WASHINGTON (Nov. 16, 2001)—Tire and auto manufacturers are far apart in their views of what tire pressure monitoring should encompass.
In comments to the National Highway Traffic Safety Administration, which will present the requirements this month, the Alliance of Automobile Manufacturers rebutted remarks point-by-point from the Rubber Manufacturers Association, the Tire Association of North America, the International Tire & Rubber Association, Goodyear, the Tire and Rim Association and other groups. It accused some of these organizations of misrepresenting NHTSA's research and others of misunderstanding the proposed standard.
The biggest bones of contention are whether onboard tire pressure monitoring systems should directly or indirectly record tire pressures and whether the systems registering tire pressures 20 to 25 percent below the vehicle manufacturer's recommended cold pressure—as suggested by NHTSA—is adequate to ensure tire safety.
The RMA, supplementing its earlier comments, urged NHTSA to create a minimum load capacity requirement on the federal level. Otherwise, the proposed tire monitoring standard “would allow, in many cases, pressures insufficient to carry the load on the tire,” in the words of RMA President Donald B. Shea.
One commenter opposed the concept of warning drivers of low tire pressure while driving—largely to push its own invention which gives low pressure warnings when the driver is outside the vehicle. The ITRA was outspoken in saying tire pressure monitoring systems should directly record low tire inflation, and that indirect systems “leave much to be desired.'' The AAM, Sumitomo Rubber Industries Ltd. and Toyota Motor North America Inc. all objected to this.
“ITRA assumed that all direct TPMSs would notify which tire is underinflated,” the AAM said. “ITRA misunderstood NHTSA's proposal.
“Most vehicles are not equipped with the advanced reconfigurable displays required to show actual tire pressure and location, so most vehicles will employ the small illuminated telltale, whether the vehicle is equipped with a direct TPMS or an indirect TPMS,” the alliance added. “Thus, ITRA's basis for preferring direct TPMSs is not applicable to the proposed rule.”
The AAM said the RMA supports “a modified version” of the direct TPMS. “Yet RMA has provided no data or arguments demonstrating a safety need to mandate direct TPMSs and to abolish the very technology—indirect TPMSs—that Congress discussed during enactment of the TREAD Act,” it said.
Sumitomo and Toyota, meanwhile, championed indirect systems—largely because they sell them. Sumitomo said it has provided “basic technology” to indirect systems on vehicles in the U.S., Europe and Japan, including the Toyota Sienna and BMW 750i. NHTSA tests on the efficacy of these systems “got a good result,” the Kobe, Japan-based tire maker said.
Toyota said Rep. Edward Markey, D-Mass., one of the chief supporters of the Transportation Recall Efficiency, Accountability and Documentation Act in the House, referred to the TPMS in his Toyota Sienna during TREAD Act hearings.
“Based upon Mr. Markey's statements...we would infer that the congressman's intent was to allow systems of similar design and function,” the auto maker said. Therefore, both direct and indirect systems should be allowed under the final rule, it added.
Goodyear and the world tire and rim associations joined with the RMA and TANA in opposing NHTSA's plan to have tire monitoring systems notify drivers only after underinflation had reached 20 to 25 percent below the vehicle manufacturer's recommended cold pressure.
Goodyear, the Tire and Rim Association, the Japan Automobile Tyre Manufacturers Association and the European Tyre and Rim Technical Organisation all agreed tires are designed to safely carry prescribed loads at the proper minimum inflation pressures.
“This is not to say that any operation below the minimum pressure results in an immediate safety problem,” Goodyear said. “However, the longer the underinflated operation and the greater the underinflation, the more that safety is degraded,” according to the tire manufacturer.
“Consequently...the tire pressure monitoring system mandated by the TREAD Act should warn vehicle operators any time the inflation pressure is less than the pressure required to carry the actual vehicle load,” Goodyear added.
The Tire and Rim Association said the proposed tire monitoring rule would “redefine the load/inflation standards for the tires in the U.S. We do not believe that this is NHTSA's intent, but that would be the result with the current proposals.”
Toyota and Sumitomo argued the NHTSA proposal didn't go far enough.
“If the agency prefers to tie the TPMS threshold to the vehicle manufacturer's tire placard, Toyota recommends that the agency adopt 30 percent below the tire placard pressure as the TPMS threshold,” the auto maker said.
With Toyota's TPMS, it said, there is a margin of error of plus-or-minus 10 percent. Sumitomo seconded this motion, saying, “we believe this threshold level is suitable.”
The RMA left no question that it considered the Toyota and Sumitomo position ridiculous. “It is totally inconsistent to try to argue on one hand the improvements in tires are needed, while at the same time...to argue that tires may be operated at 20 to 25 percent below the pressure for which they were designed,” Mr. Shea said.
A minimum reserve load capacity requirement easily could be added to existing federal tire safety standards, according to Mr. Shea.
“Vehicle manufacturers already voluntarily provide for such a safety margin in many, if not most, of the light vehicles on the road today,” he said. “Universal application of this safety margin will provide for a reasonable and practicable standard.”
Rea Technologies, a technology development company whose headquarters wasn't listed on its submission, said current tire pressure monitoring systems “are simply inappropriate for both technical and human factors reasons. (They) alert the driver at the wrong time, when driving.”
“It is better to warn drivers of low pressure when they are outside the vehicles and in a position to put air in the tires,” Rea said.
The system it developed provides an audio alarm alerting motorists of low pressures when they stand several feet from the tires.