Then please explain the observed behavior I've seen, on the same freeway (interstate 80 between my home and Sacramento), as the speed limits were changed:

- When the speed limit was 55, the average traffic speed was 65-70.

- Now that the speed limit is 65, the average traffic speed is 75-80.

Because in California, cops typically won't bother pulling you over if you're only doing 10-15 over. Cop tolerance for speeding seems to depend on the region. Last time I was in Detroit, it seemed like it was 5-7 over. Along the 401 in Ontario, it seemed like it was 15-20Km/h.

My preferred speed on roads that can handle it is between 110-120Km/h, decreasing as road conditions deteriorate. It has nothing to do with the posted limit -- that's just a reasonable compromise between what my truck can handle, and not burning through gas at an even more unreasonable rate than what the truck does normally.