• Even in areas without air quality problems, cost, other environmental restrictions, and community opposition prevent significant capacity expansions;

• The regulatory restrictions on motorist behavior called for in federal (and California) law appear to some to be less palatable than congestion pricing;

• The substantial revenues that can be raised are appealing in an era of financial stringencies in many states and regions;

• Past efforts to resolve congestion through capacity enhancement have not worked because latent demand fills up any added capacity in areas experiencing population or employment growth; and

• Advances in technology have made it possible to charge users at low cost and with minimal inconvenience or intrusion on privacy.

These reasons why congestion pricing appears more appealing to some do not mean that the political barriers to this policy have disappeared. The political and administrative challenges faced by congestion pricing are as significant as before. Many continue to view congestion pricing as an ugly duckling. What is different is that elected officials in a few places are coming to appreciate congestion pricing's potential to emerge as a swan.

Congestion pricing has a proven track record in stifling latent demand: it has significantly dampened demand for peak-period travel in Singapore since 1975. Peak-period automobile travel into the core of the city almost 20 years later is still some 25 percent below what it was in 1974. No other transportation demand management policy tried in the United States has achieved results anywhere close to these.

Actually, the success of Singapore's policy has not been questioned as much as its transferability to other places. Singapore is not a Western-style democracy, nor do officials there have to deal with the multiple, often conflicting governmental units that exist in U.S. metropolitan areas. The lack of existing institutions to manage regional congestion pricing in the United States remains a significant barrier. The proposals going forward in the United States, however, apply to single corridors in which, despite the conflicting goals of different governmental units within regions, entities (public and private) do exist that can propose and manage the projects.

The kinds of technology that would allow for automatic, convenient pricing are being applied today. The technology being used in the Norwegian toll rings could be readily extended to congestion pricing. Electronic tolling costs far less than attended or automatic toll booths and allows for high traffic volumes since vehicles equipped with transponders