Peak-Period Congestion on High-Volume Truck Portions of the National Highway System: 2012 Map
High-volume truck portions of the National Highway System carry more than 8,500 trucks per day, including freight-hauling long-distance trucks, freight hauling local trucks, and other trucks with six or more tires. Highly congested segments are stop-and go conditions with volume/service flow ratios greater than 0.95. Congested segment have reduced traffic speeds with volume/service flow ratios between 0.75 and 0.95. The volume/service flow ration is estimated using the procedures outlined in the HPMS Field Manual Appendix N.
U.S. Department of Transportation, Federal Highway Administration, Office of Freight Management and operations, Freight Analysis Framework, version 4.3, 2017.
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