How common are Stop signs in the US?
In the UK, "Give Way" (i.e. "yield") signs outnumber them 100-to-1 or more. You normally only find Stop signs at blind junctions (mostly in places where the road layout hasn't changed since the middle ages).
Invert that ratio and you get the US.
Basically, traffic laws in the US are optimised to generate maximum fine revenue for the local police so they are designed to create as many violations as possible with no regard for safety. At the extreme end of the scale you've got red light cameras which might as well be called "murder cameras" for the number of people they kill.
The evidence is very clear that if you actually want safety on roads the way to get it is with fewer or no rules and signs, but since that directly contradicts the reveune purpose of having the signs and rules it would take a regime change to see that happen.