An introduction to road vulnerability: what has been done, is done and should be done

Vulnerability in the road transportation system, studied not only from a safety point of view but also as a problem of an insufficient level of service, is proposed as a setting for future transport studies. This relatively new notion is conceptualised by discussing a number of definitions and related concepts, reviewing especially the concept of reliability as a feasible theoretical approach. The paper relates how vulnerability related problems have been addressed so far, current developments and finally what the future should hold in order to provide us with the comprehensive network analysis tool that our complex society calls for.