Whereas road for buses costs nothing, because it's already there, because we can't imagine a country in which we cannot trace an uninterrupted asphalt path from the driveway of a house in one city, to the driveway of another house in another city.

Roads cost practically nothing compared to rail. We have two to three million miles of paved roads in this country, and we spend around $200 billion a year maintaining it and building more. People drive 3 trillion miles on highways alone, adding up to a per passenger mile subsidy of $0.01-0.02. Rail subsidies (for local transit) add up to $0.50 per passenger mile.