On July 27, 2009, NHTSA published a final rule in the Federal Register at 74 FR 37122 amending FMVSS 121 to improve the stopping distance performance of truck tractors. The rule requires the vast majority of new heavy truck tractors to achieve a 30 percent reduction in stopping distance compared to currently required levels. For these heavy truck tractors, the amended standard requires those vehicles to stop in not more than 250 feet when loaded to their GVWR and tested at a speed of 60 miles mph. For a small number of very heavy severe service tractors, the stopping distance requirement will be 310 feet under these same conditions. In addition, this final rule requires that all heavy truck tractors must stop within 235 feet when loaded to their “lightly loaded vehicle weight” (LLVW).
NHTSA estimates that the rule changes will save approximately 227 lives and prevent 300 serious injuries annually.
According to NHTSA, there are a number of simple and effective manufacturing solutions that vehicle manufacturers can use to meet the requirements of the final rule. These solutions include installation of enhanced drum brakes, air disc brakes, or hybrid disc/drum systems.
With respect to compliance dates, three-axle tractors with a GVWR of 59,600 pounds or less must meet the reduced stopping distance requirements specified in the final rule by August 1, 2011. Two-axle tractors and tractors with a GVWR above 59,600 pounds must meet the new requirements by August 1, 2013. Voluntary early compliance is permitted before those dates.
Petitions for Reconsideration are due Sep. 10, 2009.
