Shoulder belts are on inertia reels that allow upper body movement during normal driving but lock during hard braking or in a crash. Belt webbing is stored on the reel, and during a frontal crash any slack in the webbing can allow some forward movement of your upper body. The airbags in all new cars enhance protection by providing additional restraint to the head and upper body. The airbag doubles the protection against serious head injury offered by the safety belt alone. In some serious crashes, the forces produced by the shoulder belt on the upper body can cause rib fractures and other injuries.
More new cars offer shoulder belts with force limiting designs.
The risk occurs if you're on top of, or very close to, an airbag when it first begins to inflate. Using belts correctly and choosing a proper seating position can eliminate serious airbag injury risk without sacrificing the benefits. Drivers should always use belts and sit with the center of the chest at least 10 inches away from the steering wheel. Belted drivers potentially at risk of serious airbag injury are the few sitting very close to the wheel. Choose a vehicle that allows you to reach the pedals comfortably without sitting too close to the steering wheel.