In terms of sustainable development, the current situation in the field of infrastructure varies greatly from one country to another. Certain countries have laid down regulations; a few have set objectives to be achieved, while others have no regulations at all. So far, the World Road Association has not issued any recommendations for road tunnels which reflect the current'State of the Art' in various countries. This document has therefore been produced as an initial means of making up for this shortfall.

The main focus of the report is on tunnels already in use. However, as the options available for the operation of a tunnel are closely linked to the design and construction stages, the scope has been extended to all phases in the tunnel life. New tunnels are taken into account, with a range of economic, social and environmental aspects that could be considered when appraising schemes. Therefore, the construction phase and, most importantly, the design phase have been included in the reflections.

The report defines the concept of sustainable development and its relevance to road tunnels. It then examines existing regulations across the world, focusing particular attention on regulatory texts and requirements applying to road tunnels. Given the constant and rapid changes in this area, we cannot strive to be exhaustive. Special attention is then paid to initiatives undertaken in the field of road tunnels, with both traditional cost-reduction actions and actions that encompass a more sustainable development approach.

The report ends with recommendations and, to conclude, avenues for future studies in the field of sustainable development.