Do these requirements for the levels you mention anticipate the changes in traffic patterns that will occur? What I mean is, if we could save all the space that the author is noting, could we relegate entire lanes of bikers into completely separate streets? If bikers were gone, for example, could we get away with not needing cars to go to level 5? I'm speaking hypothetically about one hazard but has anyone modeled what would be the environment for cars if everything changes? If your train travels in an enclosed tube, it would require fewer safeguards against obstacles, and could we put autonomous vehicles in a similar kind of enclosed environmental tube?