
Method of 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:
Rduration
Rdirection
Rintensity
Based on the evaluation of this data, the
restraint system control unit triggers the Emer-
gency Tensioning Devices during a frontal or
rear collision.
An Emergency Tensioning Device can only be
triggered, if:
Rthe ignition is switched on
Rthe components of the restraint system are
operational. You can find further information
under: "Restraint system warning lamp"
(
Ypage 42)
Rthe belt tongue is engaged in the buckle on
the respective front-passenger seat
The Emergency Tensioning Devices in the rear
compartment are triggered independently of the
lock status of the seat belts.
If the restraint system control unit detects a
more severe accident, further components of
the restraint system are activated independ-
ently of each other in certain frontal collision
situations:
RFront air bags as well as driver's and front-
passenger knee bags
RHead bag, if the system determines that
deployment can offer additional protection to
that provided by the seat belt
The front-passenger front air bag is activated or
deactivated depending on the person on the
front-passenger seat. The front-passenger front
air bag can only deploy in an accident if the
PASSENGER AIR BAG OFF indicator lamp is off. Observe the information on the PASSENGER AIR
BAG indicator lamps (
Ypage 42).
Your vehicle has two-stage front air bags. During
the first deployment stage, the front air bag is
filled with propellant gas to reduce the risk of
injuries. The front air bag is fully deployed with
the maximum amount of propellant gas if a sec-
ond deployment threshold is reached within a
few milliseconds.
The activation threshold of the Emergency Ten-
si
oning Devices and the air bag are determined
by evaluating the rate of vehicle deceleration or acceleration which occurs at various points in
the vehicle. This process is pre-emptive in
nature. Deployment 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:
Rthe distribution of forces during the collision
Rthe collision angle
Rthe deformation characteristics of the vehicle
Rthe 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 air bag. Nor do
they provide an indication of air bag deploy-
ment.
The vehicle can be deformed considerably, with-
out an air bag 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, air bags may be deployed even
though the vehicle suffers only minor deforma-
tion. This is the case if, for example, very rigid
vehicle parts such as longitudinal body mem-
bers are hit, and sufficient deceleration occurs
as a result.
If the restraint system control unit detects a side
impact or if the vehicle rolls over, the applicable
components of the restraint system are activa-
ted independently of each other depending on
the apparent type of accident.
RSide impact air bags on the side of impact,
independently of the Emergency Tensioning
Device and the use of the seat belt on the
driver's seat and in the rear compartment
seats
The side impact air bag on the front-
passenger side deploys under the following
conditions:
-the OCS system detects that the front-
pa
ssenger seat is occupied or
-the belt tongue is engaged in the belt
buckle of the front-passenger seat
RHead bag on the side of impact, independ-
ently of the use of the seat belt and inde-
pendently of whether the front-passenger
seat is occupied
Occupant safety55
Safety
Z

REmergency Tensioning Devices, if the systemdetermines that deployment can offer addi-
tional protection in this situation
RHead 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 additional protec-
tion to that provided by the seat belt
iNot all air bags are deployed in an accident.
The different air bag systems work independ-
ently of each other.
How the air bag system works is determined
by the severity of the accident detected,
especially the vehicle deceleration or accel-
eration and the apparent type of accident:
RFrontal collision
RSide impact
RRollover
PRE-SAFE®(anticipatory occupant
protection system)
Introduction
In certain hazardous situations, PRE-SAFE®
takes pre-emptive measures to protect the vehi-
cle occupants.
Important safety notes
!Make sure that there are no objects in the
footwell or behind the seats. There is a danger that the seats and/or objects could be dam-
aged when PRE-SAFE
®is activated.
Despite your vehicle being equipped with the
PRE-SAFE
®system, the possibility of personal
injuries occurring as a result of an accident can-
not be eliminated. Always adapt your driving
style to suit the prevailing road and weather
conditions and maintain a safe distance from
the vehicle in front. Drive carefully.
Function
PRE-SAFE®intervenes:
Rin emergency braking situations, e.g. when
BAS is activated
Rin critical driving situations, e.g. when physi-
cal limits are exceeded and the vehicle under-
steers or oversteers severely
Rvehicles with the Driving Assistance package:
when a driver assistance system intervenes
powerfully or the radar sensor system detects
an imminent danger of collision in certain sit- uations
PRE-SAFE
®takes the following measures
depending on the hazardous situation detected:
Rthe front seat belts are pre-tensioned.
Rif the vehicle skids, the front side windows are
closed.
Rthe front-passenger seat is adjusted if it is in
an unfavorable position.
Rvehicles with a multicontour seat: the air pres-
sure in the side bolsters of the seat backrest
is increased.
If the hazardous situation passes without result-
ing in an accident, PRE-SAFE
®slackens the belt
pre-tensioning. On vehicles with multicontour
seats, the air pressure in the side bolsters is
reduced again. All settings made by PRE-SAFE
®
can then be reversed.
If the seat belt pre-tensioning is not reduced:
XMove the seat backrest or seat back slightly
when the vehicle is stationary.
The s
eat 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. Informa-
tion about the convenience function can be
found under "Belt adjustment" (
Ypage 46).
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 hazardous sit-
56Occupant safety
Safety

uations, PRE-SAFE®PLUS takes pre-emptive
measures to protect the veh icleoccupants.
Important safety notes
The intervention of PRE-SAFE®PLUS cannot
prevent an imminent co llision.
The driverisnot warned when PRE-SAFE
®PLUS
intervenes.
PRE-SAFE
®PLUS does not intervene ifthe veh i-
cle isbacking up.
When driving, or when parking or exiting a park-
ing space with assistance from Active Parking
Assist, PRE-SAFE
®PLUS willnotapply the
brakes.
Function
PRE-SAFE®PLUS intervenes incertain situa-
tions ifthe radar sensor system detects an
imminent head-on or rear-end co llision.
PRE-SAFE
®PLUS takes the foll owing measures
dependin g on the hazardous situation detected:
Rifthe radar sensor system detects that a
head-on co llisionis imminent, the seat belts
are pre-tensioned.
Rif the radar sensor system detects that a rear-
end co llisionis imminent:
-the brake pressure isincreased ifthe driv er
applies the brakes when the veh icle issta-
tionary.
-the seat belts are pre-tensioned.
The PRE-SAFE®PLUS braking applicationiscan-
celed:
Rif the accelerator pedal is depressed when a
gear isengaged
Rifthe risk of a co llision passes or isno longer
detected
Rif DI ST RONIC PLUS indicates an intention to
pull away
If the hazardous situation passes without result-
ing inan acc ident, the original settings are
restored.
Automatic measures after an acci-
dent
Im mediate lyafter an accident, the foll owing
measures are implemented, depending on the
type and severity of the impact:
Rthe hazard warning lamps are activated
Rthe emergency lighting is activated
Rthe vehicle doors are unlocked
Rthe front side wind ows are lowered
Rthe electrically adjustable steering wheel is
raised
Rthe engine is switched off and the fuel supply
is cut off
Rvehicles with mbrace: automatic emergency
call
Children in the vehicle
Important safety notes
Accident statistics show that ch ildren secured
in the rear seats are safer than ch ildren secured
in the front-passenger seat. For this reason,
Mercedes-Benz strongly advises that you install
a child restraint system on a rear seat. Children
are generally better protected there.
If a child younger than twelve years old and
under 5 ft (1.50 m) in height is traveling in the
vehicle:
Ralways secure the child ina child restraint
system suitable for Mercedes-Benz vehicles.
The child restraint system must be appropri-
ate to the age, weight and size of the child
Rbe sure to observe the instructions and safety
notes inthis section inaddition to the child
restraint system manufacturer's installation
instructions
Rbe sure to observe the instructions and safety
notes on the "Occupant classification system
(OCS)" (
Ypage 49)
GWARNING
If you leave children unsupervised in the vehi-
cle, they could set it inmotion by, for example:
Rrelease the parking brake.
Rshift the automatic transmission out of the
parking position P.
Rstart the engine.
Children in the vehicle57
Safety
Z

In addition, they may operate vehicle equip-
ment and become trapped. There is a risk of
an accident and injury.
When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. Never
leave children unsupervised in the vehicle.
GWARNING
If persons, particularly children are subjected to prolonged exposure to extreme heat or
cold, there is a risk of injury, possibly even
fatal. Never leave children unattended in the
vehicle.
GWARNING
If the child restraint system is subjected to
direct sunlight, parts may get very hot. Chil-
dren may burn themselves on these parts,
particularly on the metal parts of the child
restraint system. There is a risk of injury.
If you leave the vehicle, taking the child with
you, always ensure that the child restraint
system is not exposed to direct sunlight. Pro- tect it with a blanket, for example. If the child
restraint system has been exposed to direct
sunlight, let it cool down before securing the
child in it. Never leave children unattended in
the vehicle.
Always ensure that all vehicle occupants have
their seat belts fastened correctly and are sitting
properly. Particular attention must be paid to
children.
Observe the safety notes on the seat belt
(
Ypage 43) and the notes on correct use of seat
belts (Ypage 44).
A booster seat may be necessary to achieve
proper seat belt positioning for children over
41 lbs (18 kg) until they reach a height where a
three-point seat belt can be properly fastened
without a booster seat.
Special seat belt retractor
GWARNING
If the seat belt is released while driving, the
child restraint system will no longer be
secured properly. The special seat belt retrac- tor is disabled and the inertia real draws in a
portion of the seat belt. The seat belt cannot
be immediately refastened. There is an
increased risk of injury, possibly even fatal.
Stop the vehicle immediately, paying atten-
tion to road and traffic conditions. Reactivate
the special seat belt retractor and secure the
child restraint system properly.
All seat belts except the driver's seat belt are
equipped with a special seat belt retractor.
When activated, the special seat belt retractor
ensures that the seat belt will not slacken once
the child restraint system has been secured.
Installing a child restraint system:
XAlways comply with the child restraint system
manufacturer's installation instructions.
XPull the front seat belt smoothly out of the
seat-belt extender and the rear seat belt out
of the belt outlet.
XEngage the seat belt tongue in the belt buckle.
Activating the special seat belt retractor:
XPull the seat belt out fully and let the inertia
reel retract it again.
While the seat belt is retracting, you should
hear a ratcheting sound. The special seat belt
retractor is activated.
XPush the child seat restraint system down so
that the seat belt is tight and does not loosen.
Removing a child restraint system and deacti-
vating the special seat belt retractor:
XAlways comply with the child restraint system
manufacturer's installation instructions.
XPress the release button of the belt buckle,
hold the belt tongue firmly and guide it back to
the seat-belt extender in the front and the belt
outlet in the rear.
The special seat belt retractor is deactivated.
Child restraint system
The use of seat belts and child restraint systems
is required by law in:
Rall 50 states
Rthe U.S. territories
Rthe District of Columbia
Rall Canadian provinces
58Children in the vehicle
Safety

correctly routed from the seat-belt extender of
the front-passenger seat to the shoulder belt
guide on the child restraint system. The shoul-
der belt strap must be routed forwards from the
retracted seat-belt extender for the front-
passenger seat.
Always observe the child restraint system man-
ufacturer's installation and operating instruc-
tions.
Pets in the vehicle
GWARNING
If you leave animals unattended or unsecured
in the vehicle, they could press buttons or
switches, for example.
As a result, they could:
Ractivate vehicle equipment and become
trapped, for example
Ractivate or deactivate systems, thereby
endangering other road users
Unsecured animals could also be flung around
the vehicle in the event of an accident or sud-
den steering or braking, thereby injuring vehi-
cle occupants. There is a risk of an accident
and injury.
Never leave animals unattended in the vehi-
cle. Always secure animals properly during
the journey, e.g. use a suitable animal trans-
port box.
Driving safety systems
Overview of driving safety systems
In this section, you will find information about
the following driving safety systems:
RABS ( Anti-lock Braking System)
(Ypage 61)
RBAS ( Brake Assist System) (Ypage 62)
RBAS PLUS ( BrakeAssist System PLUS) with
Cross-Traffic Assist (Ypage 62)
RCOLLISION PREVENTION ASSIST PLUS
(Ypage 64)
RESP®( E lectronic StabilityProgram)
(Ypage 66)
REBD ( Electronic Brake force Distribution)
(Ypage 68)
RADAPTIVE BRAKE (Ypage 68)
RPRE-SAFE®Brake (Ypage 68)
RSTEER CONTROL (Ypage 70)
Important safety notes
If you fail to adapt your driving style or if you are
inattentive, the driving safety systems can nei-
ther reduce the risk of an accident nor override
the laws of physics. Driving safety systems are
merely aids designed to assist driving. You are
responsible for maintaining the distance to the
vehicle in front, for vehicle speed, for braking in good time, and for staying in lane. Always adapt
your driving style to suit the prevailing road and weather conditions and maintain a safe distance
from the vehicle in front. Drive carefully.
The driving safety systems described only work as effectively as possible when there is ade-
quate contact between the tires and the road
surface. Pay particular attention to the informa-
tion regarding tires, recommended minimum
tire tread depths etc. in the "Wheels and tires"
section (
Ypage 302).
In wintry driving conditions, always use winter
tires (M+S tires) and if necessary, snow chains.
Only in this way will the driving safety systems
described in this section work as effectively as
possible.
ABS (Anti-lock Braking System)
General information
ABS regulates brake pressure in such a way that the wheels do not lock when you brake. This
allows you to continue steering the vehicle when
braking.
The ! ABS warning lamp in the instrument
cluster lights up when the ignition is switched
on. It goes out when the engine is running.
ABS works from a speed of about 5 mph
(8 km/h), regardless of road-surface conditions.
ABS works on slippery surfaces, even when you
only brake gently.
Driving safety systems61
Safety
Z

Important safety notes
iObserveth e"Importan tsafet ynotes" sec -
tion (Ypage 61).
GWARNIN G
If AB Sis faulty, th ewheels could loc kwhen
braking .The steerabilit yand braking charac -
teristics may be severely impaired .Addition -
ally, further driving safet ysystems are deac -
tivated. Ther eis an increased danger of skid-
din gand accidents .
Drive on carefully. Hav eAB Schecke dimme-
diately at aqualified specialist workshop.
When AB Sis malfunctioning ,other systems ,
includin gdriving safet ysystems ,will also
become inoperative. Observ eth einformation
on th eAB Swarning lamp (
Ypage 235) and dis-
play message swhic hmay be shown in th e
instrumen tcluste r (
Ypage 205).
Braking
XIf ABS intervenes: continue to depress th e
brak epedal vigorously until th ebraking sit -
uation is over.
XTo make afull brak eapplication: depress
th ebrak epedal wit hfull force .
If AB Sintervenes when braking ,you will fee l a
pulsing in th ebrak epedal .
The pulsating brak epedal can be an indication
of hazardous road conditions, and function sas a
reminder to tak eextr acar ewhile driving .
BAS (Brake Assist System)
General information
BA Soperate sin emergenc ybraking situations.
If you depress th ebrak epedal quickly, BA S
automatically boosts th ebraking force ,thus
shortening th estopping distance.
Important safety notes
iObserv eth e"Importan tsafet ynotes" sec -
tion (Ypage 61) .
GWARNIN G
If BA Sis malfunctioning ,th ebraking distanc e
in an emergenc ybraking situation is
increased. Ther eis aris kof an accident.
In an emergenc ybraking situation ,depress
th ebrak epedal wit hfull force .AB Sprevents
th ewheels from locking.
Brakes
XKee pth ebrak epedal firmly depressed until
th eemergenc ybraking situation is over.
AB Sprevents th ewheels from locking.
The brakes will function as usual once you
release th ebrak epedal .BA Sis deactivated.
BAS PLUS (Brake Assist System
PLUS) with Cross-Traffic Assist
General information
BA SPLU Scan help you to minimiz eth eris kof a
collision wit h avehicl eor apedestrian and
reduce th eeffects of suc h acollision .If BA S
PLU Sdetects adanger of collision ,you are
assisted when braking .
iPay attention to theimportant safet ynote s
in th e"Drivin gsafet ysystems "section
(
Ypage 61).
BA SPLU Sis only available in vehicles wit hth e
Drivin gAssistanc ePlus package.
Fo rBA SPLU Sto assist you when driving ,th e
radar sensor system and th ecamera system
must be operational.
Wit hth ehelp of asensor system and acamera
system, BA SPLU Scan detec tobstacles:
Rthat are in th epat hof your vehicl efor an
extended period of time
Rthat cross th epat hof your vehicl e
In addition ,pedestrian sin th epat hof your vehi-
cle can be detected.
BA SPLU Sdetects pedestrian sby usin gtypical
characteristics suc has th ebody contours and
postur eof aperson standing upright .
If th eradar sensor system or th ecamera system
is malfunctioning ,BA SPLU Sfunction sare
restricted or no longer available. The brak esys-
te m is still available wit hcomplete brak eboost-
ing effec tand BAS.
62Driving safety systems
Safety

At speeds of up to approximately 44 mph
(70 km/h), BAS PLUS can react to:
Rstationary objects in the path of your vehicle,
e.g. stopped or parked vehicles
Rpedestrians in the path of your vehicle
Robstacles crossing your path, which move in
the detection range of the sensors and are
recognized by them
iIf BAS PLUS demands particularly high brak-
ing force, preventative passenger protection
measures (PRE-SAFE
®) are activated simulta-
neously (Ypage 56).
XKeep 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, if:
Ryou release the brake pedal.
Rthere is no longer a risk of collision.
Rno obstacle is detected in front of your vehi-
cle.
Ryou depress the accelerator pedal.
Ryou activate kickdown.
COLLISION PREVENTION ASSIST
PLUS
General information
COLLISION PREVENTION ASSIST PLUS consists
of a distance warning function with an autono-
mous 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:
Rthere is dirt on the sensors or anything else
covering the sensors
Rthere is snow or heavy rain
Rthere is interference by other radar sources
Rthere are strong radar reflections, for exam-
ple in parking garages
Ra narrow vehicle is traveling in front, e.g. a
motorbike
Ra vehicle is traveling in front on a different line
Rthe vehicle is new or after a service on the
COLLISION PREVENTION ASSIST PLUS sys-
tem
Observe the notes in the section on breaking-
in (
Ypage 123).
Following damage to the front end of the vehicle,
have the configuration and operation of the
radar sensor checked at a qualified specialist
workshop. This also applies to collisions at slow
speeds where there is no visible damage to the
front of the vehicle.
Activating/deactivating
The COLLISION PREVENTION ASSIST PLUS is
automatically active after switching on the igni-
tion.
You can activate or deactivate COLLISION PRE-
VENTION ASSIST PLUS in the on-board com-
puter (
Ypage 199). When deactivated, the dis-
tance warning function and the autonomous
braking function are also deactivated.
If COLLISION PREVENTION ASSIST PLUS is
deactivated, the æsymbol appears in the
assistance graphics display.
Distance warning function
General information
iObserve the "Important safety notes" sec-
tion for driving safety systems (Ypage 61).
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.
With the help of the radar sensor system, the
distance warning function can detect obstacles
that are in the path of your vehicle for an exten-
ded period of time.
64Driving safety systems
Safety

If adaptive Brake Assist demands particularly
high braking force, preventative passenger pro-
tection measures (PRE-SAFE
®) are activated
simultaneously (Ypage 56).
XKeep the brake pedal depressed until the
emergency braking situation is over.
ABS prevents the wheels from locking.
The brakes will work normally again if:
Ryou release the brake pedal.
Rthere is no longer any danger of a collision.
Rno obstacle is detected in front of your vehi-
cle.
Adaptive Brake Assist is then deactivated.
Important safety notes
GWARNING
Adaptive Brake Assist cannot always clearly
identify objects and complex traffic situa-
tions.
In such cases, Adaptive Brake Assist can:
Rintervene unnecessarily
Rnot 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.
GWARNING
Adaptive Brake Assist does not react:
Rto people or animals
Rto oncoming vehicles
Rto crossing traffic
Rwhen 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 conditions
may also cause Brake Assist to intervene.
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.
ESP®(Electronic Stability Program)
General notes
iObserve the "Important safety notes" sec-
tion (Ypage 61).
ESP
®monitors driving stability and traction, i.e.
power transmission between the tires and the
road surface.
If ESP
®detects that the vehicle is deviating from
the direction desired by the driver, one or more
wheels are braked to stabilize the vehicle. The
engine output is also modified to keep the vehi-
cle on the desired course within physical limits.
ESP
®assists the driver when pulling away on
wet or slippery roads. ESP®can also stabilize
the vehicle during braking.
ETS/4ETS (Electronic Traction System)
iObserve the "Important safety notes" sec-
tion (Ypage 61).
ETS traction control is part of ESP
®. On vehicles
with 4MATIC, 4ETS is part of ESP®.
Traction control brakes the drive wheels indi-
vidually if they spin. This enables you to pull
away and accelerate on slippery surfaces, for
example if the road surface is slippery on one
side. In addition, more drive torque is transfer-
red to the wheel or wheels with traction.
Traction control remains active, even if you
deactivate ESP
®.
Important safety notes
GWARNING
If ESP
®is malfunctioning, ESP®is unable to
stabilize the vehicle. Additionally, further driv-
ing safety systems are deactivated. This
increases the risk of skidding and an accident.
Drive on carefully. Have ESP
®checked at a
qualified specialist workshop.
If the å ESP
®OFF warning lamp lights up
continuously, then ESP®is deactivated.
If the ÷ ESP®warning lamp lights up contin-
uously, ESP®is not available due to a malfunc-
tion.
Observe the information on warning lamps
(
Ypage 235) and display messages which may
66Driving safety systems
Safety