Hidium, that's good advice. Most times a legitimate cop will call in backup. It's usually safe once two or more cars are on the scene. This advice was actually given by our local police chief when the guy in north Mississippi was killing people on the highway by posing as a cop. Apparently people use this method in Jackson Mississippi to rob tourists as well. BTW you should drive at a slightly reduced speed to give the police an idea of what you're doing. If you drive crazy they will pit maneuver you and make you crash. In fact it wouldn't hurt to phone the station if you are able.
I am the king of all things stupid!