GMC 2002 Envoy Owner's Manual page 38

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
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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
9 to 16 mph (14 to 26 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, side
impacts, or rear impacts, because inflation would not
help the occupant.
1-26
The side impact air bags are designed to inflate in
moderate to severe side crashes. A 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. Side impact air bags are not
designed to inflate in frontal or near
rollovers or rear impacts, because inflation would not
help the occupant. A side impact air bag will only
deploy on the side of the vehicle that is struck.
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 side impact air
bags, inflation is determined by the location and severity
of the impact.
The air bag system is designed to work properly under a
wide range of conditions, including off
Observe safe driving speeds, especially on rough terrain.
As always, wear your safety belt. See "Off
Driving" in the Index for more tips on off
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frontal impacts,
-
road usage.
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Road
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road driving.