The National Highway Traffic Safety Administration has a chance to improve the safety of the motoring public with its proposed new rule requiring tire pressure monitoring systems (TPMS) in new vehicles.
But the agency could well end up failing if the standard it ultimately approves allows tire inflation to fall 25 percent below the vehicle manufacturer's recommended pressure before the monitor issues a warning.
This, according to tire industry experts, is too low and would fail to warn motorists early enough that their tires are severely underinflated. That would give drivers a false sense of security.
Both major tire industry trade groups-the Tire Industry Association (TIA) and Rubber Manufacturers Association (RMA)-have serious concerns about the proposed regulation, largely over the 25-percent threshold.
So does mail order tire distributor Tire Rack, which calls itself the nation's largest independent tire tester.
Under NHTSA's recently proposed rule, new vehicles with a gross vehicle weight rating of 10,000 pounds or less must be equipped with a TPMS capable of detecting any tire that is inflated 25 percent be-low the recommended pressure.
In a press release, Tire Rack warned that monitors that send an alert when inflation pressure drops 25 percent below vehicle manufacturer recommendations ``gives drivers the impression that they don't have to worry about tire pressures until the system alerts them.'' Yet ``a tire underinflated by just two psi starts losing its load-carrying capacity and begins degrading almost immediately,'' the company said.
The RMA, which represents tire manufacturers, called the proposed rule ``flawed'' and warned it may increase the risk of tire failures. It also pointed out how a 25-percent drop in a tire's recommended pressure may be insufficient to carry a fully loaded vehicle.
Two years ago, the RMA petitioned NHTSA urging it to adopt a requirement that tires have sufficient inflation and load reserve to accommodate a 25-percent drop in inflation pressure. ``A mandated reserve pressure would allow a tire pressure monitoring system to alert motorists when the vehicle load exceeds the design specifications of the tire,'' the RMA said.
TIA, for its part, raised the question of whether pressure monitors ``should enact before or after the unsafe condition occurs.'' And it agreed the concept of a reserve load limit still must be resolved, noting ``the current proposal does not adequately address the issue.''
It's rare that any industry would want tighter government regulations, but that's the case with tire pressure monitoring systems.
For the safety of the motoring public, NHTSA should strengthen its standard so it adequately warns drivers before an unsafe condition occurs. Lives depend on it.