The purpose of this manual is to provide highway and rail transit tunnel owners guidance for establishing procedures and practices for the inspection, documentation, and priority classification of deficiencies for various elements that comprise an existing tunnel. It is also the intent that this manual be used as part of a comprehensive inspection and maintenance program. The preliminary research performed indicates that a majority of tunnel owners believe there is a need to develop guidance for procedures for managing tunnel activities that could be readily implemented.This manual addresses inspection procedures for the functional aspect of the tunnel, focusing on the civil/structural, mechanical, and electrical components.