The Intermodal Surface Transportation Efficiency Act of 1991 requires that land use be considered in transportation planning, but currently available models do not adequately simulate the effects of major transit investments on land use.

Research is currently underway to develop integrated transportation and land-use planning models, specifically the Travel Model Improvement Program (TMIP). TMIP is jointly sponsored by the Federal Highway Administration, the Federal Transit Administration, the Office of the Secretary in the U.S. Department of Transportation, the Environmental Protection Agency, and the Department of Energy. There are five tracks to TMIP: (A) Outreach, (B) Near-Term Improvements, (C) Long-Term Improvements, (D) Data, and (E) Land Use. Some work has been done linking the effects of highway congestion to land-use forecasts, but work is needed to address the effects of transit access on land use.

TMIP short-term research is looking for opportunities to improve the traditional four-step, zone-based, forecasting process--trip generation, distribution, mode split, and network assignment. TMIP long-term research is focused on the Transportation Analysis and Simulation System (TRANSIMS), a microsimulation modeling approach being developed by the Los Alamos National Laboratory. TRANSIMS is based on a 24-hour simulation of individual travel behavior, and is designed to yield improved estimates of travel volumes, transportation-related emissions, and transportation/land-use interactions.

Land-use interactions are not handled well by the traditional transportation modeling process. Research is needed to ensure that the next generation of travel demand models simulates land-use and transportation interactions more accurately, and, specifically, the effect of public transit access on land use. This research should identify ongoing efforts to improve these models and assess the likelihood that the weaknesses identified above will be corrected, and in what time frame.

The objectives of this research are to define more clearly the effect of transit access on land use, evaluate the access component of current land-use models, and augment ongoing work sponsored by the TMIP (and others, if appropriate) to incorporate the effect of transit access into land-use forecasts.

Status: The final report has been published as TCRP Report 48, "Integrated Urban Models for Simulation of Transit and Land Use Policies: Guidelines for Implementation and Use." Double-click on the file below to access the report. (A free copy of the Adobe Acrobat Reader is available at https://www.adobe.com.) PLEASE NOTE: Because of the very large size of these files, it may take a long time--possibly more than 1 hour collectively--to download. We regret the inconvenience.

The contractor's final report has been published as TCRP Web Document 9.