California's speed trap law [1] prevents enforcement of speed limits that weren't set by a traffic survey within 5 years of the violation; subject to some exclusions --- school zone limits can be enforced.

IIRC, highway speed limits at or above 55 (maybe 60?) also don't need a survey either.

Unlike some other states, California has a truck speed limit of 55 mph. I don't think it's great to have the car speed limit set too much beyond that. Especially on the middle of nowhere freeways where people tend to find room to really speed... It's not great when people are doing 80+ and come across a group of 55 mph trucks.

[1] https://leginfo.legislature.ca.gov/faces/codes_displaySectio...