The manual provides guidance on designing and building steel and concrete highway bridge superstructures using the LRFD method. It includes design examples and explanations to help engineers follow the AASHTO specifications. The manual is divided into four volumes, covering general design considerations, composite steel bridge design, composite concrete bridge design, and detailed design examples. Key topics include load combinations, deck design, bearing design, girder types, connections, and post-tensioning. The goal is to assist bridge engineers in implementing the AASHTO LRFD Bridge Design Specifications effectively.