Statewide Travel Forecasting Practice: A Critical Review

Many states are now in the process of creating or upgrading their statewide travel forecasting methods. To assist those states, a review of existing forecasting practice was undertaken. This review consisted of interviews and documents from 45 states and of articles from the literature. Passenger models, freight models, and time-series models were reviewed. In addition, statewide models were compared to the many intercity models that were described in academic literature. Little consensus was found as to what should constitute a statewide model, and states varied greatly in their approaches. Those states with complete models tended to follow an urban modeling framework and used software originally designed for urban travel forecasting, in spite of the inherent differences in scales, planning needs, and data availability. Recommendations are made on how states can improve their forecasting methods and tailor them better to statewide planning requirements.