One of the most important exceptions to the warrant requirement is the automobile exception, permitting officers to search anywhere inside a movable vehicle (even if it is not immediately mobile) without a warrant as long as there is probable cause to believe that that area of the vehicle could contain evidence of a crime.
This is justified because vehicles have lower expectations of privacy because they are made to transport one through the public and because they are subject to many regulations.
The automobile exception applies not only to the passenger compartment. It also permits searches of the trunk or containers inside a vehicle provided that the police have probable cause that contraband is contained therein.
- If a container that police have probable cause to search is put into a vehicle, police then have probable cause to search both the vehicle and the container.
- This includes passengers' items if police have probable cause for them too, such as by virtue of them being in the area of control of a suspect.
The automobile exception does not permit police to enter the curtilage of one's home to conduct a warrantless search of his automobile.