Standard Specifications for Highway Bridges, 17th Edition The design standards for the maintenance and rehabilitation of older, existing structures. For new bridge designs, superseded by the AASHTO LRFD Bridge Design Specifications (see related item). The CD-ROM Easy access to specific sections; Hyperlinks from table of contents and within text to sections/articles, commentary, figures, tables, and equations; Search by section, subject, table/figure, article number, equation, or ASTM reference; Extensive index; and Detailed tutorial and help menu. Customary U.S. units. Replaces the 16th edition and its interims (1997–2003).