OCTOBER TERM, 2000SyllabusCITY OF INDIANAPOLIS ET AL.
v. EDMOND ET AL.CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR THE SEVENTHCIRCUITNo. 99-1030. Argued October 3, 2000-Decided November 28,2000Petitioner city operates vehicle checkpoints on its roads in aneffort to interdict unlawful drugs. Respondents, who were eachstopped at such a checkpoint, filed suit, claiming that theroadblocks violated the Fourth Amendment. The District Court deniedrespondents a preliminary injunction, but the Seventh Circuitreversed, holding that the checkpoints contravened the FourthAmendment.
Held: Because the checkpoint program's primary purpose isindistinguishable from the general interest in crime control, thecheckpoints violate the Fourth Amendment. Pp. 37-48.(a) The rule that a search or seizure is unreasonable under theFourth Amendment absent individualized suspicion of wrongdoing haslimited exceptions. For example, this Court has upheld brief,suspicionless seizures at a fixed checkpoint designed to interceptillegal aliens,
United States v.
Martinez-Fuerte,428 U. S. 543,and at a sobriety checkpoint aimed at removing drunk drivers fromthe road,
Michigan Dept. of State Police v.
Sitz,496 U. S. 444.The Court has also suggested that a similar roadblock to verifydrivers' licenses and registrations would be permissible to serve ahighway safety interest.
Delaware v.
Prouse,440 U. S. 648, 663.However, the Court has never approved a checkpoint program whoseprimary purpose was to detect evidence of ordinary criminalwrongdoing. Pp. 37-40.(b) The latter purpose is what principally distinguishes thecheckpoints at issue from those the Court has previously approved,which were designed to serve purposes closely related to theproblems of policing the border or the necessity of ensuringroadway safety. Petitioners state that the
Sitz and
Martinez-Fuerte checkpoints had the same ultimate purpose ofarresting those suspected of committing crimes. Securing the borderand apprehending drunken drivers are law enforcement activities,and authorities employ arrests and criminal prosecutions to pursuethese goals. But if this case were to rest at such a high level ofgenerality, there would be little check on the authorities' abilityto construct roadblocks for almost any conceivable law enforcementpurpose. The checkpoint program is also not justified by the severeand intractable nature of the drug problem. The gravity of thethreat alone
33cannot be dispositive of questions concerning what means lawenforcement may employ to pursue a given purpose. Rather, indetermining whether individualized suspicion is required, the Courtmust consider the nature of the interests threatened and theirconnection to the particular law enforcement practices at issue.Nor can the checkpoints' purpose be rationalized in terms of ahighway safety concern similar to that in
Sitz, or merelylikened to the antismuggling purpose in
MartinezFuerte.Neither
Whren v.
United States,517 U. S. 806, nor
Bond v.
United States,529 U. S. 334, precludesan inquiry into the checkpoint program's purposes. And if theprogram could be justified by its lawful secondary purposes ofkeeping impaired motorists off the road and verifying licenses andregistrations, authorities would be able to establish checkpointsfor virtually any purpose so long as they also included a licenseor sobriety check. That is why the Court must determine the primarypurpose of the checkpoint program. This holding does not alter theconstitutional status of the checkpoints approved in
Sitzand
Martinez-Fuerte, or the type of checkpoint suggested in
Prouse. It also does not affect the validity of bordersearches or searches in airports and government buildings, wherethe need for such measures to ensure public safety can beparticularly acute. Nor does it impair police officers' ability toact appropriately upon information that they properly learn duringa checkpoint stop justified by a lawful primary purpose. Finally,the purpose inquiry is to be conducted only at the programmaticlevel and is not an invitation to probe the minds of individualofficers acting at the scene. Pp. 40-48.
183 F.3d659, affirmed.O'CONNOR, J., delivered the opinion of the Court, in whichSTEVENS, KENNEDY, SOUTER, GINSBURG, and BREYER, JJ., joined.REHNQUIST, C. J., filed a dissenting opinion, in which THOMAS, J.,joined, and in which SCALIA, J., joined as to Part I,
post,p. 48. THOMAS, J., filed a dissenting opinion,
post, p.56.A. Scott Chinn argued the cause for petitioners. With him on thebriefs were Anthony W Overholt, Matthew R. Gutwein, and Thomas M.Fisher.Patricia A. Millett argued the cause for the United States asamicus curiae urging reversal. With her on the brief were SolicitorGeneral Waxman, Assistant Attorney General Robinson, and DeputySolicitor General Dreeben.
34Kenneth J. Falk argued the cause for respondents. With him onthe brief were Jacquelyn E. Bowie, Sean C. Lemieux, and Steven R.Shapiro. *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 highwaycheckpoints for the purposes of combating drunk driving andintercepting illegal immigrants were constitutional. We nowconsider the constitutionality of a highway checkpoint programwhose primary purpose is the discovery and interdiction of illegalnarcotics.IIn August 1998, the city of Indianapolis began to operatevehicle checkpoints on Indianapolis roads in an effort to interdictunlawful drugs. The city conducted six such roadblocks betweenAugust and November that year, stopping*Briefs of
amici curiae urging reversal were filed forthe State of Kansas et al. by
Carla J.
Stovall,Attorney General of Kansas,
Stephen R. McAllister, StateSolicitor,
Jared S.
Maag, Assistant Attorney General,and
John M. Bailey, Chief State's Attorney of Connecticut,and by the Attorneys General for their respective States asfollows:
Bill Pryor of Alabama,
Janet Napolitano ofArizona,
Mark Pryor of Arkansas,
Bill Lockyer ofCalifornia,
Robert A. Butterworth of Florida,
James E.Ryan of Illinois,
Karen M. Freeman-Wilson of Indiana,
Thomas J.
Miller of Iowa,
Michael C.
Moore of Mississippi,
Don Stenberg of Nebraska,
WA. Drew Edmondson of Oklahoma,
Jan Graham of Utah, and
Mark L. Earley of Virginia; for the National League ofCities et al. by
Richard Ruda and
James I. Crowley;and for the Washington Legal Foundation et al. by
Daniel J.
Popeo.Briefs of
amici curiae urging affirmance were filed forthe National Association of Criminal Defense Lawyers et al. by
Wesley MacNeil Oliver and
Barbara Bergman; and forthe Rutherford Institute by
John W Whitehead and
StevenH. Aden.Wayne W Schmidt, James P. Manak, Richard Weintraub, and BernardJ. Farber filed a brief for Americans for Effective LawEnforcement, Inc., et al. as amici curiae.
351,161 vehicles and arresting 104 motorists. Fifty-five arrestswere for drug-related crimes, while 49 were for offenses unrelatedto drugs. Edmond v. Goldsmith,
183 F.3d659, 661 (CA7 1999). The overall "hit rate" of the program wasthus approximately nine percent.The parties stipulated to the facts concerning the operation ofthe checkpoints by the Indianapolis Police Department (IPD) forpurposes of the preliminary injunction proceedings institutedbelow. At each checkpoint location, the police stop a predeterminednumber of vehicles. Approximately 30 officers are stationed at thecheckpoint. Pursuant to written directives issued by the chief ofpolice, at least one officer approaches the vehicle, advises thedriver that he or she is being stopped briefly at a drugcheckpoint, and asks the driver to produce a license andregistration. The officer also looks for signs of impairment andconducts an open-view examination of the vehicle from the outside.A narcoticsdetection dog walks around the outside of each stoppedvehicle.The directives instruct the officers that they may conduct asearch only by consent or based on the appropriate quantum ofparticularized suspicion. The officers must conduct each stop inthe same manner until particularized suspicion develops, and theofficers have no discretion to stop any vehicle out of sequence.The city agreed in the stipulation to operate the checkpoints insuch a way as to ensure that the total duration of each stop,absent reasonable suspicion or probable cause, would be fiveminutes 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 thecheckpoints. According to Sergeant DePew, checkpoint locations areselected weeks in advance based on such considerations as areacrime statistics and traffic flow. The checkpoints are generallyoperated during daylight hours and are identified with lightedsigns reading, "'NARCOTICS
36CHECKPOINT __ MILE AHEAD, NARCOTICS K-9 IN USE, BE PREPARED TOSTOP.'" App. to Pet. for Cert. 57a. Once a group of cars has beenstopped, other traffic proceeds without interruption until all thestopped cars have been processed or diverted for furtherprocessing. Sergeant DePew also stated that the average stop for avehicle not subject to further processing lasts two to threeminutes or less.Respondents James Edmond and J oell Palmer were each stopped ata narcotics checkpoint in late September 1998. Respondents thenfiled a lawsuit on behalf of themselves and the class of allmotorists who had been stopped or were subject to being stopped inthe future at the Indianapolis drug checkpoints. Respondentsclaimed that the roadblocks violated the Fourth Amendment of theUnited States Constitution and the search and seizure provision ofthe Indiana Constitution. Respondents requested declaratory andinjunctive relief for the class, as well as damages and attorney'sfees for themselves.Respondents then moved for a preliminary injunction.Although respondents alleged that the officers who stopped themdid not follow the written directives, they agreed to thestipulation concerning the operation of the checkpoints forpurposes of the preliminary injunction proceedings. The partiesalso stipulated to certification of the plaintiff class. The UnitedStates District Court for the Southern District of Indiana agreedto class certification and denied the motion for a preliminaryinjunction, holding that the checkpoint program did not violate theFourth Amendment. Edmond v. Goldsmith, 38 F. Supp. 2d 1016 (1998).A divided panel of the United States Court of Appeals for theSeventh Circuit reversed, holding that the checkpoints contravenedthe Fourth Amendment.
183 F.3d659 (1999). The panel denied rehearing. We granted certiorari,528 U. S. 1153 (2000), and now affirm.
37IIThe Fourth Amendment requires that searches and seizures bereasonable. A search or seizure is ordinarily unreasonable in theabsence of individualized suspicion of wrongdoing.
Chandlerv.
Miller,520U. 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 inwhich the usual rule does not apply. For example, we have upheldcertain regimes of suspicionless searches where the program wasdesigned to serve "special needs, beyond the normal need for lawenforcement." See,
e. g., Vernonia School Dist. J,7J 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 seekingtransfer 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 trainaccidents or found to be in violation of particular safetyregulations). We have also allowed searches for certainadministrative purposes without particularized suspicion ofmisconduct, 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-damagedpremises 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 withcity housing code).We have also upheld brief, suspicionless seizures of motoristsat a fixed Border Patrol checkpoint designed to intercept illegalaliens,
Martinez-Fuerte, supra, and at a sobriety checkpointaimed at removing drunk drivers from the road,
Michigan Dept. ofState Police v.
Sitz,496 U. S. 444 (1990). Inaddition, in
Delaware v.
Prouse,440 U. S. 648, 663(1979),
38we suggested that a similar type of roadblock with the purposeof verifying drivers' licenses and vehicle registrations would bepermissible. In none of these cases, however, did we indicateapproval of a checkpoint program whose primary purpose was todetect evidence of ordinary criminal wrongdoing.In
Martinez-Fuerte, we entertained Fourth Amendmentchallenges to stops at two permanent immigration checkpointslocated on major United States highways less than 100 miles fromthe Mexican border. We noted at the outset the particular contextin which the constitutional question arose, describing in somedetail the "formidable law enforcement problems" posed by thenorthbound tide of illegal entrants into the United States. 428 U.S., at 551-554. These problems had also been the focus of severalearlier cases addressing the constitutionality of other BorderPatrol 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 favorof the Government's interests in policing the Nation's borders. 428U. S., at 561-564. In so finding, we emphasized the difficulty ofeffectively containing illegal immigration at the border itself.
Id., at 556. We also stressed the impracticality of theparticularized study of a given car to discern whether it wastransporting illegal aliens, as well as the relatively modestdegree of intrusion entailed by the stops.
Id., at556-564.Our subsequent cases have confirmed that considerationsspecifically related to the need to police the border were asignificant factor in our
Martinez-Fuerte decision. Forexample, in
United States v.
Montoya de Hernandez,473 U. S. 531,538(1985), we counted
Martinez-Fuerte as one of a number ofFourth Amendment cases that "reflect longstanding concern for theprotection 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 andserved a border control function made necessary by the difficultyof guarding the border's entire length. See
Martinez-Fuerte,supra, at 556.In
Sitz, we evaluated the constitutionality of a Michiganhighway sobriety checkpoint program. The
Sitz checkpointinvolved brief, suspicionless stops of motorists so that policeofficers could detect signs of intoxication and remove impaireddrivers from the road. 496 U. S., at 447-448. Motorists whoexhibited signs of intoxication were diverted for a license andregistration check and, if warranted, further sobriety tests.
Id., at 447. This checkpoint program was clearly aimed atreducing the immediate hazard posed by the presence of drunkdrivers on the highways, and there was an obvious connectionbetween the imperative of highway safety and the law enforcementpractice at issue. The gravity of the drunk driving problem and themagnitude of the State's interest in getting drunk drivers off theroad weighed heavily in our determination that the program wasconstitutional. See id., at 451.In
Prouse, we invalidated a discretionary, suspicionlessstop for a spot check of a motorist's driver's license and vehicleregistration. The officer's conduct in that case wasunconstitutional primarily on account of his exercise of"standardless and unconstrained discretion." 440 U. S., at 661. Wenonetheless acknowledged the States' "vital interest in ensuringthat only those qualified to do so are permitted to operate motorvehicles, that these vehicles are fit for safe operation, and hencethat licensing, registration, and vehicle inspection requirementsare being observed."
Id., at 658. Accordingly, we suggestedthat "[q]uestioning of all oncoming traffic at roadblock-typestops" would be a lawful means of serving this interest in highwaysafety.
Id., at 663.We further indicated in
Prouse that we considered thepurposes of such a hypothetical roadblock to be distinct from ageneral purpose of investigating crime. The State prof-
40fered the additional interests of "the apprehension of stolenmotor vehicles and of drivers under the influence of alcohol ornarcotics" in its effort to justify the discretionary spot check.
Id., at 659, n. 18. We attributed the entirety of the latterinterest to the State's interest in roadway safety.
Ibid. Wealso noted that the interest in apprehending stolen vehicles may bepartly subsumed by the interest in roadway safety.
Ibid. Weobserved, however, that "[t]he remaining governmental interest incontrolling automobile thefts is not distinguishable from thegeneral interest in crime control."
Ibid. Not only does thecommon thread of highway safety thus run through
Sitz and
Prouse, but
Prouse itself reveals a difference in theFourth Amendment significance of highway safety interests and thegeneral interest in crime control.IIIIt is well established that a vehicle stop at a highwaycheckpoint effectuates a seizure within the meaning of the FourthAmendment. See,
e. g., Sitz, supra, at 450. The fact thatofficers walk a narcotics-detection dog around the exterior of eachcar at the Indianapolis checkpoints does not transform the seizureinto a search. See
United States v.
Place,462 U. S. 696, 707(1983). Just as in
Place, an exterior sniff of an automobiledoes not require entry into the car and is not designed to discloseany information other than the presence or absence of narcotics.See
ibid. Like the dog sniff in
Place, a sniff by adog that simply walks around a car is "much less intrusive than atypical search."
Ibid. Cf.
United States v.
Turpin,920 F.2d1377, 1385
(CA8 1990). Rather, what principallydistinguishes these checkpoints from those we have previouslyapproved is their primary purpose.As petitioners concede, the Indianapolis checkpoint programunquestionably has the primary purpose of interdicting illegalnarcotics. In their stipulation of facts, the parties repeatedlyrefer to the checkpoints as "drug checkpoints" and
41describe them as "being operated by the City of Indianapolis inan effort to interdict unlawful drugs in Indianapolis." App. toPet. for Cert. 51a-52a. In addition, the first document attached tothe parties' stipulation is entitled "DRUG CHECKPOINT CONTACTOFFICER DIRECTIVES BY ORDER OF THE CHIEF OF POLICE."
Id., at53a. These directives instruct officers to "[a]dvise the citizenthat they are being stopped briefly at a drug checkpoint."
Ibid. The second document attached to the stipulation isentitled "1998 Drug Road Blocks" and contains a statisticalbreakdown of information relating to the checkpoints conducted.
Id., at 55a. Further, according to Sergeant DePew, thecheckpoints are identified with lighted signs reading, "'NARCOTICSCHECKPOINT __ MILE AHEAD, NARCOTICS K-9 IN USE, BE PREPARED TOSTOP.'"
Id., at 57a. Finally, both the District Court andthe Court of Appeals recognized that the primary purpose of theroadblocks is the interdiction of narcotics. 38 F. Supp. 2d, at1026 (noting that both parties "stress the primary purpose of theroadblocks as the interdiction of narcotics" and that "[t]he IPDhas made it clear that the purpose for its checkpoints is tointerdict narcotics traffic"); 183 F. 3d, at 665 (observing that"the City concedes that its proximate goal is to catch drugoffenders").We have never approved a checkpoint program whose primarypurpose was to detect evidence of ordinary criminal wrongdoing.Rather, our checkpoint cases have recognized only limitedexceptions to the general rule that a seizure must be accompaniedby some measure of individualized suspicion. We suggested in
Prouse that we would not credit the "general interest incrime control" as justification for a regime of suspicionlessstops. 440 U. S., at 659, n. 18. Consistent with this suggestion,each of the checkpoint programs that we have approved was designedprimarily to serve purposes closely related to the problems ofpolicing the border or the necessity of ensuring roadway safety.Because the
42primary purpose of the Indianapolis narcotics checkpoint programis to uncover evidence of ordinary criminal wrongdoing, the programcontravenes the Fourth Amendment.Petitioners propose several ways in which the narcoticsdetectionpurpose of the instant checkpoint program may instead resemble theprimary purposes of the checkpoints in
Sitz and
Martinez-Fuerte. Petitioners state that the checkpoints inthose cases had the same ultimate purpose of arresting thosesuspected of committing crimes. Brief for Petitioners 22. Securingthe border and apprehending drunk drivers are, of course, lawenforcement activities, and law enforcement officers employ arrestsand 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 ofgenerality, there would be little check on the ability of theauthorities to construct roadblocks for almost any conceivable lawenforcement purpose. Without drawing the line at roadblocksdesigned primarily to serve the general interest in crime control,the Fourth Amendment would do little to prevent such intrusionsfrom becoming a routine part of American life.Petitioners also emphasize the severe and intractable nature ofthe drug problem as justification for the checkpoint program. Brieffor Petitioners 14-17, 31. There is no doubt that traffic inillegal narcotics creates social harms of the first magnitude. Cf.
Von Raab, 489 U. S., at 668. The law enforcement problemsthat the drug trade creates likewise remain daunting and complex,particularly in light of the myriad forms of spin-off crime that itspawns. Cf.
M on
toya de Hernandez, 473 U. S., at 538.The same can be said of various other illegal activities, if onlyto a lesser degree. But the gravity of the threat alone cannot bedispositive of questions concerning what means law enforcementofficers may employ to pursue a given purpose. Rather, indetermining whether individualized suspicion is required, we mustconsider the nature of the interests threatened and their con-
43nection to the particular law enforcement practices at issue. Weare particularly reluctant to recognize exceptions to the generalrule of individualized suspicion where governmental authoritiesprimarily pursue their general crime control ends.Nor can the narcotics-interdiction purpose of the checkpoints berationalized in terms of a highway safety concern similar to thatpresent in
Sitz. The detection and punishment of almost anycriminal offense serves broadly the safety of the community, andour streets would no doubt be safer but for the scourge of illegaldrugs. Only with respect to a smaller class of offenses, however,is society confronted with the type of immediate, vehicle-boundthreat to life and limb that the sobriety checkpoint in
Sitzwas designed to eliminate.Petitioners also liken the anticontraband agenda of theIndianapolis checkpoints to the antismuggling purpose of thecheckpoints in
Martinez-Fuerte. Brief for Petitioners 1516.Petitioners cite this Court's conclusion in
MartinezFuertethat the flow of traffic was too heavy to permit "particularizedstudy of a given car that would enable it to be identified as apossible carrier of illegal aliens," 428 U. S., at 557, and claimthat this logic has even more force here. The problem with thisargument is that the same logic prevails any time a vehicle isemployed to conceal contraband or other evidence of a crime. Thistype of connection to the roadway is very different from the closeconnection to roadway safety that was present in
Sitz and
Prouse. Further, the Indianapolis checkpoints are farremoved from the border context that was crucial in
Martinez-Fuerte. While the difficulty of examining eachpassing car was an important factor in validating the lawenforcement technique employed in
Martinez-Fuerte, thisfactor alone cannot justify a regime of suspicionless searches orseizures. Rather, we must look more closely at the nature of thepublic interests that such a regime is designed principally toserve.
44The primary purpose of the Indianapolis narcotics checkpoints isin the end to advance "the general interest in crime control,"
Prouse, 440 U. S., at 659, n. 18. We decline to suspend theusual requirement of individualized suspicion where the police seekto employ a checkpoint primarily for the ordinary enterprise ofinvestigating crimes. We cannot sanction stops justified only bythe generalized and everpresent possibility that interrogation andinspection may reveal that any given motorist has committed somecrime.Of course, there are circumstances that may justify a lawenforcement checkpoint where the primary purpose would otherwise,but for some emergency, relate to ordinary crime control. Forexample, as the Court of Appeals noted, the Fourth Amendment wouldalmost certainly permit an appropriately tailored roadblock set upto thwart an imminent terrorist attack or to catch a dangerouscriminal who is likely to flee by way of a particular route. See183 F. 3d, at 662663. The exigencies created by these scenarios arefar removed from the circumstances under which authorities mightsimply stop cars as a matter of course to see if there just happensto be a felon leaving the jurisdiction. While we do not limit thepurposes that may justify a checkpoint program to any rigid set ofcategories, we decline to approve a program whose primary purposeis ultimately indistinguishable from the general interest in crimecontrol.l1 THE CHIEF JUSTICE'S dissent erroneously characterizes ouropinion as resting on the application of a "non-law-enforcementprimary purpose test."
Post, at 53. Our opinion nowheredescribes the purposes of the
Sitz and
Martinez-Fuerte checkpoints as being "not primarily relatedto criminal law enforcement."
Post, at 50. Rather, ourjudgment turns on the fact that the primary purpose of theIndianapolis checkpoints is to advance the general interest incrime control.THE CHIEF JUSTICE'S dissent also erroneously characterizes ouropinion as holding that the "use of a drug-sniffing dog ... annulswhat is otherwise plainly constitutional under our Fourth Amendmentjurisprudence."
Post, at 48. Again, the constitutionaldefect of the program is that its primary purpose is to advance thegeneral interest in crime control.
45Petitioners argue that our prior cases preclude an inquiry intothe 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), tosupport the proposition that "where the government articulates andpursues a legitimate interest for a suspicionless stop, courtsshould not look behind that interest to determine whether thegovernment's 'primary purpose' is valid." Brief for Petitioners 34;see also id., at 9. These cases, however, do not control theinstant situation.In
Whren, we held that an individual officer's subjectiveintentions are irrelevant to the Fourth Amendment validity of atraffic stop that is justified objectively by probable cause tobelieve that a traffic violation has occurred. 517 U. S., at810-813. We observed that our prior cases "foreclose any argumentthat the constitutional reasonableness of traffic stops depends onthe actual motivations of the individual officers involved."
Id., at 813. In so holding, we expressly distinguished caseswhere we had addressed the validity of searches conducted in theabsence 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 generalrummaging 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 purelyinvestigative purpose were relevant to the validity of an inventorysearch), and
Burger, 482 U. S., at 716-717, n. 27 (observingthat a valid administrative inspection conducted with neither awarrant nor probable cause did not appear to be a pretext forgathering evidence of violations of the penal laws)).
Whren therefore reinforces the principle that, while"[sJubjective intentions play no role in ordinary, probablecauseFourth Amendment analysis," 517 U. S., at 813, programmaticpurposes may be relevant to the validity of Fourth Amendmentintrusions undertaken pursuant to a
46general scheme without individualized SuspICIOn. Accordingly,
Whren does not preclude an inquiry into programmatic purposein 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 SanFrancisco,387 U.S. 523 (1967). It likewise does not preclude an inquiry intoprogrammatic purpose here.Last Term in
Bond, we addressed the question whether alaw enforcement officer violated a reasonable expectation ofprivacy in conducting a tactile examination of carry-on luggage inthe overhead compartment of a bus. In doing so, we simply notedthat the principle of
Whren rendered the subjective intentof 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 Amendmentanalysis,"
Whren, supra, at 813, nothing in
Bondsuggests that we would extend the principle of
Whren to allsituations where individualized suspicion was lacking. Rather,subjective intent was irrelevant in
Bond because the inquirythat our precedents required focused on the objective effects ofthe actions of an individual officer. By contrast, our casesdealing with intrusions that occur pursuant to a general schemeabsent individualized suspicion have often required an inquiry intopurpose at the programmatic level.Petitioners argue that the Indianapolis checkpoint program isjustified by its lawful secondary purposes of keeping impairedmotorists off the road and verifying licenses and registrations.Brief for Petitioners 31-34. If this were the case, however, lawenforcement authorities would be able to establish checkpoints forvirtually any purpose so long as they also included a license orsobriety check. For this reason, we examine the available evidenceto determine the primary purpose of the checkpoint program. Whilewe recognize the challenges inherent in a purpose inquiry,courts
47routinely engage in this enterprise in many areas ofconstitutional jurisprudence as a means of sifting abusivegovernmental conduct from that which is lawful. Cf. 183 F. 3d, at665. As a result, a program driven by an impermissible purpose maybe proscribed while a program impelled by licit purposes ispermitted, even though the challenged conduct may be outwardlysimilar. While reasonableness under the Fourth Amendment ispredominantly an objective inquiry, our special needs andadministrative search cases demonstrate that purpose is oftenrelevant when suspicionless intrusions pursuant to a general schemeare at issue.2It goes without saying that our holding today does nothing toalter the constitutional status of the sobriety and bordercheckpoints that we approved in
Sitz and
Martinez-Fuerte, or of the type of traffic checkpoint thatwe suggested would be lawful in
Prouse. Theconstitutionality of such checkpoint programs still depends on abalancing of the competing interests at stake and the effectivenessof the program. See
Sitz, 496 U. S., at 450-455;
Martinez-Fuerte, 428 U. S., at 556-564. When law enforcementauthorities pursue primarily general crime control purposes atcheckpoints such as here, however, stops can only be justified bysome quantum of individualized suspicion.Our holding also does not affect the validity of border searchesor searches at places like airports and government2 Because petitioners concede that the primary purpose of theIndianapolis checkpoints is narcotics detection, we need not decidewhether the State may establish a checkpoint program with theprimary purpose of checking licenses or driver sobriety and asecondary purpose of interdicting narcotics. Specifically, weexpress no view on the question whether police may expand the scopeof a license or sobriety checkpoint seizure in order to detect thepresence of drugs in a stopped car. Cf.
New Jersey v.
T.L. Q,
469 U. S.325, 341 (1985) (search must be "'reasonably related in scopeto the circumstances which justified the interference in the firstplace'" (quoting
Terry v.
Ohio,392 U. S. 1, 20 (1968)));
Michigan v.
Clifford,
464 U. S. 287, 294-295(1984) (plurality opinion).
48buildings, where the need for such measures to ensure publicsafety can be particularly acute. Nor does our opinion speak toother intrusions aimed primarily at purposes beyond the generalinterest in crime control. Our holding also does not impair theability of police officers to act appropriately upon informationthat they properly learn during a checkpoint stop justified by alawful primary purpose, even where such action may result in thearrest of a motorist for an offense unrelated to that purpose.Finally, we caution that the purpose inquiry in this context is tobe conducted only at the programmatic level and is not aninvitation to probe the minds of individual officers acting at thescene. Cf.
Whren, supra.Because the primary purpose of the Indianapolis checkpointprogram is ultimately indistinguishable from the general interestin crime control, the checkpoints violate the Fourth Amendment. Thejudgment of the Court of Appeals is, accordingly, affirmed.It is so ordered.CHIEF JUSTICE REHNQUIST, with whom JUSTICE THOMAS joins, andwith whom JUSTICE SCALIA joins as to Part I, dissenting.The State's use of a drug-sniffing dog, according to the Court'sholding, annuls what is otherwise plainly constitutional under ourFourth Amendment jurisprudence: brief, standardized,discretionless, roadblock seizures of automobiles, seizures whicheffectively serve a weighty state interest with only minimalintrusion on the privacy of their occupants. Because these seizuresserve the State's accepted and significant interests of preventingdrunken driving and checking for driver's licenses and vehicleregistrations, and because there is nothing in the record toindicate that the addition of the dog sniff lengthens theseotherwise legitimate seizures, I dissent.
49IAs it is nowhere to be found in the Court's opinion, I beginwith blackletter roadblock seizure law. "The principal protectionof Fourth Amendment rights at checkpoints lies in appropriatelimitations 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 Amendmentif 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 "aweighing of the gravity of the public concerns served by theseizure, the degree to which the seizure advances the publicinterest, and the severity of the interference with individualliberty."
Id., at 50-51.We first applied these principles in
Martinez-Fuerte,supra, which approved highway checkpoints for detecting illegalaliens. In
Martinez-Fuerte, we balanced the United States'formidable interest in checking the flow of illegal immigrantsagainst the limited "objective" and "subjective" intrusion on themotorists. The objective intrusion-the stop itself,l the briefquestioning of the occupants, and the visual inspection of thecar-was considered "limited" because "[n]either the vehicle nor itsoccupants [were] searched."
Id., at 558. Likewise, thesubjective intrusion, or the fear and surprise engendered inlaw-abiding motorists by the nature of the stop, was found to beminimal because the "regularized manner in which [the] establishedcheckpoints [were] operated [was] visible evidence, reassuring tolaw-abiding motorists, that the stops [were] duly authorized andbelieved to serve the public interest."
Id., at 559. Indeed,the standardized operation of the roadblocks was viewed as1 The record from one of the consolidated cases indicated thatthe stops lasted between three and five minutes. See
UnitedStates v.
MartinezFuerte,428 U. S. 543, 546-547(1976).
50markedly different from roving patrols, where the unbridleddiscretion of officers in the field could result in unlimitedinterference with motorists' use of the highways. Cf.
UnitedStates v.
Brignoni-Ponce,422 U. S. 873 (1975). Andalthough the decision in
Martinez-Fuerte did not turn on thecheckpoints' effectiveness, the record in one of the consolidatedcases demonstrated that illegal aliens were found in 0.12 percentof the stopped vehicles. See 428 U. S., at 554.In
Michigan Dept. of State Police v.
Sitz,496 U. S. 444(1990), we upheld the State's use of a highway sobriety checkpointafter applying the framework set out in
Martinez-Fuerte,supra, and
Brown v.
Texas, supra. There, werecognized the gravity of the State's interest in curbing drunkendriving and found the objective intrusion of the approximately25-second seizure to be "slight." 496 U. S., at 451. Turning to thesubjective intrusion, we noted that the checkpoint was selectedpursuant to guidelines and was operated by uniformed officers. Seeid., at 453. Finally, we concluded that the program effectivelyfurthered the State's interest because the checkpoint resulted inthe arrest of two drunk drivers, or 1.6 percent of the 126 driversstopped. See id., at 455-456.This case follows naturally from
Martinez-Fuerte and
Sitz.Petitioners acknowledge that the "primary purpose" of theseroadblocks is to interdict illegal drugs, but this fact should notbe controlling. Even accepting the Court's conclusion that thecheckpoints at issue in
Martinez-Fuerte and
Sitz werenot primarily related to criminal law enforcement,2 the2 This gloss, see
ante, at 38-40, 41-43, is not at allobvious. The respondents in
Martinez-Fuerte were criminallyprosecuted for illegally transporting aliens, and the Courtexpressly noted that "[i]nterdicting the flow of illegal entrantsfrom Mexico poses formidable law enforcement problems." 428 U. S.,at 552. And the
Sitz Court recognized that if an "officer'sobservations suggest that the driver was intoxicated, an arrestwould be made." 496 U. S., at 447. But however persuasive thedistinction, the Court's opinion does not impugn the continuingvalidity of
Martinez-Fuerte and
Sitz. See
ante, at 47.
51question whether a law enforcement purpose could support aroadblock seizure is not presented in this case. The District Courtfound that another "purpose of the checkpoints is to check driver'slicenses 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 ofroadblocks to look for signs of impairment was validated by
Sitz, and the use of roadblocks to check for driver'slicenses and vehicle registrations was expressly recognized in
Delaware v.
Prouse,440 U. S. 648, 663(1979).3 That the roadblocks serve these legitimate state interestscannot be seriously disputed, as the 49 people arrested foroffenses unrelated to drugs can attest.
Edmond v.
Goldsmith,183 F.3d659, 661
(CA7 1999). And it would be speculative toconclude-given the District Court's findings, the writtendirectives, and the actual arrests-that petitioners would not haveoperated these roadblocks but for the State's interest ininterdicting drugs.Because of the valid reasons for conducting these roadblockseizures, it is constitutionally irrelevant that petitioners alsohoped to interdict drugs. In
Whren v.
United States,517 U. S. 806(1996), we held that an officer's subjective intent would notinvalidate an otherwise objectively justifiable stop of anautomobile. The reasonableness of an officer's discretionarydecision to stop an automobile, at issue in
Whren, turns onwhether there is probable cause to believe that a traffic violationhas occurred. The reasonableness of highway checkpoints, at issuehere, turns on whether they effectively serve a significant stateinterest with minimal intrusion on motorists. The stop in
Whren was objectively reasonable because the police officershad witnessed traffic violations; so too the roadblocks here areobjectively3 Several Courts of Appeals have upheld roadblocks that checkfor driver's licenses and vehicle registrations. See,
e. g.,
United States v.
Galindo-Gonzales,142 F.3d1217 (CAlO 1998);
United States v.
McFayden,865 F.2d1306 (CADC 1989).
52reasonable because they serve the substantial interests ofpreventing drunken driving and checking for driver's licenses andvehicle registrations with minimal intrusion on motorists.Once the constitutional requirements for a particular seizureare satisfied, the subjective expectations of those responsible forit, be it police officers or members of a city council, areirrelevant. Cf.
Scott v.
United States,436 U. S. 128, 136 (1978)("Subjective intent alone ... does not make otherwise lawfulconduct illegal or unconstitutional"). It is the objective effectof the State's actions on the privacy of the individual thatanimates the Fourth Amendment. See
Bond v.
UnitedStates,529 U. S.334, 338, n. 2 (2000) (applying
Whren to determine if anofficer's conduct amounted to a "search" under the Fourth Amendmentbecause "the issue is not his state of mind, but the objectiveeffect of his actions"). Because the objective intrusion of a validseizure does not turn upon anyone's subjective thoughts, neithershould our constitutional analysis.4With these checkpoints serving two important state interests,the remaining prongs of the
Brown v.
Texas balancingtest are easily met. The seizure is objectively reasonable as itlasts, on average, two to three minutes and does not involve asearch. App. to Pet. for Cert. 57a. The subjective intrusion islikewise limited as the checkpoints are clearly marked and operatedby uniformed officers who are directed to stop every vehicle in thesame 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 doesnot require physical intrusion of the object being sniffed and itdoes not ex-4 Of course we have looked to the purpose of the program inanalyzing the constitutionality of certain suspicionless searches.As discussed in Part II,
infra, that doctrine has never beenapplied to seizures of automobiles.
53pose anything other than the contraband items.
UnitedStates v.
Place,462 U. S. 696, 706-707(1983). And there is nothing in the record to indicate that the dogsniff lengthens the stop. Finally, the checkpoints' success rate-49arrests for offenses unrelated to drugs-only confirms the State'slegitimate interests in preventing drunken driving and ensuring theproper licensing of drivers and registration of their vehicles. 183F. 3d, at 661.5These stops effectively serve the State's legitimate interests;they are executed in a regularized and neutral manner; and theyonly minimally intrude upon the privacy of the motorists. Theyshould therefore be constitutional.IIThe Court, unwilling to adopt the straightforward analysis thatthese precedents dictate, adds a new non-Iawenforcement primarypurpose test lifted from a distinct area of Fourth Amendmentjurisprudence relating to the
searches of homes andbusinesses. As discussed above, the question that the Court answersis not even posed in this case given the accepted reasons for theseizures. But more fundamentally, whatever sense anon-law-enforcement primary purpose test may make in the searchsetting, it is ill suited to brief roadblock seizures, where wehave consistently looked at "the scope of the stop" in assessing aprogram's constitutionality.
Martinez-Fuerte, 428 U. S., at567.We have already rejected an invitation to apply thenonlaw-enforcement primary purpose test that the Court now finds soindispensable. The respondents in
Sitz argued that the
Brown v.
Texas balancing test was not the "propermethod of analysis" with regards to roadblock seizures:
"Respondents argue that there must be a showing of some specialgovernmental need 'beyond the normal
5 Put in statistical terms, 4.2 percent of the 1,161 motoristsstopped were arrested for offenses unrelated to drugs.
54need' for criminal law enforcement before a balancing analysisis appropriate, and that [the State] ha[s] demonstrated no suchspecial need.
"But it is perfectly plain from a reading of[TreasuryEmployees v.]Von Raab[,489 U. S. 656 (1989)],which cited and discussed with approval our earlier decision inUnited States v.Martinez-Fuerte,428 U. S. 543 (1976),that it was in no way designed to repudiate our prior cases dealingwith police stops of motorists on public highways.Martinez-Fuerte, supra, which utilized a balancing analysisin approving highway checkpoints for detecting illegal aliens, andBrown v.Texas, supra, are the relevant authoritieshere." 496 U. S., at 449, 450.
Considerations of
stare decisis aside, the "perfectlyplain" reason for not incorporating the "special needs" test in ourroadblock seizure cases is that seizures of automobiles "dealneither with searches nor with the sanctity of private dwellings,ordinarily afforded the most stringent Fourth Amendmentprotection."
Martinez-Fuerte, supra, at 561.The "special needs" doctrine, which has been used to upholdcertain suspicionless searches performed for reasons unrelated tolaw enforcement, is an exception to the general rule that a searchmust 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 andCounty of San Francisco,387 U. S. 523 (1967)(home administrative search). The doctrine permits intrusions intoa person's body and home, areas afforded the greatest FourthAmendment protection. But there were no such intrusions here."[O]ne's expectation of privacy in an automobile and of freedomin its operation are significantly different from the traditionalexpectation of privacy and freedom in one's residence."
Martinez-Fuerte, supra, at 561. This is because"[a]utomobiles, unlike homes, are subjected to pervasive andcontinuing governmental regulation and controls."
South
55Dakota v.
Opperman,428 U. S. 364, 368(1976); see also
New York v.
Class,475 U. S. 106, 113 (1986)("[A]utomobiles are justifiably the subject of pervasive regulationby the State");
Cardwell v.
Lewis,417 U. S. 583, 590 (1974)("One has a lesser expectation of privacy in a motor vehiclebecause its function is transportation and it seldom serves asone's residence or as the repository of personal effects"). Thelowered expectation of privacy in one's automobile is coupled withthe limited nature of the intrusion: a brief, standardized,nonintrusive seizure.6 The brief seizure of an automobile canhardly be compared to the intrusive search of the body or the home.Thus, just as the "special needs" inquiry serves to both define andlimit the permissible scope of those searches, the
Brown v.
Texas balancing test serves to define and limit thepermissible scope of automobile seizures.Because of these extrinsic limitations upon roadblock seizures,the Court's newfound non-law-enforcement primary purpose test isboth unnecessary to secure Fourth Amendment rights and bound toproduce wide-ranging litigation over the "purpose" of any givenseizure. Police designing highway roadblocks can never be sure oftheir validity, since a jury might later determine that a forbiddenpurpose exists. Roadblock stops identical to the one that we upheldin
Sitz 10 years ago, or to the one that we upheld 24 yearsago in
Martinez-Fuerte, may now be challenged on the groundsthat they have some concealed forbidden purpose.Efforts to enforce the law on public highways used by millionsof motorists are obviously necessary to our society. The Court'sopinion today casts a shadow over what had been assumed, on thebasis of
stare decisis, to be a perfectly lawful activity.Conversely, if the Indianapolis police had assigned a differentpurpose to their activity here, but in no way changed what was doneon the ground to individual6 This fact distinguishes the roadblock seizure of an automobilefrom an inventory search of an automobile. Cf.
Colorado v.
Bertine,479U. S. 367 (1987) (automobile inventory search).
56motorists, it might well be valid. See
ante, at 47, n. 2.The Court's non-law-enforcement primary purpose test simply doesnot serve as a proxy for anything that the Fourth Amendment is, orshould be, concerned about in the automobile seizure context.Petitioners' program complies with our decisions regardingroadblock seizures of automobiles, and the addition of a dog sniffdoes not add to the length or the intrusion of the stop. Becausesuch stops are consistent with the Fourth Amendment, I wouldreverse the decision of the Court of Appeals.JUSTICE THOMAS, dissenting.Taken together, our decisions in
Michigan Dept. of StatePolice v.
Sitz,496 U. S. 444 (1990), and
United States v.
Martinez-Fuerte,428 U. S. 543 (1976),stand for the proposition that suspicionless roadblock seizures areconstitutionally permissible if conducted according to a plan thatlimits the discretion of the officers conducting the stops. I amnot convinced that
Sitz and
Martinez-Fuerte werecorrectly decided. Indeed, I rather doubt that the Framers of theFourth Amendment would have considered "reasonable" a program ofindiscriminate stops of individuals not suspected ofwrongdoing.Respondents did not, however, advocate the overruling of
Sitz and
Martinez-Fuerte, and I am reluctant toconsider such a step without the benefit of briefing and argument.For the reasons given by THE CHIEF JUSTICE, I believe that thosecases compel upholding the program at issue here. I, therefore,join his opinion.
