What Makes An Airbag Inflate; How Does An Airbag Restrain - GMC Envoy Owner's Manual

What Makes an Airbag Inflate?
In an impact of sufficient severity, the airbag sensing
system detects that the vehicle is in a crash. In the case
of a "rollover capable" roof-mounted airbag, the
sensing system detects that the vehicle is about to roll
over. For both frontal and roof-mounted airbags, 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. For vehicles
with roof-mounted airbags, the airbag modules are
located in the ceiling of the vehicle, near the side
windows.

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. In moderate to severe side
collisions, even belted occupants can contact the inside
of the vehicle. The airbag supplements 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 the
frontal 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 the airbag. Roof-mounted airbags
would not help you in many types of collisions, including
frontal or near frontal collisions, and rear 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 for the driver's and right front passenger's
frontal airbags, and only in moderate to severe
side collisions or rollovers for the roof-mounted airbags.
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