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Vehicle Searches Under the Fourth Amendment - FindLaw

Generally, the Fourth Amendment requires law enforcement officers to have a warrant to conduct a search of someone’s home or person. However, over the years the Supreme Court has carved out exceptions to the warrant requirement. One of the most common is the exception for motor vehicles, which can be searched without a warrant if the officer has probable cause to believe the vehicle contains illegal materials. 

What the Fourth Amendment Says

“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.”

Does the Fourth Amendment Apply to Vehicle Searches?

United States Library of Congress, The Constitution of the United States of America: Analysis and Interpretation

In the early days of the automobile, the Court created an exception for searches of vehicles, holding in Carroll v. United States1 that vehicles may be searched without warrants if the officer undertaking the search has probable cause to believe that the vehicle contains contraband. The Court explained that the mobility of vehicles would allow them to be quickly moved from the jurisdiction if time were taken to obtain a warrant.2

Initially, the Court limited Carroll’s reach, holding impermissible the warrantless seizure of a parked automobile merely because it is movable, and indicating that vehicles may be stopped only while moving or reasonably contemporaneously with movement.3 The Court also ruled that the search must be reasonably contemporaneous with the stop, so that it was not permissible to remove the vehicle to the station house for a warrantless search at the convenience of the police.4

The Court next developed a reduced privacy rationale to supplement the mobility rationale, explaining that the configuration, use, and regulation of automobiles often may dilute the reasonable expectation of privacy that exists with respect to differently situated property.5 One has a lesser expectation of privacy in a motor vehicle because its function is transportation and it seldom serves as one’s residence or as the repository of personal effects. It travels public thoroughfares where both its occupants and its contents are in plain view.’6 Although motor homes serve as residences and as repositories for personal effects, and their contents are often shielded from public view, the Court extended the automobile exception to them as well, holding that there is a diminished expectation of privacy in a mobile home parked in a parking lot and licensed for vehicular travel, hence readily mobile.7

If My Car Is Parked in the Driveway, Can Police Search My Home Too?

The Court has stated, however, that the automobile exception does not permit an officer without a warrant to enter a home or its curtilage in order to search a vehicle therein.8 This limit to the exception exists because the scope of the automobile exception extends no further than the automobile itself.9 To search a vehicle under the automobile exception, an officer must have a lawful right of access to that vehicle,10 and generally, law enforcement officers have no right to enter a home or its curtilage without express or implied permission or without a warrant.11

The reduced expectancy concept has broadened police powers to conduct automobile searches without warrants, but they still must have probable cause to search a vehicle12 and they may not make random stops of vehicles on the roads, but instead must base stops of individual vehicles on probable cause or some articulable and reasonable suspicion13 of traffic or safety violation or some other criminal activity.14 If police stop a vehicle, then the vehicle's passengers, as well as its driver, are deemed to have been seized from the moment the car comes to a halt, and the passengers as well as the driver may challenge the constitutionality of the stop.15 A driver with lawful possession and control of a rental car may also be able to challenge the constitutionality of a stop, even if that driver is not listed as an authorized driver on the rental agreement.16 Likewise, a police officer may frisk (patdown for weapons) both the driver and any passengers whom he reasonably concludes might be armed and presently dangerous.17

By contrast, fixed-checkpoint stops in the absence of any individualized suspicion have been upheld for purposes of promoting highway safety18 or policing the international border,19 but not for more generalized law enforcement purposes.20 Once police have validly stopped a vehicle, they may also, based on articulable facts warranting a reasonable belief that weapons may be present, conduct a Terry-type protective search of those portions of the passenger compartment in which a weapon could be placed or hidden.21 And, in the absence of such reasonable suspicion as to weapons, police may seize contraband and suspicious items in plain view inside the passenger compartment.22

Although officers who have stopped a car to issue a routine traffic citation may conduct a Terry-type search, even including a pat-down of driver and passengers if there is reasonable suspicion that they are armed and dangerous, they may not conduct a full-blown search of the car23 unless they exercise their discretion to arrest the driver instead of issuing a citation.24 And once police have probable cause to believe there is contraband in a vehicle, they may remove the vehicle from the scene to the station house in order to conduct a search, without thereby being required to obtain a warrant.25 [T]he justification to conduct such a warrantless search does not vanish once the car has been immobilized; nor does it depend upon a reviewing court’s assessment of the likelihood in each particular case that the car would have been driven away, or that its contents would have been tampered with, during the period required for the police to obtain a warrant.26 Because of the lessened expectation of privacy, inventory searches of impounded automobiles are justifiable in order to protect public safety and the owner’s property, and any evidence of criminal activity discovered in the course of the inventories is admissible in court.27 The Justices were evenly divided, however, on the propriety of warrantless seizure of an arrestee’s automobile from a public parking lot several hours after his arrest, its transportation to a police impoundment lot, and the taking of tire casts and exterior paint scrapings.28

Police in undertaking a warrantless search of an automobile may not extend the search to the persons of the passengers therein29unless there is a reasonable suspicion that the passengers are armed and dangerous, in which case a Terry patdown is permissible,30 or unless there is individualized suspicion of criminal activity by the passengers.31 But because passengers in an automobile have no reasonable expectation of privacy in the interior area of the car, a warrantless search of the glove compartment and the spaces under the seats, which turned up evidence implicating the passengers, invaded no Fourth Amendment interest of the passengers.32 Luggage and other closed containers found in automobiles may also be subjected to warrantless searches based on probable cause, regardless of whether the luggage or containers belong to the driver or to a passenger, and regardless of whether it is the driver or a passenger who is under suspicion.33 The same rule now applies whether the police have probable cause to search only the containers34 or whether they have probable cause to search the automobile for something capable of being held in the container.35

Searches of Containers Within a Vehicle

Not only is the warrant requirement inapplicable to brief stops of vessels, but also none of the safeguards applicable to stops of automobiles on less than probable cause are necessary predicates to stops of vessels. In United States v. Villamonte-Marquez,36 the Court upheld a random stop and boarding of a vessel by customs agents, lacking any suspicion of wrongdoing, for purpose of inspecting documentation. The boarding was authorized by statute derived from an act of the First Congress,37 and hence had an impressive historical pedigree carrying with it a presumption of constitutionality. Moreover, important factual differences between vessels located in waters offering ready access to the open sea and automobiles on principal thoroughfares in the border area justify application of a less restrictive rule for vessel searches. The reason why random stops of vehicles have been held impermissible under the Fourth Amendment, the Court explained, is that stops at fixed checkpoints or roadblocks are both feasible and less subject to abuse of discretion by authorities. But no reasonable claim can be made that permanent checkpoints would be practical on waters such as these where vessels can move in any direction at any time and need not follow established ‘avenues’ as automobiles must do.38 Because there is a substantial governmental interest in enforcing documentation laws, especially in waters where the need to deter or apprehend smugglers is great, the Court found the limited but not minimal intrusion occasioned by boarding for documentation inspection to be reasonable.39 Dissenting Justice Brennan argued that the Court for the first time was approving a completely random seizure and detention of persons and an entry onto private, noncommercial premises by police officers, without any limitations whatever on the officers’ discretion or any safeguards against abuse.40

More on the Fourth Amendment


1.    267 U.S. 132 (1925). Carroll was a Prohibition-era liquor case, whereas a great number of modern automobile cases involve drugs.

2.    267 U.S. at 153. See also Husty v. United States, 282 U.S. 694 (1931)Scher v. United States, 305 U.S. 251 (1938)Brinegar v. United States, 338 U.S. 160 (1949). All of these cases involved contraband, but in Chambers v. Maroney, 399 U.S. 42 (1970), the Court, without discussion, and over Justice Harlan’s dissent, id. at 55, 62, extended the rule to evidentiary searches.

3.    Coolidge v. New Hampshire, 403 U.S. 443, 458–64 (1971). This portion of the opinion had the adherence of a plurality only, Justice Harlan concurring on other grounds, and there being four dissenters. Id. at 493, 504, 510, 523.

4.    Preston v. United States, 376 U.S. 364 (1964)Dyke v. Taylor Implement Mfg. Co., 391 U.S. 216 (1968).

5.    Arkansas v. Sanders, 442 U.S. 753, 761 (1979).

6.    Cardwell v. Lewis, 417 U.S. 583, 590 (1974) (plurality opinion), quoted in United States v. Chadwick, 433 U.S. 1, 12 (1977)See also United States v. Ortiz, 422 U.S. 891, 896 (1975)United States v. Martinez-Fuerte, 428 U.S. 543, 561 (1976)South Dakota v. Opperman, 428 U.S. 364, 367–68 (1976)Robbins v. California, 453 U.S. 420, 424–25 (1981)United States v. Ross, 456 U.S. 798, 807 n.9 (1982).

7.    California v. Carney, 471 U.S. 386, 393 (1985) (leaving open the question of whether the automobile exception also applies to a mobile home being used as a residence and not readily mobile).

8.    Collins v. Virginia, 138 S. Ct. 1663, 1675 (2018).

9.    Id. at 1671.

10. Id. at 1672.

11. See, e.g., Florida v. Jardines, 569 U.S. 1, 7–8 (2013).

12. Almeida-Sanchez v. United States, 413 U.S. 266 (1973) (roving patrols); United States v. Ortiz, 422 U.S. 891 (1975)Cf. Colorado v. Bannister, 449 U.S. 1 (1980). An automobile’s ready mobility [is] an exigency sufficient to excuse failure to obtain a search warrant once probable cause is clear; there is no need to find the presence of unforeseen circumstances or other additional exigency. Pennsylvania v. Labron, 527 U.S. 465 (1996)AccordMaryland v. Dyson, 527 U.S. 465 (1999) (per curiam). Cf. Florida v. Harris, 568 U.S. 237 (2013).

13. Delaware v. Prouse, 440 U.S. 648, 663 (1979) (discretionary random stops of motorists to check driver’s license and automobile registration constitute Fourth Amendment violation); United States v. Brignoni-Ponce, 422 U.S. 873 (1975) (affirming an appellate court's judgment that stopping a vehicle on a highway near an international border merely because the occupants appeared to be of Mexican ancestry was an unconstitutional search for unlawfully present aliens). But cf. United States v. Arvizu, 534 U.S. 266 (2002) (reasonable suspicion justified stop by border agents of vehicle traveling on unpaved backroads in an apparent effort to evade a border patrol checkpoint on the highway). In Prouse, the Court cautioned that it was not precluding the states from developing methods for spot checks, such as questioning all traffic at roadblocks, that involve less intrusion or that do not involve unconstrained exercise of discretion. 440 U.S. at 663.

14. For example, an officer who learns, through a license plate search of a vehicle, that the registered owner has a revoked license may have a reasonable suspicion to stop that vehicle if it matches the description of the registered car and if, at the time of the stop, the officer has no countervailing reason to think the driver is not the registered owner. Kansasv. Glover, 140 S. Ct. 1183, 1184, 1191 (2020). An officer who observes a traffic violation may stop a vehicle even if his real motivation is to investigate for evidence of other crime. Whren v. United States, 517 U.S. 806 (1996). The existence of probable cause to believe that a traffic violation has occurred establishes the constitutional reasonableness of traffic stops regardless of the actual motivation of the officers involved, and regardless of whether it is customary police practice to stop motorists for the violation observed. Similarly, pretextual arrest of a motorist who has committed a traffic offense is permissible. Arkansas v. Sullivan, 532 U.S. 769 (2001) (per curiam) (upholding search of the motorist’s car for a crime not related to the traffic offense).

15. Brendlin v. California, 551 U.S. 249, 263 (2007).

16. Byrd v. United States, 138 S. Ct. 1518, 1523–24 (2018). But see id. at 1529 (noting that a car thief would not have a reasonable expectation of privacy in a stolen car).

17. Arizona v. Johnson, 129 S. Ct. 781, 786 (2009).

18. Michigan Dep’t of State Police v. Sitz, 496 U.S. 444 (1990) (upholding a sobriety checkpoint at which all motorists are briefly stopped for preliminary questioning and observation for signs of intoxication).

19. United States v. Martinez-Fuerte, 428 U.S. 543 (1976) (rejecting a Fourth Amendment challenge to a Border Patrol stop of vehicles at a permanent checkpoint designed to apprehend unlawfully present aliens). See also United States v. Flores-Montano, 541 U.S. 149 (2004) (upholding a search at the border involving disassembly of a vehicle's fuel tank).

20. City of Indianapolis v. Edmond, 531 U.S. 32 (2000) (vehicle checkpoint set up for the primary purpose [of] detect[ing] evidence of ordinary criminal wrongdoing (here interdicting illegal narcotics) does not fall within the highway safety or border patrol exception to the individualized suspicion requirement, and hence violates the Fourth Amendment). Edmond was distinguished in Illinois v. Lidster, 540 U.S. 419 (2004), upholding use of a checkpoint to ask motorists for help in solving a recent hit-and-run accident that had resulted in death. The public interest in solving the crime was deemed grave, while the interference with personal liberty was deemed minimal.

21. Michigan v. Long, 463 U.S. 1032, 1049 (1983) (holding that contraband found in the course of such a search is admissible).

22. Texas v. Brown, 460 U.S. 730 (1983). Similarly, because there is no reasonable privacy interest in the vehicle identification number, required by law to be placed on the dashboard so as to be visible through the windshield, police may reach into the passenger compartment to remove items obscuring the number and may seize items in plain view while doing so. New York v. Class, 475 U.S. 106 (1986). Because there also is no legitimate privacy interest in possessing contraband, and because properly conducted canine sniffs are generally likely[] to reveal only the presence of contraband, police may conduct a canine sniff around the perimeter of a vehicle stopped for a traffic offense so long as the stop is not prolonged beyond the time needed to process the traffic violation. Compare Illinois v. Caballes, 543 U.S. 405 (2005) (a canine sniff around the perimeter of a car following a routine traffic stop does not offend the Fourth Amendment if the duration of the stop is justified by the traffic offense) with Rodriguez v. United States, 135 S. Ct. 1609, 1613, 1614–15 (2015) (finding that the stop in question had been prolonged for seven to eight minutes beyond the time needed to resolve the traffic offense in order to conduct a canine sniff).

23. Knowles v. Iowa, 525 U.S. 113 (1998) (invalidating an Iowa statute permitting a full-blown search incident to a traffic citation).

24. See Atwater v. City of Lago Vista, 532 U.S. 318 (2001) (police officers, in their discretion, may arrest a motorist for a minor traffic offense rather than issuing a citation); New York v. Belton, 453 U.S. 454 (1981) (officers who arrest an occupant of a vehicle may make a contemporaneous search of the entire passenger compartment, including closed containers); Thornton v. United States, 541 U.S. 615 (2004) (the Belton rule applies regardless of whether the arrestee exited the car at the officer's direction, or whether he did so prior to confrontation); Arizona v. Gant, 556 U.S. 332, 351 (2009)(the Belton rule applies only if the arrestee is within reaching distance of the passenger compartment at the time of the search or it is reasonable to believe that the vehicle contains evidence of the offense of arrest); Arkansas v. Sullivan, 532 U.S. 769 (2001) (pretextual arrest of motorist who has committed a traffic offense is permissible even if purpose is to search vehicle for evidence of other crime).

25. Michigan v. Thomas, 458 U.S. 259 (1982). The same rule applies if it is the vehicle itself that is forfeitable contraband; police, acting without a warrant, may seize the vehicle from a public place. Florida v. White, 526 U.S. 559 (1999).

26. Michigan v. Thomas, 458 U.S. at 261. See also Chambers v. Maroney, 399 U.S. 42 (1970)Texas v. White, 423 U.S. 67 (1975)United States v. Ross, 456 U.S. 798, 807 n.9 (1982).

27. Cady v. Dombrowski, 413 U.S. 433 (1973)South Dakota v. Opperman, 428 U.S. 364 (1976)See also Cooper v. California, 386 U.S. 58 (1967)United States v. Harris, 390 U.S. 234 (1968). Police, in conducting an inventory search of a vehicle, may open closed containers in order to inventory contents. Colorado v. Bertine, 479 U.S. 367 (1987).

28. Cardwell v. Lewis, 417 U.S. 583 (1974). Justice Powell concurred on other grounds.

29. United States v. Di Re, 332 U.S. 581 (1948);Ybarra v. Illinois, 444 U.S. 85, 94–96 (1979).

30. Knowles v. Iowa, 525 U.S. 113, 118 (1998).

31. Maryland v. Pringle, 540 U.S. 366 (2003) (probable cause to arrest passengers based on officers finding $783 in glove compartment and cocaine hidden beneath back seat armrest, and on driver and passengers all denying ownership of the cocaine).

32. Rakas v. Illinois, 439 U.S. 128 (1978).

33. Wyoming v. Houghton, 526 U.S. 295, 307 (1999) (police officers with probable cause to search a car may inspect passengers’ belongings found in the car that are capable of concealing the object of the search).

34. California v. Acevedo, 500 U.S. 565 (1991) (overruling Arkansas v. Sanders, 442 U.S. 753 (1979).

35. United States v. Ross, 456 U.S. 798 (1982). A Ross search of a container found in an automobile need not occur soon after its seizure. United States v. Johns, 469 U.S. 478 (1985) (three-day time lapse). See also Florida v. Jimeno, 500 U.S. 248 (1991) (consent to search automobile for drugs constitutes consent to open containers within the car that might contain drugs).

36. 462 U.S. 579 (1983).

37. 19 U.S.C. § 1581(a), derived from § 31 of the Act of Aug. 4, 1790, ch. 35, 1 Stat. 164.

38. 462 U.S. at 589. Justice Brennan’s dissent argued that a fixed checkpoint was feasible in this case, involving a ship channel in an inland waterway. Id. at 608 n.10. The fact that the Court’s rationale was geared to the difficulties of law enforcement in the open seas suggests a reluctance to make exceptions to the general rule. Note as well the Court’s later reference to this case as among those reflect[ing] longstanding concern for the protection of the integrity of the border. United States v. Montoya de Hernandez, 473 U.S. 531, 538 (1985).

39. 462 U.S. at 593.

40. 462 U.S. at 598. Justice Brennan contended that all previous cases had required some discretion-limiting feature such as a requirement of probable cause, reasonable suspicion, fixed checkpoints instead of roving patrols, and limitation of border searches to border areas, and that these principles set forth in Delaware v. Prouse, 440 U.S. 648 (1979), should govern. Id. at 599, 601.

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