A large problem in speed limit setting is that 85th percentile is used many times for setting the speed limit and other factors are ignored or aren't weighted as heavily.

It's a very fuzzy practice, and I think as we continue towards an automated driving world, we need to be more critical of how speed limits are set.

Using the 85th percentile as a means to determine speed limits ends up with 15% of all drivers exceeding the speed limit, or worse, more drivers exceed the speed limit than those original 15% because they know consequences may be rare.

https://www.ite.org/technical-resources/topics/speed-managem...