Time-space constraints and the formation of trip chains

Abstract This study is concerned with a worker's decision to chain trips when a non-work, out-of-home activity is pursued together with obligatory work activities. Using a simple model, factors related to the likelihood of combining activities into a multi-sojourn trip chain are examined. The analysis indicates that the likelihood depends on whether marginal benefit of the time spent for in-home activities diminishes or not. It is shown that if marginal benefit diminishes, a longer activity duration, larger distance between the home and non-work activity locations, larger distance between the home and work location, and slower speed of the travel mode used, tend to favor a multi-sojourn trip chain. When the marginal benefit does not diminish, the relation is in general reversed. Tabulation of origin-destination survey results in general supports the notion of non-diminishing marginal benefit of in-home activity time. Estimation of constrained discrete-choice models also offers results that are consistent with non-diminishing benefit of in-home time. It is also indicated that trip chaining behavior is less sensitive to the sojourn duration and travel mode in the evening period than in the morning.