Economic Enhancements to Statewide Model
Lochmueller Group (Lochroup) performed several updates to the Ohio Department of Transportation’s (ODOT) statewide, activity-based, travel demand model over a 3-year period as part of a contract for economic modeling enhancements. An array of modifications was instituted to enhance the model’s ability to forecast the economic benefits of transportation infrastructure investments. Specific updates included the following:
- Instituted a logit-based Toll Choice model to provide more robust forecasts for toll roads, replacing the traditional method of identifying toll users in assignment.
- Disaggregated vehicles classes from 2 (car and truck) to 7 (low-, medium-, high-income for cars; 4-tire commercial vehicles; and small, medium, and large trucks).
- Achieved a faster and more stable assignment convergence by instituting relative gap or cost-based convergence criteria and adjusting the assignment algorithm.
- Developed a user-benefits tool to estimate the costs of transportation and the anticipated savings resulting from infrastructure projects. Cost components included vehicle operating costs, travel time costs, travel time reliability, safety and work zones.
- Introduced asset deterioration so the effects of routine maintenance, deferred maintenance, or completely new infrastructure could be considered in routing decisions and the identification of transportation user benefits.
- Extended the user-benefits tool to address economic impacts, converting travel cost savings into job creation, increased household income, and increased output and production using a version of the nationally-recognized TREDIS tool, which was individually customized for ODOT.
The enhanced model better facilitates project evaluations and provides a more complete picture of the economic impact of ODOT’s transportation spending.