Criminals are just not suspected to have a gun. Another example: When German police is trying to stop one on the road they are driving ahead and then decelerate

Criminals are just not suspected to have a gun. Another example: When German police is trying to stop one on the road they are driving ahead and then decelerate, so you can't escape. American police, at least in the movies I know, are driving behind you so they can see every move of you and you do better the show-your-hands-and-no-quick-moves-thing.