Is That Really A Police Car Behind Me?

There was a recent story in the Charlotte Observer about a person who allegedly impersonated a police officer in Mint Hill by trying to initiate a traffic stop on a motorist. The story stated that an individual was driving towards Charlotte on Lebanon Road when a Mercedes pulled up beside him with flashing lights. The Mercedes pulled in front of him and attempted to get the motorist out of the vehicle.
http://www.charlotteobserver.com/breaking/story/922673.html?q=impersonating+police+officer

I don't know anything about this case except what was written in the Observer, but it brings up an interesting point about police cars, specifically state troopers. Am I the only one who has a hard time telling if a state trooper car is actually a police car? I see them pulled over on the side of the interstate issuing citations. Many times they are a dull brown color with very little writing on the vehicles. Some barely have any overhead lights on the vehicle. If you travel on the I-40 to Asheville, the troopers drive black Pontiac type sports cars with little writing and lights. What ever happened to traditional black and white or blue/ white police cars?

Check out this You Tube video. Someone put together all the state trooper cars from the 50 states. Many of them are actual sports cars.  I don't know how a person could tell these were actually state trooper cars behind them when traveling at night on a dark road or interstate.
http://www.youtube.com/watch?v=EXdeFpflr3o

Finally, have you ever been travelling down the interstate at night and you see a car pull behind you with dim lights flashing. You're not sure if that actually is a police car. Do you use your cell phone, call 911, hear the phone ring 50 times before any operator actually picks up, and tell the 911 operator that you don't know if that is actually a police car behind you. I guess when 3 additional cars suddenly appear with all lights flashing and you find yourself arrested in the back of the police car you originally questioned, you will probably know it was a cop.

Although I'm confident the budget doesn't allow police officers to be driving Mercedes, I'm just saying that the a person should be a little nervous about the lights flashing behind them sometimes.