July 2023 - September 2024

Caltrans and other agencies rely on travel demand models (TDMs) to forecast the outcomes that will result from proposed projects, such as highway expansions. These models are not perfectly suited to their mission, in that they are not capable of analyzing certain kinds of projects or providing forecasts of all of the outcomes of interest, and the accuracy of the forecasts are uncertain.  The first goal of this project is to delineate the capabilities of TDMs to provide accurate forecasts for different types of projects and plans for different outcome measures of interest given particular regulatory settings. The second goal of the project is to determine the susceptibility of TDM analyses to bias introduced by the operator, to determine their usefulness in regulatory settings. This project aims to inform the choice of assessment tools and to shed light on the need for further tool development. It will also inform policymakers on the opportunities for and limitations to relying on TDMs as regulatory tools.