Modeling Daily Activity Program Generation Considering Within-Day and Day-to-Day Dynamics in Activity-Travel Behavior

This paper presents Kuhn-Tucker demand system models for daily activity program generation. The models are for day-specific activity program generations of a week-long modeling span. The models accommodate within-day and day-to-day dynamics in time-use and activity-travel behavior explicitly. The activity types considered are the non-skeletal and flexible activities. These activities are divided into 15 generic categories. Under the daily time budget and non-negativity of participation rate constraints, the models predict the optimal set of activities (given the average duration of each activity type). The daily time budget considers the at-home basic needs and night sleep activities as a composite activity. The concept of composite activity ensures the behavioral dimension of time allocation and activity/travel behavior in a sense that the activities corresponding to the composite activity are regular skeletal activities but highly flexible in nature. We are sure to execute these activities but do not often allocate precisely a specific amount of time to them during advanced planning. Workers? total working hours (skeletal activity and not a part of the time budget) are considered as a variable in the models to accommodate the scheduling effects inside the generation model. The incorporation of previous day?s total executed activities as variables introduces day-to-day dynamics into the activity program generation models. The possibility of zero frequency of any specific activity under consideration is ensured by the Kuhn-Tucker optimality condition used. The models use the concept of goal/direct utility of activity episodes. The empirical estimations of the models are done using 2002-2003 CHASE survey data collected in Toronto. The models perform well in terms of fitting the observed data.