This Report has been commissioned specifically to assist those concerned with aspects of transport policy and planning which may involve the inclusion of road tunnels. The initiative represents in part a response to a request from the World Bank.

While most readers may well belong to countries with no tradition in planning or operating road tunnels, the more general aspects, representing advice currently more widely overlooked, should be of interest to those concerned with decision-making on roads. A common fundamental fault is to overlook a tunnelled option until the planning of a road network is too far advanced to permit optimal incorporation of the tunnelled element.

This report is an outstanding synthesis of all the knowledge and expertise gathered by one of the PIARC Committees over the last twenty five years. It offers to specialists in various areas clear and simple references, allowing easy access to the results of the PIARC work carried out on these topics since the XVth World Road Congress held in Mexico in 1975.