(CNN) — They are popular but are they safe? The results of the latest safety tests of nine mid-size SUVs are in and only one earned the title as best overall performer.

From the front, side and rear, the Insurance Institute for Highway Safety put nine mid-size SUVs through the most common crashes. But in the end, only one vehicle earned a good rating, the highest possible, in each category — the redesigned 2009 Nissan Murano.

But there was one set of results testers were not expecting.

"Three of these SUVs earned marginal or poor ratings in our side impact tests,” said IIHS Spokesman Russ Rader.

Those vehicles were the 2008 Kia Sorento and Jeep Liberty and the four-door Wrangler. All of them, the Institute says, failing to provide good chest and abdomen protection in side crashes.

The Liberty and Wrangler were also among seven vehicles that scored marginal to poor ratings in rear crash tests.

"The rear impact tests look at how well your head restraints protect you in a collision,” explained Rader.

Chrysler, which makes both the Wrangler and Jeep Liberty, defends its vehicles saying, “No single test can determine a vehicle's overall safety performance and other tests and features make the vehicles safe.”

Kia responded by saying in separate tests conducted by the National Highway Traffic Safety Administration, the Sorento "received a five-star crash rating and that Kia's vehicles meet or exceed all federal safety standards."

But despite some poor ratings, the Insurance Institute says overall, the safety of SUVs is improving.

The bottom line is before you buy, do your research. You can get the complete test results by logging onto IIHS.org