Social Context of Activity Scheduling: Discrete-Continuous Model of Relationship Between "with Whom" and Episode Start Time and Duration

Activity-based approaches to travel demand modeling are increasingly moving from theoretical to operational models. In this context, agent-based micro-simulation models are a promising approach since they explicitly conceive travel as an emergent phenomenon from peoples’ activity characteristics, and more explicitly, from their activity scheduling processes. Behaviorally, activity-scheduling processes are influenced not only by individuals’ characteristics, but also by the other people with whom they interact. Thus, the activity scheduling process has an intrinsic social context. Using social activities as a case study, the objective of this paper is to empirically investigate the relationship between the social context (measured by with whom the respondents interacted) and two key aspects of activity scheduling: start time and duration. Econometric models of the combined decisions regarding “with whom” to participate and when to start or how much time to spend on are estimated to investigate the correlations between “with whom” and the start time / duration decisions. Data collected by a seven-day activity diary survey are used for the model developments. Findings suggest that the social context has a relevant role in activity scheduling processes. For example, the investigations indicate that it is “with whom” we socialize what influences the social activity scheduling processes more than the travel time or the distances to social travel. Overall, and additionally to the theoretical understanding of the questions posed to investigate in this paper, the models serve as an empirical support for agent-based microsimulation models that could incorporate the role of social networks in activity scheduling attributes