An IIHS study released Wednesday concluded that knee airbags didn’t significantly reduce the risk of injury in real-world crashes, and test data from the agency may show that the supplemental airbags may have increased injury rates in certain crashes performed by the insurance industry-funded agency.
The organization gathered data from its internal crash testing as well as that from real-world crashes, and compared injury results between vehicles with and without knee airbags. In real-world crashes, knee airbags barely reduced the likelihood of injuries from 7.9% for cars without them to 7.4% for cars with them. In the IIHS’s controlled testing, it found that in moderate overlap frontal tests, the airbags had no effect. In the small overlap frontal test, the airbags slightly increased the risk for injury around the legs, though they also slightly reduced the risk for head injuries.
In more than 400 crashes performed by the IIHS on new vehicles, knee airbags increased the risk of lower leg injuries and right femur injuries in driver-side small- and moderate-overlap crash tests but reduced the risk of head injuries. The IIHS said that knee airbags may be included by carmakers to reduce injuries in unbelted passengers by distributing impact forces across both legs. The knee airbags are also designed to reduce the risk of upper body injuries by controlling lower body movement.
Many automakers, including General Motors and Toyota have installed driver-side knee airbags on most of their new models for several years.