Safety is becoming one of the most important selling points for pretty much every vehicle, with a special emphasis being put on Sport Utility Vehicles. The reason for this is the higher risk of rollover and the huge increase in fatalities due to rollovers in SUV as compared to sedans and coupes. It was this same statistic that led the Insurance Institute for Highway Safety (IIHS) to begin a new kind of testing on vehicles.
The crash test rating is not really a crash test at all, but rather a test to see how much pressure the roof of a vehicle would be able to hold in the event of a rollover. The procedure for testing is very simple; a metal ram is pressed against certain points along the roof. The ram is moving at a pre-determined speed and applies a known amount of force. The ram will continue to apply pressure until it has been able to crush into the metal a full 5 inches. Depending on the amount of pressure required, the IIHS will be able to determine the safety rating.
The actual rating begins before the vehicle even goes near the new testing equipment. It must first be weighed, so the test for one vehicle will not be the same as the other. After that, that weight is put into a computer and a corresponding set of data will be produced and be used to judge the strength of the roof. To achieve the best rating available, the roof must be able to withstand a full 4 times the amount of the vehicle weight. A strength-to-weight ratio of 3.25 will net a rating of acceptable, while the marginal category requires at least a 2.5. Anything less than that is considered poor and should probably be redesigned.
Why did the IIHS decide on a 4 to 1 strength-to-weight ratio? Their studies show that this magical number represents a 50% decrease in the likelihood of a serious or fatal injury due to rollover. According to the IIHS, testing like this forces automakers to build stronger, and therefore safer vehicles. When the Institute began more thorough testing of side impact and frontal offset strength in vehicles, automakers responded by making them stronger. They believe the same pattern will be seen with this new kind of testing.
The testing also means that the number of vehicles that qualify for the coveted Top Safety Pick will be greatly reduced. Out of the 73 vehicles that qualified for the 2009 model year, only 3 have been able to pass the roof strength test with a rating of "good."
What does this mean for you? Stronger and safer vehicles on the road and protecting you loved ones.