Why do policemen touch a tail light when they pull you over?

1941

Few things strike as much fear into people as seeing blue lights in their rear view mirror. When an officer attempts to pull you over, things can get dicey. There’s one odd thing that cops often do when they pull people over. They will generally approach your vehicle on the driver’s side. As they come toward the driver’s window, they will tap the tail light on your car. Why do they do this? Is it to let you know that they are coming? Or is there some other purpose that has to do with the proof in your case? There’s a logical answer to why cops behave in this way.

The need for tangible proof
With most traffic stops, the officer will need to prove that he or she approached your car while pulling you over. By tapping your tail light, or putting their hand fully on it, they can leave a fingerprint. This is one of the oldest tricks in the book for officers who need to have physical proof of what took place.

In the old days, they might have gone and authenticated that fingerprint if the case went to trial. A suspect at trial might have said that the officer never came to their window, making it much more difficult for an officer to testify to things he noticed while approaching that window. By touching the taillight, the officer could then show the jury that his fingerprints were on the car, and thus, he had approached the vehicle.

Officer cameras making the touch method obsolete
Today’s police officers have all sorts of technology to assist them in the process. They have dash cameras installed in each cruiser that shows the traffic stop in its entirety. Beyond that, they also have body cameras that record everything they do during a given traffic stop. These videos provide a much easier method for proving to any jury that the officer actually approached the car. In most cases, the existence of this video will even serve as a deterrent to suspects who may want to lie in their defense over whether or not the officer approached the car.

Still, with the rise of these cameras, some officers will still make it a point to touch the taillight or some other part of the vehicle. They do so in part because of habit. For many of the old school officers who have been around for a while, it is hard to break the habit of touching for authentication. In addition, some officers today use a subtle tap to scare or spook people in the car. A person trying to hide drug evidence or put on their seat belt very quickly might have to stop their process if they hear a tap on the back of their vehicle. In so doing, the person will have a harder time destroying evidence, making it much easier for the police officer to do his job as he approaches the window of the vehicle.