The Insurance Institute for Highway Safety gave higher marks to the bumpers on General Motors' Chevrolet TrailBlazer, which won an "acceptable" rating, and to those on the Dodge Ram 1500 pickup, which were graded "marginal."
The institute tests bumpers by ramming vehicles into a variety of structures at 5 miles per hour and estimating repair costs.
The Liberty, built by the Chrysler arm of DaimlerChrysler AG sustained the highest average damage at $1,417 per test. The IIHS said in a statement that the Liberty's results were driven up in part by the spare tire mounted on the rear hatch, which hit the barrier before the bumper did.
Several other small SUVs have received similar ratings.
The Ford Motor Co. Explorer sustained an average of $1,358 damage per test. In one test where vehicles are smacked against an angled barrier, the Explorer suffered $2,334 in damage, including frame rail damage, a bent hood and a broken headlight.
IIHS hailed the improvement in the TrailBlazer's bumpers over the model it replaced, because it averaged $611 in damage. Although the Ram averaged $961 per test, it still suffered less damage than other full-size trucks IIHS has tested.