The National Highway Traffic Safety Administration (NHTSA) is upgrading rear underride guard standards. The recently completed rulemaking applies to newly-manufactured trailers and semitrailers with a gross weight of 10,000 pounds or more.
Previous Federal Motor Vehicle Safety Standards (FMVSS) called for rear underride guards to withstand a 30 mph impact from a passenger car, in which 50% of the width of the passenger motor vehicle overlaps the rear of the trailer or semitrailer. The new NHTSA rules upgrade the crash velocity to 35 mph, consistent with the rear underride guard standards used in Canada. The new standards also align with the FMVSS test speed for passenger vehicle seat belt and airbag protection. An estimated 94% of U.S. trailers and semitrailers already meet the finalized higher standards.
The NHTSA announcement brought immediate criticism from highway safety groups, which had urged NHTSA to adopt standards to meet even higher crash speeds and a wider range of impact overlap. In response, NHTSA indicated that those recommendations would have increased costs and necessitated the exclusion of certain trailer types.
The U.S. Department of Transportation incorporated the new standards in the National Roadway Safety Strategy after the bipartisan Infrastructure Bill called for the final rule on rear underride guards.
NHTSA announced the formation of a federal advisory committee on side underride guards for trailers and semitrailers. The highway safety agency also wants a plan to publish an advance notice of proposed rulemaking (ANPRM) to gather public comments on side underride guards. In a nod to the highway safety groups, which did not like the final rule on rear underride guards, NHTSA announced it would commission research on rear impact guard designs to “better protect occupants of passenger vehicles in even more rear underride crash scenarios.”
