[ghaff]

I don't really care for the L5 definition. Humans can't drive on all roads in all conditions even if their vehicles are theoretically capable of it. There are certainly weather conditions I don't want to be driving in. And there are certainly some unpaved roads I don't want to be driving on even with high clearance 4WD.

[jsmith45]

The realistic definition would be that if a human could not reasonably be expected to drive in it (fog/smog with less than 6 inches visibility, hurricane, blizzard, military invasion) then the cars are not required to drive it in. And perhaps the cars can accept a circumstance or two where humans can't drive, in exchange for one or two where humans could, but the cars can't. But it would need to be circumstances that humans can predict/understand. Like if the car won't drive if the countrywide car-to-car comms network is down or something.