Office of Operations Freight Management and Operations

Peak-Period Congestion on High-Volume Truck Portions of the National Highway System: 2007 Map

U.S. map showing heavy congestion in the largest cities and moderate congestion on intercity routes in the Northeast and in California.

High-Resolution Images


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 segments have reduced traffic speeds with volume/service flow ratios between 0.75 and 0.95. The volume/service flow ratio is estimated using the procedures outlined in the HPMS Field Manual, Appendix N.


U.S. Department of Transportation, Federal Highway Administration, Office of Highway Policy Information, Highway Performance Monitoring System, and Office of Freight Management and Operations, Freight Analysis Framework, version 3.4, 2012.

Download the free Adobe Reader to view PDFs You will need the Adobe Reader to view the PDFs on this page.

Office of Operations