Officers may follow motorists for as long as they like without stopping them. They must have probable reason to stop a vehicle, such as speeding, a broken taillight, or disobedience to a traffic signal.
A police car following someone does not necessarily indicate that the officer suspects the driver of committing an offence. It is possible that the police officer is heading in the same direction as you. Similarly, police are unlikely to follow someone for an extended amount of time unless they are certain a crime has been committed and are awaiting a valid reason to pull them over. Some police departments have protocols prohibiting officers from following automobiles beyond a certain distance without halting them, but judges almost invariably rule in favour of law enforcement in this “grey area.”
