5 of 12 midsize SUVs earn marginal ratings in rollover tests

Arlington, Virginia – In the first Insurance Institute for Highway Safety roof strength tests of midsize SUVs, six earned the top rating of ‘good’ for rollover protection, one was ‘acceptable’, and five others earned the second lowest rating of ‘marginal’.

Midsize SUVs that earned good ratings are the 2010 Chevrolet Equinox (twin GMC Terrain) built after March 2010, Jeep Liberty (twin Dodge Nitro), Toyota Highlander and Venza, plus the Jeep Grand Cherokee and Kia Sorento, both 2011 models. The 2010 Ford Edge is rated acceptable.

The worst performers, which earned marginal ratings, are the Honda Accord Crosstour, Honda Pilot, Mazda CX-7, Mitsubishi Endeavor, and Nissan Murano, all 2010 models.

Vehicles rated ‘good’ must have roofs that are more than twice as strong as the minimum required under the current federal safety standard.

In addition to earning good ratings for rollover protection, the Equinox, Grand Cherokee, Highlander, Sorento, and Venza also earned the Institute’s Top Safety Pick award. To achieve this, a vehicle has to earn good ratings for occupant protection in front, side, rear, and rollover crashes. It also has to have electronic stability control.

“Midsize SUVs are a big group so we’re testing them in stages,” says Institute president Adrian Lund. “First results show that automakers are making progress in rollover protection, but it’s disappointing that a new design like the Crosstour didn’t perform better.”

In the Institute’s roof strength test, a metal plate is pushed against one corner of a roof at a constant speed. To earn a good rating, a roof must withstand a force of four times the vehicle’s weight before reaching five inches of crush. For an acceptable rating, the minimum strength-to-weight ratio that’s required is 3.25. A marginal rating value is 2.5, and anything lower than that is poor. The Grand Cherokee, Highlander, Liberty, and Venza, for example, withstood forces of nearly 5 times their weights. This compares with 2.8 times weight for the Crosstour and about 3 times weight for the Endeavor and Pilot. A strength-to-weight ratio of 4 reflects an estimated 50 per cent reduction in serious or fatal injury risk in single-vehicle rollover crashes, compared with the current federal standard of 1.5.