The 1985 AASHTO Standard Specifications for Structural Supports for Highway Signs, Luminaires, and Traffic Signals (referred to here as the current Supports Specifications) has been revised in its entirety with significant additions to its content and scope. This work is the result of an extensive research study performed under NCHRP project 17-10. The main objective of the study was to update the previous edition of the Supports Specifications based on the most recent state-of-the-art information for the design and use of structural supports. Considerable effort was made to specify the best practice, realizing the characteristics and limitations of each material. From a design safety standpoint, all materials for structural supports were treated equitably. Safety, aesthetics, and economy were three main guidelines in developing the provisions of the Supports Specifications, but manufacturing practices and experiences were also considered. The proposed specification is presented in a specification/commentary side-by-side format that will enable the engineer to review with ease the basis of Supports Specifications' provisions. References are updated to provide a resource for the most recent research studies related to the structural behavior and performance of structural supports. An extensive table of contents is provided to allow easy reference and quick access to various provisions of the Supports Specifications. The purpose of this report is to present highlights of the proposed revisions to the specification. The supporting information, scope, and basis for the proposed changes are also discussed.