It is possible that human driven cars will be banned although I don't see how stop signs etc.. will no longer be needed. There will still be pedestrians and cyclists and what will happen with the motorcycle if human driven cars are banned. The notion that people will choose to not own, but instead will have one pick them up is naive. The car will still need to park somewhere and trying to get one to pick you up at 7am on a weekday will lead to major congestion as a parking lot full of autonomous vehicles suddenly need to exit. Certainly the combination of both human driven cars and self-driving cars is a potential nightmare, however another possibility  is that some jurisdictions will ban the self-driving car once it becomes apparent how disruptive this technology is. Fortunately it appears that it will be at least a couple decades before a completely autonomous vehicle will be ready.