VMT-based traffic impact assessment : development of a trip length model.

This report develops models that relate the trip-lengths to the land-use characteristics at the trip-ends (both production- and attraction-ends). Separate models were developed by trip purpose. The results indicate several statistically significant and intuitively reasonable effects of land-use patterns. High residential densities and a good mixing of complementary land-uses are associated with shorter trips. Larger establishments attract longer trips and the home-based other (HBO) trip lengths decrease with increased number of convenient-commercial land-use parcels in the neighborhood. The connectivity provided by the roadway network and the urban-form of the area (measured in terms of number of intersections and cul-de-sacs) also affect trip lengths. In addition to the local land-use characteristics, the trip lengths also vary significantly by the location of the neighborhood with the region. All these results hold even after controlling for several trip and traveler characteristics. Trip length models are applied within a regional, neighborhood and project context to estimate trip lengths of a hypothetical development. Two simplified tools are presented that utilize the proposed models within an Excel and Geographical Information System environment that enable a user to estimate trip length as a metric of demand on the transportation network from a proposed project.