The National Highway Traffic Safety Administration (NHTSA) has issued a new proposed rule on tire pressure monitoring systems, a little over a year after a federal court made it scrap the old one.
While the new proposal contains the modifications the U.S. Court of Appeals for the Second Circuit ordered, it postpones action on the chief recommendation from the Rubber Manufacturers Association (RMA) for change: a provision to establish a minimum tire reserve load requirement.
The RMA issued a press release Sept. 15-the same day the proposed rule came out-complaining that the standard as written may not give motorists a timely low-pressure warning. The association has been unhappy from the beginning with NHTSA's provision-also in the previous, vacated final rule-that tire monitoring systems do not warn motorists until their tires were at least 25 percent below the vehicle manufacturer's recommended pressure.
A tire pressure that low, the RMA said, probably is insufficient to bear the vehicle load. ``A tire pressure monitor that doesn't provide a timely low-pressure warning to motorists is not enhancing safety,'' said RMA President Donald B. Shea in the release.
The RMA was not alone in its criticism.
Roy E. Littlefield III, executive vice president for the Tire Industry Association (TIA), said: ``If the new proposed threshold of 25 percent is adopted, the driver could be driving on an overloaded tire for a significant period of time.''
Internet tire and wheel marketer The Tire Rack, based in South Bend, Ind., also weighed in on the issue, saying the proposed regulations give drivers a false sense of security.
``By the time the light on the dash comes on, it's already too late,'' said John Rastetter, the online firm's lead tire tester, in a press release. Under the proposed rule, a tire that should be filled to 30 pounds per square inch (psi) would be down almost 8 psi by the time the system sends a warning. And ``that's a lot considering a tire underinflated just 2 psi starts losing its load capacity and begins degrading almost immediately,'' he added.
Tire Rack warned that TPMS should not be a substitute for inspecting tires and checking pressure with a tire gauge on a regular basis. ``A tire 25 percent low on air,'' Mr. Rastetter said, ``also has about zero load capacity, making adding even the weight of a driver unsafe.''
Clarence M. Ditlow III, executive director of the Center for Auto Safety (CAS)-which with Public Citizen sued successfully to get the previous tire pressure monitoring standard overturned-could not immediately be reached for comment.
CAS and Public Citizen claimed the original June 2002 final rule-which allowed the use of monitoring systems that measured one tire indirectly through the vehicle's anti-lock brake system and a 30-percent drop in pressure before the warning light came on-was inadequate to protect motorists.
The Second Circuit Court in New York agreed, and in August 2003 vacated the standard. It ordered NHTSA to write a new rule, emphasizing a four-tire direct system with a 25-percent pressure differential, as CAS and Public Citizen wanted.
In the new standard, the agency does require the four-tire direct system but also states its neutrality on monitoring technology and leaves the door open for future technological innovation.
The new phase-in schedule for the monitoring technology requires auto makers to install tire pressure monitoring systems on 50 percent of its light vehicle fleet between Sept. 1, 2005, and Aug. 31, 2006. This would increase to 90 percent between Sept. 1, 2006, and Aug. 31, 2007, with 100-percent participation required by Sept. 1, 2007.
Regarding the tire reserve load, NHTSA noted that the RMA petitioned the agency for that requirement to be added to the federal tire and rim selection standard and to become effective the same time as the final tire pressure monitoring rule.
The agency sent special orders to tire makers for data on the potential correlation between tire reserve load and real-world tire failures and currently is analyzing that information.
``A 1981 study of tire failure and reserve load did not demonstrate such a correlation,'' the proposed rule stated. ``If new data indicate a sufficiently strong correlation, NHTSA will propose appropriate amendments to its standards,'' it said.
Interested parties will have 60 days from the rule's publication in the Federal Register-or roughly until mid-November-to comment on it.