A comprehensive set of Global Positioning System (GPS) vehicle location data from Lexington, Kentucky, households was analyzed to determine if such data can be helpful in improving path choice assumptions in traffic assignment models. The portion of the data used consisted primarily of a reconstruction of the street network and the lists of street segments in each path. Analysis was based on matches of trips (e.g., pairs of trips with similar origins and destinations). Matches were obtained for trips within households and for trips across households. Statistics used to compare trips in matches were a path deviation index and the percentage of identical links. It was found that the path chosen on a trip was quite sensitive to the location of the origin and destination and that the chosen path most often differed considerably from the shortest time path across the network. Paths for trips made by the same driver were very consistent over time; paths by different drivers showed more deviations even when the trip ends were the same or very similar. As a result of this research, recommendations are made as to how GPS data on path choice can be better collected in the future for improvement of traffic assignment models.

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A psychological scaling technique, magnitude estimation, is used to rate time spent on various elements of bus transit trips. Relative values of time are found for in-vehicle portions of trips, walking, waiting and transferring. Because magnitude estimation produces a ratio scale, results can be directly incorporated into modal choice analyses, route planning and evaluation procedures where monetary values of time are not necessarily required.

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The original 1985 Highway Capacity Manual (HCM85) described widely recognized relationships for traffic delay that could be incorporated into travel forecasts. Applications of the HCM85 procedures demonstrated that such delay relationships were both technically feasible and beneficial. In early 1995, the Transportation Research Board released the 1994 update to the HCM (HCM94), heavily revising the signalized and two-way stop intersection procedures and introducing a detailed all-way stop intersection procedure. These new procedures have the potential to improve the accuracy of forecasts and to make forecasts consistent with other design practices. Implementation of the HCM94 procedures into travel forecasts reveals that fewer adjustments are required to make them work within equilibrium traffic assignments. The two-way stop procedure can be used nearly intact. The signalized intersection procedure, although still requiring some adjustments, allows a greater range of traffic conditions and phasing options. The all-way stop procedure cannot be incorporated into travel forecasts because of its restrictions on allowable volumes and turning movements. Tests of the HCM94 procedures in traffic assignments indicate that they produce noticeably different results (both volumes and link delays) than the original HCM85 procedures. Multiple equilibrium solutions are possible, but the differences between these solutions are small and manageable.