The National Highway Traffic Safety Administration has issued a final rule in the Federal Register [RIN 2127-AH75] that clarifies the standards for underride guards for trailers and semitrailers that were established in 1996. The rule is effective immediately.
The final rule was enacted in recognition that certain vehicles that can’t practically have underride guards installed because of equipment mounted on the rear and underneath a trailer or a semi-trailer. Such vehicles are designated as “special purpose vehicles,” by NHTSA.
The rule defines the space an area on the rear and underneath the trailer or semitrailer that such equipment must occupy to exclude a vehicle from the underride guard requirements specified under FMVSS No. 224.
“The vertical area specified in today’s final rule 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.”