As the European Union¿s transport policy is developing, the idea of establishing a shared approach to the management of transport flows in particularly environmentally sensitive areas has gained support. This idea was born from the experience gained in the Alpine region, then translated to other transnational mountainous areas (the Pyrenees) and finally expanded to coastal regions and urban areas. This paper reviews how the ¿transport sensitive area¿ (TSA) concept has matured. This is followed by a discussion on the practical use of the concept and the key concepts on both, the identification of a TSA and the policy instruments for transport policy and regulation that could be applied. A practical case-study (the Pyrenees region) serves to illustrate the effectiveness, barriers and further developments needed. It is concluded that formalizing the concept of TSA would facilitate the institutional cooperation, which is needed to intervene in regions where several Authorities are involved. Furthermore, a comprehensive approach to mobility within/ through those areas seems to be necessary in order to avoid unexpected results. However, the extension of the concept to other contexts (particularly urban areas) seems to duplicate already existing instruments of coordination, and thus introduce further confusion in an already over-regulated environment. Modeling may greatly facilitate the complex decision-taking process involving multiple local, regional and national authorities, and facilitate consensus on a long term vision, thus mobilizing resources to develop alternative, environmentally-friendly infrastructure (in this case, a new rail crossing)