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

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SUMMARY The CEMDAP project represents a significant effort in the development and implementation of an activity- based travel forecasting system. The recent efforts by the researchers have been focused on incorporating sev- eral enhancements (such as modeling the travel pat- terns of children and incorporating children–parent interactions) to the overall modeling framework and applying the framework to an expanded 4,874 zone system in the Dallas–Fort Worth area. All the models have been reestimated for this new zoning system with household travel survey and disaggregate land use and interzonal level- of- service data from the Dallas–Fort Worth area. The researchers are now engaged in the implementa- tion and integration testing of the software for the expanded and enhanced software version. Simultane- ously, data inputs are being assembled for evaluation and sensitivity testing of the software outputs. The tasks planned for the immediate future include the following: (a) comparison of the travel patterns pre- dicted for the estimation sample against the observed patterns in the activity- travel survey, (b) complete soft- ware run for the entire baseline population (synthetically generated for Year 2000), (c) evaluation of sampling strategies, (d) comparisons of CEMDAP outputs with those from four- step models currently employed by NCTCOG, (e) validations against ground counts and other measures, (f) sensitivity tests and comparisons of CEMDAP and NCTCOG results, and (g) predictions for a future year and corresponding comparisons with NCTCOG model results. ACKNOWLEDGMENTS The authors appreciate the help of the NCTCOG travel modeling team in the CEMDAP sensitivity testing efforts, for providing the data for model estimation, and for their overall support of this research effort. The research is sponsored by the Texas Department of Transportation. REFERENCES Bhat, C. R., J. Guo, S. Srinivasan, and A. Sivakumar. Activity- Based Travel Demand Modeling for Metropolitan Areas in Texas: Software- Related Processes and Mechanisms for the Activity- Travel Pattern Generation Micro- Simulator. Report 4080-5, Center for Transportation Research, Uni- versity of Texas at Austin, Oct. 2003. Guo, J. Y., S. Srinivasan, N. Eluru, A. Pinjari, R. Copperman, and C.R. Bhat. Activity- Based Travel- Demand Analysis for Metropolitan Areas in Texas: CEMSELTS Model Estima- tions and Prediction Procedures, 4,874 Zone System CEM- DAP Model Estimations and Procedures, and the SPG Software Details. Report 4080-7. Center for Transporta- tion Research, University of Texas at Austin, Oct. 2005. 81COMPREHENSIVE ECONOMETRIC MICROSIMULATOR TABLE 4 Impact of IVTT on PHT Home- Based Work Home- Based Other Non- Home- Based Overall PHT* % Diff. PHT* % Diff. PHT* % Diff. PHT* % Diff. Base case 1.68 — 3.12 — 0.79 — 5.59 — 10% increase 1.77 5.53 3.10 0.73 0.78 0.74 5.66 1.15 25% increase 1.91 13.89 3.06 1.89 0.78 1.34 5.76 2.93 10% decrease 1.58 5.73 3.15 0.94 0.80 0.84 5.53  1.08 25% decrease 1.44 14.13 3.21 2.64 0.81 2.67 5.46 2.39 *PHT is in millions of hours.