For a government-implemented strategy, congestion pricing offers remarkably consistent positive results -- at least according to its proponents. It seems to achieve its goals across the board, to varying degrees.
San Diego's I-15 HOT lanes have resulted in significant increases in both bus ridership and carpooling, which reduces traffic and greenhouse-gas emissions. Congestion pricing on bridges and tunnels between New York and New Jersey ended up reducing peak-hour traffic between 4 and 7 percent [source: NCPA]. Rush-hour travel speeds in London's city center have increased 37 percent, travel times have decreased 30 percent, and CO2 emissions have dropped 20 percent since congestion pricing was introduced [source: NCPA]. Similarly, Stockholm has seen a 10 to 14 percent drop in CO2 emissions in its city center, and Singapore's zone-based program has reduced congestion by 45 percent [sources: FHWA, NCPA].
Despite the positive results, there are at least a couple of potential downsides to congestion pricing. The most unpopular aspect, of course, is the increased cost of tolls. Few people are happy about spending more money to get to work, and the expense can be particularly difficult for the working poor.
Some cities, though, are talking about using congestion pricing to avoid further gas-tax increases, and some might offer discounts to low-income commuters. And congestion-pricing proponents point out that since toll revenues are often put toward improvement in public transit, which is used more by low-income than by high-income commuters, the former can actually end up benefiting more from the setup.
The other, less concrete concern is the potential for privatization. Implementing congestion pricing on a grand scale will most likely involve private companies coming in to handle certain aspects like monitoring, billing and enforcement. Some people find the partial privatization of public roadways to be a cause for trepidation. Placing such a crucial piece of infrastructure in capitalist hands can be a harrowing proposition.
Resistance aside, congestion pricing is set to become a more familiar concept in the United States. The U.S. Department of Transportation has started offering special funding to cities looking to set up congestion pricing, including Seattle, Miami, San Francisco, Los Angeles, Minneapolis-St. Paul, and Chicago [source: EDF]. In the next 10 years, time-sensitive tolls could become as commonplace as HOV lanes.
For more information on congestion pricing and related topics, look over the links on the next page.