摘要: |
This report documents roadway congestion and mobility measures in 70 major urban areas in the U.S. This study contains vehicle travel, facility length and operation estimates, and urban area characteristics from 1982 to 1996 for each of these urban areas. Various federal, state, and local agencies provided the information used to update and verify the primary database -- the Federal Highway Administration's Highway Performance Monitoring System (HPMS). Two primary measures used to monitor congestion levels in each urban area are the Roadway Congestion Index (RCI) and the Travel Rate Index (TRI). The RCI combines vehicle travel and system length data to provide an indicator of the relative congestion levels for each area. The TRI combines peak period travel speeds into an indicator that shows the additional travel time needed to make a peak period trip during congestion versus a trip that would occur during uncongested conditions. Researchers used several additional indicators to measure congestion and its effects in each urban area. Some of these measures include the percent of congested travel and facilities, travel delay, wasted fuel, and congestion cost. The delay, wasted fuel, and cost were estimated on an areawide, per eligible driver, and per capita basis. The impact of congestion was also estimated by the amount of additional facility capacity that would be required to provide urban mobility. |