As numerous tunnels in the United States began to show signs of considerable deterioration, it became necessary to develop a Tunnel Management System to guide highway and rail transit tunnel owners. This manual provides specific information for the maintenance and rehabilitation of tunnels; provides specific recommendations for performing preventive maintenance to the tunnel structure, mechanical systems, electrical elements, track systems, and miscellaneous appurtenances; and offers general procedural recommendations for making structural repairs to various types of tunnel liner materials.