Mixed-Use Development Trip Generation Model

The mixed-use development (MXD) trip generation model provides a mechanism for estimating vehicle, walking, and transit trips for an MXD. The model applies trip modifications to standard single-use trip generation estimates developed by ITE. MXDs with diverse internal activities have been shown to capture internal trips at a rate higher than conventional suburban developments; therefore, the MXD trip generation model accounts for the internal capture of MXD sites by reducing the external trips produced and estimating the number of walking and transit trips that would typically be conducted by automobile. In addition, MXDs in central areas have been shown to generate shorter vehicle trips, and this factor has been taken into account in the model, as internal and external vehicle miles traveled (VMT) are estimated on the basis of published travel characteristics of MXDs. The MXD trip generation model provides a straightforward method of testing transportation-related metrics of MXDs. The model uses ratios from a leading research-based MXD model to reduce ITE vehicle trip estimates and presents a summary of results that show the effects on VMT, internal capture, and mode split as a result of enhanced activity density and diversity of land uses within the MXD. The MXD trip reductions are based on a methodology that analyzed data sets for 239 MXDs in six large and diverse metropolitan regions. Benefits of locally calibrated characteristics on vehicle ownership are also included in the mode split of the trip estimates of the MXD trip generation model.