This paper presents results from an in-depth survey method for capturing the content and attributes of peoples' preplanned schedules. The focus ison preplanned daily activity and travel events, their typically observable attributes (event type, start/end time, location, and involved person), and the extent to which these attributes are specified/elaborated upon. The survey starts by simply asking subjects to write down or discuss their schedule for the next two days in as much or little detail as they know. The interviewer subsequently probed for further details as needed. This method elicited considerable detail on decision hierarchies in the subjectsown words. Overall, it was found that activity type is the most often preplanned activity attribute, followed by location, start time, involved persons and end time. For trips, the mode type and start time are most often planned, followed by involved persons and end time. Further analysis further confirms that the preplanning is an-going decision process, wherein tentative decisions on each attribute are often made, then revisited at some point closer to execution. The implications of these findings for modeldevelopment and future survey design are discussed. In particular, the results imply that activity scheduling models should adopt a nested or continuous planning loop, wherein certain activity attributes decisions are made first but followed by subsequent stages of refinement and elaboration.
Abstract