What to do when the police want to search your car

If a Madison police officer or Dane County sheriff’s deputy pulls you over and wants to search your vehicle, you need to know your rights. Specifically, whether you have the right to decline the search or if you must comply.

Generally, under the Fourth Amendment of the Bill of Rights, the police do not have the right to search your vehicle without getting a search warrant first. But there are several exceptions.


Police do not need a warrant when the driver gives them permission to search their vehicle. You have the right to refuse consent when asked.

Probable Cause

When a police officer has reason to believe there is evidence of a crime inside a vehicle, that is called probable cause, which allows them to conduct a search without asking a judge for a warrant. To show probable cause, the officer must be able to show that a reasonable person would believe that a crime has been or is being committed in the vehicle or that it contains evidence. An example of probable cause is when there is a marijuana smell inside the vehicle, and the driver shows signs of being high.


A police officer can search a vehicle without a warrant if they reasonably believe doing so is necessary for their own safety.

Following an arrest

Finally, a warrant vehicle search is allowed if the police have arrested the driver and are searching for evidence related to the arrest.

Defending your rights happens in the courtroom

Despite police officers’ training on the rules of a legal vehicle search, illegal searches still happen. When an officer violates your rights, there may not be anything you can do about it at the time. But you can alert your defense attorney later. They will investigate the incident and, if there is evidence of wrongdoing, use it to fight to get the resulting evidence thrown out as “fruit of the poisonous tree” — meaning, the result of illegal police procedure.