Integration of Travel Demand Models with Operational Analysis Tools

Continuing growth in urban travel demand inevitably leads to a need for more physical capacity within the transportation system. However, limited financial resources, high construction costs, environmental considerations, long timelines, and an increasingly complex regulatory process have essentially rendered capacity-adding projects to be actions of last resort. Before such projects are undertaken, decision makers, planners, and engineers evaluate alternative operational improvement strategies that can eliminate, mitigate, or forestall the need for a more traditional highway construction project. Effectively evaluating the wide range of operational improvement strategies that are available is not a trivial matter, and this is particularly true when the performance of such strategies is compared to the construction of new lanes. The purpose of this study was to recommend methods to obtain input data for operational analysis tools that operate as post-processors to travel demand models. Among all operational planning tools compatible with the four-step planning process, the Florida ITS Evaluation (FITSEval) tool was selected to be integrated with the primary planning software used by the Virginia Department of Transportation, i.e., Cube. To achieve the objective of this study, methods for estimating peak period flows from travel forecasting model outputs were investigated and Virginia data were examined for areas where planning forecasts and 24-hour travel patterns were available. Relationships between peak period flows and 24-hour data were studied. Procedures for obtaining the time-of-day factors for link and trip tables are provided using continuous count stations and National Household Travel Survey Data for Virginia. The modeling process was demonstrated by two case studies for the Hampton Roads area where the latest travel demand model was recently completed and many potential capacity enhancing operational strategies were available. Two case studies, Incident Management systems and High Occupancy Toll (HOT) lanes deployment, were evaluated, and the results of the base case and operational strategy deployment scenarios were compared to make recommendations on the feasibility of the evaluated projects. This report is designed to serve as a reference for users of FITSEval or similar operational analysis tools for evaluating operational capacity enhancements.