The social and economic costs of lost productivity and wasted fuel from traffic-choked streets are estimated to be $87 billion a year, according to the Texas Transportation Institute’s 2009 Urban Mobility Report. So far, federal, state and local efforts — focused mostly on expanding road capacity — have been largely unsuccessful at slowing the growing congestion on U.S. roads. Transportation experts now advocate a different approach, changing the emphasis from increasing supply to reducing demand. To reinforce smart growth policies, plug mounting transportation funding gaps and achieve immediate traffic relief, London, Stockholm, Singapore, Milan and three cities in Norway have...