When Should an Air Bag Inflate?The driver’s and right front passenger’s frontal air bagsare designed to inflate in moderate to severe frontalor near-frontal crashes. But they are designed to inflateonly if the impact speed is above the system’sdesigned “threshold level.”In addition, your vehicle has “dual stage” frontal airbags, which adjust the amount of restraint according tocrash severity. For moderate frontal impacts, theseair bags inflate at a level less than full deployment. Formore severe frontal impacts, full deployment occurs.If the front of your vehicle goes straight into a wall thatdoesn’t move or deform, the threshold level for thereduced deployment is about 12 to 16 mph (19 to26 km/h), and the threshold level for a full deployment isabout 18 to 24 mph (29 to 38.5 km/h).The threshold level can vary, however, with specificvehicle design, so that it can be somewhat aboveor below this range.If your vehicle strikes something that will move ordeform, such as a parked car, the threshold level will behigher. The driver’s and right front passenger’s frontalair bags are not designed to inflate in rollovers, rearimpacts, or in many side impacts because inflationwould not help the occupant.The side impact air bags are designed to inflate inmoderate to severe side crashes. A side impact air bagwill inflate if the crash severity is above the system’sdesigned “threshold level.” The threshold level can varywith specific vehicle design. Side impact air bags arenot designed to inflate in frontal or near-frontal impacts,rollovers or rear impacts, because inflation would nothelp the occupant. A side impact air bag will only deployon the side of the vehicle that is struck.In any particular crash, no one can say whether an airbag should have inflated simply because of the damageto a vehicle or because of what the repair costs were.For frontal air bags, inflation is determined by the angleof the impact and how quickly the vehicle slows downin frontal and near-frontal impacts. For side impactair bags, inflation is determined by the locationand severity of the impact.What Makes an Air Bag Inflate?In an impact of sufficient severity, the air bag sensingsystem detects that the vehicle is in a crash. Forboth frontal and side impact air bags, the sensingsystem triggers a release of gas from the inflator, whichinflates the air bag. The inflator, air bag and relatedhardware are all part of the air bag modules inside thesteering wheel, instrument panel, the side of thefront seatbacks closest to the door and the ceiling of thevehicle, near the side windows.1-57
