Under what condition may an officer frisk the passenger compartment of an automobile?

An officer may frisk the passenger compartment of an automobile under the condition of having reasonable suspicion of a weapon and a safety concern. This is rooted in the principles established by the Fourth Amendment, which protects against unreasonable searches and seizures, while balancing the need for officer safety.

When an officer has a reasonable belief that a person may be armed and poses a threat, they are permitted to conduct a limited search of the passenger compartment—known as a "frisk"—to ensure their safety and the safety of others. This procedure is not meant to be a search in the traditional sense for evidence of a crime; rather, it is focused on finding weapons that could potentially harm the officer. The emphasis is on the officer's perception of threat derived from the circumstances they are facing, including the behavior of individuals present and the environment of the traffic stop.

In this context, while other scenarios like the presence of visible drugs or a nervous driver may raise concerns for an officer, they do not by themselves warrant a frisk unless they also indicate a potential threat involving weapons. Thus, the condition that specifically allows for a frisk of the passenger compartment is the reasonable suspicion of a weapon combined with a concern for safety.