Hint: be careful of your kneecaps.
Since arriving on the scene 30 years ago, airbags have become a major safety feature component in new vehicles. What started off as a driver's side airbag located in the steering wheel has expanded to the front passenger, side-impact airbags, curtain airbags, and knee airbags. It's the latter, however, that is now under scrutiny following a research investigation just published by theInsurance Institute for Highway Safety (IIHS). The IIHS was interested to know whether driver's knee airbags help to prevent serious injury in case of a serious accident.
Its researchers examined data from more than 400 frontal crash tests as well as real-world crash reports compiled from 14 states. The IIHS ultimately concluded that there was not a big difference between having knee airbags and not having them.
For example, the analysis of real-world crash data showed that "knee airbags reduced injury risk by half a percentage point, from 7.9 percent to 7.4 percent." Crash tests further showed that, depending on circumstance, knee airbags could actually increase the chances of a leg injury. "There are many different design strategies for protecting against the kind of leg and foot injuries that knee airbags are meant to address," said Becky Mueller, an IIHS senior research engineer. "Other options may be just as, if not more, effective."
So if knee airbags aren't as effective as some may claim, why do automakers even bother? After all, they are an added expense.
The IIHS believes one reason for installing them is to help vehicles pass federally mandated crash tests with unbelted dummies. The agency didn't study data involving crashes where people opted not to buckle up, but during its own tests, the dummies are always properly strapped in. So basically, if drivers are wearing their seat belts as required by law (and common sense), then knee airbags may only not be unnecessary, but also potentially dangerous for the lower extremities.