Big tire manufacturers are formally opposing portions of a proposed regulation that would require tire pressure monitoring systems on all passenger vehicles, saying the government's current plan could actually increase the risk of tire failure, according to Reuters on November 10."Our intent is to work with (safety regulators) to get this regulation right and to get it done soon," Donald Shea, president of the Rubber Manufacturers Association, said in written comments this week to the Transportation Department. Congress ordered the National Highway Traffic Safety Administration (NHTSA) to come up with a monitoring system to warn consumers when tires are significantly under-inflated. Under-inflation can expose rubber and other materials to more heat — especially during hot weather — and create dangerous wear at the edges and sides of a tire. The federal mandate stemmed from the Firestone tire debacle several years ago when nearly 300 people in the United States were killed in crashes linked to tread separations and blowouts. Many of those deadly accidents involved Ford Explorer SUV rollovers. After long legal and other delays, NHTSA proposed a system in September to measure pressure simultaneously on all four tires. The system would alert motorists with a warning light when a tire is under-inflated by more than 25 percent. While not opposed to monitoring systems, tire makers oppose a single threshold at which the alert is activated because tires vary in size and thickness. They argue alert points for under-inflation should reflect these differences. Shea says a 25 percent drop in recommended pressure may leave some tires so under inflated that they are unable to carry a fully loaded vehicle safely. Regulators estimate the plan would cost industry between $800 million and $1.1 billion to phase in the technology on all new vehicles from 2005 to 2007. The industry estimate is higher.Tire-monitoring systems are installed on roughly 2 million vehicles on the road today. Most are tied into the vehicle's braking system. Safety regulators plan to move forward with the rule in the coming months. Auto manufacturers do not oppose the proposal.