I don’t know where this idea that driving in SF is easy mode comes from. No one who has actually driven in SF would say that. Yes it doesn’t have snow, but it has rain, zero-visibility fog, lots of pedestrians and cyclists, heavy traffic, narrow roads, steep grades, bus-only lanes, lots of cars parked on the street and double parked. Self-driving companies don’t pick SF because it’s easy, they pick it because it’s the most challenging city that’s close to their engineers.