When should an air bag inflate?; What makes an air bag inflate?- Page 31

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When should an air bag inflate?

The driver’s and right front passenger’s frontal air bags
are designed to inflate in moderate to severe frontal or
near

-

frontal crashes. But they are designed to inflate

only if the impact speed is above the system’s designed
“threshold level.”

If your vehicle goes straight into a wall that doesn’t move
or deform, the threshold level is about 12 to 18 mph 
(19 to 29 km/h). The threshold level can vary, however,
with specific vehicle design, so that it can be somewhat
above or below this range.

If your vehicle strikes something that will move or
deform, such as a parked car, the threshold level will be
higher. The driver’s and right front passenger’s frontal
air bags are not designed to inflate in rollovers, rear
impacts, or in many side impacts because inflation
would not help the occupant.

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.