Pougala, J., Hillel, T., and Bierlaire, M. (2020)

Scheduling of daily activities: an optimization approach

20th Swiss Transport Research Conference, Ascona, Switzerland

Transport planners and operators have to face nowadays increasingly saturated networks and shifts in mobility behaviors driven by societal changes and emerging technologies. Traditional trip-based models become very limited in terms of behavioral realism when it comes to anticipating and accommodating the users’ new, and often hard-to-capture needs. The shift towards activity-based approaches is thus natural, as this alternative is better equipped to deal with individual-level granularity (Castiglione et al., 2014). The assumption behind these models is that all transport-related choices made by a person (e.g. number of trips, location and mode choice) are derived from the need to do activities (Bowman and Ben-Akiva, 2001), and their spatiotemporal sequence. We propose a modeling approach based on first principles: a traveler schedules their activities in order to maximize the total time-dependent utility they can derive out of them, thus solving a mixed integer optimization problem. The new model generates distributions of schedules for each individual, from which likely outcomes can be drawn. Thisapproach enables simultaneous consideration of multiple choice dimensions (e.g. activity, location, mode choices). This allows for more flexibility than sequential approaches which tend to not appropriately represent scheduling trade-offs. The model is tested using trip diary data from the 2015 Swiss Mobility and Transport Microcensus and a dataset collected by the authors.The results show that the model can generate realistic activity schedules for a wide range of individuals.