A landmark Supreme Court Case in 1968 – Terry v. Ohio – gave law enforcement legal permission to conduct a brief search without the need for probable cause. After this case, “stop and frisk” became alternatively known as a “Terry Stop.” Stop-and-frisk allows police to detain an individual based on reasonable suspicion (a step below probable cause) and conduct a minimally invasive pat-down, usually for drugs or a weapon.
This pat-down is intended to determine whether the person in question is armed or engaged in or about to engage in some form of criminal conduct. In the context of a traffic stop, the police do not necessarily need to believe anyone in the vehicle is involved in criminal activity to perform a cursory search of the glove box if there is reasonable suspicion that there is a weapon inside. As you might imagine, Terry Stop and stop-and-frisk remain surrounded by controversy.