WASHINGTON - Some Ford Motor Co.'s SUVs, including models of the best-selling Explorer and the Mountaineer, are among the worst on the road for rollover risk, the government said on Monday.
The Explorer Sport Trac two-wheel drive posted the single worst rating for rollover propensity among all 2004 vehicles analyzed -- including cars, vans and SUVs -- in updated safety ratings released by the National Highway Traffic Safety Administration.
The Explorer Sport Trac four-wheel drive, the Explorer four-door, two-wheel drive, and the Mountaineer four-door, two-wheel drive were in the bottom six of the SUV class, which as a group posted the lowest scores.
The Mercury Mountaineer is the corporate twin of the Explorer.
Safety experts concluded long ago that SUVs are more prone to roll than passenger cars in single-vehicle crashes, but the government's five-star safety ratings were criticized as incomplete and overly vague.
To address that concern, NHTSA for the first time assigned a percentage risk for rollover to its star ratings, which are based on a mathematical calculation of a vehicle's measurements and a road test that includes extremely sharp turns.
Most cars did better than the highest-ranked SUV for rollover safety. Minivans, including the Nissan Quest, also outperformed the SUV class. Pickups were similar to the underperforming SUVs but fared worse than vans and cars.
The safest vehicle overall, the Mazda Motor Corp. RX-8 four-door, has an 8 percent chance of rolling over. By comparison, the two-wheel drive Explorer Sport Trac has a nearly 35 percent chance, the government said.
DaimlerChrysler's Pacifica four-wheel drive was the top rated SUV at 13 percent, although one safety engineer said it performs more like a station wagon than a traditional SUV.
In response, Ford said its own analysis show Explorer models perform similarly or better than other vehicles in the same class.
"We're trying to work through the data and see how NHTSA's applying these numbers. While we believe the NHTSA rating system has some value, we don't believe it's a good indicator of how a vehicle performs in the real world," said Ford spokeswoman Kristen Kinley.
Explorers are closely watched because of the vehicle's popularity and troubled rollover history. Explorers were involved in most deadly crashes linked several years ago to defective Firestone tires.
Rollovers represent only a small fraction of crashes on U.S. roads but a quarter of all traffic deaths, which rose to 43,000 in 2003, preliminary statistics show. Most rollover deaths occur in single-vehicle accidents.
Rollovers accounted for nearly 40 percent of fatal accidents that involved SUVs last year. Rollover deaths in those vehicles rose by 10 percent to 2,700 in 2003, government figures show.
Jeffrey Runge, administrator of the highway safety agency and outspoken on SUV risks, stopped well short of supporting a suggestion that government order low-rated vehicles off the road. "We can accomplish a lot with consumer information," Runge said as he underscored the importance of the new ratings. "If no one buys vehicles that rollover, then manufacturers will probably stop making them."
But Joan Claybrook, president of consumer group Public Citizen and a former NHTSA administrator, said the new ratings can be difficult for many consumers to obtain and should also be placed on the vehicle's window sticker at the showroom.