When should an air bag inflate?
The air bag is designed
to
inflate
in
moderate
to
severe
frontal or near-frontal crashes. The air bag
will
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 15 mph (14
to
24
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
air bag is not designed to inflate in rollovers, side
impacts 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.
.
Inflation is determined
by
the
angle
of
the
impact and
the vehicle’s deceleration. Vehicle damage is only one
indication of this.
What makes an air bag inflate?
In
a frontal or near-frontal impact of sufficient severity,
the air bag sensing system detects that the vehicle is
suddenly stopping as
a
result of a crash. The sensing
system triggers a chemical reaction
of
the sodium azide
sealed in the inflator. The reaction produces nitrogen
gas, which inflates the air bag. The inflator, air bag and
related hardware are all
part
of the air bag modules
packed inside the steering wheel and in the instrument
panel in front of the right front passenger.
How
does
an air bag restrain?
In
moderate to severe frontal or near-frontal collisions,
even belted occupants can contact the steering wheel
or
the instrument panel. The air bag supplements the,
protection provided by safety belts.
Air
bags distribute
the force of the impact more evenly over
the
occupant’s
upper body, stopping the occupant more gradually. But
air
bags would not help you in
many
types
of
collisions,
including rollovers, rear impacts and side impacts,
primarily because
an
occupant’s motion is not toward
the
air bag.
Air
bags 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.
-.
--
.I
