Re: Stepping stones
I think it will take longer than Google or others think, at least to move beyond low-speed assistance for the elderly. If self-driving cars are appreciably slower than regular cars, the wealthy will opt to drive themselves (or a chauffeur), leaving the poor to accept less capable transportation.
Also, having seen how a robot tries to avoid people in a crowded room, I wonder how a group of automated cars will do when they arrive at an the same intersection. Is there a potential deadlock condition when they all get too close to move and lack the human initative to do something unorthodox, like drive up on the sidewalk, to break the logjam?