WASHINGTON-More than one in four passenger cars and one in three light trucks in the U.S. are being driven on one or more ``substantially'' underinflated tires, according to a new study by the National Highway Traffic Safety Administration.
This is the first such government study of the situation in more than 20 years.
For this study, NHTSA said, underinflated meant any tire operating at least 8 psi or more below the recommended inflation pressure. The study is based on information gathered on 11,530 passenger vehicles during a 14-day period in February. The information was collected from motorists at 300 service stations in urban, suburban and rural settings across the country.
The data show 27 percent of cars monitored had at least one underinflated tire, and 32 percent of light trucks-including sport utility vehicles, vans and pickups-were in the same plight.
Looking at the data breakdown, the study shows light truck owners are worse at maintaining their tires than passenger car owners. Key findings to support this include:
* 6 percent of light trucks were found to have all four tires underinflated by 8 or more psi, compared with 3 percent of passenger cars;
* 10 percent of light trucks are driven with three or more tires underinflated by 8 or more psi, compared with 6 percent of passenger cars: and
* 20 percent of light trucks had two or more tires underinflated by 8 psi or more, compared with 13 percent of passenger cars.
The survey also indicates that owners of older vehicles are more likely to operate them with underinflated tires than are operators of newer vehicles.
NHTSA estimates that 49 to 79 deaths and 6,585 to 10,635 injuries could be prevented annually if all vehicles were equipped with tire pressure monitoring systems. NHTSA's National Center for Statistics and Analysis, which conducted the survey, plans to complete a detailed report on its tire pressure study by the end of 2001.
U.S. Transportation Secretary Norman Y. Mineta used the release of the study to urge consumers to check their tires before setting out on trips over Labor Day weekend.
``Driving with substantially underinflated tires can lead to crashes and tragedy, in addition to reducing fuel efficiency and shortening tire life,'' Mr. Mineta said.