What Makes An Airbag Inflate; How Does An Airbag Restrain - GMC 2005 Savana Van Owner's Manual

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.
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