This research report represents the results of the third year analysis of a six year research effort focused on quantifying urban mobility. The study contains roadway information 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 from 1982 to 1988. Various federal, state, and local information sources were used to develop and update the data base with the primary source being the Federal Highway Administration's Highway Performance Monitoring System. Vehicle-miles of travel and lane-mile data were used to develop roadway congestion index values for the seven largest Texas and 32 other US 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 auto insurance premiums as the economic analysis factors. Congestion costs were estimated on an urban areawide, per registered vehicle, and per capita basis (A).