Forecasts of travel historically provided by the Idaho Transportation Department (ITD) have been extensions of trends of growth on existing facilities. This approach has not allowed for changes in travel patterns or behavior including routings over new facilities, new trip origins or destinations, or truck travel required by new industries. Nor has ITD been able to forecast the performance of the transportation system or how project policies and programs might impact travel patterns, traveler behavior or system performance.

ITD undertook a study to assess ways for incorporating statewide travel demand and economic impact modeling into their transportation planning activities, and identify the steps needed to develop data and analysis tools. A series of workshops and interviews with ITD staff were designed to help determine if ITD was institutionally ready to incorporate the two modeling processes into their planning process. Through this process, the ITD was able to develop a cohesive strategy to implement both modeling processes and develop a better institutional understanding of what the models could contribute to the planning process. ITD staff members gained better understandings of what to, and what not to, expect from both types of models. ITD staff also gained better understandings of where they fit in relation to the modeling and planning processes.

An outcome of the workshops and interviews was the understanding that a statewide travel demand model could help ITD make wise decisions regarding the maintenance and enhancement of the transportation system. Based on the workshops and interviews, building the model in an incremental fashion, initially based on existing ITD data and counts, was recommended. This initial model would help ITD analyze routing changes and roadway system performance for future personal and truck (freight movement) travel. The model could subsequently be expanded to incorporate more sophisticated modeling of the factors that motivate personal and business travel choices. This incremental model development approach has been used by other state departments of transportation and could provide ITD with the capability to not simply “look in the rear view mirror, but to confidently look out the front window at the road ahead.”