When I worked in a major city I would go on a half-joke rant anytime someone brought up traffic, parking,or obesity. If I were somehow the king of a major city, I would have a giant parking lot on the outside, and ban all cars. You could buy day passes if you need access to the roads to move or something, but it would be discouraged. People would walk more, and be healthier, The air would be higher quality, and most importantly you wouldn't have to wait to cross the street when you're walking to lunch.