Even if you were able to partially disable an attacker, it is still possible for the attacker to kill someone, especially if they are armed. We are trained to aim at the middle of the chest, because then we are most likely to hit something and able to stop the attacker from continuing their attack. We are taught to clock speeders by staying a fixed distance from the car and checking our own calibrated speedometers. There are also many other violations which are reasons to stop someone. During the late hours, equipment violations are a common reason to stop a suspicious looking vehicle and see if the occupants are up to no good.
All officers receive some hand to hand training.
I find that many of them take outside classes to increase their skills. In St. Paul we are given three hours a week, on duty, to do physical training. Many officers spend the three hours and much of their own time in the gym. We have found that it makes for a better and healthier officer. Sir Robert was the British Home Secretary in the early 1800's.