Models of household joint decision making in activities and travel

This research endeavors to explain household decision making as it pertains to the generation and scheduling of activities and travel that involve multiple household members. Previous research in the area of activity-based travel forecasting focused on the generation of activity episodes by households or the spatio-temporal scheduling of activities and travel, with more recent efforts seeking to develop integrated activity generation and scheduling models at increasing levels of complexity. This study addresses a relatively undeveloped facet of household activity-travel systems, the generation and scheduling of joint activities and shared travel.; The research presented here makes three general contributions. First, it places joint activities and travel in the context of household activity-travel systems, considering both short- and long-term decision making. Theoretical motivations and constraints that affect joint activity participation are proposed and formalized in a utility-based analytical framework.; Second, descriptive analysis of household travel diary data identifies several travel patterns in which two household members interact through joint out-of-home activity participation and shared rides, including partially joint tours.; Third, this study proposes a new discrete choice model to predict the choice of a full-day activity travel patterns for each of two household members. The structure represents two decision-makers in parallel, while linking their common decisions to engage in shared activities and travel. The model represents individual utility at a base level and collective utility at a higher level, enabling the estimation of cross-person elasticities. Estimation results show that the proposed model is superior to more restrictive models that do not represent correlation across individuals and choice alternatives.; The empirical results presented in this research confirm and clarify many of the theorized motivations and constraints on joint activity participation. Foremost among these are the primacy of work schedules, which constrain joint activity participation; the efficiency of joint activity participation when automobiles must be shared; and the role of children in both generating activities and constraining interaction between adults.