[ardecila]

This is the tail wagging the dog. The 85th percentile rule isn't really the problem, street design is. If you provide a street where drivers automatically slow down due to design factors - narrow width, lots of obstacles, etc - then you don't really need the speed limit. You still have to set one, but it just serves as a justification for punishing the most reckless drivers who refuse to pay attention to the design cues.

America is full of terribly designed "stroads" that encourage very fast speeds by virtue of their drag-strip style design. The 85th-percentile rule recognizes the reality of these roads and attempts to legalize the behavior of MOST drivers who are only reacting rationally to the infrastructure that is provided to them. But getting rid of the 85th-percentile rule and setting the speed limits lower won't reduce the average speed, it'll just let cops write more tickets.