The Insurance Institute for Highway Safety (IIHS) is a safety-research group that conducts its own series of crash tests, to the front, side, and rear. The primary frontal crash series runs a vehicle at 40 mph into a deformable barrier. Instead of engaging the whole width of the car's front end, which the government’s traditional front-crash test does, the barrier covers just the 40 percent of the car that’s in front of the driver.
That’s known as a frontal offset crash.
Using a deformable barrier instead of a rigid one, the test simulates a car-to-car, driver's-side-to-driver's-side collision, which is a common form of fatal crash. By focusing the crash on only a portion of the car's front, this test severely stresses the car's structural integrity and its ability to protect the area around the driver without collapsing.
The IIHS scores its frontal-crash results as Good, Acceptable, Marginal, or Poor.
In 2012 the IIHS inaugurated a second set of frontal offset crashes, one that engages just 25 percent of the car’s front end. Think of it as a head-on crash between two vehicles that meet left-headlight to left-headlight, or a single-vehicle crash into a utility pole or tree. In a crash like that the driver’s foot well can deform, causing serious injury to a driver’s lower legs, and the car pivots to the side, throwing the driver against the front door and window. It will take some time for the IIHS to accumulate enough results from the small-overlap tests to make meaningful comparisons across the car market. But early results show a wide range of performance from Good to Poor. You can find ratings for all tested vehicles on the IIHS website, at www.hwysafety.org.
Since 2003, the IIHS also has conducted its own side-impact tests, which simulate a vehicle being struck in the side at 31 mph by a vehicle the height and weight of a typical SUV or pickup. Two dummies representing small (5th percentile) women or 12-year-old children are positioned in the driver seat and the rear seat behind the driver.
IIHS also compiles rollover ratings by measuring roof strength. The test uses a metal plate pushed down on one front corner of a vehicle's roof to see how much weight the roof can withstand. Top scores go to vehicles that can withstand four times the vehicle’s weight without much deformation.
For more information on crash testing and ratings, see our Crash test 101 report.