But that's true (look up the Solomon curve), and it's exactly why the 85th percentile would be better.
> Delusional rationalizations like "if the limit is 50 then going 10 over must be fine too, due to <reasons>!". Bonus points for applying the "5/10/15/20 over" rule for every possible speed limit — basic maths and physics say hello!
You have cause and effect backwards. People think it's safe to go over the speed limit precisely because most speed limits are too low.
> Changing speed limits has little effect compared to changing the physical infrastructure. Show me a picture of a road and I'll tell you how fast people will drive on it.
Right. So even if going slower is safer, just making the speed limit lower won't accomplish that.