Freight Facts and Figures 2012
Figure 3-16. Peak-Period Congestion on the National Highway System: 2040
Assuming no changes in network capacity, increases in truck and passenger vehicle traffic are forecast to expand areas of recurring peak-period congestion to 37 percent of the NHS in 2040 compared with 11 percent in 2007. This will slow traffic on 21,000 miles of the NHS and create stop-and-go conditions on an additional 40,000 miles.
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.
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