I think you will see cities of the future when the petroleum runs out with tubes between buildings and fancy people movers and cars being lifted high out of the way while delivery trucks and people mill about below with the high rise highways only people that must drive like people that live far away and drive in to designated cites and then their are like 100 sites arround the city where everyone parks there cars and walks into the buildings they work at and there are roads for delivry trucks to go from building to building and they will run off biodiesel and electric motors