Contrary to what most believe about SUVs, you actually may not be safer on the road in a midsize model, according to new test results from the Insurance Institute for Highway Safety. In fact, many cars produce better test results than the six midsize SUVs recently tested.

The Jeep Grand Cherokee, Chevrolet TrailBlazer, Nissan Pathfinder, Toyota 4Runner, Nissan Xterra, and Ford Explorer were the models IIHS scrutinized. The two main tests included a front collision into a barrier at 40 mph, and a side-impact evaluation where a weighted sled (simulating a truck or SUV) crashes into the side of the subject vehicle at 31 mph.

The performance of all models improved since the last time the IIHS tested. In the off-set frontal collision, five of six SUVs earned a rating of Good. Chevy's TrailBlazer was rated Acceptable. This test is particularly brutal on larger, heavier vehicles, as their collisions involve more kinetic energy than a lighter car. With heavy vehicles, automakers must engineer systems that direct crash energy away from occupants to keep them safe. Their efforts are paying off, but there is still room for improvement.

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Side-impact test results weren't as positive. "The performance of some of these models in the side test was surprising," said Institute senior vice president David Zuby. "SUVs should have an advantage in side crashes because the driver and passengers ride higher up than in cars. People often think they're safer in one of these vehicles, but many cars hold up better than some of these midsize SUVs in this test."

Two of the six SUVs have side airbags that don't protect the torso: the Grand Cherokee and TrailBlazer are equipped with standard curtain-style side airbags designed to protect the heads of occupants in front and rear seats, especially in rollover-type accidents. But unlike most cars with side airbags, these two SUVs don't have additional sets of airbags to protect front-seat occupants' chests and abdomens.

"Head protection is rated good in both vehicles, but the lack of chest protection and weak side structures that allowed a lot of intrusion contributed to high forces on the driver dummies' chests and abdomens," Zuby said.

The side structures of the 4Runner, Pathfinder, and Xterra performed better, allowing less intrusion into the occupant compartment. The standard side airbags in the 4Runner and the optional ones in the Pathfinder and Xterra include torso as well as head protection.

Torso and head curtain airbags also are standard in the Explorer. While head protection was good in the Ford, intrusion into the occupant compartment contributed to the possibility that someone in a real-world crash of similar severity would sustain a broken pelvis.

Standard side airbags are becoming more common across cars and trucks sold in this country. Once a luxury-car exclusive, they're becoming standard on economy cars such as the 2008 Ford Focus and Honda Civic. This expansion has favored cars over SUVs, as side airbags are standard in more cars than in SUVs. Among 2007 models, 71 percent of the cars have standard side airbags, while such protection is standard in only 48 percent of SUVs.

If safety is your top consideration, none of the six midsized SUVs tested earned the IIHS "Top Safety Pick" because of low ratings for protection in side and/or rear impacts.

"If you're in the market for a midsize SUV, there's no reason to buy one with mediocre crash test ratings," Zuby said. "Vehicles like the Ford Edge and TaurusX, Honda Pilot, Hyundai Santa Fe, and Subaru Tribeca would be safer choices. These five models, tested earlier this year, are our highest rated midsize SUVs, earning the Top Safety Pick award. If you're willing to spend a little more, the Acura MDX and RDX, Lincoln MKX, Mercedes M Class, and Volvo XC90 also are Top Safety Pick choices."

More information on IIHS testing and results can be found at the organization's web site, www.iihs.org.

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