Ain't nothing going to happen with autonomous vehicles until they solve the rain and snow problem. Maybe California doesn't have to worry about vehicles in precipitation, but the rest of the nation does.
I see this complaint every time an autonomous car story comes up. Is there actual evidence somewhere that rain and snow have any significant impact on the vehicles' ability to perceive an environment or on their ability to navigate it? The sensor fusion algorithms already deal with noise exclusion and transitory sensing failures. I can believe heavy snow which obscures the lane markings would be an issue, but even then that doesn't really prevent collision avoidance, or even safe driving ability so long as there's always to option to just go slower. The rules of traffic interactions in the absence of lane markings are pretty well defined, and are mostly just "do what boats do".