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Innovations in Travel Demand Modeling, Volume 2: Papers (2008)

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Suggested Citation:"T57054 txt_037.pdf." National Academies of Sciences, Engineering, and Medicine. 2008. Innovations in Travel Demand Modeling, Volume 2: Papers. Washington, DC: The National Academies Press. doi: 10.17226/13678.
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37 Application of Mid- Ohio Regional Planning Commission Microsimulation Model New Starts Review Dave Schmitt, AECOM Consult, Inc. FTA has very high standards for travel demand modelsused to generate ridership forecasts for its New Startsprogram. A model’s ability to meet these standards must be assessed early on so that potential FTA concerns with the forecasts or model structure can be addressed in a timely manner. Model structure changes require long, iter- ative development times. The Mid- Ohio Regional Planning Commission (MORPC) microsimulation model is being used to gen- erate forecasts for the North Corridor Transit Project (NCTP)—currently in the stage requiring a draft envi- ronmental impact statement— with a potential New Starts submittal within the next few years. The NCTP is analyzing various travel modes along a 13-mi corridor that includes three major employment centers inter- spersed with large residential areas: the central business district (CBD), Ohio State University (OSU), and the Crosswoods and Polaris areas. NCTP team members investigated many areas of the MORPC model, including its overall structure, automo- bile and transit travel times, path building parameters, mode choice coefficient values, and results. The analysis of the model’s trip distribution and user benefit results will be discussed, as these two elements have been iden- tified as concerns by the FTA on other New Starts projects. The regional figures were divided into 13 districts for analysis purposes (Figure 1). Six districts are for the cor- ridor: CBD, the OSU area, Clintonville, Worthington, Crosswoods, and Polaris. The remaining area of Franklin County is divided into four districts: northwest, northeast, southeast, and southwest. The remaining area of Delaware County is another district, and Licking County is its own district. Portions of the surrounding counties, including Pickaway and Union, are in the final district. TRAVEL DISTRIBUTION Travel distribution is one of the most difficult aspects of travel demand to model effectively. FTA has identified travel distribution as a potential upstream model error that can lead to poorly calibrated mode choice models containing large, unexplainable alternative- specific con- stants. To explore the reliability of the work component of the distribution model, the simulated Year 2000 work tour distribution was compared with the 2000 Census Transportation Planning Package (CTPP), which cap- tures work journeys. The first step was to compare the regionwide magnitude of modeled work trip tours to CTPP. On a regionwide basis, the model estimated 660,031 work tours compared with 630,550 CTPP records— a difference of only 4.7%. Next, district- to- district tours were compared with the CTPP (scaled so that regional CTPP records match modeled journeys). The modeled work tour distribution is shown in Table 1. The CTPP journey distribution is shown in Table 2. Table 3 displays the ratio of the modeled to the observed distribution. Overall, the modeled trip distribution for work pur- poses appeared to be as good as or better than that of comparable models used elsewhere in the United States. The model was representing trips to the CBD very

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TRB Conference Proceedings 42, Innovations in Travel Demand Modeling, Volume 2: Papers includes the papers that were presented at a May 21-23, 2006, conference that examined advances in travel demand modeling, explored the opportunities and the challenges associated with the implementation of advanced travel models, and reviewed the skills and training necessary to apply new modeling techniques. TRB Conference Proceedings 42, Innovations in Travel Demand Modeling, Volume 1: Session Summaries is available online.

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