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BREAKOUT SESSION Validation David Kurth, Parsons Transportation Group Suzanne Childress, Parsons Transportation Group Erik Sabina, Denver Regional Council of Governments Thomas Rossi, Cambridge Systematics, Inc. Ram Pendyala, University of South Florida Chandra Bhat, University of Texas at Austin Rebekah Anderson, Ohio Department of Transportation Robert Donnelly, PB Consult, Inc. PROPOSED VALIDATION AND SENSITIVITY between 1997 and 2001, enhancing the effectiveness of TESTING OF DENVER REGION the transit component calibration and validation. ACTIVITY-BASED MODELS The Integrated Regional Model vision phase occurred during 2004 and 2005. The vision phase David Kurth, Suzanne Childress, Erik Sabina, included a review of other advanced modeling projects and Thomas Rossi in the country, convening panels of experts to provide overall guidance and developing a list of the top 10 core David Kurth described the proposed validation process planning issues that models must support. The develop- and sensitivity testing to be used with the new Denver ment of the activity-based model was initiated in 2005. Regional Council of Governments (DRCOG) activity- Although the activity-based model is still being based modeling system. He summarized the develop- finalized, it is anticipated that it will include 13 compo- ment of the new activity-based model, the validation nents. These components will include a synthetic popu- philosophy, and the validation and sensitivity testing lation generator, a regular work place location choice plan. Volume 2 includes a paper on this topic.1 The fol- model for each worker, a regular school location choice lowing points were covered in his presentation. model for each student, and a household automobile ownership choice model. Other components include a During the 4-year period from 1997 through 2000, daily activity pattern choice model for each person day, DRCOG collected a variety of survey data for use in a number of tours choice model for each person day, and refreshing the agency's traditional four-step travel model. a work-based subtour generation model. Still other com- The actual refreshing of the model took place from 2002 ponents include the tour-level destination choice, the to 2004. Activities conducted in this phase included tour-level mode choice, the tour-level time-of-day choice, model component validation, validation to the 1997 and the trip-level destination choice models. The final base year, and validation to travel conditions in 2001. two components are a trip-level mode choice model, The light rail system in Denver doubled in length which is conditional on tour mode choice, and a trip- level time-of-day choice model, which is conditional on 1See Kurth, D. L., S. Childress, E. Sabina, and T. Rossi. Proposed time windows remaining after all previous choices. Validation and Sensitivity Testing of Denver Region Activity-Based The validation plan, which outlined the validation Models. In Conference Proceedings 42: Innovations in Travel Demand Modeling, Volume 2: Papers, Transportation Research tests to be conducted for the model components and the Board of the National Academies, Washington, D.C., 2008, pp. overall model system, was developed at the same time as 153156. the specifications of the model. It is anticipated that the val- 50