About this Document
The Office of the Secretary of Transportation (OST) at the United States Department of Transportation has commissioned this study to assess the cost of surface transportation congestion from a national perspective. For road travel, a number of previous reports have assessed the cost of congestion nationally or for particular areas. For the most part, however, these reports measure a circumscribed range of costs. The most widely recognized national study of road congestion costs, the Texas Transportation Institute’s (TTI) Urban Mobility Report (UMR), measures only the costs in wasted time and fuel.
Potential costs of congestion that have received much less study are those relating to safety, pollution from vehicle emissions, indirect costs in reduced business productivity, vehicle operating costs other than fuel cost, and reliability of travel time. Moreover, even for the more commonly measured costs, considerable uncertainty surrounds their magnitudes. For estimating the cost of wasted time, a particular challenge is valuing the cost of an increase in time required for freight delivery. For congestion delay to truck movements, the UMR measures the resulting cost in driver labor and vehicle operation,
but make no allowance for cargo-related cost.
One of the objectives of this study is to estimate the national costs of road congestion including the above-mentioned costs omitted from the UMR. That these costs are quite large is apparent from previous statistics, such as the UMR estimate for 2007 that congestion on U.S. roads consumed $78 billion in wasted time and fuel. But even without statistics, Americans understand from their everyday experiences the toll congestion is taking on their economy and society.