The NCHRP Report 776 provides proposed revisions to Section 1.3—Design Philosophy of the AASHTO LRDF Bridge Design Specifications with detailed examples of the application of the proposed revisions. The proposed revisions include system factors that can be used during the design and safety assessment of bridges subjected to distributed lateral load being evaluated using the displacement-based approached specified in the AASHTO Guide Specifications for LRFD Seismic Bridge Design or the traditional force-based approach. Also, the report presents system factors calibrated for application with bridge systems subjected to vertical vehicular loads. The material in this report will be of immediate interest to highway design engineers.