after an accident. Take this into account, par-
ticularly if a seat belt tensioner was triggered or
an airbag was deployed.
An electric motor is used by PRE-SAFE
®
to trig-
ger the tightening of the seat belt in hazardous
situations. This procedure is reversible.
If the belt tensioners are triggered or an airbag is
deployed, you will hear a bang, and a small
amount of powder may also be released. The
6
restraint system warning lamp lights up.
Only in rare cases will the bang affect your hear-
ing. In general, the powder released is not haz-
ardous to health but may cause short-term
breathing difficulties to persons suffering from
asthma or other pulmonary conditions. Provided
it is safe to do so, you should leave the vehicle
immediately or open the window in order to pre-
vent breathing difficulties.
Operation
During the first stage of a collision, the restraint
system control unit evaluates important physi-
cal data relating to vehicle deceleration or accel-
eration, such as:
R
duration
R
direction
R
intensity
Based on the evaluation of this data, the
restraint system control unit triggers the seat
belt tensioners in the event of a head-on or rear
collision.
A seat belt tensioner can only be triggered if:
R
the ignition is switched on
R
the components of the restraint system are
operational. You can find further information
under: "Restraint system warning lamp"
(
Y
page 40)
R
the belt tongue has engaged in the belt buckle
of the respective front seat
The seat belt tensioners in the rear compart-
ment are triggered independently of the lock
status of the seat belts.
If the restraint system control unit detects a high
severity accident, in certain head-on collisions,
additional components of the restraint system
are deployed independently of each other:
R
front airbags and driver's kneebag
R
windowbag, if the system determines that
deployment can offer additional protection to
that provided by the seat belt
On vehicles with the automatic front-passenger
front airbag deactivation system: depending on
the person in the front-passenger seat, the
front-passenger front airbag is either disabled or
enabled. The front-passenger front airbag can
only be deployed in an accident if the
PASSENGER AIR BAG ON indicator lamp is lit.
Observe the information on the PASSENGER AIR
BAG indicator lamps (
Y
page 40).
Your vehicle has two-stage front airbags. In the
first deployment stage, the front airbag is filled
with propellant gas to reduce the risk of injuries.
The front airbag is fully deployed if the second
deployment stage is activated within a few mil-
liseconds.
The activation threshold for the seat belt ten-
sioners and airbags is determined based on the
evaluation of the vehicle's rate of deceleration
or acceleration at various points in the vehicle.
This process is pre-emptive in nature. The trig-
gering/deployment process should take place
in good time at the start of the collision.
The rate of vehicle deceleration or acceleration
and the direction of the force are essentially
determined by:
R
the distribution of forces during the collision
R
the collision angle
R
the deformation characteristics of the vehicle
R
the characteristics of the object with which
the vehicle has collided
Factors which can only be seen and measured
after a collision has occurred do not play a deci-
sive role in the deployment of an airbag, nor do
they provide an indication of airbag deployment.
The vehicle may be deformed significantly with-
out an airbag being deployed. This is the case if
only parts which are relatively easily deformed
are affected and the rate of deceleration is not
high. Conversely, an airbag may be deployed
even though the vehicle suffers only minor
deformation. This is the case if, for example,
very rigid vehicle parts such as longitudinal body
members are hit, and sufficient deceleration
occurs as a result.
If the restraint system control unit detects a side
impact, the applicable components of the
restraint system are activated independently of
each other.
R
Sidebags on the side on which an impact
occurs, independent from the seat belt ten-
sioner and seat belt usage
Vehicles with the automatic front-passenger
airbag deactivation system: the sidebag on
Occupant safety
53
Saf
ety
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