CITY OF INDIANAPOLIS et al. v. EDMOND et al.

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Syllabus
CITY OF INDIANAPOLIS et al. v. EDMOND et al.
certiorari to the united states court of appeals for
the seventh circuit
No. 99–1030. Argued October 3, 2000—Decided November 28, 2000
Petitioner city operates vehicle checkpoints on its roads in an effort to
interdict unlawful drugs. Respondents, who were each stopped at such
a checkpoint, filed suit, claiming that the roadblocks violated the Fourth
Amendment. The District Court denied respondents a preliminary in-
junction, but the Seventh Circuit reversed, holding that the checkpoints
contravened the Fourth Amendment.
Held: Because the checkpoint program’s primary purpose is indistinguish-
able from the general interest in crime control, the checkpoints violate
the Fourth Amendment. Pp. 37–48.
(a) The rule that a search or seizure is unreasonable under the Fourth
Amendment absent individualized suspicion of wrongdoing has limited
exceptions. For example, this Court has upheld brief, suspicionless sei-
zures at a fixed checkpoint designed to intercept illegal aliens, United
States v. Martinez-Fuerte, 428 U. S. 543, and at a sobriety checkpoint
aimed at removing drunk drivers from the road, Michigan Dept. of
State Police v. Sitz, 496 U. S. 444. The Court has also suggested that
a similar roadblock to verify drivers’ licenses and registrations would
be permissible to serve a highway safety interest. Delaware v. Prouse,
440 U. S. 648, 663. However, the Court has never approved a check-
point program whose primary purpose was to detect evidence of ordi-
nary criminal wrongdoing. Pp. 37–40.
(b) The latter purpose is what principally distinguishes the check-
points at issue from those the Court has previously approved, which
were designed to serve purposes closely related to the problems of po-
licing the border or the necessity of ensuring roadway safety. Petition-
ers state that the Sitz and Martinez-Fuerte checkpoints had the same
ultimate purpose of arresting those suspected of committing crimes.
Securing the border and apprehending drunken drivers are law enforce-
ment activities, and authorities employ arrests and criminal prosecu-
tions to pursue these goals. But if this case were to rest at such a high
level of generality, there would be little check on the authorities’ ability
to construct roadblocks for almost any conceivable law enforcement pur-
pose. The checkpoint program is also not justified by the severe and
intractable nature of the drug problem. The gravity of the threat alone

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33 Cite as: 531 U. S. 32 (2000)
Syllabus
cannot be dispositive of questions concerning what means law enforce-
ment may employ to pursue a given purpose. Rather, in determining
whether individualized suspicion is required, the Court must consider
the nature of the interests threatened and their connection to the partic-
ular law enforcement practices at issue. Nor can the checkpoints’ pur-
pose be rationalized in terms of a highway safety concern similar to that
in Sitz, or merely likened to the antismuggling purpose in Martinez-
Fuerte. Neither Whren v. United States, 517 U. S. 806, nor Bond v.
United States, 529 U. S. 334, precludes an inquiry into the checkpoint
program’s purposes. And if the program could be justified by its lawful
secondary purposes of keeping impaired motorists off the road and veri-
fying licenses and registrations, authorities would be able to establish
checkpoints for virtually any purpose so long as they also included a
license or sobriety check. That is why the Court must determine the
primary purpose of the checkpoint program. This holding does not
alter the constitutional status of the checkpoints approved in Sitz and
Martinez-Fuerte, or the type of checkpoint suggested in Prouse. It
also does not affect the validity of border searches or searches in air-
ports and government buildings, where the need for such measures to
ensure public safety can be particularly acute. Nor does it impair police
officers’ ability to act appropriately upon information that they properly
learn during a checkpoint stop justified by a lawful primary purpose.
Finally, the purpose inquiry 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. Pp. 40–48.
183 F. 3d 659, affirmed.
O’Connor, J., delivered the opinion of the Court, in which Stevens,
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 the briefs were Anthony W. Overholt, Matthew R.
Gutwein, and Thomas M. Fisher.
Patricia A. Millett argued the cause for the United States
as amicus curiae urging reversal. With her on the brief
were Solicitor General Waxman, Assistant Attorney Gen-
eral Robinson, and Deputy Solicitor General Dreeben.

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34 INDIANAPOLIS v. EDMOND
Opinion of the Court
Kenneth J. Falk argued the cause for respondents. With
him on the 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 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 inter-
diction of illegal narcotics.
I
In August 1998, the city of Indianapolis began to operate
vehicle checkpoints on Indianapolis roads in an effort to in-
terdict unlawful drugs. The city conducted six such road-
blocks between August and November that year, stopping
*Briefs of amici curiae urging reversal were filed for the State of
Kansas et al. by Carla J. Stovall, Attorney General of Kansas, Stephen R.
McAllister, State Solicitor, 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 as follows: Bill Pryor of
Alabama, Janet Napolitano of Arizona, Mark Pryor of Arkansas, Bill
Lockyer of California, 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, W. A.
Drew Edmondson of Oklahoma, Jan Graham of Utah, and Mark L. Earley
of Virginia; for the National League of Cities 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 for the National
Association of Criminal Defense Lawyers et al. by Wesley MacNeil Oliver
and Barbara Bergman; and for the Rutherford Institute by John W.
Whitehead and Steven H. Aden.
Wayne W. Schmidt, James P. Manak, Richard Weintraub, and Bernard
J. Farber filed a brief for Americans for Effective Law Enforcement, Inc.,
et al. as amici curiae.

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Opinion of the Court
1,161 vehicles and arresting 104 motorists. Fifty-five ar-
rests were for drug-related crimes, while 49 were for of-
fenses 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 opera-
tion of the checkpoints by the Indianapolis Police Depart-
ment (IPD) for purposes of the preliminary injunction pro-
ceedings instituted below. At each checkpoint location, the
police stop a predetermined number of vehicles. Approxi-
mately 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 quan-
tum 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 vehi-
cle 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’ stip-
ulation, provides further insight concerning the operation
of the checkpoints. According to Sergeant DePew, check-
point 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

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CHECKPOINT 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 vehi-
cle not subject to further processing lasts two to three min-
utes 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 Consti-
tution 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 attor-
ney’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 mo-
tion 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 Cir-
cuit 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.

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Opinion of the Court
II
The Fourth Amendment requires that searches and sei-
zures be reasonable. A search or seizure is ordinarily un-
reasonable 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 student-
athletes); Treasury Employees v. Von Raab, 489 U. S. 656
(1989) (drug tests for United States Customs Service em-
ployees 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 cer-
tain administrative purposes without particularized suspi-
cion of misconduct, provided that those searches are appro-
priately 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 inspec-
tion 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 in-
spection to ensure compliance with city housing code).
We have also upheld brief, suspicionless seizures of mo-
torists at a fixed Border Patrol checkpoint designed to inter-
cept 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),

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we suggested that a similar type of roadblock with the pur-
pose 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 pri-
mary purpose was to detect evidence of ordinary criminal
wrongdoing.
In Martinez-Fuerte, we entertained Fourth Amendment
challenges to stops at two permanent immigration check-
points 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 enforce-
ment problems” posed by the northbound tide of illegal en-
trants 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 im-
migration 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 have confirmed that considerations
specifically related to the need to police the border were a
significant factor in our Martinez-Fuerte decision. For ex-
ample, in United States v. Montoya de Hernandez, 473 U. S.
531, 538 (1985), we counted Martinez-Fuerte as one of a num-
ber 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

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border 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 im-
paired drivers from the road. 496 U. S., at 447–448. Motor-
ists 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 grav-
ity 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 constitu-
tional. See id., at 451.
In Prouse, we invalidated a discretionary, suspicionless
stop for a spot check of a motorist’s driver’s license and vehi-
cle registration. The officer’s conduct in that case was un-
constitutional 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 “[q]uestioning of all oncom-
ing traffic at roadblock-type stops” would be a lawful means
of serving this interest in highway safety. Id., at 663.
We further indicated in Prouse that we considered the
purposes of such a hypothetical roadblock to be distinct from
a general purpose of investigating crime. The State prof-

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fered 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 in-
terest 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 concede, the Indianapolis checkpoint pro-
gram unquestionably has the primary purpose of interdicting
illegal narcotics. In their stipulation of facts, the parties re-
peatedly refer to the checkpoints as “drug checkpoints” and

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describe 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 docu-
ment 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 break-
down 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 road-
blocks 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 check-
points is to interdict narcotics traffic”); 183 F. 3d, at 665 (ob-
serving that “the City concedes that its proximate goal is to
catch drug offenders”).
We have never approved a checkpoint program whose pri-
mary 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 sus-
picion. 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. Con-
sistent with this suggestion, each of the checkpoint programs
that we have approved was designed primarily to serve pur-
poses closely related to the problems of policing the border
or the necessity of ensuring roadway safety. Because the

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primary purpose of the Indianapolis narcotics checkpoint
program is to uncover evidence of ordinary criminal wrong-
doing, the program contravenes the Fourth Amendment.
Petitioners propose several ways in which the narcotics-
detection purpose of the instant checkpoint program may in-
stead resemble the primary purposes of the checkpoints in
Sitz and Martinez-Fuerte. Petitioners state that the check-
points 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 prose-
cutions 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 pur-
pose. Without drawing the line at roadblocks designed pri-
marily to serve the general interest in crime control, the
Fourth Amendment would do little to prevent such intru-
sions from becoming a routine part of American life.
Petitioners also emphasize the severe and intractable na-
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 like-
wise remain daunting and complex, particularly in light of
the myriad forms of spin-off crime that it spawns. Cf. Mon-
toya 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 deter-
mining whether individualized suspicion is required, we must
consider the nature of the interests threatened and their con-

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nection to the particular law enforcement practices at issue.
We are particularly reluctant to recognize exceptions to the
general rule of individualized suspicion where governmen-
tal authorities primarily pursue their general crime control
ends.
Nor can the narcotics-interdiction purpose of the check-
points be rationalized in terms of a highway safety concern
similar to that present in Sitz. The detection and punish-
ment 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 In-
dianapolis 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 “par-
ticularized 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 road-
way safety that was present in Sitz and Prouse. Further,
the Indianapolis checkpoints are far removed from the bor-
der 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.

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The primary purpose of the Indianapolis narcotics check-
points 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, there are circumstances that may justify a law
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 appro-
priately tailored roadblock set up to thwart an imminent ter-
rorist 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 indistin-
guishable from the general interest in crime control.1
1 The Chief Justice’s dissent erroneously characterizes our opinion as
resting on the application of a “non-law-enforcement primary purpose
test.” Post, at 53. Our opinion nowhere describes the purposes of the
Sitz and Martinez-Fuerte checkpoints as being “not primarily related to
criminal law enforcement.” Post, at 50. Rather, our judgment turns on
the fact that the primary purpose of the Indianapolis checkpoints is to
advance the general interest in crime control.
The Chief Justice’s dissent also erroneously characterizes our opinion
as holding that the “use of a drug-sniffing dog . . . annuls what is otherwise
plainly constitutional under our Fourth Amendment jurisprudence.”
Post, at 48. Again, the constitutional defect of the program is that its
primary purpose is to advance the general interest in crime control.

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Petitioners 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 pur-
sues 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 of-
ficers involved.” Id., at 813. In so holding, we expressly
distinguished cases 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
“[s]ubjective 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

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46 INDIANAPOLIS v. EDMOND
Opinion of the Court
general scheme without individualized suspicion. Accord-
ingly, 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 Term in Bond, we addressed the question whether a
law enforcement officer violated a reasonable expectation of
privacy in conducting a tactile examination of carry-on lug-
gage 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 ob-
serve, 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 sus-
picion 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 pro-
gram 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 rea-
son, we examine the available evidence to determine the pri-
mary purpose of the checkpoint program. While we recog-
nize the challenges inherent in a purpose inquiry, courts

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47 Cite as: 531 U. S. 32 (2000)
Opinion of the Court
routinely engage in this enterprise in many areas of constitu-
tional jurisprudence as a means of sifting abusive govern-
mental 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 demon-
strate that purpose is often relevant when suspicionless in-
trusions pursuant to a general scheme are at issue.2
It goes without 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 check-
point 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 primar-
ily 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
2 Because petitioners concede that the primary purpose of the Indianap-
olis checkpoints is narcotics detection, we need not decide whether the
State may establish a checkpoint program with the primary purpose of
checking licenses or driver sobriety and a secondary purpose of interdict-
ing narcotics. Specifically, we express no view on the question whether
police may expand the scope of a license or sobriety checkpoint seizure in
order to detect the presence of drugs in a stopped car. Cf. New Jersey v.
T. L. O., 469 U. S. 325, 341 (1985) (search must be “ ‘reasonably related in
scope to the circumstances which justified the interference in the first
place’ ” (quoting Terry v. Ohio, 392 U. S. 1, 20 (1968))); Michigan v. Clif-
ford, 464 U. S. 287, 294–295 (1984) (plurality opinion).

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48 INDIANAPOLIS v. EDMOND
Rehnquist, C. J., dissenting
buildings, 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 be-
yond the general interest in crime control. Our holding also
does not impair the ability of police officers to act appropri-
ately 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 of the Indianapolis check-
point program is ultimately indistinguishable from the gen-
eral 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 constitu-
tional under our Fourth Amendment jurisprudence: brief,
standardized, discretionless, roadblock seizures of automo-
biles, seizures which effectively serve a weighty state inter-
est with only minimal intrusion on the privacy of their occu-
pants. 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 legiti-
mate seizures, I dissent.

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49 Cite as: 531 U. S. 32 (2000)
Rehnquist, C. J., dissenting
I
As it is nowhere to be found in the Court’s opinion, I begin
with blackletter roadblock seizure law. “The principal pro-
tection 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 Amend-
ment if they are “carried out pursuant to a plan embodying
explicit, neutral limitations on the conduct of individual offi-
cers.” 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 im-
migrants against the limited “objective” and “subjective” in-
trusion 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 na-
ture of the stop, was found to be minimal because the “regu-
larized 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
1 The record from one of the consolidated cases indicated that the stops
lasted between three and five minutes. See United States v. Martinez-
Fuerte, 428 U. S. 543, 546–547 (1976).

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50 INDIANAPOLIS v. EDMOND
Rehnquist, C. J., dissenting
markedly 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 consoli-
dated 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 Police v. Sitz, 496 U. S. 444
(1990), we upheld the State’s use of a highway sobriety
checkpoint af ter 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 ap-
proximately 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 op-
erated 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
2 This gloss, see ante, at 38–40, 41–43, is not at all obvious. The re-
spondents in Martinez-Fuerte were criminally prosecuted for illegally
transporting aliens, and the Court expressly noted that “[i]nterdicting the
flow of illegal entrants from Mexico poses formidable law enforcement
problems.” 428 U. S., at 552. And the Sitz Court recognized that if an
“officer’s observations suggest that the driver was intoxicated, an arrest
would be made.” 496 U. S., at 447. But however persuasive the distinc-
tion, the Court’s opinion does not impugn the continuing validity of
Martinez-Fuerte and Sitz. See ante, at 47.

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51 Cite as: 531 U. S. 32 (2000)
Rehnquist, C. J., dissenting
question 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. Gold-
smith, 183 F. 3d 659, 661 (CA7 1999). And it would be spec-
ulative 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 road-
block seizures, it is constitutionally irrelevant that petition-
ers also hoped to interdict drugs. In Whren v. United
States, 517 U. S. 806 (1996), we held that an officer’s subjec-
tive intent would not invalidate an otherwise objectively jus-
tifiable stop of an automobile. The reasonableness of an of-
ficer’s discretionary decision to stop an automobile, at issue
in Whren, turns on whether there is probable cause to be-
lieve that a traffic violation has occurred. The reasonable-
ness of highway checkpoints, at issue here, turns on whether
they effectively serve a significant state interest with mini-
mal intrusion on motorists. The stop in Whren was objec-
tively reasonable because the police officers had witnessed
traffic violations; so too the roadblocks here are objectively
3 Several Courts of Appeals have upheld roadblocks that check for
driver’s licenses and vehicle registrations. See, e. g., United States
v. Galindo-Gonzales, 142 F. 3d 1217 (CA10 1998); United States v. Mc-
Fayden, 865 F. 2d 1306 (CADC 1989).

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52 INDIANAPOLIS v. EDMOND
Rehnquist, C. J., dissenting
reasonable because they serve the substantial interests of
preventing drunken driving and checking for driver’s li-
censes and vehicle registrations with minimal intrusion on
motorists.
Once the constitutional requirements for a particular sei-
zure are satisfied, the subjective expectations of those re-
sponsible 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) (apply-
ing Whren 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 ac-
tions”). 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 two important state inter-
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 in-
volve 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 physi-
cal intrusion of the object being sniffed and it does not ex-
4 Of course we have looked to the purpose of the program in analyz-
ing the constitutionality of certain suspicionless searches. As discussed
in Part II, infra, that doctrine has never been applied to seizures of
automobiles.

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53 Cite as: 531 U. S. 32 (2000)
Rehnquist, C. J., dissenting
pose 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 en-
suring the proper licensing of drivers and registration of
their vehicles. 183 F. 3d, at 661.5
These stops effectively serve the State’s legitimate inter-
ests; they are executed in a regularized and neutral manner;
and they only minimally intrude upon the privacy of the
motorists. They should therefore be constitutional.
II
The Court, unwilling to adopt the straightforward analy-
sis 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 fundamen-
tally, whatever sense a non-law-enforcement primary pur-
pose 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 constitu-
tionality. Martinez-Fuerte, 428 U. S., at 567.
We have already rejected an invitation 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
5 Put in statistical terms, 4.2 percent of the 1,161 motorists stopped were
arrested for offenses unrelated to drugs.

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54 INDIANAPOLIS v. EDMOND
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need’ for criminal law enforcement before a balancing
analysis is appropriate, and that [the State] ha[s] demon-
strated no such special need.
“But it is perfectly plain from a reading of [Treasury
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 dwell-
ings, ordinarily afforded the most stringent Fourth Amend-
ment protection.” Martinez-Fuerte, supra, at 561.
The “special needs” doctrine, which has been used to up-
hold certain suspicionless searches performed for reasons un-
related 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 Execu-
tives’ Assn., 489 U. S. 602 (1989) (drug test search); Camara
v. Municipal Court of City and County of San Francisco,
387 U. S. 523 (1967) (home administrative search). The doc-
trine permits intrusions into a person’s body and home, areas
afforded the greatest Fourth Amendment protection. But
there were no such intrusions here.
“[O]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 resi-
dence.” Martinez-Fuerte, supra, at 561. This is because
“[a]utomobiles, unlike homes, are subjected to pervasive and
continuing governmental regulation and controls.” South

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55 Cite as: 531 U. S. 32 (2000)
Rehnquist, C. J., dissenting
Dakota 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 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 expec-
tation of privacy in one’s automobile is coupled with the lim-
ited 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 de-
fine 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 of these extrinsic limitations upon roadblock sei-
zures, the Court’s newfound non-law-enforcement primary
purpose test is both unnecessary to secure Fourth Amend-
ment 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 to enforce the law on public highways used by mil-
lions 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
6 This fact distinguishes the roadblock seizure of an automobile from an
inventory search of an automobile. Cf. Colorado v. Bertine, 479 U. S. 367
(1987) (automobile inventory search).

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56 INDIANAPOLIS v. EDMOND
Thomas, J., dissenting
motorists, 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 auto-
mobile seizure context.
Petitioners’ program complies with our decisions regard-
ing 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. 543 (1976), stand for the propo-
sition that suspicionless roadblock seizures are constitu-
tionally 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 cor-
rectly decided. Indeed, I rather doubt that the Framers of
the Fourth Amendment would have considered “reasonable”
a program of indiscriminate stops of individuals not sus-
pected of wrongdoing.
Respondents did not, however, advocate the overruling
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.