The traditional travel demand modeling process is designed to develop relationships among travel characteristics, land use activities, and a simulated transportation system network. The models are calibrated to base year conditions through comparisons of theoretical travel patterns, trip length characteristics, and traffic volumes with similar observed values. For projections of travel to future time periods, the assumption is made that the established database and relationships, and in particular the traffic analysis zones to which these data are assigned, will be the same for the forecast period as at the time of calibration. The primary objective of this research was to establish criteria for decision-making regarding which zones should be subdivided and to develop a technique for deciding how to subdivide. The eventual goal of the research was to improve travel demand forecasts. This research investigated whether travel demand estimates can be improved through the reconfiguration of traffic analysis zones for the future year projection period and through an associated restructuring of the centroid connectors for the future network. Similar subarea techniques have been applied by others in attempts to develop more accurate traffic data for project-specific needs. The subarea approach suffices for project needs, but the adjustments and modifications are not usually fed back into the modeling process. Therefore, the time and effort expended in obtaining project data are not applied to the improvement of the overall travel demand forecasts on a study-wide or regional basis. Under these conditions, system planning efforts and corridor analyses do not receive the benefit of updated information or system refinements. The findings of this research indicate that there is little improvement in the travel forecasts as a result of the subdivision of 9 zones in the New Castle County model into a total of 23 new units. Link-by-link comparisons of traffic assignments based on the New Castle County original 228 zone system and the modified 242 zone system reveal no significant improvements. One reason that can be identified is the detail of the simulated roadway system, which nearly duplicates the existing street and highway network and leaves little opportunity to provide alternative travel routings resulting from the creation of small traffic analysis zones.
| Identifer | oai:union.ndltd.org:UMASS/oai:scholarworks.umass.edu:dissertations-7808 |
| Date | 01 January 1990 |
| Creators | Crevo, Charles C |
| Publisher | ScholarWorks@UMass Amherst |
| Source Sets | University of Massachusetts, Amherst |
| Language | English |
| Detected Language | English |
| Type | text |
| Source | Doctoral Dissertations Available from Proquest |
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