Does Sprawl Make Us Fat?
I've been in many countries in Europe and also spent some time in the US and in Japan. My conclusion is that -- unless extremely wealthy -- a community can only support one primary mode of transportation. If most people drive to work then the road infrastructure will be pretty decent and public transportation horrible. If few people own cars it will be vice versa.
In Tokyo very few people drive, therefore they have plenty of cash to spend on subway and train tickets (which add up to a hefty sum by the end of the month). In most US cities people have cars and the market just isn't there for building a tram, or even for buying a fleet of buses (buses, btw, provide very little advantage over cars as they are subject to the same traffic and weather hindrances).
Some European cities get around this limitation by artificially injecting wads of taxpayer cash into the public transport infrastructure, so they can have functioning roads and public transport at the same time. But in the US very few communities would put up with this kind of "waste".