External Costs as Competitiveness Factors for Freight Transport — A State of the Art

External costs have been a key issue in the last years of transport research. In Europe, this trend is in line with the political willingness to internalize externalities in transport pricing policies. This paper has two purposes. It first identifies the recent work achieved in the field of external costs of road and intermodal freight transport, where each paper is assessed in terms of its perspective (academic or project oriented), its objective (prescription, application, projection), the type of externality (air pollution, climate change, noise, accidents, congestion) and the type of cost (marginal, average, total) that is considered. The literature review reveals a gap in the development of generic mathematical functions for external costs of transport. The second objective of the paper is thus to highlight the usefulness of such functions by identifying the main parameters that influence freight transport competitiveness in terms of external costs, and by determining which of these parameters should be incorporated in further research works.