Hummer 2005 H2 - Manual (Page 69)

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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