
The side impact air bag on the front-
passenger side (front) deploys in the fol-
lowing situations:
- the OCS system detects that the front-
passenger seat is occupied or
- the belt tongue is engaged in the belt
buckle of the front-passenger seat
R Window curtain air bag on the side of
impact, independently of the use of the
seat belt and independently of whether the front-passenger seat is occupied
R Window curtain air bags on the driver's and
front-passenger side in certain situations
when the vehicle rolls over, if the system
determines that deployment can offer addi-
tional protection to that provided by the
seat belt
i Not all air bags are deployed in an acci-
dent. The different air bag systems work
independently of each other.
How the air bag system works is deter-
mined by the severity of the accident detec- ted, especially the vehicle deceleration or
acceleration and the apparent type of acci-dent:
R frontal collision
R side impact
R rollover PRE-SAFE
®
(anticipatory occupant
protection system)
Introduction In certain hazardous situations, PRE-SAFE
®
takes pre-emptive measures to protect the
vehicle occupants.
Important safety notes !
Make sure that there are no objects in the
footwell under or behind the seats when
moving the seats back. There is a risk that
the seats and/or the objects could be dam-
aged. Despite your vehicle being equipped with the
PRE-SAFE ®
system, the possibility of per-
sonal injuries occurring as a result of an acci- dent cannot be eliminated. Always adapt your
driving style to suit the prevailing road and
weather conditions and maintain a safe dis-
tance from the vehicle in front. Drive care-
fully.
Function PRE-SAFE
®
intervenes:
R in emergency braking situations, e.g. when
BAS is activated
R in critical driving situations, e.g. when phys-
ical limits are exceeded and the vehicle
understeers or oversteers severely
R vehicles with the Driving Assistance pack-
age: when a driver assistance system inter-
venes powerfully or the radar sensor sys-
tem detects an imminent danger of colli-
sion in certain situations
PRE-SAFE ®
takes the following measures
depending on the hazardous situation detec-
ted:
R the front seat belts are pre-tensioned.
R if the vehicle skids, the panorama roof with
power tilt/sliding panel and the side win-
dows are closed so that only a small gap
remains.
R the front-passenger seat is adjusted if it is
in an unfavorable position.
R for vehicles with electrically adjustable rear
seats: the outer rear seats are adjusted if
they are in an unfavorable position.
R vehicles with a multicontour seat: the air
pressure in the side bolsters of the seat
backrest is increased.
R vehicles with seat belt extenders: the seat
belts of the outer rear seats are pre-ten-
sioned.
If the hazardous situation passes without
resulting in an accident, PRE-SAFE ®
slackens
the belt pre-tensioning. On vehicles with mul-
ticontour seats, the air pressure in the side Occupant safety
67Safety Z

bolsters is reduced again. All settings made
by PRE-SAFE ®
can then be reversed.
If the seat belt pre-tensioning is not reduced:
X Move the seat backrest or seat back
slightly when the vehicle is stationary.
The seat belt pre-tensioning is reduced and
the locking mechanism is released.
The seat-belt adjustment is an integral part of
the PRE-SAFE ®
convenience function. Infor-
mation about the convenience function can
be found under "Belt adjustment"
(Y page 55). PRE-SAFE
®
PLUS (anticipatory occu-
pant protection system PLUS)
Introduction PRE-SAFE
®
PLUS is only available in vehicles
with the Driving Assistance package.
Using the radar sensor system, PRE-SAFE ®
PLUS is able to detect that a head-on or rear-
end collision is imminent. In certain hazard-
ous situations, PRE-SAFE ®
PLUS takes pre-
emptive measures to protect the vehicle
occupants.
Important safety notes The intervention of PRE-SAFE
®
PLUS cannot
prevent an imminent collision.
The driver is not warned when PRE-SAFE ®
PLUS intervenes.
PRE-SAFE ®
PLUS does not intervene if the
vehicle is backing up.
PRE-SAFE ®
PLUS does not perform braking
actions while the vehicle is in motion or when
Parking Guidance is active.
Function PRE-SAFE
®
PLUS intervenes in certain situa-
tions if the radar sensor system detects an
imminent head-on or rear-end collision. PRE-SAFE
®
PLUS takes the following meas-
ures depending on the hazardous situation
detected:
R if the radar sensor system detects that a
head-on collision is imminent, the seat
belts are pre-tensioned.
R if the radar sensor system detects that a
rear-end collision is imminent:
- the brake pressure is increased if the
driver applies the brakes when the vehi-
cle is stationary.
- the seat belts are pre-tensioned.
The PRE-SAFE ®
PLUS braking application is
canceled:
R if the accelerator pedal is depressed when
a gear is engaged
R if the risk of a collision passes or is no lon-
ger detected
R if DISTRONIC PLUS indicates an intention
to pull away
If the hazardous situation passes without
resulting in an accident, the original settings
are restored. Automatic measures after an acci-
dent
Immediately after an accident, the following
measures are implemented, depending on
the type and severity of the impact:
R the hazard warning lamps are activated
R the emergency lighting is activated
R the vehicle doors are unlocked
R the front side windows are lowered
R the electrically adjustable steering wheel is
raised
R the engine is switched off and the fuel sup-
ply is cut off
R vehicles with seat belt extenders: the seat-
belt buckles for the outer rear seats are
illuminated and extend forwards 68
Occupant safetySafety

The
! ABS warning lamp in the instrument
cluster lights up when the ignition is switched on. It goes out when the engine is running.
Important safety notes i
Observe the "Important safety notes" sec-
tion (Y page 76). G
WARNING
If ABS is faulty, the wheels could lock when
braking. The steerability and braking charac-
teristics may be severely impaired. Addition-
ally, further driving safety systems are deac-
tivated. There is an increased danger of skid- ding and accidents.
Drive on carefully. Have ABS checked imme-
diately at a qualified specialist workshop.
When ABS is malfunctioning, other systems,
including driving safety systems, will also
become inoperative. Observe the information on the ABS warning lamp (Y page 358) and
display messages which may be shown in the
instrument cluster (Y page 317).
ABS works from a speed of about 5 mph
(8 km/h) , regardless of road-surface condi-
tions. ABS works on slippery surfaces, even
when you only brake gently.
Braking X
If ABS intervenes: continue to depress the
brake pedal vigorously until the braking sit- uation is over.
X To make a full brake application:
depress the brake pedal with full force.
If ABS intervenes when braking, you will feel a pulsing in the brake pedal.
The pulsating brake pedal can be an indica-
tion of hazardous road conditions, and func-
tions as a reminder to take extra care while
driving. BAS (Brake Assist System)
General information BAS operates in emergency braking situa-
tions. If you depress the brake pedal quickly,
BAS automatically boosts the braking force,
thus shortening the stopping distance.
Important safety notes i
Observe the "Important safety notes" sec-
tion (Y page 76). G
WARNING
If BAS is malfunctioning, the braking distance
in an emergency braking situation is
increased. There is a risk of an accident.
In an emergency braking situation, depress
the brake pedal with full force. ABS prevents
the wheels from locking.
Braking X
Keep the brake pedal firmly depressed until
the emergency braking situation is over.
ABS prevents the wheels from locking.
The brakes will function as usual once you
release the brake pedal. BAS is deactivated. BAS PLUS (Brake Assist System
PLUS) with Cross-Traffic Assist
General information i
Observe the "Important safety notes" sec-
tion (Y page 76).
BAS PLUS is only available on vehicles with
the Driving Assistance package.
For BAS PLUS to assist you when driving, the radar sensor system and the camera system
must be operational.
With the help of a sensor system and a cam-
era system, BAS PLUS can detect obstacles:
R that are in the path of your vehicle for an
extended period of time
R that cross the path of your vehicle Driving safety systems
77Safety Z

In addition, pedestrians in the path of your
vehicle can be detected.
BAS PLUS detects pedestrians by using typi-
cal characteristics such as the body contours and posture of a person standing upright.
If the radar sensor system or the camera sys-
tem is malfunctioning, BAS PLUS functions
are restricted or no longer available. The
brake system is still available with complete
brake boosting effect and BAS.
i Observe the restrictions described in the
"Important safety notes" sec-
tion“ (Y page 78).
BAS PLUS can help you to minimize the risk of a collision with a vehicle or a pedestrian and
reduce the effects of such a collision. If BAS
PLUS detects a danger of collision, you are
assisted when braking.
Important safety notes G
WARNING
BAS PLUS cannot always clearly identify
objects and complex traffic situations.
In such cases, BAS PLUS may:
R intervene unnecessarily
R not intervene
There is a risk of an accident.
Always pay careful attention to the traffic sit- uation and be ready to brake. Terminate the
intervention in a non-critical driving situation. G
WARNING
BAS PLUS does not react:
R to small people, e.g. children
R to animals
R to oncoming vehicles
R when cornering
As a result, BAS PLUS may not intervene in all
critical situations. There is a risk of an acci-
dent.
Always pay careful attention to the traffic sit- uation and be ready to brake. In the event of snowfall or heavy rain, the rec-
ognition can be impaired.
Recognition by the radar sensor system is
also impaired in the event of:
R there is dirt on the sensors or anything else
covering the sensors
R there is interference by other radar sources
R there are strong radar reflections, for
example in parking garages
R a narrow vehicle traveling in front, e.g. a
motorbike
R a vehicle traveling in front on a different line
R vehicles quickly moving into the radar sen-
sor system detection range
Recognition by the camera system is also
impaired in the event of:
R dirt on the camera or if the camera is cov-
ered
R there is glare on the camera system, e.g.
from the sun being low in the sky
R darkness
R if:
- pedestrians move quickly, e.g. into the
path of the vehicle
- the camera system no longer recognizes
a pedestrian as a person due to special
clothing or other objects
- a pedestrian is concealed by other
objects
- the typical outline of a person is not dis-
tinguishable from the background
Following damage to the front end of the vehi-
cle, have the configuration and operation of
the radar sensors checked at a qualified spe-
cialist workshop. This also applies to colli-
sions at low speeds where there is no visible
damage to the front of the vehicle.
Following damage to the windshield, have the configuration and operation of the camera
system checked at a qualified specialist work- shop. 78
Driving safety systemsSafety

Function
To avoid a collision, BAS PLUS calculates the
brake force necessary if:
R you approach an obstacle, and
R BAS PLUS has detected a risk of collision
When driving at a speed under 20 mph
(30 km/h) : if you depress the brake pedal,
BAS PLUS is activated. The increase in brake pressure will be carried out at the last possi-
ble moment.
When driving at a speed above 20 mph
(30 km/h) : if you depress the brake pedal
sharply, BAS PLUS automatically raises the
brake pressure to a value adapted to the traf-
fic situation.
BAS PLUS provides braking assistance in haz- ardous situations with vehicles in front within
a speed range between 4 mph (7 km/h) and
155 mph (250 km/h).
At speeds of up to approximately 44 mph
(70 km/ h), BAS PLUS can react to:
R stationary objects in the path of your vehi-
cle, e.g. stopped or parked vehicles
R pedestrians in the path of your vehicle
R objects crossing your path and that are
recognized in the detection range of the
sensors
i If BAS PLUS demands particularly high
braking force, preventative passenger pro-
tection measures (PRE-SAFE ®
) are activa-
ted simultaneously.
X Keep the brake pedal depressed until the
emergency braking situation is over.
ABS prevents the wheels from locking.
BAS PLUS is deactivated and the brakes func-
tion as usual again, if:
R you release the brake pedal.
R there is no longer a risk of collision.
R no obstacle is detected in front of your
vehicle.
R you depress the accelerator pedal.
R you activate kickdown. COLLISION PREVENTION ASSIST
PLUS
General information COLLISION PREVENTION ASSIST PLUS con-
sists of a distance warning function with an
autonomous braking function and adaptive
Brake Assist.
COLLISION PREVENTION ASSIST PLUS can
help you to minimize the risk of a front-end
collision with a vehicle ahead or reduce the
effects of such a collision.
If COLLISION PREVENTION ASSIST PLUS
detects that there is a risk of a collision, you
will be warned visually and acoustically. If you do not react to the visual and audible collision
warning, autonomous braking can be initiated in critical situations. If you apply the brake
yourself in a critical situation, the COLLISION PREVENTION ASSIST PLUS adaptive Brake
Assist assists you.
Important safety notes In particular, the detection of obstacles can
be impaired if:
R there is dirt on the sensors or anything else
covering the sensors
R there is snow or heavy rain
R there is interference by other radar sources
R there are strong radar reflections, for
example in parking garages
R a narrow vehicle traveling in front, e.g. a
motorbike
R a vehicle traveling in front on a different line
R new vehicles or after a service on the COL-
LISION PREVENTION ASSIST PLUS system
Observe the notes in the section on break-
ing-in (Y page 188).
Following damage to the front end of the vehi- cle, have the configuration and operation of
the radar sensor checked at a qualified spe-
cialist workshop. This also applies to colli-
sions at low speeds where there is no visible
damage to the front of the vehicle. Driving safety systems
79Safety Z

Distance warning function
Important safety notes
i Observe the "Important safety notes" sec-
tion for driving safety systems (Y page 76).G
WARNING
The distance warning function does not react:
R to people or animals
R to oncoming vehicles
R to crossing traffic
R when cornering
Thus, the distance warning function cannot
provide a warning in all critical situations.
There is a risk of an accident.
Always pay careful attention to the traffic sit-
uation and be ready to brake. G
WARNING
The distance warning function cannot always
clearly identify objects and complex traffic
situations.
In such cases, the distance warning function
may:
R give an unnecessary warning
R not give a warning
There is a risk of an accident.
Always pay careful attention to the traffic sit-
uation and do not rely solely on the distance
warning function.
Function X To activate/deactivate: activate or deac-
tivate the distance warning function in the
on-board computer (Y page 309).
If the distance warning function is not activa-
ted, the æsymbol appears in the assis-
tance graphics display.
The distance warning function can help you to minimize the risk of a front-end collision with
a vehicle ahead or reduce the effects of such
a collision. If the distance warning function
detects that there is a risk of a collision, you
will be warned visually and acoustically. Starting at a speed of around 4 mph (7 km/h),
the distance warning function warns you if
you rapidly approach a vehicle in front. An
intermittent warning tone will then sound,
and the ·distance warning lamp will light
up in the instrument cluster.
X Brake immediately in order to increase the
distance from the vehicle in front.
or
X Take evasive action, provided it is safe to do
so.
Due to the nature of the system, particularly
complicated but non-critical driving condi-
tions may also cause the system to display a
warning.
With the help of the radar sensor system, the
distance warning function can detect obsta-
cles that are in the path of your vehicle for an extended period of time.
Up to a speed of around 44 mph (70 km/h),
the distance warning function can also react
to stationary obstacles, such as stopped or
parked vehicles.
If you approach an obstacle and the distance
warning function detects a risk of a collision,
the system will initially alert you both visually
and acoustically.
Autonomous braking function If the driver does not react to the distance
warning signal in a critical situation, COLLI-
SION PREVENTION ASSIST PLUS can assist
with the autonomous braking function.
The autonomous braking function:
R gives the driver more time to react to criti-
cal driving situations
R can help the driver to avoid an accident or
R reduces the effects of an accident
The autonomous braking function is available in the following speed ranges:
R from 5 mph (7 km/h) to approx. 65 mph
(105 km/ h)for moving objects
R from 5 mph (7 km/h) to approx. 31 mph
(50 km/h) for stationary objects 80
Driving safety systemsSafety

If the autonomous braking function requires a
particularly high braking force, preventative
passenger protection measures (PRE-SAFE ®
)
are activated simultaneously.
Adaptive Brake Assist i
Observe the "Important safety notes" sec-
tion (Y page 76).
Adaptive Brake Assist provides braking assis-
tance in hazardous situations at speeds
above 4 mph (7 km/h). It uses radar sensor
technology to assess the traffic situation. G
WARNING
Adaptive Brake Assist cannot always clearly
identify objects and complex traffic situa-
tions.
In such cases, Adaptive Brake Assist can:
R intervene unnecessarily
R not intervene
There is a risk of an accident.
Always pay careful attention to the traffic sit- uation and be ready to brake. Terminate the
intervention in a non-critical driving situation. G
WARNING
Adaptive Brake Assist does not react:
R to people or animals
R to oncoming vehicles
R to crossing traffic
R when cornering
As a result, the Adaptive Brake Assist may not intervene in all critical conditions. There is a
risk of an accident.
Always pay careful attention to the traffic sit- uation and be ready to brake.
Due to the nature of the system, particularly
complicated but non-critical driving condi-
tions may also cause Brake Assist to inter-
vene.
If adaptive Brake Assist is not available due to a malfunction in the radar sensor system, the brake system remains available with full
brake boosting effect and BAS.
With the help of adaptive Brake Assist, the
distance warning signal can detect obstacles
that are in the path of your vehicle for an
extended period of time.
If adaptive Brake Assist detects a risk of col-
lision with the vehicle in front, it calculates
the braking force necessary to avoid a colli-
sion. If you apply the brakes forcefully, adap-
tive Brake Assist will automatically increase
the braking force to a level suitable for the
traffic conditions.
X Keep the brake pedal depressed until the
emergency braking situation is over.
ABS prevents the wheels from locking.
The brakes will work normally again if:
R you release the brake pedal.
R there is no longer any danger of a collision.
R no obstacle is detected in front of your
vehicle.
Adaptive Brake Assist is then deactivated.
If adaptive Brake Assist demands particularly
high braking force, preventative passenger
protection measures (PRE-SAFE ®
) are activa-
ted simultaneously.
Up to a speed of approximately 155 mph
(250 km/h), adaptive Brake Assist is capable
of reacting to moving objects that have
already been detected as such at least once
over the period of observation.
Up to a speed of approximately 44 mph
(70 km/h), adaptive Brake Assist reacts to
stationary obstacles. ESP
®
(Electronic Stability Program)
General notes i
Observe the "Important safety notes" sec-
tion (Y page 76).
ESP ®
monitors driving stability and traction,
i.e. power transmission between the tires and
the road surface. Driving safety systems
81Safety Z

Observe information regarding indicator and
warning lamps (Y page 358) as well as dis-
play messages (Y page 320).ADAPTIVE BRAKE
ADAPTIVE BRAKE enhances braking safety
and offers increased braking comfort. In addi-
tion to the braking function, ADAPTIVE BRAKE
also has the HOLD function (Y page 242) and
hill start assist (Y page 192). PRE-SAFE
®
Brake
General information i
Pay attention to the important safety
notes in the "Driving safety systems" sec-
tion (Y page 76).
PRE‑SAFE ®
Brake is only available for vehi-
cles with the Driving Assistance package.
For PRE-SAFE ®
Brake to assist you when driv-
ing, the radar sensor system and the camera
system must be switched on and be opera-
tional.
With the help of the radar sensor system and
the camera system, PRE-SAFE ®
Brake can
detect obstacles that are in front of your vehi-
cle for an extended period of time.
In addition, pedestrians in the path of your
vehicle can be detected.
PRE-SAFE ®
Brake detects pedestrians using
typical characteristics such as the body con-
tours and posture of a person standing
upright.
Observe the restrictions described in the
"Important safety notes" sec-
tion“ (Y page 84).
PRE-SAFE ®
Brake can help you to minimize
the risk of a collision with a vehicle ahead or a pedestrian, and reduce the effects of such a
collision. If PRE-SAFE ®
Brake has detected a
risk of collision, you will be warned visually
and acoustically as well as by automatic brak- ing. Important safety notes G
WARNING
PRE-SAFE ®
Brake will initially brake your vehi-
cle by a partial application of the brakes if a
danger of collision is detected. There may be
a collision unless you brake yourself. Even
after subsequent full application of the brakes
a collision cannot always be avoided, partic-
ularly when approaching at too high a speed.
There is a risk of an accident.
Always apply the brakes yourself and try to
take evasive action, provided it is safe to do
so. G
WARNING
PRE-SAFE ®
Brake cannot always clearly iden-
tify objects and complex traffic conditions.
In these cases, PRE-SAFE ®
Brake may:
R give an unnecessary warning and then
brake the vehicle
R not give a warning or intervene
There is a risk of an accident.
Always pay particular attention to the traffic
situation and be ready to brake, especially if
PRE-SAFE ®
Brake warns you. Terminate the
intervention in a non-critical driving situation.
In order to maintain the appropriate distance
to the vehicle in front and thus prevent a col- lision, you must apply the brakes yourself.
PRE-SAFE ®
Brake can also brake the vehicle
automatically under the following conditions:
R the driver and front-passenger have their
seat belts fastened
and
R the vehicle speed is between approx-
imately 4 mph (7 km/h) and 124 mph
(200 km/h)
At a speed of up to approximately 44 mph
(70 km/h), PRE-SAFE ®
Brake can also detect:
R stationary objects in the path of your vehi-
cle, e.g. stopped or parked vehicles
R pedestrians in the path of your vehicle 84
Driving safety systemsSafety