Project Summary
This research constructs a statewide freight forecasting model for California, as the follow-up to an initial preparation phase conducted for the California Department of Transportation (Caltrans). In that initial phase, the scope of the model was defined, the modeling methodology and data needs determined, and a preliminary software platform selected. The objective of this phase is to implement the statewide freight forecasting model so that it can be used to evaluate policy scenarios and integrate with local and state models. The final deliverables of this project include a core model framework that can address the basic immediate needs of the state and local agencies, to be completed within a 2-year time frame. The core model is designed as a state of the art model to address the highest priority needs of the state, for which a state of the practice four-step commodity flow model would be inadequate. It consists of several primary modules: a commodity generation module, a commodity distribution module built on a destination-based logit allocation model called fractional split distribution, and a logit-based joint mode-route choice model. Factors are used to convert annual commodity flows to daily or peak period flows, and to convert commodities to commercial vehicles which are then assigned along the routes determined from the joint mode-route choice model. The handling of transshipments in the core model will be based on either Cube Cargo's TLN module or a network assignment approach that incorporates transfer costs that is available in TransCAD.
