At the dawn of the automobile era, suppose Henry Ford and John D. Rockefeller had asked how urban planners could increase the demand for cars and gasoline. Consider three options. First, divide the city into separate zones (housing here, jobs there, shopping over there) to generate trips between them. Second, limit density to spread everything out and increase those trips even further. Third, require ample off-street parking everywhere, making cars the easiest and cheapest way to travel.