How about teaching officers not to sit in the car at all during a stop? Have the officer work from the curb side of his car and if he needs any paperwork he/she can stand in an open passenger door. If the officer is standing outside the car in the open passenger door he/she can see any movement from the other car or someone walking up from behind. If the driver of the car you just stopped exits the vehicle with a gun or any other weapon, you have the rear of his car and the front of your car between you and him. Just a thought.