ARLINGTON, VA - The Cadillac SRX, a midsize luxury SUV, has drawn the Insurance Institute for Highway Safety's top safety designation -- the Top Safety Pick award.

The Cadillac SRX drew a "good" rating for rollover protection -- the highest rating possible. The SRX had previously earned "good" ratings for front, side and rear crash protection.

The "Top Safety Pick" recognizes the vehicles that earn the highest ratings in all four IIHS safety evaluations. Top Safety Picks also must have electronic stability control, which is standard on the SRX.

Based on research of real-world crashes, the institute evaluates rollover protection using a roof strength test. In this test, a metal plate is pushed against one corner of a vehicle's roof at a constant speed. The maximum force sustained by the roof before five inches of crush is compared to the vehicle's weight to find the strength-to-weight ratio. This is a good assessment of vehicle structural protection in rollover crashes, IIHS said. Vehicles rated "good" have roofs that can withstand a force equal to at least four times the vehicle's weight.

The roof of the 2010 SRX withstood a force equal to 4.14 times weight. For comparison, the current federal standard is 1.5 times weight.

General Motors strengthened the roof structure of the SRX during the 2010 model year. The Top Safety Pick award applies to models built after May 2010.