Most of the problem, however, is that people don't need to be driving so much, so far, or so fast. To start with, every interstate should have a passenger rail in the median strip with car ferrying capacity.

On speed limits, I suggest, like starting a meeting, you shouldn't use a fudgable number, and it should be 57 or 61 or even 66, and it should be enforced to the 1/10th of a mph over that number (Iowa uses camera speed detectors, but always contested to death) to the limit posted. Fixed speed detectors can be calibrated precisely (ask Ethan how precisely we can detect the motion of a star 4 billion lightyears away).

Then, there's the marketing. We need to start eliminating advertising (theft of time and attention to sell products that people don't need: like trucks) that doesn't meet actual needs (basically, all of it).

People are driving fast to get places they don't need to go in vehicles they shouldn't be allowed to drive (better proficiency testing) and they are angry ALL THE TIME because "profits" and "competition".

I think about the speed limit every time I get on the road. Then I realize we are a country of assholes, and speed limits wouldn't make any difference about that.