To project future conditions of the roadway system, the TPO uses a computer-modeling tool known as a travel demand forecasting model.
To develop the model, household travel behavior surveys were conducted in the years 2000 and 2008. Households with similar socio-economic characteristics such as income, number of school-age children, and vehicle ownership are assumed to have similar travel behaviors. The roadway network is represented in the model and used to determine capacity and travel time. The model can be used to test alternative improvement strategies such as increasing the number of lanes or construction of a new roadway.
Travel demand modeling has been in national practice for over 50 years and more agencies are now shifting from original models to an activity-based approach. Activity-based models predict when and where activities take place, how long they take, with whom they’re conducted, and the travel choices necessary to complete them. The TPO has introduced some elements from activity-based travel demand modeling and is currently researching best practices to determine what method to use for the next update of the Metropolitan Transportation Plan.