Innovations in Travel Demand Modeling, Volume 1: Session Summaries (2008)

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• An application of the tour model was also used on the proposed New Central Subway project in downtown San Francisco. This analysis represented one of the first applications of a tour- based travel model on an FTA New Starts program submission. Software was developed to collapse the microsimulation output of the tour and trip mode choice models into a format compatible with the FTA SUMMIT program. The SUMMIT program was used to analyze user benefits accruing to the project. MID- OHIO REGIONAL PLANNING COMMISSION TOUR- BASED MODEL DEVELOPMENT Rebekah Anderson Rebekah Anderson discussed the development and appli- cation of a tour- based travel forecasting model at the Mid- Ohio Regional Planning Commission (MORPC) in Columbus, Ohio. She described the model development process, including the use of a multiagency advisory committee, and highlighted elements of the model. More detailed information on the model components and the validation process are described in other sessions. Vol- ume 2 includes a paper on the topic.4 The following points were covered in her presentation. • In the summer of 2001, MORPC issued a request for proposal for improving the existing four- step model, which was a destination- choice model, oriented to journey- to- work trip purposes. In the fall of 2001, PB Consult, Inc. was selected to conduct the model improve- ment and proposed a disaggregate microsimulation tour- based model. • An advisory committee provided guidance during the development of the new tour- based model. The advi- sory committee included representatives from MORPC, the Licking County Area Transportation Study (LCATS), the Ohio Department of Transportation, Ohio State Uni- versity, the Northeast Ohio Areawide Coordinating Agency, the Ohio- Kentucky Indiana Regional Council of Governments, FTA, and the Central Ohio Transit Authority. The committee examined elements related to the advantages of tour- based models, as well as data requirements and cost implications. LCATS was also interested in being able to freeze the non– Licking County portion of the model. Overall, the advisory committee favored the structure of the model. The committee also thought the ability to present a range of forecasts was valuable. FHWA and FTA staff supported the use of the microsimulation model and provided feedback during the development process. • It is important not to underestimate the model development time. The development of the MORPC model took longer than anticipated. In December 2001, MORPC accepted the disaggregate model approach. In June 2004, the highway model validation and the long- range transportation plan were adopted. In December 2004, the advisory committee accepted the full model validation. The MORPC experience also indicates the importance of validating the existing model first. • Since 2004 the model has been used on the draft of the Environmental Impact Study on the North Corridor Transit Project and other studies. AECOM Consulting was also hired to conduct a quality assurance and qual- ity control analysis of the model. PB Consult, Inc. also conducted a transit refinement. APPLICATION OF A MICROSIMULATION MODEL FOR USER BENEFIT CALCULATION IN TRANSIT PROJECTS Peter Vovsha Peter Vovsha discussed the use of microsimulation travel models for estimating user benefits of New Starts transit projects. He described the FTA requirements for estimat- ing user benefits, the use of microsimulation models in this process, and the application of the MORPC activity- based model in the North Corridor study. Volume 2 con- tains a paper on the topic.5 The following points were covered in his presentation. • The FTA requirements for estimating user benefits are based on the general methodology of assessing the dif- ference between the total composite utilities before the project is implemented and after the project is operational. FTA limits the composite utility choices to mode and route choices. The total trip table is assumed fixed and the mode and route choice attributes that are used for calculation of the composite choice utility are reported. • The FTA approach and the SUMMIT software developed to meet the requirements are designed primar- ily for traditional four- step models that are characterized by the ability to separate the trip distribution and the mode choice steps. This permits a fixed trip table to be run through the mode choice step for each alternative being evaluated. The more complicated structure of activity- based, tour- based microsimulation models requires reconsideration of calculating user benefits. Trip generation, trip distribution, and time of day are fixed across all scenarios in the four- step model. Mode choice, estimation of user benefits, and assignment are rerun for 17TOUR-BASED MODELS 4 See Anderson, R. Development of Mid- Ohio Regional Planning Commission Tour- Based Model. Volume 2, pp. 30–32. 5 See Vovsha, P. Application of Microsimulation Model for User Benefit Calculation in Transit Projects. Volume 2, pp. 33–36.