percent of the total cost of their transport. The other 75 percent is typically borne by their employers (e.g., providing free parking), by others (in increased congestion, reduced safety, etc.), by fellow workers or residents (in air or noise pollution, etc.) and by governments. (Johnson 1993, 10–11)

Supporters of congestion pricing and fees on automobile use believe that if highway users paid directly for more of the costs they impose, the demand for automobile use, or the negative impacts of automobile travel, would be reduced.

Road pricing, of which congestion pricing is a primary ingredient, has been a matter of policy debate in the United States before. During the expansionist period of highway construction following passage of the Federal Highway Revenue Act of 1956, it was discussed as an alternative approach for defining long-run investment needs and for solving the urban congestion problem, but was never acted upon. Following the passage of the Clean Air Act (CAA) of 1970 and the energy crisis of 1973, federal transportation policy shifted somewhat away from an emphasis on highway construction toward concern for achieving greater efficiency in urban transportation (Altshuler 1979). Federal funding for public transit increased and the transportation system management (TSM) concepts for increasing the efficiency of highway use came into vogue. Interest was further stimulated by the Environmental Protection Agency (EPA) transportation control plans for those urban areas that failed to meet the ambient air quality standards of the CAA. Congestion pricing was one of the major policy instruments considered during this period. For example, beginning in 1976, then-Secretary of Transportation William Coleman offered several cities federal funding if they would participate in studies of congestion pricing.

Although subject to serious intellectual discussion, actual congestion pricing proposals were greeted by policy makers with skepticism if not downright hostility. The Bureau of Public Roads (forerunner of the Federal Highway Administration) rejected road pricing proposals as unworkable (St. Clair 1964). Congress prohibited the EPA from using areawide parking pricing, one approach to congestion pricing, when EPA moved toward this proposal in 1973. Although a few cities gave Secretary Coleman's invitation to study congestion pricing serious consideration, no