Taking a new approach to parking, by building less and charging more, is a central tenet of the new urbanism that has gripped planners and developers in suburbs and cities across the country. The planners said that parking, especially free parking, encourages people to drive. Cars allow for development sprawl, highway congestion and air pollution. The parking lots coat the ground with impervious asphalt that sends dirty runoff into rivers and streams. And, the planners said, parking is often ugly and creates spaces that discourage walking or the use of a transit system.