The National Highway Traffic Safety Administration (NHTSA) has issued a final rule in the Federal Register [2127-AH75] that clarifies standards for under-ride guards for trailers and semi-trailers that were established in 1996. The rule is effective immediately.
The final rule was enacted to resolve the issue for vehicles that can't practically have under-ride guards installed due to having certain equipment mounted on the rear and underneath a trailer or semi-trailer. Such vehicles are designated as “special purpose vehicles” by NHTSA.
The rule defines the space as an area at the rear and underneath the trailer or semi-trailer that such equipment must occupy to exclude a vehicle from the under-ride guard requirements specified under FMVSS No. 224.
“The vertical area specified …extends from the ground to a horizontal plane 660 mm above the ground,” NHTSA stated. “If the cubic area extended to the bottom of the trailer, as specified in the interpretation letter, a trailer with any portion of work-performing equipment located just underneath the trailer would not be required to have a guard.”
