This paper presents an activity chaining model described as a time use problem. Unlike existing activity chaining models, the time use problem includes all choice attributes related with time, not only when and where the activity is performed, but also the duration of the activity. In order to apply the time use problem to transportation network demand analysis, the opportunity cost of travel time is modeled through a constraint approach and the value of activity is represented by time-dependent utility profiles. In the model, among activity alternatives, the activity with the biggest utility is sequentially included within individual's daily disposable income. Through the sequential selection process, not only the activity type, but also its start time and duration are simultaneously determined based on individual's perceived time-dependent travel time for the activity. Since the activity chaining is performed based on the dynamic travel times calculated via traffic network simulation, the activity chaining is iteratively updated through a day-to-day dynamic process. The model developed in this study is applied to a medium size network to show its applicability. The example sheds lights on the practicality of activity-based models and extends applications of the travel demand model to market analysis by illustrating how the model can analyze impacts of transportation network improvement on the activity pattern and zonal socio-economic conditions particularly associated with shopping and leisure activities.
Samenvatting