Well, as long as the thread is hijacked...
One theory I read a long time ago, and liked, was to set speed limits at what 80% of people are doing, anyway. That way, you only ticket the minority of people who just won't go with the flow.
The countervailing safetycrat theory is that no matter what the speed limit is, people will drive 10mph over it. But I think people go 10 over because they know the set limit is ridiculously low from a "safe passage" standpoint. A "reasonable" speed limit, based on what most people consider a safe speed, would be adhered to by most people.
