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Reduce Road Congestion by Eliminating Critical Bottlenecks to Enhance Mobility and Improve Air Quality

Background:

• One of the leading causes of greenhouse gasses is not transportation itself, but congestion. Over the past quarter century, the number of new lane miles in the United States has only increased by 6 percent. In contrast, vehicle miles traveled (VMT) has grown by 157 percent, while the number of vehicles and licensed drivers on the road has increased by 112 percent and 73 percent, respectively, and Gross Domestic Product has grown by 167 percent.

Â鶹´«Ã½ Message:

• Road Congestion Levels Continue to Grow. As a result of road capacity failing to keep up with demand, congestion levels grew continuously between 1982 and 2005. A recent study shows that the average annual hours of delay experienced by commuters has increased from 14 hours per year to 38 hours. At the same time, travelers are wasting an estimated 4.2 billion gallons of fuel due to congestion. The nation's road system is failing to keep up with the growth in system usage resulting in an ever-growing congestion problem.
• Congestion Relief at Specific Bottlenecks Would Reduce Greenhouse Gas Emissions. Specific capacity problems are reported to cause 50 percent of total congestion on the nation's freeways. In 2004, a study of the nation's most severely congested highways found that significant reductions in emissions require a reduction in vehicle time traveled, not vehicle miles traveled. The study concluded that modest improvements to traffic flow at 233 bottlenecks would reduce carbon dioxide emissions by as much as 77 percent and conserve more than 40 billion gallons of fuel over a 20-year period. Addressing congestion will also lead to reduced levels of CO, VOCs, and NOx, since vehicles caught in stop-and-go traffic emit far more of these pollutants than they do operating without frequent braking and acceleration.