Computer simulation of household activity scheduling

An operational model of household activity scheduling is proposed. The model is based on a theory entailing behavioral principles of how persons acquire, represent, and use information from and about the environment. Choices of destinations and departure times are consequences of the scheduling of a set of activities to be executed in a given time cycle. Illustrative computer simulations of the operational model show realistic effects of work hours, living in or outside the center, and travel speed. Several necessary improvements of the theory and operational model are discussed, such as incorporating learning effects and choice of travel mode for home-based trip chains. Strategies outlined for empirical tests include comparisons with existing models, psychological experiments illuminating basic assumptions, and the use of geographical information systems to process travel-diary data for single cases. Introduction A substantial amount of research has been devoted to the disaggregate modelling of households' travel choices (Pas, 1990). In this research, models of choices of, for instance, travel mode, departure time, and destination have been estimated from travel-diary data It has become increasingly obvious that travel choices should be viewed as the outcome of a process of scheduling activities (Jones et al, 1990; Root and Recker, 1983). At times modelling single independent travel choices may therefore be futile, particularly in view of the impact that changing values, lifestyles , and roles appear to have on travel in contemporary societies (Jones et al, 1983). An important problem is thus how to model dependencies between choices and activities. Some approaches to travel-choice modelling have attempted to take activities into account (see reviews by may also be mentioned in this connection. Furthermore, related research has been carried out with the aim of describing activity patterns, taking into account spatial, temporal, and interpersonal Although many of the approaches followed to date perhaps are useful, they seem to lack a substantive theoretical underpinning. Thus, there is no guarantee that they are descriptive of how people actually make choices. Axhausen (1997) and Garling (1994a) therefore argued for approaches which are more firmly based on behavioral theories,