Post-Car World: data collection methods and response behavior in a multi-stage travel survey

The main research question addressed by this study is to what degree individuals would change travel modes, time allocation and activity patterns after experiencing large changes in generalized transportation costs and how they would react regarding their longer-term ownership in mobility tools, assessing suppressed demand effects from an activity-based perspective. The empirical basis is a multi-day travel and online diary that is required to obtain the personalized reference values for the later stated choice and stated adaptation tasks. This paper provides first detailed information of the survey methods, recruitment and fieldwork. An initial investigation of the data and its quality attributes, descriptions of the sampling structure and response behavior are presented. Participation choice models indicate that a high incentive level leads to a higher participation rate, but the net-effect on completing the survey is zero: once recruited, higher incentives also lead to a higher drop-out incidence. Certain socioeconomic characteristics are consistently overrepresented in the sample: season ticket ownership, better education and higher income strongly increase participation and completion of the survey. Findings reveal saliency effects, whereby response behavior is influenced by the respondents’ interest in the survey topic. While general fatigue effects can only be detected for the number of reported online activities, better educated and car-less respondents exhibit an increased reporting behavior of trips over time. Importantly, while showing no effects on completion of the survey, higher incentives tend to increase response quality in terms of absolute levels (trips) and stability (online activities).