Police officers touch the back of your car during a traffic stop primarily for safety and evidentiary reasons. By touching the rear of the vehicle, officers leave their fingerprints on it, which serves as proof that they were present at the scene in case something goes wrong during the stop. This fingerprint evidence can be crucial if the officer is harmed or if there's an investigation afterward. Additionally, officers touch the back of the car to check that the trunk is securely closed and that no one is hiding inside who could pose a threat by suddenly emerging. This action also helps officers assess the driver's mental state and reaction, providing clues about whether the driver might be hiding something illegal or behaving suspiciously. Overall, this practice is a safety protocol used to protect both the officer and the driver during the stop and to gather important information if needed.
