A joint model of weekend discretionary activity participation and episode duration

Research on travel demand modeling has primarily focused on weekday activity-travel patterns. However, weekend activities and travel constitute a major component of individuals’ overall weekly activity-travel participation. This paper describes a modeling effort that focuses on discretionary-event weekend activity-travel demand. This study bridges the gap in the literature by modeling discretionary event type participation, duration of participation, and accompaniment type jointly in a simultaneous equations model system. A joint discrete-continuous modeling framework is formulated for analyzing these dimensions as a choice bundle. Specifically, the combination of event type and accompaniment type constitutes the discrete component while the duration of participation constitutes the continuous component. The model employs a copula-based sample selection approach that ties the discrete choice error component with the duration error component in a flexible manner. The data used in the paper is drawn from the 2008-2009 National Household Travel Survey sample of the Greater Phoenix metropolitan area in Arizona. The results from the estimation process clearly highlight the presence of sample selection in the joint modeling context. Furthermore, the results also highlight the flexibility of copula models in capturing such sample selection. The best copula model results were employed to generate hazard profiles for various alternative related duration intervals. The profiles generated highlight the inaccurate predictions obtained using approaches that ignore the presence of sample selection.