2005 GMC Savana Van Owner's Manual - Page 73

Dual Stage Airbags If your vehicle has frontal airbags with dual stage deployment, the restraint will adjust according to the crash severity. Your vehicle is equipped with electronic frontal sensors which help the sensing system distinguish between a moderate and a more severe frontal impact. For moderate frontal impacts, these airbags inflate at a level less than full deployment. For more severe frontal impacts, full deployment occurs. If the front of your vehicle goes straight into a wall that does not move or deform, the threshold level for the reduced deployment is about 12 to 16 mph (19 to 26 km/h), and the threshold level for a full deployment is about 16 to 25 mph (26 to 40 km/h). (The threshold level can vary, however, with specific vehicle design, so that it can be somewhat above or below this range.) Vehicles with dual stage airbags are also equipped with special sensors which enable the sensing system to monitor the position of both the driver and passenger front seats. The seat position sensors provide information which is used to determine if the airbags should deploy at a reduced level or at full deployment. What Makes an Airbag Inflate? In an impact of sufficient severity, the airbag sensing system detects that the vehicle is in a crash. 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. 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. Airbags supplement 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 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 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. 1-67