Intermodal freight transport has become a policy priority at national and European levels in order to cope with problems of rising traffic congestion, environmental damage and associated economic losses. However, to improve the basis for defining policy measures, statistics are needed on the volume and structure of transport flows. Some data exist, but often only on a mode-by-mode basis. Moreover, the development of the European internal market has led to a decrease in data collection by customs authorities, and increasing competition and deregulation are making operators more reluctant to disclose information. Therefore, there is a need to identify effective methods for assembling sufficient data for policy purposes.