Automakers would have to install tire-pressure sensors in new vehicles beginning next year under a regulation proposed yesterday by the National Highway Traffic Safety Administration.

The proposal calls for monitors on all four wheels that would alert the driver if any tire's air pressure drops below recommended levels by 25 percent or more. Underinflation can cause tires to fail, and blowouts can cause a driver to lose control of the vehicle.

NHTSA estimates that 149 people die every year in accidents related to tire-pressure problems.

Congress ordered the agency to adopt a tire-pressure rule in 2000 in the wake of hundreds of deaths and injuries linked to Firestone tires failing on Ford Explorer sport-utility vehicles. The agency originally put forth a less stringent tire-pressure rule, requiring sensors that did not specify which tire was underinflated, but the consumer group Public Citizen filed suit claiming the measure didn't meet Congress's intent.

The U.S. Court of Appeals for the 2nd Circuit agreed and last year ordered NHTSA to develop a new rule.

Joan Claybrook, president of Public Citizen, praised the new proposal but said the agency should have imposed it immediately instead of simply submitting it for a 60-day public comment period.

"We urge the agency to issue a new and legal final rule promptly and without further delay," Claybrook said in a news release.

The proposed rule would require the warning system to include a malfunction indicator, so the driver would know if the system was not working. It would apply to all new passenger cars and trucks with a gross weight of 10,000 pounds or less, except for vehicles with dual wheels on a single axle.

The regulation would be phased in, with sensors required in half of all qualifying cars and trucks manufactured after Sept. 1, 2005, and in all such vehicles manufactured after Sept. 1, 2007.