What is required to perform an "automobile exception" search?

To perform an "automobile exception" search, the critical requirement is having probable cause to believe that the vehicle contains contraband. The automobile exception is a legal principle that allows law enforcement officers to search a vehicle without a warrant if there is a reasonable belief that it holds evidence of a crime, typically because of the mobility of vehicles and the diminished expectation of privacy associated with them. This principle acknowledges that obtaining a warrant could result in the loss of evidence due to the vehicle's ability to move.

Other options like needing the presence of a witness or the vehicle's owner aren't necessary for executing this type of search. Similarly, a search warrant is not required when the officers have probable cause, as the nature of vehicles permits a more immediate response. Thus, the legal focus is on the evidence officers perceive at the moment rather than procedural requirements that could delay the search.