholding the FRA’s plan for blood and urine testing, the *655majority bends time-honored and textually based principles of the Fourth Amendment — principles the Framers of the Bill of Rights designed to ensure that the Government has a strong and individualized justification when it seeks to invade an individual’s privacy. I believe the Framers would be appalled by the vision of mass governmental intrusions upon the integrity of the human body that the majority allows to become reality. The immediate victims of the majority’s constitutional timorousness will be those railroad workers whose bodily fluids the Government may now forcibly collect and analyze. But ultimately, today's decision will reduce the privacy all citizens may enjoy, for, as Justice Holmes understood, principles of law, once bent, do not snap back easily. I dissent.

Justice Kennedy

delivered the opinion of the Court.

We granted certiorari to decide whether it violates the Fourth Amendment for the United States Customs Service to require a urinalysis test from employees who seek transfer or promotion to certain positions.

I

A

The United States Customs Service, a bureau of the Department of the Treasury, is the federal agency responsible for processing persons, carriers, cargo, and mail into the United States, collecting revenue from imports, and enforcing customs and related laws. See United States Customs Service, Customs U. S. A., Fiscal Year 1985, p. 4. An important responsibility of the Service is the interdiction and *660seizure of contraband, including illegal drugs. Ibid. In 1987 alone, Customs agents seized drugs with a retail value of nearly $9 billion. See United States Customs Service, Customs U. S. A., Fiscal Year 1987, p. 40. In the routine discharge of their duties, many Customs employees have direct contact with those who traffic in drugs for profit. Drug import operations, often directed by sophisticated criminal syndicates, United States v. Mendenhall, 446 U. S. 544, 561-562 (1980) (Powell, J., concurring), may be effected by violence or its threat. As a necessary response, many Customs operatives carry and use firearms in connection with their official duties. App. 109.

In December 1985, respondent, the Commissioner of Customs, established a Drug Screening Task Force to explore the possibility of implementing a drug-screening program within the Service. Id., at 11. After extensive research and consultation with experts in the field, the task force concluded that “drug screening through urinalysis is technologically reliable, valid and accurate.” Ibid. Citing this conclusion, the Commissioner announced his intention to require drug tests of employees who applied for, or occupied, certain positions within the Service. Id., at 10-11. The Commissioner stated his belief that “Customs is largely drug-free,” but noted also that “unfortunately no segment of society is immune from the threat of illegal drug use.” Id., at 10. Drug interdiction has become the agency’s primary enforcement mission, and the Commissioner stressed that “there is no room in the Customs Service for those who break the laws prohibiting the possession and use of illegal drugs.” Ibid.

In May 1986, the Commissioner announced implementation of the drug-testing program. Drug tests were made a condition of placement or employment for positions that meet one or more of three criteria. The first is direct involvement in drug interdiction or enforcement of related laws, an activity the Commissioner deemed fraught with obvious dangers to the mission of the agency and the lives of Customs *661agents. Id., at 17, 113. The second criterion is a requirement that the incumbent carry firearms, as the Commissioner concluded that “[pjublic safety demands that employees who carry deadly arms and are prepared to make instant life or death decisions be drug free.” Id., at 113. The third criterion is a requirement for the incumbent to handle “classified” material, which the Commissioner determined might fall into the hands of smugglers if accessible to employees who, by reason of their own illegal drug use, are susceptible to bribery or blackmail. Id., at 114.

After an employee qualifies for a position covered by the Customs testing program, the Service advises him by letter that his final selection is contingent upon successful completion of drug screening. An independent contractor contacts the employee to fix the time and place for collecting the sample. On reporting for the test, the employee must produce photographic identification and remove any outer garments, such as a coat or a jacket, and personal belongings. The employee may produce the sample behind a partition, or in the privacy of a bathroom stall if he so chooses. To ensure against adulteration of the specimen, or substitution of a sample from another person, a monitor of the same sex as the employee remains close at hand to listen for the normal sounds of urination. Dye is added to the toilet water to prevent the employee from using the water to adulterate the sample.

Upon receiving the specimen, the monitor inspects it to ensure its proper temperature and color, places a tamper-proof custody seal over the container, and affixes an identification label indicating the date and the individual’s specimen number. The employee signs a chain-of-custody form, which is initialed by the monitor, and the urine sample is placed in a plastic bag, sealed, and submitted to a laboratory.1

*662The laboratory tests the sample for the presence of marijuana, cocaine, opiates, amphetamines, and phencyclidine. Two tests are used. An initial screening test uses the enzyme-multiplied-immunoassay technique (EMIT). Any specimen that is identified as positive on this initial test must then be confirmed using gas chromatography/mass spectrometry (GC/MS). Confirmed positive results are reported to a “Medical Review Officer,” “[a] licensed physician. . . who has knowledge of substance abuse disorders and has appropriate medical training to interpret and evaluate an individual’s positive test result together with his or her medical history and any other relevant biomedical information.” HHS Reg. § 1.2, *66353 Fed. Reg. 11980 (1988); HHS Reg. §2.4(g), 53 Fed. Reg., at 11983. 'After verifying the positive result, the Medical Review Officer transmits it to the agency.

Customs employees.who test positive for drugs and who can offer no satisfactory explanation are subject to dismissal from the Service. Test results may not, however, be turned over to any other agency, including criminal prosecutors, without the employee’s written consent.

B

Petitioners, a union of federal employees and a union official, commenced this suit in the United States District Court for the Eastern District of Louisiana on behalf of current Customs Service employees who seek covered positions. Petitioners alleged that the Custom Service drug-testing program violated, inter alia, the Fourth Amendment. The District Court agreed. 649 F. Supp. 380 (1986). The court acknowledged “the legitimate governmental interest in a drug-free work place and work force,” but concluded that “the drug testing plan constitutes an overly intrusive policy of searches and seizures without probable cause or reasonable suspicion, in violation of legitimate expectations of privacy.” Id., at 387. The court enjoined the drug-testing program, and ordered the Customs Service not to require drug tests of any applicants for covered positions.

A divided panel of the United States Court of Appeals for the Fifth Circuit vacated the injunction. 816 F. 2d 170 (1987). The court agreed with petitioners that the drug-screening program, by requiring an employee to produce a urine sample for chemical testing, effects a search within the meaning of the Fourth Amendment. The court held further that the searches required by the Commissioner’s directive are reasonable under the Fourth Amendment. It first noted that “[t]he Service has attempted to minimize the intrusiveness of the search” by not requiring visual observation of the act of urination and by affording notice to the employee that *664he will be tested. Id., at 177. The court also considered it significant that the program limits discretion in determining which employees are to be tested, ibid., and noted that the tests are an aspect of the employment relationship, id., at 178.

The court further found that the Government has a strong interest in detecting drug use among employees who meet the criteria of the Customs program. It reasoned that drug use by covered employees casts substantial doubt on their ability to discharge their duties honestly and vigorously, undermining public confidence in the integrity of the Service and concomitantly impairing the Service’s efforts to enforce the drug laws. Ibid. Illicit drug users, the court found, are susceptible to bribery and blackmail, may be tempted to divert for their own use portions of any drug shipments they interdict, and may, if required to carry firearms, “endanger the safety of their fellow agents, as well as their own, when their performance is impaired by drug use.” Ibid. “Considering the nature and responsibilities of the jobs for which applicants are being considered at Customs and the limited scope of the search,” the court stated, “the exaction of consent as a condition of assignment to the new job is not unreasonable.” Id., at 179.

The dissenting judge concluded that the Customs program is not an effective method for achieving the Service’s goals. He argued principally that an employee “given a five day notification of a test date need only abstain from drug use to prevent being identified as a user.” Id., at 184. He noted also that persons already employed in sensitive positions are not subject to the test. Ibid. Because he did not believe the Customs program can achieve its purposes, the dissenting judge found it unreasonable under the Fourth Amendment.

We granted certiorari. 485 U. S. 903 (1988). We now affirm so much of the judgment of the Court of Appeals as upheld the testing of employees directly involved in drug interdiction or required to carry firearms. We vacate the *665judgment to the extent it upheld the testing of applicants for positions requiring the incumbent to handle classified materials, and remand for further proceedings. II

hH

In Skinner v. Railway Labor Executives’ Assn., ante, at 616-618, decided today, we held that federal regulations requiring employees of private railroads to produce urine samples for chemical testing implicate the Fourth Amendment, as those tests invade reasonable expectations of privacy. Our earlier cases have settled that the Fourth Amendment protects individuals from unreasonable searches conducted by the Government, even when the Government acts as an employer, O’Connor v. Ortega, 480 U. S. 709, 717 (1987) (plurality opinion); see id., at 731 (Scalia, J., concurring in judgment), and, in view of our holding in Railway Labor Executives that urine tests are searches, it follows that the Customs Service’s drug-testing program must meet the reasonableness requirement of the Fourth Amendment.

While we have often emphasized, and reiterate today, that a search must be supported, as a general matter, by a warrant issued upon probable cause, see, e. g., Griffin v. Wisconsin, 483 U. S. 868, 873 (1987); United States v. Karo, 468 U. S. 705, 717 (1984), our decision in Railway Labor Executives reaffirms the longstanding principle that neither a warrant nor probable cause, nor, indeed, any measure of individualized suspicion, is an indispensable component of reasonableness in every circumstance. Ante, at 618-624. See also New Jersey v. T. L. O., 469 U. S. 325, 342, n. 8 (1985); United States v. Martinez-Fuerte, 428 U. S. 543, 556-661 (1976). As we note in Railway Labor Executives, our cases establish that where a Fourth Amendment intrusion serves special governmental needs, beyond the normal need for law enforcement, it is necessary to balance the individual’s privacy expectations against the Government’s interests to determine whether it is impractical to require a warrant or *666some level of individualized suspicion in the particular context. Ante, at 619-620.

It is clear that the Customs Service’s drug-testing program is not designed to serve the ordinary needs of law enforcement. Test results may not be used in a criminal prosecution of the employee without the employee’s consent. The purposes of the program are to deter drug use among those eligible for promotion to sensitive positions within the Service and to prevent the promotion of drug users to those positions. These substantial interests, no less than the Government’s concern for safe rail transportation at issue in Railway Labor Executives, present a special need that may justify departure from the ordinary warrant and probable-cause requirements.

A

Petitioners do not contend that a warrant is required by the balance of privacy and governmental interests in this context, nor could any such contention withstand scrutiny. We have recognized before that requiring the Government to procure a warrant for every work-related intrusion “would conflict with ‘the common-sense realization that government offices could not function if every employment decision became a constitutional matter.’” O’Connor v. Ortega, supra, at 722, quoting Connick v. Myers, 461 U. S. 138, 143 (1983). See also 480 U. S., at 732 (Scalia, J., concurring in judgment); New Jersey v. T. L. O., supra, at 340 (noting that “[t]he warrant requirement ... is unsuited to the school environment: requiring a teacher to obtain a warrant before searching a child suspected of an infraction of school rules (or of the criminal law) would unduly interfere with the maintenance of the swift and informal disciplinary procedures needed in the schools”). Even if Customs Service employees are more likely to be familiar with the procedures required to obtain a warrant than most other Government workers, requiring a warrant in this context would serve only to divert valuable agency resources from the Service’s primary mis*667sion. The Customs Service has been entrusted with pressing responsibilities, and its mission would be compromised if it were required to seek search warrants in connection with routine, yet sensitive, employment decisions.

Furthermore, a warrant would provide little or nothing in the way of additional protection of personal privacy. A warrant serves primarily to advise the citizen that an intrusion is authorized by law and limited in its permissible scope and to interpose a neutral magistrate between the citizen and the law enforcement officer “engaged in the often competitive enterprise of ferreting out crime.” Johnson v. United States, 333 U. S. 10, 14 (1948). But in the present context, “the circumstances justifying toxicological testing and the permissible limits of such intrusions are defined narrowly and specifically . . . , and doubtless are well known to covered employees.” Ante, at 622. Under the Customs program, every employee who seeks a transfer to a covered position knows that he must take a drug test, and is likewise aware of the procedures the Service must follow in administering the test. A covered employee is simply not subject “to the discretion of the official in the field.” Camara v. Municipal Court of San Francisco, 387 U. S. 523, 532 (1967). The process becomes automatic when the employee elects to apply for, and thereafter pursue, a covered position. Because the Service does not make a discretionary determination to search based on a judgment that certain conditions are present, there are simply “no special facts for a neutral magistrate to evaluate.” South Dakota v. Opperman, 428 U. S. 364, 383 (1976) (Powell, J., concurring).