In Terry v. Ohio (1968), the United States Supreme Court recognized one exception to the warrant requirement established by the Fourth Amendment. The Court held that a police officer may conduct a brief, warrantless search of an individual’s person for weapons if the officer has a reasonable and articulable suspicion that the “individual whose suspicious behavior he is investigating at close range is armed and presently dangerous to the officer or to others.”
This exception was later extended to protective searches of automobiles in Michigan v. Long (1983). Long holds that “the search of the passenger compartment of an automobile, limited to those areas in which a weapon may be placed or hidden, is permissible if the police officer possesses a reasonable belief based on specific and articulable facts which . . . reasonably warrant the officers in believing that the suspect is dangerous and the suspect may gain immediate control of weapons.”
The Court justified this type of warrantless search by arguing that it is necessary in order to ensure the safety of the officer(s) and others. In Arizona v. Gant (2009), it is outlined that in the “no-arrest case, the possibility of access to weapons in the vehicle always exists, since the driver or passenger will be allowed to return to the vehicle when the interrogation is completed.” Therefore, a protective search without a warrant would be appropriate.
However, in a situation where the operator has been placed under arrest and there are no other passengers that might have access to the vehicle, a warrantless search is not justified. As explained in Gant, the exception to the warrant requirement “does not authorize a vehicle search incident to a recent occupant’s arrest after the arrestee has been secured” because the operator “cannot access the interior of the vehicle” and therefore poses no threat to the officer(s) or others.
So justification for warrantless searches comes down to one thing: safety. In determining this, the courts rely on “whether a reasonably prudent man in the circumstances would be warranted in the belief that his safety or that of others was in danger.” (Terry v. Ohio 1968). Factors such as the time of day, the experience of the officers involved, and suspicious activities by the defendant (including excessive nervousness), both before and during the stop, are all taken into consideration when determining if the officer(s) had reasonable suspicion which would allow for a warrantless search.