Self driving vehicles will not show up overnight. The road to 100% penetration will be a long one, with many intermediate steps. I'd say as low as ~20 but as high as 75 year time frame.
Perhaps for recreational use, yes. But I would assume that humans will be a hinderance on the road system and would far increase the possible accidents. Self driving vehicles will be able to 'cluster' and travel, literally, as fast as they can. I don't see any human keeping up with that.