Dynamics of Change: Fifteen-Year German Mobility Panel

Germany has taken an approach to analyze and monitor travel demand development which encompasses different surveys: Cross-sectional surveys with large samples (Kontiv, MID) are carried out every 5 to 10 years. These cross-sectional surveys are supplemented by two longitudinal (panel) surveys: the German Mobility Panel (MOP) with focus on everyday travel and the INVERMO panel survey of long distance travel. The MOP has been conducted annually since 1994 with an annual sample of about 800 households. Each participant reports his mobility in a 7-day mobility diary in three consecutive years before he drops out. With respect to these dropouts and attrition the sample is being refreshed on a yearly basis. Moreover, the MOP includes an odometer survey over two months period. The INVERMO survey was carried out between 1999 and 2002 and started off with a screening survey via telephone with a sample of 17,000 interviews. In the subsequent panel survey, respondents reported their long distance journeys (journeys over 100 km) over four two months periods. Longitudinal surveys provide a broader image of individual mobility than cross-sectional surveys because respondents report on their mobility over several days and over several years. This enables new analysis of the stability and variability of individual behavior e.g. mode choice over a period of time. Particularly the German Mobility Panel (MOP) which provides such longitudinal data has been analyzed intensively in a number of research projects and has thus contributed extensively to a new understanding of the composition of travel.