Search Incident to an Arrest vs. Automobile Exception

Both a search incident to a lawful arrest and the automobile exception are exceptions to the warrant requirement. Though similar, the MBE is far more likely to test the differences.

Search Incident to an Arrest:

A valid arrest requires among other things that it is based on probable cause to believe that a law has been violated. Incident to such an arrest, the police without a warrant may search the person arrested and areas into which that person might reach either to obtain weapons or to destroy evidence. It is sometimes said that as per this exception, the police can search the "wingspan" of the arrestee. Also allowable is a "protective sweep" of the area if the police believe that accomplices may be present.

Importantly, the search must be contemporaneous in time and place with the arrest. This requirement is applied rather broadly when the arrest occurs in an automobile. The police may search the interior of an automobile even after securing a recent occupant of the automobile if the police have reason to believe that the vehicle contains evidence of the crime for which the recent occupant was arrested.

Contemporaneous with an arrest for intoxicated drivers, police may administer a warrantless breath test to determine the arrestee's alcohol level. In contrast, to conduct a blood test will require a warrant. Police officers may also examine a person's cell phone upon arrest but that examination does not extend to the data on a cell phone. To examine the data will require obtaining a warrant to do so.

Once at the police station, the police can make an inventory search of the arrestee's belongings pursuant to department procedures. Inventory searches of impounded vehicles are also proper. 

The Automobile Exception:

One important distinction between the automobile exception and the search incident to an arrest is that with the automobile exception the police generally can search more of the vehicle. Specifically, if the police have probable cause to believe that a vehicle contains evidence of a crime, they may search the whole vehicle and any container that might reasonably contain the item they have probable cause to search. If the probable cause extends only to the containers then only the containers in the vehicle may be searched. If a search is valid under the automobile exception, the police may tow the vehicle to the station and search it later. The search of the vehicle may extend to packages belonging to a passenger; the search is not limited to packages belonging to the driver.

Plain View:

One last consideration that would apply both to the search incident to an arrest and to the automobile exception is the exception to the warrant requirement called "plain view." In both instances, the police can make a warrantless seizure if they are in a place they are legally entitled to be and if they have probable cause to believe that items in their plain view of sight are evidence of a crime.