WASHINGTON (July 19, 2002) — Tire manufacturers have asked federal highway safety officials to adopt a new safety regulation requiring motor vehicle tires to have a reserve inflation pressure.
This action is necessary, according to the Washington-based Rubber Manufacturers Association (RMA), to ensure that a recent government regulation mandating tire pressure monitoring systems (TPMS) in vehicles will protect motorist safety by providing an adequate warning to motorists when their tires are underinflated.
Under the RMA proposal, a vehicle's tires would be required to have a recommended inflation pressure that would be sufficient to carry the vehicle load even if the tire suffers as much as a 30 percent loss of pressure.
Underinflation, the RMA pointed out, causes excessive heat buildup in tires and, over time, can result in hidden damage possibly resulting in tire failure.
The National Highway Traffic Safety Administration (NHTSA) formally issued its final rule mandating tire pressure monitoring systems on June 5. The regulation requires the systems to warn motorists when tires are 25 or 30 percent underinflated, depending on the type of system. The RMA said it is concerned the regulation would allow many vehicles' tires to reach an unsafe condition well before a motorist is warned.
The regulation to require tire pressure monitoring systems is mandated by the Transportation Recall Enhancement, Accountability, and Documentation (TREAD) Act, which Congress enacted in 2000. The systems will be mandatory equipment on vehicles beginning with the 2004 model year.
“We want to work with NHTSA so that the tire pressure monitoring system regulation promotes motorist safety,” RMA President and CEO Donald B. Shea said. “By adopting a reserve pressure requirement, these systems can give motorists an immediate safety benefit that Congress intended to provide under the TREAD Act.”
RMA asserts in its petition to NHTSA that this action is necessary to “ensure that consumers receive sufficient advance warning from the new TPMS before experiencing tire damage or tire failure.”
“Our goal with this petition is to improve the government's tire pressure monitoring system rule so that it promotes safety,” Mr. Shea said. “A tire pressure monitoring system can be an effective safety tool for motorists only if it provides a timely warning to consumers.”
He added that “many vehicles today have a low fuel warning light that warns motorists before the tank is dry. Similarly, a tire pressure warning light should alert motorists before tires reach a point where hidden damage can occur.”
To make sure a tire has sufficient reserve pressure, vehicle manufacturers could increase the recommended inflation pressure in their vehicles' tires or use a larger size tire for a particular vehicle, the RMA suggested. Federal regulations require vehicle manufacturers, not tire makers, to establish the recommended inflation pressures for tires.
“The trigger point for a tire pressure monitoring system to warn a driver must be when the tire is overloaded for its inflation pressure,” Mr. Shea said. “Without a reserve requirement for tires, a significant number of motorists may wrongly believe that their vehicle's tire pressure monitoring system will warn them before their tires are operating in an unsafe condition.”
Included in RMA's comments were data on 100 vehicle/tire combinations and the tire pressure reserve currently available. The data are not representative of all vehicles in use today. However, if the vehicles in this sample were outfitted with tire pressure monitoring systems using NHTSA's new standard, the RMA said more than seventy percent would fail to warn motorists before the vehicle's tires reach a point when the inflation pressure can no longer carry the load.
NHTSA data shows that one in four passenger cars and nearly one in three sport-utility vehicles, minivans and pickup trucks have at least one significantly underinflated tire. Other NHTSA data indicates that about two-thirds of motorists would be less concerned about routine tire maintenance if vehicles had a tire pressure monitoring system.
“Moreover, RMA believes there is a substantial risk that the new TPMS standard will, in practice, confuse or mislead consumers into believing that their tires are properly inflated even when the TPMS warning is not illuminated,” RMA said in its petition to NHTSA. “This is precisely the opposite of what Congress intended in enacting…the TREAD Act,” Mr. Shea concluded.
“If tire pressure monitoring systems do not provide an adequate warning to motorists and drivers become more complacent about proper tire care, the risk of tire failures may increase,” he added.