Knee Airbags Contribute Very Little to Safety, Says IIHS Study

The Insurance Institute for Highway Safety (IIHS) recently released a study that found knee airbags do very little to reduce the risk of injury in real-world crashes. 

On the contrary, the study found that their presence may have lead to increased injury rates in certain crashes.

Knee airbags are often stored in the lower dashboard. In the event of a crash, they are expected to diffuse impact forces to keep legs from suffering serious injuries. Supposedly, they also help protect the chest and abdomen by reducing lower body movement.

IIHs attempted to confirm these alleged benefits by examining data gathered from crash tests and real-world accident reports. The agency looked at 400 frontal crash tests to see if the risk of injury was reduced if vehicles were equipped with knee airbags. Instead, knee airbags increased the risk of lower leg and right femur injuries in driver-side small- and moderate-overlap crash tests. However, they were found to reduce the risk of head injuries.

IIHS also looked at crash reports from 14 states and compared injury risk in vehicles with and without knee airbags. In these real-world crashes, knee airbags were said to reduce overall injury risk by 0.5 percent, a barely significant difference.

"There are many different design strategies for protecting against the kind of leg and foot injuries that knee airbags are meant to address," said IIHS Senior Research Engineer and study co-author Becky Mueller in a statement. "Other options may be just as, if not more, effective."

However, the IIHS said its study did not examine whether passengers were belted in at the time of impact.

IIHs acknowledged that it's still possible for knee airbags to benefit unbelted occupants in the event of a frontal crash.