Different cars are used by a variety of police agencies. Here in the U.S. the main choice is obviously the Crown Vic, but others are used for certain areas also. For example, you might see STi's, Corvette's, Mustangs, Camaros, GTO's, Durango's, Explorers, and others. In Japan, they have used NSX's, Skylines, Rx-7's, 3000GT's, and others.
As mentioned earlier, programs such as D.A.R.E. or others also get in on the fun and do up other cars to attract attention and awareness to their cause.
Here in Delaware, we use an old punch buggy. Pretty corny but hey, the thing's a classic!

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