The AASHTO Manual for Maintenance Inspection of Bridges is the standard by which publicly owned bridges in the United States are inspected and rated. The present Manual was initially adopted in 1970 and was intended as an engineering guide for bridge owners to inspect and evaluate highway bridges as required by the National Bridge Inspection Standards issued by the U.S. Congress in 1968. During a period of almost twenty years, advances in technologies and research have resulted in many innovations, improvements and changes in the state-of-the-art of bridge inspection and evaluation. While the existing Manual has received minor revisions periodically, the basic text and procedures have remained unchanged. It is the intent of Project NCHRP 12-23, which is sponsored by the Transportation Research Board, AASHTO Bridge Committee and the Federal Highway Administration, to update and modernize the present Manual to reflect the latest advances in inspection methods, tools and rating systems. New major items in the revised Manual will be Scour Inspection, Treatment of Fracture Critical Bridge Members, Non-Destructive Testing, Load Tests, and Load Rating Systems. The revised Manual is expected to be approved by AASHTO in the Spring of 1991. For the covering abstract of the Conference see IRRD Abstract no. 807839.