New IIHS tests show how a well-built side underride guard can prevent a passenger vehicle from sliding beneath the side of a semitrailer.
The tests mark the first time that IIHS has evaluated a side underride guard. IIHS ran two 35-mph crash tests: one with a fiberglass side skirt intended to improve aerodynamics, not to prevent underride, and another with an AngelWing side underride protection device from Airflow Deflector Inc. The results were dramatically different.
In both tests, a midsize car struck the center of a 53-foot-long dry van trailer. In the AngelWing test, the underride guard bent but didn’t allow the car to go underneath the trailer, so the car’s airbags and safety belt could properly restrain the test dummy in the driver seat. In the test with no underride guard for protection, the car ran into the trailer and kept going. The impact sheared off part of the roof, and the sedan became wedged beneath the trailer. In a real-world crash like this, any occupants in the car would likely sustain fatal injuries.