To comply with the regulation, which has its roots in the Firestone tire recall of 2000, automakers most likely will attach tiny sensors to each wheel that will signal if a tire falls 25 percent below the recommended inflation pressure. If any one of the four tires is underinflated, the sensors set off a dashboard warning light.
Automakers will begin implementing the technology in September. The National Highway Traffic Safety Administration estimates the upgrade will cost manufacturers between $48.44 and $69.89 per vehicle.
The government said underinflated tires hurt a vehicle's fuel economy and can increase stopping distances, increase likelihood of tire failure and lead to skidding on wet surfaces.
All new four-wheel vehicles weighing 10,000 pounds or less will be required to be equipped with the systems by the 2008 model year. The regulation affects passenger cars, sport utility vehicles, pickup trucks and minivans.
NHTSA estimates that 120 lives a year will be saved when all new vehicles are equipped with the systems.
The regulation was proposed last September. Tire manufacturers have questioned whether the warning system would signal low pressure early enough. Automakers have raised concerns that motorists may ignore the lights if they appear too frequently.
Donald B. Shea, president and chief executive of the Rubber Manufacturers Association, the trade group that represents tire makers, said, "Unfortunately, this regulation may give motorists a false sense of security that their tires are properly inflated when they may be significantly underinflated."
Eron Shosteck, a spokesman for The Alliance of Automobile Manufacturers, which represents nine automakers, said about 18 percent of their vehicles already have the technology. It first appeared in the 1997 Chevrolet Corvette and is currently used in some luxury vehicles.