1997 GMC Jimmy Owner's Manual - Page 34

When should an air bag inflate? An air bag is designed to inflate in a moderate t o severe frontal or near-frontal crash. The airbag will inflate only if the impact speed is above the system's designed "threshold level." If your vehicle goes straight into a w a l l that doesn't move or deform. the threshold level is about 14 t o 18 mph (23 to 29 km/h). The threshold level can vary, however, with specific vehicle design. so that it can be somewhat aboveor below this range. If your vehicle strikes something that will move or deform, such a s a parked car. the threshold level will be higher. The air bag is not designed to inflate in rollovers, side impacts or rear impacts. because inflation would not help the occupant. What makes an air bag inflate? In an impact of sufficient severity, the a i r bag sensing system detects that the vehicle is i n a crash. The sensing system triggers a releaseof gas from the inflator. which inflates the air bag. The inflator, air bag and related hardware are all part of the air bag module inside the steering wheel. How does an air bag restrain? I n any particular crash, no one can say whether an air bag should have inflated simply becauseof the damage to a vehicle or becauseof what the repair costs were. Inflation is determined by the angle of the impact and how quickly the vehicle slows down i n frontal and near-frontal impacts. The air bag system is designed to work properly under a wide range of conditions, including off-road usage. Observe safe driving speeds. especiallyon rough terrain. As always. wear your safetybelt. See "Off-Road Driving" in the Index for Inore tips on off-road driving. In tnoderate t o severe frontal or near-frontal collisions. even belted occupants can contactthe steering wheel. 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 air bags would n o t help you in many types of collisions, including rollovers. rear impacts and side impacts. primarily because an occupant's motion is n o t toward the air bag. Air bags should never be regarded a s anything more than a supplement t o safety belts. and then only in moderate t o severe frontal or near-frontal collisions. 1-23