2002 Chevrolet Impala Owner's Manual - Page 34

The driver's side impact air bag is designed to inflate in moderate to severe side crashes involving the driver's door. The side impact air bag will inflate if the crash severity is above the system's designed "threshold level." The threshold level can vary with specific vehicle design. The driver's side impact air bag is not designed to inflate in frontal or near-frontal impacts, rollovers or rear impacts, because inflation would not help the occupant. In any particular crash, no one can say whether an air bag should have inflated simply because of the damage to a vehicle or because of what the repair costs were. For frontal air bags, inflation is determined by the angle of the impact and how quickly the vehicle slows down in frontal and near-frontal impacts. For the side impact air bag, inflation is determined by the location and severity of the impact. What makes an air bag inflate? In an impact of sufficient severity, the air bag sensing system detects that the vehicle is in a crash. For both frontal and side impact air bags, the sensing system triggers a release of gas from the inflator, which inflates the air bag. The inflator, air bag and related hardware are all part of the air bag modules inside the steering wheel, instrument panel and the side of the driver's seatback closest to the door. How does an air bag restrain? In moderate to severe frontal or near frontal collisions, even belted occupants can contact the steering wheel or the instrument panel. In moderate to severe side collisions, even belted occupants can contact the inside of the vehicle. The air bag supplements the protection provided by safety belts. Air bags distribute the force of the impact more evenly over the occupant's upper body, stopping the occupant more gradually. But the frontal air bags would not help you in many types of collisions, including rollovers, rear impacts, and many side impacts, primarily because an occupant's motion is not toward the air bag. The side impact air bag would not help you in many types of collisions, including frontal or near frontal collisions, rollovers, and rear impacts, primarily because the occupant's motion is not toward that air bag. Air bags should never be regarded as anything more than a supplement to safety belts, and then only in moderate to severe frontal or near-frontal collisions for the driver's and right front passenger's frontal air bags, and only in moderate to severe side collisions for the driver's side impact air bag. 1-28