"Other reports go further. In 2005 Congress established the National Surface Transportation Policy and Revenue Study Commission. In 2008 the commission reckoned that America needed at least $255 billion per year in transport spending over the next half-century to keep the system in good repair and make the needed upgrades. Current spending falls 60% short of that amount." The Economist, 4/28/2011
Coincidentally, farm subsidies -- which raise food prices and skew markets -- cost taxpayers $20 billion a year.