The results of the third year of analysis of a 6-year research effort focused on quantifying urban mobility are described. Roadway information is provided for 39 urban areas representing a geographic cross section throughout the country. The data base used for this research contains vehicle travel, urban area information, facility mileage, and vehicle travel per lane-mile information. Various federal, state, and local information sources were used to develop and update the data base with the primary source being the fhwa's highway performance monitoring system. Vehicle-miles of travel (vmt) and lane-mile data were used to develop roadway congestion index values for the 7 largest texas and 32 other u.S. Urban areas. These index values serve as indicators of the relative mobility level within an urban area. An analysis of the cost of congestion was performed using travel delay, increased fuel consumption, and increased automobile insurance premiums as the economic analysis factors. Congestion costs wereestimated on urban-areawide, per-registered-vehicle, and per-capitabases. The 39 urban areas were categorized in five geographic regions: northeastern, midwestern, southern, southwestern, and western. Comparing the amount of vmt served by freeway and principal arterial street systems and roadway congestion index values, it was concludedthat the amount of urban area vmt served by freeway and principal arterial street systems indicated which system urban areas relied on for mobility. Analyses indicated that the northwestern and southern regions tended to rely equally on both systems, whereas the remaining regions had a greater reliance on their freeway systems. A comparison of regional roadway congestion index values indicated that the northeastern area was the only region with increasing congestion growth rate. The largest decrease in congestion growth rate was exemplified by the southwestern region. In 1988, the total annual cost of congestion exceeded $34 billion. The average annual congestion cost, studywide, was approximately $880 million; however, 10 of the urban areas had annual costs exceeding $1 billion. The largest contribution(65%) to congestion costs may be directly attributed to travel delay. This paper appears in transportation research record no. 1305, Finance, planning, programming, economic analysis, and land development 1991.
Abstract