I can't say that I have noticed one potential issue about driverless cars being discussed - how will they stop users doing unsavoury things in them whilst going for the ride?
Come on, everyone has heard stories about airline passengers trying to get away with sex under blankets, or in the toilet; and that's in a place with the obvious potential for detection. I predict it will be barely a week from when the first driverless car fleet comes into service that someone will have a video on the net of "what my girlfriend and I got up to when we didn't have to drive". Or there'll be some solo act on show. Maybe big windows will be a daytime deterrent from this. Not sure about nighttime, though.
How will they stop it? Photos taken inside every 30 seconds? Random video monitoring? Apart from the likely privacy uproar, how hard would it be to cover the camera, anyway?
For that matter, there might also be issues with littering in them; or late night drunks' vomit. (I suppose if one is too much of a mess, the person being picked up may just report it and wait for the next. But it would be much better not to have them messed up in the first place.)
I trust Google is working on this...