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50 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 TESTING OF DENVER REGION ACTIVITY- BASED MODELS David Kurth, Suzanne Childress, Erik Sabina, and Thomas Rossi David Kurth described the proposed validation process and sensitivity testing to be used with the new Denver Regional Council of Governments (DRCOG) activity- based modeling system. He summarized the develop- ment of the new activity- based model, the validation philosophy, and the validation and sensitivity testing plan. Volume 2 includes a paper on this topic.1 The fol- lowing points were covered in his presentation. ⢠During the 4-year period from 1997 through 2000, DRCOG collected a variety of survey data for use in refreshing the agencyâs traditional four- step travel model. The actual refreshing of the model took place from 2002 to 2004. Activities conducted in this phase included model component validation, validation to the 1997 base year, and validation to travel conditions in 2001. The light rail system in Denver doubled in length between 1997 and 2001, enhancing the effectiveness of the transit component calibration and validation. ⢠The Integrated Regional Model vision phase occurred during 2004 and 2005. The vision phase included a review of other advanced modeling projects in the country, convening panels of experts to provide overall guidance and developing a list of the top 10 core planning issues that models must support. The develop- ment of the activity- based model was initiated in 2005. ⢠Although the activity- based model is still being finalized, it is anticipated that it will include 13 compo- nents. These components will include a synthetic popu- lation generator, a regular work place location choice model for each worker, a regular school location choice model for each student, and a household automobile ownership choice model. Other components include a daily activity pattern choice model for each person day, a number of tours choice model for each person day, and a work- based subtour generation model. Still other com- ponents include the tour- level destination choice, the tour- level mode choice, the tour- level time- of- day choice, and the trip- level destination choice models. The final two components are a trip- level mode choice model, which is conditional on tour mode choice, and a trip- level time- of- day choice model, which is conditional on time windows remaining after all previous choices. ⢠The validation plan, which outlined the validation tests to be conducted for the model components and the overall model system, was developed at the same time as the specifications of the model. It is anticipated that the val- BREAKOUT SESSION Validation 1 See Kurth, D. L., S. Childress, E. Sabina, and T. Rossi. Proposed Validation and Sensitivity Testing of Denver Region Activity- Based Models. In Conference Proceedings 42: Innovations in Travel Demand Modeling, Volume 2: Papers, Transportation Research Board of the National Academies, Washington, D.C., 2008, pp. 153â156.
