Air Bags -- How They Work
Driver and front-passenger air bags are designed to offer protection, in addition to the protection offered by safety belts, in moderate to severe frontal and near frontal collisions. When a frontal or near frontal collision occurs, special crash sensors on an air bag-equipped vehicle measure crash severity and then trigger the air bag to deploy. It inflates by means of a chemical reaction that produces harmless nitrogen gas, which fills the air bag.
As contact is made with the the air bag, it rapidly deflates as the nitrogen gas is vented. Sometimes a momentary residue can be seen, appearing as smoke, which is mostly cornstarch or talcum powder. The inflation process takes only about one-twentieth of a second. Deflation may take up two or three seconds, meaning that vision is obstructed only momentarily.
Why Air Bags Save Lives
In frontal or near-frontal collisions, the vehicle,s forward motion begins to decelerate as impact occurs. However, occupants inside the vehicle remain in motion. Unless restrained, an unbelted front-seat occupant in a vehicle not equipped with an air bag would be stopped in a collision by the instrument panel, steering wheel or the windshield, possibly causing serious injury. A restrained occupant could avoid this type of impact -- wearing a safety belt would, in most cases, provide the stopping force necessary to avoid impact with interior surfaces, thereby avoiding injury that comes from contact. In a severe collision, even belted occupants may contact the steering wheel or instrument panel, causing injury. The air bag(s) supplements the protection provided by safety belts by distributing the impact forces more evenly over the occupant's body, reducing injuries from concentrated loading.
Simply put, safety belts are the most effective occupant protection system on a vehicle. For this reason, all Chevrolet models provide 3-point lap/shoulder safety belts for outboard front- and rear-seat occupants and lap belts for center-seat occupant positions.