Premise: How to tell if you're being pulled over by a legit police officer<br>Check to see if it's a marked vehicle. If the vehicle has police markings, it is highly unlikely that it would be an imposter. A civilian driving a marked police vehicle would most likely be spotted very quickly by an actual police officer, and that individual would quickly get arrested for impersonating an officer.
Hypothesis: the possibility of a civilian driving a marked police car is unlikely on the high scale