So far, other than piece by Bloomberg: http://www.bloomberg.com/news/articles/2015-12-07/stronger-truck-guards-proposed-by-u-s-to-cut-rear-impact-deaths there is no national media coverage of new rear guard requirements for trailers.
NHTSA NPRM Document here: NHTSA full 2015 NPRM
NHTSA says on page 44 of NPRM: “However, the full overlap crash test results indicate that trailers that have the main vertical supports for the guard more outboard may not perform as well in full overlap crashes as trailers that have the vertical supports more inboard for crash speeds greater than 56 km/h (35 mph). Since full and 50 percent overlap crashes are more frequent than low overlap (30 percent or less) crashes, and since most fatal light vehicle impacts into the rear of trailers are at speeds greater than 56 km/h (35 mph), such guard designs may reduce protection against PCI in higher speed full and 50 percent overlap crashes. It has not been shown that protection in the 30 percent overlap crashes can be provided without degrading protection in the 50 and 100 percent overlap crashes. NHTSA is not convinced that improved protection in the less frequent 30 percent overlap crashes should come at the cost of adequate protection in the more common 50 and 100 percent overlap crashes.
In addition, the suggested amendment to move the vertical supports more outboard may not be practical for different trailer types. Typically, the vertical supports of rear impact guards are attached to the longitudinal members of the trailer frame that have sufficient strength to withstand loads transferred from the guard in the event of a rear impact. Moving the vertical supports further outboard would require changes to trailer designs so that in a rear impact, the loads from the guard can be transferred to substantially strong structural members of the trailer. Such changes in trailer design may add weight to the trailer, reduce payload, and may not be practicable for all trailer types.”
I think we should publicly bring attention to this knowingly false statement by NHTSA.. They clearly do not want to bring public knowledge to energy absorbing guards recommended by CRASH back in 1992. MUARC in Australia recommended an extra angled brace attached to the outside edge of the guard running to the horizontal trailer frame in their study of rear guards in the 1990’s. The Impact Project in Brazil also incorporated this outside angled brace and recommendation in their guard designs and recommendations. These braces could be added to older guard designs to improve offset impact performance and enhance full impact strength. MUARC recommended increasing energy absorption to: 50kJ minimum. These designs exist and are crash tested to 40 mph and to even higher speeds in computer models. NHTSA has published these designs and attended TOPTECs where they were presented by multiple governments and safety designers. VOLVO engineers had a formula for moving the guard outward from the trailer or truck to increase speed performance. NHTSA in their 1992 tests had a rounded honeycomb guard design that would spin the car away from the truck in high-speed extreme offset crashes.