February 5, 2004
Results of new rollover tests available
Washington, D.C. – The U.S. Department of Transportation’s National Highway Traffic
Safety Administration (NHTSA) has posted model year 2004 rollover resistance scores
that for the first time use the agency’s enhanced rating system, which now includes
results from a dynamic track test.
While none of the vehicles achieved the agency’s highest five-star rating, several
earned four-star designations, including the Chevrolet Trailblazer 4×4, Chevrolet
Silverado extended cab (4×4 and 4×2), Ford Focus wagon, Subaru Outback wagon, Toyota
Echo and Volvo XC90 4×4.
A five-star rating means the likelihood of rollover during a single vehicle crash is
less than 10 percent; four-star, between 10 and 20 percent; three-star, between 20
and 30 percent; two-star, between 30 and 40 percent; and one-star, greater than 40
Other rated vehicles were the Chevrolet Trailblazer 4×2, Ford Explorer Sport Trac
4×2, Jeep Liberty 4×4 and 4×2, Toyota 4Runner 4×4 and 4×2 and Toyota Tacoma extended
cab 4×4. Tests for several other vehicles are under review and will be released at a
later date. These are the Ford Explorer 4×4 and 4×2, Ford Explorer Sport Trac 4×4,
and Toyota Tacoma extended cab 4×2.
The dynamic test uses the so-called “fishhook” maneuver – a series of abrupt turns
at varying speeds. A computerized steering system is used in each test vehicle to
NHTSA in the past based its rollover ratings on a vehicle’s static stability factor,
which is an engineering calculation based on the track width and the height of the
center of gravity. Beginning with the 2004 model year, the rollover risk predictions
are based on the static stability factor scores and the vehicle’s performance in a
dynamic track test.