The National Highway Traffic Safety Administration (NHTSA) is pushing for new regulations requiring tractor-trailer trucks to be equipped with speed-limiting devices. This regulation, if passed, will impact not only the trucking industry but also the manufacturers of tractor-trailer trucks and tires. The intended purpose of this new regulation is to reduce the risk of tire disablement. NHTSA is reacting to recent Associated Press reports that many states have speed limits that are higher than truck tires’ speed ratings. Some states have speed limits of 75, 80 or 85 mph. Most truck tires are speed rated for 75 mph. There are, however, truck tires available with speed ratings in the low 80s.
What are “speed ratings”?
A speed rating indicates that a tire is capable of operating at a certain speed for a specific duration under normal inflation and load conditions. The speed rating is determined by operating a tire under a specific load and inflation pressure for specified durations that are set forth in federal regulations.