CRS Report for Congress
Search and Seizure in the Vehicular Context:
Fourth Amendment Issues
September 15, 1999
T.J. Halstead
Legislative Attorney
American Law Division

Congressional Research Service ˜ The Library of Congress

This report discusses the Fourth Amendment as it relates to vehicular searches and traffic
detentions conducted by law enforcement officers. An overview of exceptions to the warrant
and probable cause requirements prescribed under the Constitution is provided, outlining the
range of permissible police activity in this area. A particular emphasis is placed on recent
Supreme Court decisions, including the validity of pretextual stops and consent based
searches, which illustrate the balancing approach used by the Court to weigh personal privacy
interests against the legitimate safety and investigatory needs of law enforcement, and serve
to clarify the extent of police power in the vehicular context.

Search and Seizure in the Vehicular Context:
Fourth Amendment Issues
The Fourth Amendment to the Constitution of the United States provides that
"The right of the people to be secure in their persons, houses, papers, and effects,
against unreasonable searches and seizures, shall not be violated, and no Warrants
shall issue, but upon probable cause, supported by Oath or affirmation, and
particularly describing the place to be searched, and the persons or things to be
seized." The Supreme Court has interpreted this language as imposing a presumptive
warrant requirement on all searches and seizures predicated upon governmental
authority, and has ruled that any violations of this standard will result in the
suppression of any material or information derived therefrom.
However, the Court has also recognized that certain circumstances render the
obtainment of a warrant impractical or unnecessary, and, accordingly, has crafted
exceptions to an otherwise inflexible constitutional standard. Among the various
exceptions established by the Court are warrantless searches based on exigent
circumstances, plain view seizures, searches incident to a valid arrest, and searches
where law enforcement needs surpass the warrant requirement. Some of the most
pervasive and controversial exceptions recognized by the Court have centered on law
enforcement authority to conduct warrantless searches and investigatory detentions
in the vehicular context. Recent Court decisions in this area have imbued law
enforcement officers with greater authority to act without a warrant during traffic
stops, based upon the previously established automobile exception and the need for
adequate protective measures to ensure police safety. This apparent expansion of
police power has led many commentators to assert that Fourth Amendment
protections have been essentially eviscerated in the automobile and traffic stop setting.
Upon examining the scope of law enforcement authority subsequent to these
decisions, however, it appears that basic Fourth Amendment privacy strictures still
pertain to traffic detentions, with the recent Court rulings simply applying previously
established rationales to new factual scenarios.

Introduction ...............................................1
The Fourth Amendment.......................................1
The Automobile Exception....................................2
Investigatory Detentions......................................3
Pretextual Stops.............................................4
Post-Stop Conduct..........................................7
Protective Searches......................................7
Seizure of Items in Plain View.............................11
Consent Searches.......................................11
Search Incident to Arrest.................................13
Conclusion ................................................ 14

Search and Seizure in the Vehicular Context:
Fourth Amendment Issues
In its past few terms, the Supreme Court of the United States has exhibited a
renewed interest in Fourth Amendment issues surrounding law enforcement practices
in the traffic detention, search, and seizure contexts. In the majority of these cases,
the Court has determined that the state action at issue is either presumptively valid,
or that the public interest in the deterrence and detection of criminal activity
outweighs any potential intrusion upon asserted personal liberty and privacy interests.
This paper addresses the dynamics and scope of law enforcement authority in the
traffic detention context in light of these recent decisions, with an analytical focus on
the extent to which they impact fundamental Fourth Amendment principles.
The Fourth Amendment
The Fourth Amendment to the Constitution of the United States establishes that
a search or seizure conducted by a governmental agent must be reasonable, and that
probable cause support any judicially granted warrant. Originally, the Supreme Court1
interpreted this provision as imposing a presumptive warrant requirement, declaring
that "searches conducted outside the judicial process without prior approval by judge
or magistrate are per se unreasonable under the Fourth Amendment - subject only to2
a few specifically established and well delineated exceptions." The Court has
eschewed this approach at times, determining that "a warrant is not required to
establish the reasonableness of all government searches; and when a warrant is not
required...probable cause is not invariably required either." In the criminal setting,3

U.S. Const., Amend. IV. In full, the Fourth Amendment provides: "The right of the people1
to be secure in their persons, houses, papers, and effects, against unreasonable searches and
seizures, shall not be violated, and no Warrants shall issue, but upon probable cause,
supported by Oath or affirmation, and particularly describing the place to be searched, and
the persons or things to be seized." The probable cause standard for a valid governmental
search has been interpreted by the Supreme Court as "a fair probability that contraband or
evidence of a crime will be found in a particular place."Illinois v. Gates, 462 U.S. 213, 238
(1983). In the arrest context, probable cause to obtain a warrant to arrest or to effectuate a
warrantless arrest requires that the authorities have, at the moment of arrest, knowledge of
facts and circumstances sufficient to warrant a reasonable belief that an offense has been, or
is being, committed. See Wong Sun v. United States, 371 U.S. 471, 479 (1963).
Katz v. United States, 389 U.S. 347, 357 (1967).2
Vernonia School District 47J v. Acton, 515 U.S. 646, 653 (1995). This standards has3
generally been applied to administrative searches, but has been used in the criminal context.

however, this warrant requirement traditionally has been viewed as a protective
mechanism, placing the authority to determine probable cause in the hands of a neutral
magistrate as opposed to law enforcement authorities, who are "engaged in the often
competitive enterprise of ferreting out crime." In instances where the interests of the4
public outweigh those of private individuals, however, the Court has recognized
"specifically established exceptions" to the warrant and probable cause requirements5
of the Fourth Amendment. Indeed, such exceptions have been recognized for
searches incident to a valid arrest, plain view seizures, vehicle searches, investigatory6
detentions, and exigent circumstances, among others.
The Automobile Exception
In Carroll v. United States, the Supreme Court determined that automobiles are
inherently mobile, creating exigent circumstances which render the obtainment of a7
warrant impractical. Specifically, the Court found it significant that, unlike a building
or a house, a vehicle, and any contraband therein, could be readily removed from a
jurisdiction pending the issuance of a warrant. As such, the Court held that law8
enforcement authorities need not obtain a warrant to search an automobile when there9
is probable cause indicating illegal activity. The Supreme Court has further buttressed
the automobile exception by declaring that there is a reduced expectation in the
privacy of automobiles, given that they are rarely used as a repository for personal
effects, their occupants and contents are generally in plain view, and are subject to
extensive state regulation.10
Regarding the proper scope of searches conducted pursuant to the automobile
exception, the Supreme Court has held that when police have probable cause to
believe that a vehicle contains contraband, they may conduct a thorough warrantless11

search, including any containers which may conceal the object of the search.
See Illinois v. Rodriguez, 497 U.S. 177 (1990).
Johnson v. United States, 333 U.S. 10, 13-14 (1948).4
Camara v. Municipal Court, 387 U.S. 523, 539-540 (1967).5
For a thorough exposition of warrant and probable cause exceptions, see Twenty-Eighth6
Annual Review of Criminal Procedure: Warrantless Searches and Seizures, 87 Geo. L.J. 1124
Carroll v. United States, 267 U.S. 132, 153 (1925).7
Id. at 153-154.8
Id. at 149. See also, Chambers v. Maroney, 399 U.S. 42 (1970) (warrantless search deemed9
constitutional where probable cause existed to believe vehicle contained evidence of recently
committed robbery).
United States v. Chadwick, 433 U.S. 1, 12-13 (1977). Similarly, the Court has pointed to10
public operation and servicing as factors which further diminish the expectation of privacy
in an automobile. See California v. Carney, 471 U.S. 386, 392 (1985).
United States v. Ross, 456 U.S. 798, 825 (1982). In Ross, the Court declared that a search11
under the automobile exception may extend as far as "a magistrate could legitimately

The Supreme Court recently clarified the extent to which police officers may12
search belongings in a vehicle in Wyoming v. Houghton. There, the Court held that
police officers with probable cause to search a car may inspect a passenger's personal
belongings inside the vehicle in instances where those items are capable of concealing
the object of the search, irrespective of whether the passenger is under suspicion. In13
reaching this conclusion, the Court pointed to several factors. First, the Court noted
that there was a strong body of law empowering government agents with probable
cause to conduct warrantless searches of vessels for contraband, including the14
automobile exception as delineated in Carroll, and clarified in Ross. Also, the Court
found that none of these cases indicated that the scope of such searches rested upon
a "distinction among packages or containers based on ownership."15
Balancing the relative governmental interests against individual privacy in this
scenario, the Court determined that passengers have a reduced expectation of privacy
in property transported in automobiles, and that search of such property is minimally
intrusive. Conversely, the Court found that the governmental interests at stake were
substantial. Specifically, the Court held that law enforcement efforts would be
impaired if authorities were unable to search a passenger's belongings "when there is
reason to believe contraband or evidence of criminal wrongdoing is hidden in the car,"
given that the mobility of an automobile creates a risk that evidence will be lost while16
a warrant is obtained. Also, the Court found it significant that car passengers "will
often be engaged in a common enterprise with the driver, and have the same interest17
in concealing the fruits or the evidence of their wrongdoing." In view of these
factors, the Court ruled that such searches were permissible.
Investigatory Detentions
In Terry v. Ohio, the Supreme Court held that a police officer may stop and
question an individual who is reasonably suspected of engaging in criminal activity,
as well as perform a limited frisk to ascertain whether the individual in question is
armed. Specifically, the Court addressed a factual scenario where an officer, lacking18
both a warrant and probable cause, detained three individuals after observing them
loitering near a store in a suspicious manner. The officer stopped the individuals in
order to ascertain their identities, and, fearing that they might be armed, patted down
the outside of their clothing. This frisk resulted in the discovery of two revolvers.

authorize by warrant." Id.

119 S.Ct. 1297 (1999).12

Id .13
Id. at 1300.14
Id. at 1301.15
Id. at 1302.16
Id. at 1302-1303. The Court further noted that criminals might conceal contraband in the17
belongings of a passenger surreptitiously, and that passenger confederates could simply claim
all belongings in the car as their own.

392 U.S. 1, 22-24 (1968).18

Noting that the state action at issue was governed by the Fourth Amendment, the
Court stated that the constitutional validity of "stop and frisk" hinged upon a
reasonableness inquiry as opposed to a probable cause analysis. As such, the Court19
determined it necessary to balance "the need to search (or seize) against the invasion
which the search or seizure entails." Accordingly, the Court identified two factors20
which it deemed essential to a valid investigative detention.
First, law enforcement officers may initiate an investigative detention only when
there is a "reasonable articulable suspicion" criminal activity. Thus, for a stop to be
valid, a law enforcement officer "must be able to point to specific and articulable facts
which, taken together with rational inferences from those facts, reasonably warrant
that intrusion." Second, the scope of law enforcement activity resulting from an21
investigative detention must be reasonably related to the circumstances supporting the
initial stop. If these factors are present, according to the Court, a brief investigative
detention may be justified in light of significant governmental interests, even where
probable cause is lacking.
This analysis has been applied in the vehicular context as well. Specifically, while
the Supreme Court has ruled that even a brief traffic detention constitutes a seizure
under the Fourth Amendment, the Court has also determined that traffic stops are less22
onerous than formal custodial detentions. As such, traffic stops are equivalent to
traditional Terry stops, requiring that law enforcement action be predicated upon a
reasonable, articulable suspicion of criminal conduct and that ensuing police activity23
be reasonably related in scope to the initial basis of the stop.
Pretextual Stops
Whereas the stop and frisk rationale delineated in Terry can be of great utility to
police in the traffic detention context, it must be remembered that an officer must
have a "reasonable articulable suspicion" of illegal activity to justify an initial stop. To
surmount this potential impediment, law enforcement authorities have engaged in the
controversial practice of stopping individuals for minor offenses as a pretext to search
for evidence of other criminal wrongdoing. Generally speaking, a "pretextual traffic
stop" occurs when police effectuate a stop based on probable cause that a violation
has occurred while, in actuality, the primary motivation for the detention is to

Id. at 20. Specifically, the Court explained that a "stop and frisk" encounter involves "an19
entire rubric of police conduct--necessarily swift action predicated upon the on-the-spot
observations of the officer on the beat--which historically has not been, and as a practical
matter could not be, subjected to the warrant procedure. Instead, the conduct in this case must
be tested by the Fourth Amendment's general proscription against unreasonable searches and
seizures." Id. at 20.
Id. at 21.20
Id. at 21. Accordingly, inarticulable hunches or generalized suspicions cannot serve as the21
basis for an investigative detention. Id. at 22.
Berkemer v. McCarty, 468 U.S. 420, 439 (1984).22
See United States v. Sharpe, 470 U.S. 675, 682 (1985); Delaware v. Prouse, 440 U.S. 648,23


investigate the possibility that more egregious criminal activity is being committed.24
In United States v. Whren, the Supreme Court considered the constitutionality of this
In Whren, two plainclothes vice officers of the District of Columbia Metropolitan
Police Department were patrolling an area of high drug activity in an unmarked car.
The officers passed a dark Nissan Sentra Pathfinder with temporary license plates
occupied by two young males, and observed that the driver of the vehicle was looking
toward the lap of the passenger. The officers noticed that the vehicle had paused at
a stop sign for an abnormal period of time. As the officers executed a U-turn towards
the vehicle, the Nissan made a sudden right turn without signaling and accelerated
from the intersection at an "unreasonable" speed. The officers subsequently stopped
the vehicle and observed two large bags of crack cocaine in the defendant's hands.
The defendants were arrested, and an ensuing search resulted in the discovery of other
illegal drugs.
The defendants were indicted on four counts of federal drug law violations. The
defendants moved to suppress the evidence, maintaining that the traffic stop was not
predicated on probable cause or reasonable suspicion, and, as such, was violative of
the Fourth Amendment. The district court denied the motion, stating that the stop
conformed with normal traffic enforcement procedures. The defendants were
ultimately convicted, and the disposition of their case was affirmed by the Court of
Appeals for the District of Columbia. In regards to the suppression argument, the
court of appeals held that "regardless of whether a police officer subjectively believes
that the occupants of an automobile may be engaging in some other illegal behavior,
a traffic stop is permissible as long as a reasonable officer in the same circumstances
could have stopped the car for the suspected traffic violation."
In its subsequent consideration of the case, a unanimous Supreme Court
adopted an objective test, declaring that "the decision to stop an automobile is
reasonable where the police have probable cause to believe that a traffic violation has25
occurred." In reaching this conclusion, the Court rejected the contention that prior
precedent established that law enforcement should not be permitted "to use valid
bases of action against citizens as pretexts for pursuing other investigatory agendas."26
Specifically, the Court noted that the cases in question dealt with searches in the
administrative and inventory contexts which were conducted without probable cause.
Accordingly, the Court determined that such decisions gave no support to the
"principle that ulterior motives can invalidate police conduct that is justifiable on the
basis of probable cause to believe that a violation of law has occurred." Further27
clarifying this point, the Court stated: "Not only have we never held, outside the
context of inventory search or administrative inspection..., that an officer's motive

Thus, under this definition, a pretextual stop is an objectively reasonable and valid exercise24
of police power, as opposed to the notion that an officer may simply fabricate an underlying
justification for a stop. See United States v. Whren, 517 U.S. 806, 812 (1996).

517 U.S. at 810.25

Id. at 811.26
Id. at 811.27

invalidates objectively justifiable behavior under the Fourth Amendment; but we have28
repeatedly held and asserted the contrary."
In view of this case law, the Court held that there was no constitutional basis for
hinging the validity of a traffic stop on the actual motivations of the officers involved.
Indeed, the Court went on to state that adoption of a subjective test would require
case-by-case assessment of particular police actions at particular times, compromising29
the invariable nature of Fourth Amendment search and seizure protections.
Addressing the argument that pretextual stops might be employed in an
intentionally discriminatory fashion by authorities, the Supreme Court noted that it is
well settled that "the Constitution prohibits selective enforcement of the law based on
considerations such as race." The Court declared, however, that the proper
constitutional basis for such biased police action is the Equal Protection Clause as
opposed to the Fourth Amendment. The Court concluded its consideration of the
issue by declaring that "subjective intentions play no role in ordinary, probable-cause30
Fourth Amendment analysis."
Many commentators have decried the Whren decision, arguing that the Court has
essentially bestowed unbridled authority on law enforcement officers to detain any31
individual upon the merest of suspicions. In particular, it has been argued that, given
the pervasive and arcane nature of traffic laws, a police officer will invariably be able
to effectuate an investigatory stop upon an "inarticulable hunch," as opposed to valid
reasonable suspicion. As such, these commentators maintain, the Supreme Court has
departed from the spirit, if not the letter, of the Terry standard. While Whren indeed
imbues officers with yet another tool with which they may investigate individuals of
whom they are suspicious, a strong case can be made that the Court's decision does
not reflect a substantial change in Fourth Amendment precepts. Specifically, it is
important to note that officers conducting a stop under the Whren standard must still
possess probable cause to initially stop a vehicle, which necessarily requires that a
valid traffic law has been violated. Furthermore, the Whren decision does not abrogate
Fourth Amendment strictures which limit police power after an initial stop. Indeed,
officers must still satisfy probable cause and reasonable suspicion standards before

Id. at 812. See United States v. Villamonte-Marquez, 462 U.S. 579, 584, n.3 (1983)28
(Customs Service officer's warrantless boarding of vessel not rendered invalid by underlying
suspicion that contraband was on board); United States v. Robinson, 414 U.S. 218 (1973)
(arrest for traffic violation not rendered invalid due to the fact that it was a pretext for a
narcotics search); Scott v. United States, 436 U.S. 128, 138 (1978) (subjective intent,
standing alone, does not render otherwise lawful conduct illegal or unconstitutional).
Id. at 815. Specifically, the Court stated "police enforcement practices, even if they could29
be practicably assessed by a judge, vary from place to place and from time to time. We cannot
accept that the search and seizure protections of the Fourth Amendment are so variable."
Id. at 813.30
See David A. Harris, "Driving While Black" and All Other Traffic Offenses: The Supreme31
Court and Pretextual Traffic Stops, 87 J. Crim. L. & Criminology 544, 545-546 (1997);
Chris K. Visser, Without a Warrant, Probable Cause, or Reasonable Suspicion: Is There Any
Meaning to the Fourth Amendment While Driving a Car?, 35 Hous. L. Rev. 1683, 1708-1709

impinging upon a detainee's rights beyond the scope of the original objective purpose
for the stop.
Furthermore, the Court recognized the potential that pretextual traffic stops
could be made in an intentionally discriminatory fashion, and ruled that the proper
remedy for such an offense would be an equal protection claim. This holding is
consistent with Supreme Court precedent which mandates that objectively reasonable
enforcement measures should not be prohibited due to the possibility of
unconstitutional application. Rather, the proper remedy in such a circumstance is for
the aggrieved party to file suit. Accordingly, it seems that while the Whren decision
sanctions objective reasonable police action based upon underlying motivations, the
ruling comports with traditional constitutional principles fashioned by the Court.
Having established the main avenues by which law enforcement officers may
conduct a valid vehicular seizure or investigatory detention, it is now necessary to
ascertain the scope of and nature of permissible police activity subsequent to a traffic
Post-Stop Conduct
As noted above, the reasonableness clause of the Fourth Amendment, as
interpreted in Terry, requires that any search or seizure subsequent to a traffic stop
"be reasonably related in scope to the circumstances which justified the interference
in the first place." However, employing the officer safety rationale which supported32
the stop and frisk at issue in Terry, the Court has expanded the range of protective
measures officers may take in the traffic stop context. Recognizing that "investigative
detentions involving suspects in vehicles are especially fraught with danger," the
Court has ruled that law enforcement officers may order individuals to exit a vehicle,
search passenger compartments, and frisk individuals for weapons in certain
circumstances. 33
Protective Searches. In Pennsylvania v. Mimms, the Supreme Court held that
law enforcement officers may order a driver to exit an automobile during a traffic
stop, and may conduct a frisk if there is a reasonable belief that the detained individual34
is armed. In Mimms, two police officers observed the defendant driving with an
expired license plate. Upon stopping the vehicle, one of the officers directed the
defendant to exit the vehicle and produce his license and registration. As the
defendant exited the vehicle, one of the officers noticed a large bulge under the
defendant's clothing. Fearing that the bulge could be a weapon, the officer frisked the
defendant and discovered a loaded .38 caliber pistol. A passenger was subsequently
discovered to be in possession of a .32 caliber pistol. The defendant was arrested and
later convicted of unlawful possession of a firearm.35

Sharpe, 470 U.S. at 682 (quoting Terry, 392 U.S. at 20).32
See Michigan v. Long, 463 U.S. 1032, 1047-1048 (1983).33

434 U.S. 106, 110 (1977).34

Id. at 107.35

Analyzing the constitutionality of the order requiring the defendant to exit the
vehicle, the Court noted that there is an "inordinate risk confronting an officer as he
approaches a person seated in an automobile," and that a significant portion of police
shootings involve suspects seated in automobiles. Furthermore, the Court36
determined that asking a driver to exit a vehicle could also lessen the danger posed
by nearby moving traffic. Balancing these factors with the intrusiveness of an exit
request, the Court found that ordering an individual from a vehicle subsequent to a
lawful stop constitutes a de minimis imposition on personal liberty. In particular, the
Court explained that after being initially detained, the additional requirement that a
driver exit a vehicle exposes "little more of his person than is already exposed," and
does not constitute a "serious intrusion upon the sanctity of the person." In light of37
this minimal intrusion, the Court declared that "a mere inconvenience cannot prevail
when balanced against legitimate concerns" for officer safety. Accordingly, the38
Court held that law enforcement officers may order a driver to exit his vehicle39
pursuant to a lawful traffic detention.
The Court also determined that the frisk at issue was constitutionally valid. In
reaching this determination, the Court explained that, pursuant to Terry, the bulge
observed under the defendant's jacket provided a sufficient basis to suspect the
presence of a firearm. As such, the Court deemed the ensuing frisk to be a reasonable40
action to ensure officer safety.
Recently, in Maryland v. Wilson the Supreme Court extended upon its ruling in
Mimms, declaring that law enforcement officers could order passengers, as well as
drivers, to exit a vehicle detained in a valid traffic stop. In Wilson a police officer41
pulled over a vehicle in which three persons were traveling. Upon noticing that the
front seat passenger was sweating and "appeared extremely nervous," the officer
ordered him out of the car. When the passenger exited the vehicle, crack cocaine fell
to the ground. The passenger was arrested and subsequently convicted of possession
of cocaine with intent to distribute.
Addressing the issue of whether passengers could be subjected to such police
action pursuant to a traffic detention, the Court pointed to the same officer safety
factors considered dispositive in Mimms. While acknowledging that, in the case of42
passengers, the danger posed by incoming traffic would be lessened, the Court
determined that the presence of multiple occupants increased the danger posed to an43
officer. The Court noted that passengers possessed a slightly stronger personal
liberty interest during a stop than does a driver, in that while probable cause may exist

Id. at 109-110.36
Id. at 111.37
Id. at 111.38
Id. at 111.39
Id. at 112.40

519 U.S. 408, 415 (1997).41

Id. at 413.42
Id. at 413.43

to detain a driver, there is generally no justifiable cause to stop or detain passengers.
Noting that, as a practical matter, passengers were already stopped as a result of the
vehicle detention, the Court determined that an exit order constituted a minor
intrusion, as it would simply place a passenger outside of a vehicle which was already
Pursuant to this characterization, the Court determined that the safety concerns
at issue prevailed, since passengers ordered out of a vehicle would be denied access
to weapons concealed in the interior of the passenger compartment. This factor was
deemed especially pertinent by the Court, which surmised that a potential violent
encounter would not stem from the traffic stop itself, but, rather, from more sinister
criminal activity which might be uncovered by such a detention. Having determined44
that the danger posed to an officer during a traffic stop is greater when passengers are
present, the Court held that an exit order constituted a minimal intrusion, allowing
officers conducting such stops to order passengers from vehicles pending completion45
of the detention.
The Wilson decision has also been criticized as an unreasonable extension of
police authority by potentially increasing the impact of the plain view exception and
encouraging arbitrary police action. Indeed, it has even been argued that the Wilson
decision will ultimately lead to the Court sanctioned detention of individuals upon a46
general traffic stop. While the decision does indeed increase police authority in this
context, it is not apparent that any substantial Fourth Amendment rights have been
impinged. Indeed, the Court noted that the intrusion of an exit order appears minimal
when compared to concerns of officer safety. Also, it does not seem that the notion47
that Wilson will expand the plain view doctrine is of any substantial significance in
search and seizure analysis, given that, by its nature, the plain view exception is48
outside the purview of the Fourth Amendment. Rather, in the doctrinal sense, it
seems that Wilson, like Whren, serves mainly to illustrate the Court's preference for
objective Fourth Amendment standards. Furthermore, given the Court's matter-of-fact
analysis, Wilson could be regarded merely as the application of preexisting
constitutional standards to a new factual scenario.
The Supreme Court has also extended the Terry standard to permit protective
searches of the interior of an automobile in certain instances. In Michigan v. Long, for
instance, the Court held that limited protective searches are permissible in
circumstances where an officer reasonably believes that there may be a safety risk
from weapons potentially located within the vehicle and accessible by the detainee.
In Long, two police officers observed a car which was traveling erratically and at
excessive speed. As the officers observed the vehicle turn down a side road, it
swerved off into a ditch. Upon stopping to investigate, the officers were met by
Long, the only occupant, at the rear of the vehicle. The vehicle was projecting from
the ditch onto the road, and the driver's side door of the vehicle was open. Long failed

Id. at 414.44
Id. at 414-415.45
See Visser, supra n. 28, at 1726.46
Id. at 413-414.47
See n. 48, infra, and accompanying text.48

to respond initially when the officers requested his license, but ultimately complied.
When the officers then asked repeatedly to see his registration, Long again failed to
respond. After the officers made another production request, Long, whom the officers
now suspected of being under the influence, turned away from the officers and began
to walk toward the open door of the vehicle. The Officers followed Long and
observed a large knife on the floorboard of the driver's side of the vehicle. The
officers stopped Long from approaching the car and conducted a Terry frisk, which
revealed no weapons.
One of the officers stood with Long as the other visually inspected the interior
of the vehicle for other weapons. Upon noticing an item protruding from under the
armrest of the front seat, the officer knelt in the vehicle and lifted the armrest. The
item under the armrest was an open pouch, and, upon flashing a light into the pouch,
the officer determined that it contained marijuana. Long was then arrested. A
subsequent search of the vehicle's trunk revealed approximately 75 pounds of
Considering the question of whether the safety considerations of a Terry search
extended to a search of the passenger compartment of vehicle pursuant to a lawful
investigatory stop, the Supreme Court held that police protection principles compelled
the conclusion that such a search "is permissible if the police officer possesses a
reasonable belief based on 'specific and articulable facts which, taken together with
the rational inferences from those facts, reasonably warrant' the officers in believing
that the suspect is dangerous and the suspect may gain immediate control of
weapons." 49
In reaching this determination, the Court reiterated its holdings in Mimms and
other cases which established that officers could conduct a constitutional stop and
frisk if a reasonable suspicion of potential danger existed. Given this standard, the
Court concluded that the same safety considerations adhered to interior areas of a50
vehicle which might harbor weapons. The Court also made it clear that such a search
was justified, even though the suspect was, ostensibly, under the control of the
officers at the time of the protective search. Specifically, the Court explained that,
during the course of any investigative detention, a suspect is under police control only51
"in the sense that he 'may be briefly detained against his will...'" As such, the Court
explained that a detained individual may still produce a weapon from his clothing, or
may break away from police control long enough to retrieve a weapon from the
interior of an automobile. Furthermore, the Court noted that a detained individual
could have access to weapons inside a car after the investigate stop is completed
absent a protective sweep of the interior. In light of these factors, the Court again52
emphasized that safety considerations outweighed any potential Fourth Amendment
considerations stemming from such a sweep.

Id. at 1049 (quoting Terry, 392 U.S. at 21). 49
Id. at 1051. Furthermore, the Court stated that any contraband discovered in the course of50
a protective search of an automobile's interior would be subject to seizure. Id. at 1050.
Id. at 1051 (quoting Terry, 392 U.S. at 34).51
Id. at 1051-1052.52

Seizure of Items in Plain View. Another well established exception to the
warrant and probable cause requirements of the Fourth Amendment dictates that an
officer, acting pursuant to constitutional authority, may seize contraband or other53
evidence of criminal activity which is in plain view. This exception applies not only
to the seizure of items in plain view, but also provides that the "mere observation of
an object without its seizure may contribute to the probable or reasonable suspicion54
necessary to seize the object." Also, it has been determined that items exposed to
plain view are not within the ambit of Fourth Amendment protection. As such, upon
the inadvertent discovery of contraband pursuant to the plain view exception, no
warrant requirement adheres to its ensuing seizure. 55
Given this dynamic, the impact of this exception in the traffic detention context
is substantial. The discovery of contraband in such a fashion imbues law enforcement
officers with the authority to effectuate a seizure, and may also provide probable56
cause for a warrantless search. Furthermore, this exception has also been adapted
to allow for "plain touch" and "plain smell" seizures when illegality is immediately
apparent. 57
Consent Searches. Law enforcement officers may also conduct a warrantless
search after obtaining voluntary consent, irrespective of probable cause or reasonable58
suspicion. Consent so obtained may be either express or implied, and does not
necessarily have to be knowing and intelligent. Pursuant to this standard, the59
Supreme Court has ruled that an officer is not required to inform a lawfully detained60
driver that he is free to leave prior to requesting permission to search.
In Ohio v. Robinette, a police officer stopped a vehicle for exceeding the speed
limit. During the course of the stop, the officer requested that the driver exit the
vehicle, whereupon the driver was given a warning and his license and registration
were returned. After this exchange, the officer asked the detainee if there was any
illegal contraband in the vehicle. The officer then explicitly requested permission to
search, and received consent. Upon conducting a search of the vehicle, the officer

Coolidge v. New Hampshire, 403 U.S. 443 (1971).53
Texas v. Brown, 460 U.S. 730, 738 (1983).54
Id. at 740; See also, Katz v. United States, 389 U.S. 347, 361 (1967) (establishing that55
items in plain view are not subject to the Fourth Amendment).
See Maryland v. Wilson; Michigan v. Long, supra.56
See United States v. Downs, 151 F.3d 1301 (10 Cir. 1998).57th
Schneckloth v. Bustamonte, 412 U.S. 218, 219 (1973).58
Id. at 241. As opposed to waiver of rights in a trial setting, consent to a search and seizure59
may be given unintentionally and without specific knowledge of the right to deny a search
request. Id. at 235-236. See Twenty-Eighth Annual Review of Criminal Procedure:
Warrantless Searches and Seizures, 87 Geo. L.J. 1124 (1999).
Ohio v. Robinette, 519 U.S. 33, 33-34 (1996).60

discovered illegal narcotics. The driver was subsequently arrested and charged with61
possession of a controlled substance.
The Supreme Court of Ohio had ruled that the search was violative of the Fourth
Amendment. In particular, the Ohio court determined that the legitimate traffic stop
concluded upon the issuance of the warning and return of the driver's license and62
registration, rendering any further detention illegal. The Ohio Supreme Court found
that the subsequent search request could not be construed as a consensual encounter,
since most individuals believe they are still in custody "as long as the officer continues63
to interrogate them." Accordingly, Ohio established a bright line rule, stating that
when the purpose of an initial stop is completed, the officer involved must inform the
individual that he or she is “legally free to go.” 64
The Supreme Court of the United States reversed, declaring that law
enforcement officials do not have a constitutional duty under the Fourth Amendment
to inform individuals as to whether a particular police encounter is consensual.
Specifically, the Court explained that the central focus of any inquiry into such an
encounter must center on reasonableness, “measured in objective terms by examining
the totality of the circumstances.” Furthermore, the Court stressed that it “eschewed65
bright-line rules” of the sort proposed by Ohio, finding it more appropriate to focus
on the “fact specific nature” of a reasonableness inquiry in the Fourth Amendment66
Illustrating this approach, the Court discussed Schneckloth v. Bustamonte, where
it held that the validity of an individual’s consent to a vehicle search did not require
that the defendant know of his right to refuse such a request. Specifically, the Court
stated that “while knowledge of the right to refuse consent is one factor to be taken
into account, the government need not establish such knowledge as the sine qua non67
of an effective consent.” The Court further explained that it "would be thoroughly
impractical to impose on the normal consent search the detailed requirements of an68
effective warning." Applying this rationale to the case at hand, the Court in
Robinette declared that it would be "unrealistic to require police officers to always
inform detainees that they are free to go before a consent to search may be deemed
voluntary." The Court concluded its discussion by stressing again that the Fourth69

Id. at 35-36.61
State v. Robinette, 653 N.E.2d 695, 697 (Ohio 1995), rev’d, 519 U.S. 33 (1996)).62
State v. Robinette, 653 N.E.2d at 698-699.63
State v. Robinette, 653 N.E.2d at 699.64
Ohio v. Robinette, 519 U.S. 33, 39 (1996) (citing Florida v. Jimeno, 500 U.S. 248, 25065
Robinette, 519 U.S. at 39.66
Schneckloth v. Bustamonte, 412 U.S. 218, 227 (1973).67
Id. at 227.68
Robinette, 519 U.S. at 40.69

Amendment test for valid search consent is whether such consent was voluntary, as70
determined by a factual inquiry focusing on a totality of the circumstances.
Search Incident to Arrest. The Supreme Court has also established that,
subsequent to a lawful custodial arrest, police may conduct a warrantless search of
an arrestee, irrespective of probable cause and reasonable suspicion to indicate the71
presence of either weapons or evidence. Unlike the limited focus of a Terry stop and
frisk, police may make a full search for weapons and evidence in a search conducted
incident to a valid arrest. Furthermore, in Chimel v. California, the Supreme Court72
ruled that police could also search the area within the immediate control of an
arrestee, explaining that the scope of such a search was necessary to ensure officer73
safety and maintain evidence integrity. In New York v. Belton, the Court extended
the scope of its ruling in Chimel, holding that a custodial arrest imbued police with
the power to conduct a search of the passenger compartment of an automobile.
Specifically, the Court declared that authorities may search the passenger
compartment and any containers located therein, even after establishing exclusive
custody over the vehicle and arrestee.74
From the aforementioned cases, it is evident that the Supreme Court has placed
significant weight on officer safety considerations in delineating the scope of police
power to conduct searches and seizures in the traffic stop context. As noted these
decisions have led many legal scholars to the conclusion that the Court has established
a strong law enforcement preference in Fourth Amendment issues, impinging upon
personal liberty interests guaranteed under the Constitution. While these may be valid
concerns, it is important to note that the Court continues to operate within traditional
Fourth Amendment parameters. This is illustrated in the search incident to arrest75
context in the recent case of Knowles v. Iowa.
In Knowles v. Iowa, the United States Supreme Court overturned a ruling from
the Supreme Court of Iowa, which had validated a police officer's warrantless search
of an automobile stopped for a traffic violation, even though the driver was not
arrested for the offense, but, rather, had merely been issued a citation. The Iowa
Supreme Court validated the search on the basis that "so long as the arresting officer
had probable cause to make a custodial arrest, there need not in fact have been a

Id .70
New York v. Belton, 453 U.S. 454 (1981); United States v. Robinson, 414 U.S. 218 (1973).71
See Robinson, 414 U.S. at 229.72

395 U.S. 752, 763 (1969).73

Belton, 453 U.S. at 460. According to the Court, the term container refers to any object74
capable of holding another object, including "closed or open glove compartments, consoles or
other receptacles located anywhere within the passenger compartment, as well as luggage,
boxes, bags, clothing and the like." Id. The Court clarified the scope of its holding, noting that
authority to search did not extend to the trunk of an automobile. Id. However, a search of the
hatch area of an automobile has been upheld due to the accessibility of such an area from thest
passenger area. See United States v. Doward, 41 F.3d 789, 794 (1 Cir. 1994).

119 S.Ct. 484 (1998).75

custodial arrest." The Supreme Court of the United States, noting that none of the76
justifications supporting searches incident to arrest adhere to a typical traffic stop,
held that the police action was violative of the Fourth Amendment. Specifically, the
Court explained that the officer safety rationale was not applicable, in that the threat
posed by the issuance of a traffic citation is substantially less than in the custodial
arrest context, which is of special concern given "the extended exposure which
follows the taking of suspect into custody and transporting him to the police77
station." Clarifying this point, the Court stated that while safety concerns are present
in a routine traffic stop, they do not justify the significant intrusion effected by a full
search. Rather, the Court found it significant that officers possess other means by
which they may protect themselves, such as ordering individuals to exit vehicles, and
to conduct Terry frisks and searches where justified. Furthermore, the Court78
declared that a "search incident to citation" exception to the Fourth Amendment could
not be justified by a need to preserve evidence, since once an individual is stopped and
issued a citation, "all evidence necessary to prosecute that offense has been79
obtained." The Court also declared that such a search could not be justified on the
basis that an individual stopped for a traffic offense might destroy evidence of another
crime, noting that the possibility of discovering evidence unrelated to a traffic offense
was too remote.80
In light of the aforementioned cases, it is evident that the Supreme Court has
crafted significant exceptions to the warrant and probable cause requirements of the
Fourth Amendment in the traffic detention context. As has been shown, recent
decisions in particular have arguably expanded the scope of law enforcement power
leading some commentators to declare that the Fourth Amendment has been all but
abrogated in the vehicular context.
However, while cases such as Whren and Wilson show that the Court has indeed
clarified and sanctioned greater protective and investigative police authority in the
traffic context, it is important to remember that these rulings have been predicated
upon well settled constitutional principles. Furthermore, the Court's decision in
Knowles establishes that the same rationales supporting extensions of law enforcement
authority also serve to circumscribe police power. As such, it seems that while police
officers do indeed possess broad authority under these decisions, the Court's rulings
have adhered to the basic principles which fostered the initial development of the
exceptions discussed above. As such, rather than forging new doctrinal interpretations
of Fourth Amendment boundaries and exceptions, it appears that the Court has
applied settled constitutional principles to previously unencountered factual scenarios,
expanding police power in certain respects, while restricting it in others.

Id. at 487.76
Id. at 488 (quoting United States v. Robinson, 414 U.S. 218, 234-235 (1973)).77
Knowles, 119 S.Ct. at 488.78
Id. at 488.79
Id. at 488.80