The rules surrounding traffic stops take their cue from the Terry stop. Similar to a Terry stop and frisk, any traffic stop must be done with reasonable suspicion, based on apparent circumstances. A traffic stop is done to catch a suspect who may have just committed a crime, stop a crime that is in progress, or prevent a crime from taking place. When a police officer stops a vehicle, the process is called “pulling over”.
The police officer signifies the order to pull over by using loudspeakers and sirens. Depending on the result of the traffic stop, a search may then be performed, and from there, an arrest, detention, or issuance of a written or verbal warning might take place. Traffic stops are risky for police officers; the fact that the suspects are inside a vehicle lends itself to so many complications.
If the stop happens in an isolated area, the suspect may engage the police officer in a gun fight, and because of the element of surprise the police officer may be at a disadvantage. Again, much debate rages as far as traffic stops are concerned, and most people complain about violation of their constitutional right. The decision to do so lies on the police officer, based on probable cause and reasonable suspicion, which is evident at that time.