Google's self-driving car's main sensors are a 360 degree rotating laser and a radar, NOT a camera... unless Sebastian Thrun has been lying in his Udacity CS 373 course.
I believe (speaking from the Udacity material) it also uses a stereo camera setup for localization (e.g. where the car is within a lane). Sebastian mentioned something about how they could deal with rain, but not something like snow that covers the visible references.
