"...totally safe..." self-driving cars
So, no speed limits on them ? If they're "totally safe", then they can drive as fast as they decide. There would be no logical reason whatsoever for externally-mandated speed limits on self-driving vehicles that can provide their own "totally safe" assurance.
Well, perhaps we'd want to avoid sonic booms, so maximum ground speed should be Mach 0.95.
I suspect that we're rapidly heading into a new version of the 'omniscient omnipotent paradox', except with self-driving cars instead of gods.