The Fourth Amendment to the U.S. Constitution prohibits police from conducting “unreasonable searches and seizures.” These constitutional protections apply to the search and seizure of a vehicle.
Below we review how courts determine whether a vehicle search was lawful and what can happen if a vehicle search was illegal.
(This article is based on U.S. Constitutional law as interpreted by the U.S. Supreme Court. Note that your state’s laws might offer more protection.)
Vehicle Stops and the 4th Amendment
Most people have heard the term "search and seizure" and probably know that the constitution prohibits illegal searches and seizures by police. But what exactly does this language mean?
Here are some of the basics of how the search and seizure rules apply to vehicle stops and searches.
Traffic Stops Are Covered by the 4th Amendment
When police stop a vehicle, it is considered a seizure for Fourth Amendment purposes. So there are constitutional rights at stake and police must abide by certain rules for a traffic stop or subsequent search to be lawful (although a lawful stop doesn't automatically justify a search).
When Police Can Lawfully Stop a Vehicle Under the 4th Amendment
In most situations, the legality of a traffic stop turns on whether police had reasonable suspicion to believe the driver broke the law. If the police had no legitimate reason to pull the driver over, the stop and any subsequent search are illegal.
(There are only limited circumstances—immigration and DUI checkpoints for example—that allow law enforcement to detain vehicles without reasonable suspicion.)
Vehicle Searches and the 4th Amendment
Courts generally analyze vehicle searches in two parts:
- the initial traffic stop, and
- the search of the vehicle.
For a vehicle search to be legal under the 4th amendment, the initial stop and the search itself must be justified.
Can Police Search Your Car During a Traffic Stop?
A traffic violation, alone, generally doesn’t give police the right to search the inside of a car. Otherwise, police could rifle through your car during routine traffic stops.
Do Police Need a Warrant to Search a Stopped Vehicle?
Not usually. Police can search a car during a traffic stop without a warrant if they have probable cause to believe that the car contains evidence of criminal activity (like drugs or illegal weapons).
Probable cause is a fact-specific determination, so there’s no single rule that applies in all situations. But basically, police must have reasonable, objective grounds to believe there’s incriminating evidence inside the car. Probable cause can come from information police receive before the stop or observations made during the detention.
Examples of Probable Cause Vehicle Searches
Let's say an officer sees a vehicle pull up to the corner. As the vehicle stops at the curb, a man approaches the car window and says: “What are you looking for?” The driver then responds, “two grams.” The man hands the driver two small baggies and the driver gives him a wad of bills in return. The officer stops the motorist a few blocks down. After having the motorists step out of the vehicle, the officer finds two grams of heroin in the center console. The officer had probable cause to stop and search the vehicle based on what the saw and heard.
Or say an officer stops a vehicle for speeding but notices a gun on the floorboard while writing the ticket. The officer would likely be justified in removing the driver and searching the vehicle.
Vehicle Searches: Exception to the Probable Cause Requirement
Probable cause isn’t the only basis upon which an officer can conduct a warrantless search of a car. Common exceptions to the probable cause rule are consent, search incident to arrest, and inventory searches.
Consent Searches of Vehicles
Police can search a car without probable cause if the driver gives permission. However, consent is valid only if the driver gives it voluntarily. In other words, police aren’t supposed to threaten or coerce the motorist into agreeing to a search.
Vehicle Searches Incident to Arrest
Another exception to the probable cause rule can come into play when police arrest a driver or passenger. However, an arrest doesn’t always give police unlimited authority to rifle through the whole car. A search “incident to arrest” is valid only to the extent necessary to:
- ensure officer safety, or
- preserve evidence of the offense for which the person was arrested.
And there’s a related rule that restricts an otherwise permissible search to just those areas of the car that could contain the weapon or evidence sought. For instance, if police are looking for a stolen bike, it probably wouldn’t be reasonable to search a glove box. But if they’re on the hunt for something small like drugs, a more thorough search would be justified.
Inventory Searches of Vehicles
Sometimes a traffic stop leads to an arrest. When this occurs and no one is there to take control of the vehicle, police usually have the vehicle towed to an impound lot. Generally, police are allowed to conduct an “inventory” search of a lawfully impounded vehicle. But the purpose of an inventory search isn’t to rummage for incriminating evidence. Police are allowed to do these searches so that they can:
- protect the owner’s property while it’s in police custody
- insure against claims of lost, stolen, or damaged property, and
- guard officers from dangers that the contents of the car might pose (such as from flammable or combustible substances).
If, however, police happen to find evidence of criminal activity during a legitimate inventory search, it can usually be used against the defendant in court.
What to Do If You Think Police Illegally Searched Your Car
If police search a vehicle in violation of the Fourth Amendment, any evidence of illegal activity obtained during the search will typically be inadmissible in court. Lots of cases that end up in criminal court turn on whether a police search was legal. If it's at least debatable, defense attorneys will typically file a "motion to suppress" asking the court to throw out certain evidence recovered by police. When a defendant succeeds with a motion to suppress illegally obtained evidence, it often leads to criminal charges being thrown out altogether.
The legality of a search always depends on the facts of the case. So it's always best to talk to an attorney if you have a situation where your vehicle was searched by police.