It's generally a bad idea to fit safety regulations around the safety limitations of the item they're regulating. We set speeds, sometimes based on time of day or presence of children. Humans handle this just fine.

If your car can't, then the car needs to be fixed or it's "self-driving" functionality entirely disabled. Changing speed limit laws to compensate for these limitations is entirely the wrong direction.

My point is that FSD needs to be at least as capable as a human to follow speed limit signs.

The problem generalises - it's also unacceptable for FSD not to keep up with traffic on a freeway or randomly throw in the brakes to avoid spurious hazards for the same reasons.

I remember the story on here a while ago about a self-driving car that got rear-ended because it stopped in the merging lane of an empty highway rather than accelerating like any human would...