The nation's two major tire industry associations found themselves agreeing with an auto safety advocacy group on a tire safety question.
In comments made to the National Highway Traffic Safety Administration (NHTSA), all three said the agency's proposed rule on tire pressure monitoring systems (TPMS) fails miserably in its stated goal of protecting motorists from the dangers of tire underinflation.
The Rubber Manufacturers Association (RMA), the Tire Industry Association (TIA) and Advocates for Highway and Auto Safety told NHTSA the warning threshold to drivers in the proposed standard is unacceptable. That threshold is 25 percent below the vehicle manufacturer's recommended air pressure or 20 psi, whichever is higher.
According to the RMA, the TPMS dashboard warning light ``should illuminate when the tire's inflation pressure falls below the minimum level of pressure required to support the actual load on the tire. As real-world experience has shown, underinflated tires can be overloaded, and overloaded tires can fail.''
Arguing for a 20-percent warning trigger, the Advocates group accused NHTSA of basing its support for a 25-percent threshold by using cost-benefit arguments that don't stand up to scrutiny.
``The only conclusion to be drawn is that the agency has decide to propose a degraded level of tire safety simply to allow manufacturers of TPMS systems who currently cannot achieve a 20-percent threshold to qualify,'' Advocates said.
TIA, Advocates and the RMA also agreed that the standard's testing requirements were inadequate and that its exemption of replacement tires from the TPMS rule was egregious.
The proposed test conditions are inadequate because they don't address common driving conditions such as high speeds, heavy loads and high ambient temperatures, the RMA said.
TIA noted that four times as many replacement tires as original equipment tires are shipped every year. ``If the agency is serious about public safety and the congressional intent of the TREAD (Transportation Recall Enhancement, Accountability and Documentation) Act, it is unacceptable to allow a TPMS to not function after a vehicle's tires are replaced,'' the association said.
The RMA and TIA renewed their call for a minimum reserve pressure requirement to counterbalance the 25-percent threshold. The RMA disagreed with NHTSA's statement in the proposed rule that there was inadequate data to support the need for a reserve pressure requirement.
``The primary NHTSA safety standard governing tire selection for passenger car tires incorporates the Tire and Rim Association tables that are at the heart of the RMA position on reserve pressure,'' the association said.
Their pro-reserve-requirement argument was bolstered by the American Automobile Association (AAA), which also championed the idea in its comments.
``In that way, when the warning signal is given, the motorist has time to have their (sic) tires checked without fear of a more immediate tire failure,'' AAA said.
Of the 29.5 million service calls AAA received in 2003, nearly 13 percent were tire-related, the association added. For that reason, all parties must continue aggressive consumer education on proper tire maintenance. ``No amount of technology or regulation can replace the simple act of all motorists routinely inspecting their tires,'' it said.
Auto industry commenters were unanimous that the Sept. 1, 2005, beginning phase-in date for tire pressure monitoring systems was unrealistic and should be moved to Sept. 1, 2007.
General Motors Corp. argued that the agency set the minimum activation pressures for light-truck tire monitoring systems too high in some cases. Not only were the higher pressures unjustified by load or tire performance concerns, GM said, but they could actually have negative effects on sport-utility vehicles in such safety areas as rollover resistance, understeer, response time and on-center handling.