Mercedes-Benz 2015 M-Class Operator's Manual page 61

If the restraint system control unit detects a
high accident severity, additional compo-
nents of the restraint system are activated
independently of one another in certain fron-
tal collision situations:
Front air bags and driver's knee bag
R
Windowbag, if the system determines that
R
it can offer additional protection to that
provided by the seat belt
Depending on the person occupying the front-
passenger seat, the front-passenger air bag is
activated or deactivated. The front-passenger
front air bag can only be deployed in an acci-
dent if the PASSENGER AIR BAG OFF indica-
tor lamp is off. Observe the information on the
PASSENGER AIR BAG OFF indicator lamp
( page 45).
Y
Your vehicle has two-stage front air bags.
During the first deployment stage, the front
air bag fills with propellant gas which reduces
the risk of injury. The second stage is then
triggered within milliseconds, filling the front
air bag with the maximum amount of propel-
lant gas.
The deployment thresholds for the Emer-
gency Tensioning Devices and air bags are
calculated on the basis of the vehicle decel-
eration or acceleration occurring at various
points in the vehicle. This process is pre-emp-
tive in nature. The air bag must be deployed
on time, at the start of the collision.
The rate of vehicle deceleration or accelera-
tion and the direction of the force are essen-
tially determined by:
distribution of the force during the impact
R
collision angle
R
deformation characteristics of the vehicle
R
characteristics of the object with which the
R
vehicle has collided
Factors which can only be seen and measured
after the collision has occurred do not play a
decisive role in the deployment of an airbag,
nor do they provide an indication of air bag
deployment.
Occupant safety
The vehicle may be considerably deformed
without an air bag being deployed. This is the
case if only relatively easily deformable parts
have been hit and a high rate of deceleration
has not been reached. Conversely, an air bag
may be deployed even though the vehicle suf-
fers only minor deformation. This is the case
if, for example, very rigid vehicle parts such as
the longitudinal body members are hit in an
accident and the rate of deceleration is suffi-
cient.
If the restraint system control unit detects a
side impact or an overturn situation, the rel-
evant restraint system components are acti-
vated independently of one another depend-
ing on the apparent type of accident. If addi-
tional protection for the vehicle occupants is
determined in this situation, the belt tension-
ers are also triggered.
Side impact air bags on the side of the col-
R
lision, regardless of Emergency Tensioning
Device and use of the seat belt on the driv-
er's side and the outer seats on the second
row
The sidebag on the front-passenger side
deploys under the following conditions:
the OCS system detects that the front-
-
passenger seat is occupied or
the belt tongue has engaged in the belt
-
buckle of the front-passenger seat.
Window curtain air bag on the side of the
R
collision, regardless of seat belt use and
whether front-passenger seat is occupied
Windowbags on the driver's and front-
R
passenger sides in certain overturn situa-
tions if the system determines that they
can offer additional protection to that pro-
vided by the seat belt
i
Not all air bags are deployed in an acci-
dent. The various air bag systems work
independently of each other.
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