Driving school and being pulled over has taught me that the silly numbers are not the maximum speed, theyre the minimum speed, and the actual maximum is 5-10 higher depending on what other people are doing. "Going with the speed of traffic and going fast enough to prevent lane changes" is the real answer.

Ive begun going the exact speed limit in the right lane and ive been pulled over 3 times now and experienced more roadrage than i thought possible. I never got pulled over going 90 in a 70, or 30 in a 25, or 45 in a 35.

People are in such a hurry to save 0-30 seconds on their 15 minute drive

It quite literally is.

If you don't keep up with traffic, people pass you, and that is much more dangerous than an extra 10mph

The American mindset seems to be drive as fast as possible without being pulled over. Therefore the default speed tends to be driving 5mph over the speed limit. So, the government should just set the speed limit to 5mph under what they actually want and then it'll be fine.

the real answer to question "why people speed" is someplace closer to "why was this neighbourhood road designed like a freeway". Another is "why is it safe to have virtually no speed limits on Autobahns?". I mean people act on environmental queues - from the size of lanes to what speed fellow motorists are observing. Just pinning it on individuals is incorrect. HOWEVER there are entitled arseholes out there who will totally ride jour read bumper at high speed because they need to pass you only to turn off at nearest exit.