[eridius]

Not being able to go over the legal speed limit can be dangerous (e.g. if the other cars on the road are, and you're not, you could actually be driving relatively slowly enough that it's unsafe, and you can even technically get a ticket for that under the right circumstances).

Similarly, in most places, speed limits are actually a little lower than they would be in the ideal world where everybody obeys them, to account for the fact that most people actually go a bit over the speed limit. And there are still highways that have absurdly slow speed limits that date back to the 1973 oil crisis (federal law set a maximum speed limit of 55mph, and not all highways have recovered from that yet).