Thinking outside the box, although not car free, there are those who have considered electric highways. With the advent of electric and hybrid vehicles if we were to be able to get on a highway and hook up electronically to an electric grid and get off when we need to, pay for the electricity used and still have either a battery electric car or gas car for in town use it would eliminate the need for as much fossil fuel, you could finance it by charging for all interstate use, the electricity would be automatically paid for and as people ungraded their vehicle more and more people could be weaned off gasoline at least as it is used on the interstates. It solves the problem of massive batteries etc. It also does not require a major paradigm shift on the part of the American people (ie. moving away from independent vehicle to mass transportation). We would retain our independence and potentially, since the highway would require computer control, we might be able to attain higher speeds more safely than is done on the current highway system. I think if such a system were technically and financially feasible it might garner more support on a nationwide basis than rail.