For example, where a person gets arrested in or near his/her vehicle, the police officer may have the legal authority to search the vehicle depending on the circumstances. Many drug cases are made this way. Arrests for driving with a suspended license or driving under the influence (DUI) are obviously common arrests involving people and their vehicles.
If there is a sober person at the scene, such as a friend or relative of the person getting arrested who has permission to take the vehicle, the police officer should let that person drive the vehicle away. If not, and there is no one available to drive the vehicle from the scene, the police can impound the vehicle. In those cases, the police are allowed to conduct what is called an inventory search. The official reason for an inventory search is to document any valuable items in the vehicle so they can be secured and returned to the suspect. However, police use that opportunity to search for drugs, guns and any other evidence in the vehicle
One other basis for searching a vehicle after an arrest is the search incident to an arrest. This kind of search has been limited fairly recently, but it basically allows a police officer to search a vehicle if the person arrested is close to the vehicle to make sure there are no weapons or anything else to which the defendant may have access. However, in most cases, when the police arrest someone, they place that person in handcuffs and safely in their patrol car. If that is where the suspect is, he/she obviously cannot reach anything in his/her vehicle. In that case, there is no basis for the police officer to search the vehicle.