I question how much of it is a must. After moving to Canada I saw way fewer cops doing traffic work. It's a rarity to see a speed trap, but when I travel back home I see 2 to 3, minimum, in a 3 hour part of the road trip. But we have half as many deaths per 100k people on our roads.
When you have cars that can reach 200+mph being sold, that might be part of the problem.
We have those here, too. It's not the road deaths I am bringing up, it's that you have more cops patrolling and still more automobile related deaths and more police violence. Traffic patrols may not be as necessary as you think.