2006 GMC Envoy Owner's Manual - Page 71

What Makes an Airbag Inflate? In an impact of sufficient severity, the airbag sensing system detects that the vehicle is in a crash. In the case of a "rollover capable" roof-mounted side impact airbag, the sensing system detects that the vehicle is about to roll over. The sensing system triggers a release of gas from the inflator, which inflates the airbag. The inflator, airbag, and related hardware are all part of the airbag modules inside the steering wheel and in the instrument panel in front of the right front passenger. For vehicles with roof-mounted side impact airbags, the airbag modules are located in the ceiling of the vehicle, near the side windows. How Does an Airbag 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 airbag supplements the protection provided by safety belts. Airbags distribute the force of the impact more evenly over the occupant's upper body, stopping the occupant more gradually. But the frontal airbags 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 airbag. Roof-mounted side impact airbags would not help you in many types of collisions, including many frontal or near frontal collisions, and rear impacts, primarily because an occupant's motion is not toward those airbags. Airbags 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 airbags, and only in moderate to severe side collisions or rollovers for the roof-mounted side impact airbags. 1-65