A Stated Adaptation Approach to Surveying Activity Scheduling Decisions

Abstract Purpose — The paper reports on a research project exploring new approaches for analysing travel demand induced by changes in generalised costs of travel and activity participation. The description of the survey approach, which to our knowledge is novel in its application, reports descriptive analyses of the respondents' reactions to the changes implied in the household interviews. Methodology — A sample of respondents were administered a 5 day travel diary, from which 1 day was selected for further analysis. Travel times for trips conducted that day were changed using predefined heuristics based on the household characteristics to attain significant changes in the generalised costs of the reported trips. Respondents were then presented with these hypothetical scenarios in face-to-face interviews. All household members were asked to state how the implied changes would have affected their activity scheduling on the specified day, i.e. to adapt their reported schedule to the new conditions. Findings — The postulated induced travel effect could be observed, in that the modifications to the generalised costs of travel affect the respondents' travel patterns in general, and the number and durations of conducted out-of-home activities in particular. However, the predominant reaction to changing travel times is the adaptation of departure time, which does not directly interfere with trip generation. Indicators of the effects have been shown, and are quite weak as far as activity generation effects are concerned. The activities most likely to be re-planned are leisure activities and sojourns at the home location, as is consistent with expectations.