Perhaps San Francisco rain is solved, but I doubt the downpours we get in the South East are solved. Zero visibility is just one thing, how about hydroplaning when there is over 1" of standing water on the road because it's coming down faster than gravity can drain it away? Or spotting that your lane is fine but the opposite one is flooded so that car coming the opposite direction is going to have to borrow your lane for a bit?
These sound like edge cases but there are places where they occur very frequently and local human drivers, for all their faults, do have a way of dealing with them.
These sound like edge cases but there are places where they occur very frequently and local human drivers, for all their faults, do have a way of dealing with them.