NHTSA PUBLISHES FIRST ROLL0VER RATINGS.

The National Highway Traffic Safety Administration published its first rollover ratings last week, with the Ford Explorer Sport Trac 4x2 pickup scoring the lowest and the none of 21 other vehicles achieving the maximum five-star rating.

The federal agency now uses a "fishhook" maneuver, a series of abrupt turns at high speed made by a computerized steering system to ensure objectivity. NHTSA says a five-star rating represents the likelihood of rollover in an emergency maneuver would be less than 10 percent.

The Explorer Sport Trac 4x2 tipped up on two wheels during the test and was given a rating of two stars. The truck has two drive wheels; tests of the four-wheel-drive 4x4 are still under review.

"However, the star ratings are misleading," said NHTSA, which resisted conducting rollover tests until ordered to do so by Congress after a series of Ford Explorer rollovers. "Two stars may be interpreted as a good or safe vehicle," it said. Other ratings:

* Four stars, representing a rollover risk of between 10 percent and 20 percent: Buick Ranier 4x4; Chevrolet Trailblazer 4x4; Chevrolet Silverado extended cab pickup, both 4x2 and 4x4; Ford Focus wagon; GMC Envoy 4x4; GMC Sierra extended cab pickup, both 4x2 and 4x4; Olds Bravada 4x4; Subaru Outback wagon; Toyota Echo; Volvo XC90 4x4.

* Three stars, representing a rollover risk of between 20 percent and 30 percent: Buick Ranier 4x2; Chevrolet Trailblazer 4x2; GMC Envoy 4x2; Jeep Liberty, both 4x4 and 4x2; Olds Bravada 4x2; Toyota 4Runner, both 4x4 and 4x2; and Toyota Tacoma 4x4 extended cab pickup. The Tacoma 4x4 tipped up on two wheels during the test, however.

Tests of several other vehicles, including other versions of the Ford Explorer and its twin, the Mercury Mountaineer, are still under review.

Ford said the Sport Trac - a Ford Explorer modified to incorporate a pickup bed - "is a very safe and stable vehicle." It said NHTSA's test was more extreme than anything a driver is likely to face.

Former NHTSA Administrator Joan Claybrook, however, said the ratings allow vehicles "to be perilously tippy - earning just two or three of five possible NHTSA stars - and still be sold."

Claybrook, now president of the consumer advocacy group Public Citizen, noted pending NHTSA reauthorization legislation (S. 1978), sponsored by Senate Commerce Committee Chairman John McCain (R-AZ) and ranking minority member Ernest Hollings (D-SC), would require the government to establish a minimum rollover prevention standard.