Most urban areas of the country face rising congestion levels as increasing volumes of vehicular traffic exceed the capacity of the transportation system. The Texas Transportation Institute (TTI) reported that, in 2005, “Traffic congestion continues to worsen in American cities of all sizes, creating a $78 billion annual drain on the U.S. economy in the form of 4.2 billion lost hours and 2.9 billion gallons of wasted fuel.” At the national level, reducing congestion is one of the strategic goals of the U.S. Department of Transportation. But to reduce congestion nationwide, it is often at the local level where congestion must be addressed. Congestion patterns can vary depending on location and time of the year. Drivers may notice seasonal changes in patterns of highway congestion in many urban areas of the country. These patterns, however, can be very different for individual cities. This report looks at congestion patterns over a 3-year period for three U.S. cities–Chicago, Los Angeles, and Houston (selected to illustrate geographic diversity)–by estimating the changes in monthly congestion during the year, the differences occurring in morning and evening congestion, and differences in weekend and weekday congestion. These estimates are made using the monthly average number of congested hours per day for each of these cities. (Author/publisher)
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