The Development of a Unified Modeling Framework for the Household Activity-Travel Scheduling Process

The goal of this paper is to propose a new approach to activity-travel schedule modeling that provides a unifying framework for past research in different areas. This approach is based on empirical evidence gathered using a Computerized Household Activity SchEduling (CHASE) survey. The survey provided a means to examine the underlying scheduling behavior of household over a one week period as it occurs in reality. Results show that a clear distinction can be made between routine scheduling decisions that are pre-planned before the week commences, and the more short-term, impulsive, opportunistic decisions made as the schedule is executed during the week. This distinction allows one to conceptualize the modeling task as a multi-stage process, wherein routine planning is approached with existing optimization models (assuming that routine activities are the result of a long-term thought and experimentation process) followed by a more sub-optimal rule-based simulation model to replicate the decisions process during the week within the constructs of the optimal routine plan. Such a model is proposed in this paper as a long term development, and would rely on the type of data provided by new data collection techniques such as CHASE. Operationalization of the model as an event-oriented simulation is proposed. Various components of the model are explored in detail, and discussed within context of existing models.