The purpose of this literature review is to assess what is currently known about the ability of travel demand forecasting models (TDMs) to provide accurate forecasts for different types of transportation plans and projects with respect to different outcome measures of interest. The role of TDMs in assessing the implications of highway expansions for vehicle miles of travel (VMT) and greenhouse gas (GHG) emissions is of particular interest given the current regulatory context. Relevant studies for this review were found using a variety of search terms in the Transport Research International Documentation (TRID) database and Google Scholar. The report reviewed the available studies with respect to the themes of limitations of the models, validity testing and sensitivity testing, and VMT forecasting.
