Though the steering wheel has been maligned as a primary cause of injuries in automobile collisions, studies show it is the first passive restraint system in the automobile. Adding an airbag to the steering wheel distributes the energy load better than the wheel alone, and the airbag takes advantage of the space between occupant and steering wheel to protect the driver further.
Specifically, the airbag utilizes space to decelerate the occupant, prevents concentrated loads on the torso, stops the face from hitting the steering wheel rim, and helps distribute impact load over a larger area. The airbag has three major components-the sensor, inflator, and airbag. The functioning of these components, as well as experimental investigations conducted to determine operational capabilities of the system, are discussed.