The 2009 Nissan Murano was the best performer in new crash tests of midsize sport-utility vehicles, while the Hummer H3 posted one of the poorest showings, results released Tuesday by the Insurance Institute for Highway Safety indicated.

The institute, which is funded by the insurance industry, said the redesigned Murano was the only vehicle among the nine tested to receive the highest rating in front, side and rear crash tests. It praised Nissan for making electronic stability control standard on the 2009 Murano. The system helps prevent swerving.

General Motors’ (GM) H3 was the only vehicle in the group that didn’t receive the top rating for frontal-crash protection. It earned the second-highest rating of “acceptable” because the test indicated a high likelihood of injury to the driver’s right leg. The H3 also received an “acceptable” rating in the side crash test and the worst rating of “poor” in the rear crash test.

A message seeking comment was left Monday with GM.

The institute said it downgraded side crash results for the H3, Kia’s Sorento and Chrysler’s Jeep Liberty/Dodge Nitro — which are built on the same platform — because they lacked air bags that protected the torso. All three had curtain air bags that protected the head. But the tests indicated a likelihood of injuries to the driver’s rib cage.

The Jeep Wrangler also received a low rating for side protection because its side air bags are optional. It was the only vehicle in the group without standard side air bags.

Besides the H3, worst performers in the rear crash test were the Mitsubishi Endeavor and Jeep Liberty/Dodge Nitro. The Jeep Wrangler, Suzuki XL7, Mazda CX-7 and Mazda CX-9 got the second-lowest rating of “marginal” on that test.

The redesigned 2009 Nissan Murano has earned a Top Safety Pick rating among 10 midsize SUVs crash-tested by the Insurance Institute for Highway Safety.

The Murano was the only SUV to get a Top Safety Pick honor by scoring Good in all three crash tests. (Results in front, side and rear crash tests by IIHS are rated as Good, Acceptable, Marginal or Poor.) The 2008 Mazda CX-7 and Mazda CX-9, as well as the 2008 Mitsubishi Endeavor, fell short of the Top Safety Pick rating, IIHS says, because head-rest protection in rear crash tests was rated Marginal in the Mazdas and Poor in the Mitsubishi.

Though many would classify the Murano, CX-7 and CX-9 as crossovers, IIHS classifies them as SUVs.

The Kia Sorento was the only vehicle to get the lowest rating, Poor, in side-impact tests, even with its standard side airbags. The Jeep Liberty, Dodge Nitro and four-door Jeep Wrangler were rated Marginal in side crash tests; the Wrangler was rated Marginal in its rear crash test. The Hummer H3 was rated Acceptable in both front and side crashes, but Poor in rear crashes, as were the Endeavor, Liberty and Nitro.

The good news, IIHS says, is that in those same tests in 2001, half of the models failed to get a Good rating in front crash tests, but this year only one, the H3, missed getting a Good rating. It rated Acceptable.

The other good news is that all the models offer standard electronic stability control. IIHS won’t award any vehicle a Top Safety Pick rating without having that system, which prevents under- or oversteer and reduces the chance of slip-sliding or skidding.

While IIHS ratings provide another tidbit of safety information, they are also self-serving for the insurance industry. The higher the safety rating, the lower the cost to repair a vehicle (or care for an occupant) after an accident, and IIHS comprises insurance companies that pay motorists for their vehicles. Naturally, the safer cars are, the less insurers pay.