Airbags have been a fixture in cars for the better part of three decades now, and while they started out as a safety feature for drivers, they have since started tothroughout the vehicle to include the , side-impact airbags, curtain airbags and so on.
One increasingly prominent type of airbag is the knee protection airbag that deploys from the lower dash area to cushion an occupant's knees in the event of a serious collision. However, the benefit that knee airbags provide may be overstated, according to a report published Wednesday by the Insurance Institute for Highway Safety (IIHS).
To find out whether knee airbags actually prevented injury, the IIHS looked at data from more than 400 crash tests as well as numerous reports from real traffic collisions to see if manufacturers' claims that knee airbags would prevent leg injuries and help control passengers bodies better to reduce other injuries were true.
What the IIHS found was that there wasn't much difference between having those knee airbags and not having them. The real-world crash data showed that the airbags only reduced the probability of injury by 0.5% while the crash tests showed that in certain circumstances, they increased the likelihood of 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," says Becky Mueller, an IIHS senior research engineer, in a statement. "Other options may be just as, if not more, effective."
So, if they don't do much, why are vehicle manufacturers going to the trouble and expense of installing knee airbags? Well, the IIHS reckons that they might have more efficacy on an unbelted vehicle occupant, though the agency didn't test for that because in IIHS crash tests,, the dummies are always wearing their seatbelts.