Knee airbags are less effective, and alternatives are being developed

When a vehicle is involved in a head-on collision, the driver's knees are most likely to be injured or even fractured because the distance between the driver's knees and the bottom of the center console is short. Although models such as Mercedes-Benz GLC, Toyota Lelink, and Porsche Panamera are all equipped with knee airbags as standard, in the current automobile market, most models are still only equipped with driver and co-driver airbags and side airbags.

Recently, a study released by the Insurance Institute for Highway Safety (IIHS) in the United States showed that the deployment rate of knee airbags continues to increase. Some people believe that the more airbags a vehicle uses, the higher the safety protection performance for the occupants. However, in some accidents, knee airbags not only fail to reduce the safety risks caused by traffic accidents, but increase the risk of injury to the members.

It is reported that knee airbags are usually installed under the dashboard. When a collision occurs, the airbag will automatically pop out to reduce the damage to the driver's legs, form a collision buffer area, and also help alleviate the impact force on the driver's chest and abdomen. To confirm whether knee airbags can improve vehicle safety, IIHS researchers examined collision test data and relevant information from real accidents.

First, the researchers collected more than 400 frontal crash injury data from the IIHS vehicle rating program to confirm whether vehicles equipped with knee airbags can effectively reduce the degree of knee injuries in the event of a collision. The team then searched for data from crash accident reports in 14 states in the United States and compared the crash data of the same models equipped with knee airbags and those without knee airbags.

In the IIHS driver-side 25% and 40% overlap frontal offset collisions, the knee airbags did not provide significant protection for the test dummies, especially in the 40% overlap frontal offset collision, where the knee airbags had almost no effect in reducing injuries. After analyzing the data from real-world accidents, the knee airbags only reduced the risk of injury by 0.5 percentage points, from 7.9% to 7.4%.

Becky Mueller, a high-precision research engineer at IIHS, pointed out that they have proposed several different design solutions to provide protection for the user's thighs and calves to replace knee airbags. After all, the effectiveness of other solutions is no less than that of knee airbags. Currently, many automakers install knee airbags in order to allow their vehicles to pass the mandatory safety test of "unbelted test dolls" proposed by the US federal government. In the IIHS vehicle rating test, the test dolls are usually fixed to the seats with seat belts.