NHTSA proposes trailer rear impact upgrades

The National Highway Traffic Safety Administration issued a notice of proposed rulemaking (NPRM) on Dec. 7 that would upgrade the federal motor vehicle safety standards (FMVSSs) related to underride protection in light-vehicle crashes into the rear of trailers and semitrailers. In July, NHTSA published an advance notice of proposed rulemaking on rear underride crash protection and visibility conspicuity of single unit trucks.

Most trailers and semitrailers already are equipped with rear impact guards to prevent underride. To enhance underride protection further, NHTSA proposes to require more robust rear impact guards on trailers and semitrailers. Specifically, NHTSA proposes to adopt requirements of the Canada Motor Vehicle Safety Standard (CMVSS) for underride guards (CMVSS No. 223, “Rear impact guards,”) that took effect in 2007.

The CMVSS No. 223 requirements are intended to provide rear impact guards with sufficient strength and energy absorption capability to protect occupants of compact and subcompact passenger cars impacting the rear of trailers at 56 km/h (35 mph). The current requirements in FMVSS Nos. 223 and 224 were developed with the intent of providing underride crash protection to occupants of compact and subcompact passenger cars in impacts up to 48 km/h (30 mph) into the rear of trailers.

The NPRM also proposes to adopt Transport Canada’s definition of “rear extremity” to define where on a trailer aerodynamic fairings are to be located to avoid posing a safety hazard in rear underride crashes

NHTSA estimates that many new trailers sold in the United States subject to FMVSS Nos. 223 and 224 already comply with the more stringent performance requirements under consideration. The agency estimates that the annual incremental material and fuel cost would be $13 million.

Comments on today’s NPRM on trailer and semitrailer rear underride protection can be submitted to the docket up to 60 days after publication in the Federal Register.