Extension of activity-based modeling approach to incorporate supply side of activities: Examples for major universities and special events

Most of the recent advances in activity-based models (ABMs) have been on the demand side, that is, description of the individual needs for certain types of activities and travel as a function of person, household, and accessibility variables. The supply side of activities that describes characteristics of the locations where a certain activity can be undertaken remains largely unexplored. Two examples of specific activity generators for which the supply side of activity is essential for modeling are major universities and special events. Travel behavior and activity patterns of university students are different from that of the general population, and therefore modeling them with the necessary level of detail enhances the ABM forecasting ability. The same is true about special events such as sporting events. Special events participants can form a substantial part of the overall travel demand in the subarea on the event day, and therefore it is important to model them properly. Although previous studies have acknowledged the importance of modeling university students and special events participants, the challenge remains to integrate them in an ABM framework. This paper describes new practical methods for addressing the supply side of activities (using university students and special events as examples) in the framework of an operational ABM developed for Phoenix and Tucson, Arizona. The paper provides details on the data and methods used to develop university and special events submodels. The methodology and technical approach used to incorporate these models in the ABM framework are presented.