A successful policy change of a controversial nature at the regional level requires a great deal of public education and constituency building. Congestion pricing faces uncertain political prospects, in part because the benefits are large but diffuse, and the costs, though outweighed by the benefits, are concentrated. Research is needed for specific regions to determine which groups would benefit and which might lose (or even perceive that they might lose) and the influence these groups have at the regional level. A broad class of highway users would save several minutes a day, for example, but they might not be sufficiently motivated by this potential gain to fight for it, and their interests might not be represented at the regional level. Environmental groups might be motivated to fight for the air quality benefits and might be arrayed with groups supporting public transportation. Opposing political interests might include some commercial groups, commercial transportation, and low-income advocacy groups. The opposition, however, might be divided since some, if not many, members within these groups stand to gain. Large employers in a region might be more attracted to congestion pricing than to employee trip reduction programs. Low-income advocacy groups might be attracted to the possible benefits that improved bus services would provide their constituency. Research is needed on whether a successful constituency could be put together that would encompass the broad beneficiaries, how such a constituency might be built, and whether it could be expected to counter opposition. Alternatively, research is needed on whether opposition could be minimized by educating interest groups on how congestion pricing would benefit society generally and even groups within their own constituencies.

A new concept for applying congestion pricing would be for the government to distribute “tradable peak driving permits,” which individuals or groups could use or sell (Rom, Vol. 2). This proposal was put forward as a way of uniting interest groups and avoiding the political problem of converting a “free” road to a road with a congestion toll. With such a scheme, everyone would retain the privilege of driving during the peak that they now enjoy, and those that did not value this privilege as highly as its market price could sell it to someone who did. Instead of being “tolled