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Final rule.

This final rule establishes two Federal Motor Vehicle Safety Standards (FMVSS) which will operate together to reduce the number of injuries and fatalities resulting from the collision of passenger vehicles with the rear end of heavy trailers and semitrailers. The first standard (FMVSS No. 223, Rear Impact Guards, or the ``equipment standard'') specifies performance requirements that rear impact guards (guards) must meet before they can be installed on new trailers and semitrailers. It specifies strength requirements, as well as test procedures that NHTSA will use to determine compliance with the standard. The guard may be tested for compliance while mounted to a non-vehicle ``test fixture'' or a complete vehicle. The equipment standard also requires the guard manufacturer to provide instructions on the proper installation of the guard. The final rule also specifies requirements to ensure energy absorption by the guards. The second standard (FMVSS No. 224, Rear Impact Protection, or the ``vehicle standard'') requires that most new trailers and semitrailers with a Gross Vehicle Weight Rating of 4,536 kilograms (kg) (10,000 pounds (lbs)) or more be equipped with a rear impact guard meeting the equipment standard. Requirements for the location of the guard relative to the rear end of the trailer are also specified in the vehicle standard. The vehicle standard further requires that the guard be mounted on the trailer or semitrailer in accordance with the instructions of the guard manufacturer.

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