Roof Testing
In addition to roof strength test is significant, considering that thousands of people die annually due to rollover accidents. When you receive your vehicle at the top rating from IIHS, it means that these models are considered better able to withstand severe accidents.
As you might guess, not too many SUV passed this test yet. They are usually crossover models, such as the Toyota Venza, while higher models with high roof pillars are usually not.