Current long-distance travel in Germany: How to merge distinct data sources into a meaningful and consistent picture?

In contrast to everyday travel, long-distance passenger travel continues to increase for the German population. Although data are available for some travel segments, there is no up-to-date and consistent overall picture of this specific demand, neither in terms of total transport volumes, nor in terms of socio-demographic characteristics of the corresponding population and the driving forces. A dedicated survey – already carried out in the early 2000s (INVERMO 2002/2003) – revealed that long-distance travel was extremely unevenly distributed among the population: only a small proportion was responsible for the majority of travel volumes. The question is whether this fact has already changed in view of current societal processes, such as an increasing level of education, the conversion to a knowledge-based society, long-term socialisation in terms of travelling to distant destinations, the emergence of multi-local lifestyles or wide-ranging social networks, all of them likely to result in changing travel volumes and a shift between different groups of travellers. Analyses in this respect, however, require a meaningful data framework. An ongoing project on behalf of the German Federal Environment Agency aims to compile relevant data sources (i.e. German National Travel Surveys, tourism surveys, official transport statistics) and to amalgamate them within a 'fusion model'. The challenge is to prepare available data according to a suitable definition of 'long-distance travel' and to close data gaps based on empirically founded assumptions. Results from a survey carried out during the project will complement the data framework providing missing information i.e. on the use of particular transport modes typical for long-distance travel. \nThe objective of the paper is threefold: First, the challenges of data harmonisation are described against the background of diverging definitions of long-distance travel. Second, the approach of 'data fusion' is presented. Finally, the current picture of long-distance travel in Germany is presented.