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GMC Sierra/Chevrolet Silverado
Front impact: Good
Side Impact: Poor
Whiplash protection: Acceptable
Stability Control: Optional
Top Safety Pick: No

While they earned the top grade of "Good" for front-crash protection, General Motors big trucks got a "Poor" rating from the Insurance Institute for side-impact protection.

The problem, according to the Institute, is a weak side structure combined with the absence of body-protecting side airbags. These trucks do have head-protecting side airbags and those worked well, but those airbags don't protect ribs and internal organs.

The Silverado and Sierra earned top ratings for both front and side impact protection from the federal government's National Highway Safety Administration, which uses different tests from those used by the Insurance Institute.

"IIHS tests are valid and we do pay attention to them," GM said in a statement responding to the Insurance Institute, "but it's also important to understand the results of a single test do not determine whether a vehicle is safe or not."

GM will be making changes to these trucks for the 2010 model year that will allow them to perform better on the Insurance Institute's tests, a GM spokeswoman said separately.

NEXT: Nissan Titan

Last updated February 11 2009: 12:23 PM ET
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