DWTB OSS
The design of highway overhead sign structures (OSS) in the United States follows the guidelines set forth by the American Association of State Transportation Officials (AASHTO) in the Standard Specifications for Structural Supports for Highway Signs, Luminaires, and Traffic Signals [30].
The AASHTO specifications necessitate careful consideration of load combinations, particularly the combination of dead load (DL) and wind load (WL), as detailed in Section 3.4 Table 3.4-1 of AASHTO. For structures that present potential hazards to vehicles upon failure, a Mean Recurrence Interval (MRI) of 700 years is required.