eli5: How do they decide what the speed limit is for a road?

Question

Basically the title. I’m curious what they do to decide. surely they don’t just stick a random number on a sign and call it a day.

In: 16

Answer 1

All the reasons others explained, and then sometimes there’s politics involved, where local parents want their streets slower so they don’t have to keep their kids out of the street. Or speed traps so cops can steal from anyone passing through.