Important safety notes
ATTENTION ASSIST is only an aid. It might not
always recognize fatigue or increasing inatten -
tiveness in time or fail to recognize them at all.
The system is no t asubstitut efor awell-reste d
and attentive driver.
The functionalit yof ATTENTION ASSIST is
restricted and warning smay be delaye dor no t
occur at all:
Rif th elengt hof th ejourney is less than approx -
imately 30 minute s
Rif theroad condition is poor ,e.g. if th esurfac e
is uneven or if there are pothole s
Rif there isastron gside win d
Rif you have adopted asport ydriving style wit h
high cornerin gspeeds or high rates of accel-
eration
Rif you are predominantly driving at aspee d
belo w37 mph (60 km/ h)or above 124 mph
(200 km/h)
Rif you are driving with the DISTRONIC PLUS
Steering Assist activated
Rif the time has been set incorrectly
Rin active driving situations, such as when you
change lanes or change your speed
The attention level evaluation is deleted and
restarts when the journey is continued, if:
Ryou switch off the engine
Ryou take off your seat belt and open the driv-
er's door, e.g. for a change of drivers or to
take a break
Displaying the attention level
You can have current status information dis-
played in the assistance menu (Ypage 203) of
the on-board computer.
XSelect the Assistance display for ATTENTION
ASSIST using the on-board computer
(
Ypage 203). The following information is displayed:
Rlength of the journey since the last break.
Rthe attention level determined by ATTENTION
ASSIST, displayed in a bar display in five levels
from high to low.
Rif ATTENTION ASSIST is unable to calculate
the attention level and cannot output a warn-
ing, the
System Suspended
message
appears. The bar display then changes the
display, e.g. if you are driving at a speed below
37 mph (60 km/h) or above 124 mph
(200 km/h).
Activating ATTENTION ASSIST
XActivate ATTENTION ASSIST using the on-
board computer (Ypage 205).
The system determines the attention level of
the driver depending on the setting selected:
Standard selected: the sensitivity with which
the system determines the attention level is set
to normal.
Sensitive selected: the sensitivity is set higher.
The attention level detected by Attention Assist
is adapted accordingly and the driver is warned
earlier.
When ATTENTION ASSIST is deactivated, the
À symbol and OFF appear in the multifunc-
tion display in the assistance display when the
engine is running.
When ATTENTION ASSIST has been deactivated,
it is automatically reactivated after the engine
has been stopped. The sensitivity selected cor-
responds to the last selection activated (stand-
ard/sensitive).
Warning in the multifunction display
If fatigue or increasing lapses in concentration
are detected, a warning appears in the multi-
function display: Attention
Assist:TakeaBreak!
In addition to the message shown in the multi-
function display, you will then hear a warning
tone.
XIf necessary, take a break.
XConfirm the message by pressing the a
button on the steering wheel.
On long journeys, take regular breaks in good
time to allow yourself to rest. If you do not take
a break, you will be warned again after
15 minutes at the earliest. This will only happen
Driving systems185
Driving and parking
Z
if ATTENTION ASSIST still detects typical indi-
cators of fatigue or increasing lapses in concen-
tration.
Vehicles with COMAND:if a warning is output
in the multifunction display, a service station
search is performed in the multimedia system.
You can select a service station and navigation
to this service station will then begin. This func-
tion can be activated and deactivated in the
multimedia system.
Traffic Sign Assist
General notes
Traffic Sign Assist displays the maximum speed
permitted to the driver in the instrument cluster.
The data stored in the navigation system and
general traffic regulations are used to determine
the current speed limit.
As Traffic Sign Assist is a map-based system,
traffic signs put up temporarily (e.g. near road-
works) are not detected.
If a traffic sign that is relevant to your vehicle is
passed, the display of the speed limits is upda-
ted.
Traffic signs with a restriction indicated by an
additional sign (e.g. in wet conditions) are also
shown.
The traffic signs are only displayed with the
restrictions if:
Rthe regulation must be observed with the
restriction, or
RTraffic Sign Assist is unable to determine
whether the restriction applies
If Traffic Sign Assist is unable to determine a
maximum permitted speed from any of the avail-
able sources, no speed limit is displayed in the
instrument cluster either.
Traffic Sign Assist is not available in all coun-
tries. In this case, symbol :is shown in the
assistance graphic display (
Ypage 203).
Important safety notes
Traffic Sign Assist is only an aid and is not always
able to correctly display speed limits. Traffic
signs always have priority over the Traffic Sign
Assist display.
The system may be either functionally impaired
or temporarily unavailable if the information in
the digital street map of the navigation system is
incorrect or out of date.
Instrument cluster display
Displaying the assistance graphic
XCall up the assistance graphics display func-
tion using the on-board computer
(
Ypage 203).
XSelect the Traffic Sign Assist display.
Detected traffic signs are displayed in the
instrument cluster.
Speed limit with unknown restriction
:Maximum permitted speed
;Maximum permitted speed for vehicles for
which the restriction in the additional sign is relevant
=Additional sign for unknown restriction
A maximum permitted speed of 100 mph
(100 km/h) and a speed limit of 80 km/h
(80 mph) apply with an unknown restriction.
Speed limits in wet conditions
:Maximum permitted speed
;Additional signs for wet conditions
A maximum permitted speed of 80 mph
(80 km/h) applies in wet conditions and if Traffic
186Driving systems
Driving and parking
Sign Assist has determined that the restriction
must be observed.
Canceling the speed limit
The speed limit no longer applies:.
iThe unit for the speed limit (km/h or mph)
depends on the country in which you are driv-
ing. It is generally neither shown on the traffic
sign nor on the instrument cluster but must be
taken into account when observing the max-
imum permitted speed.
Lane Tracking package
General notes
The Lane Tracking package consists of Blind
Spot Assist (Ypage 187) and Lane Keeping
Assist (Ypage 189).
Blind Spot Assist
General notes
Blind Spot Assist uses a radar sensor system to monitor the areas on both sides of your vehicle.
It supports you from a speed of approximately
20 mph (30 km/h). A warning display in the
exterior mirrors draws your attention to vehiclesdetected in the monitored area. If you then
switch on the corresponding turn signal to
change lanes, you will also receive an optical
and audible collision warning. Blind Spot Assist
uses sensors in the rear bumper for monitoring
purposes.
Important safety notes
GWARNING
Blind Spot Assist does not react to:
Rvehicles overtaken too closely on the side,
placing them in the blind spot area
Rvehicles which approach with a large speed
differential and overtake your vehicle
As a result, Blind Spot Assist may not give
warnings in such situations. There is a risk of
an accident.
Always observe the traffic conditions care-
fully, and maintain a safe lateral distance.
Blind Spot Assist is only an aid. It may fail to
detect some vehicles and is no substitute for
attentive driving. Always ensure that there is
sufficient distance to the side for other road
users and obstacles.
iUSA only:
This device has been approved by the FCC as
a "Vehicular Radar System". The radar sensor
is intended for use in an automotive radar
system only. Removing, tampering with, or
altering the device will void any warranties,
and is not permitted by the FCC. Do not tam-
per with, alter, or use in any non-approved
way.
Any unauthorized modification to this device
could void the user’s authority to operate the
equipment.
Monitoring range of the sensors
In particular, the detection of obstacles can be
impaired if:
Rthere is dirt on the sensors or anything else
covering the sensors
Rthere is poor visibility, e.g. due to fog, heavy
rain, snow or spray
Rthere are narrow vehicles, e.g. motorcycles or
bicycles
Rthe road has very wide lanes
Rthe road has narrow lanes
Ryou are not driving in the middle of the lane
Rthere are barriers or similar lane borders
Vehicles in the moni toring ra
nge are then not
indicated.
Driving systems187
Driving and parking
Z
Switching on Blind Spot Assist
XMake sure that Blind Spot Assist
(Ypage 205) is activated in the on-board
computer.
XTurn the SmartKey to position 2in the ignition
lock.
Warning lamps :in the exterior mirrors light
up red for approximately 1.5 seconds and
then turn yellow.
Lane Keeping Assist
General notes
Lane Keeping Assist monitors the area in front of
your vehicle with camera :, which is mounted
at the top of the windshield. Active Lane Keeping
Assist detects lane markings on the road and
can warn you before you leave your lane unin-
tentionally.
This function is available in the range between
40 mph and 120 mph (60 km/h and 200 km/h).
A warning may be given if a front wheel passes
over a lane marking. It will warn you by means of
intermittent vibration in the steering wheel for
up to 1.5 seconds.
Important safety notes
GWARNING
Lane Keeping Assist may not always clearly
recognize lane markings.
In this case, Lane Keeping Assist may:
Rgive an unnecessary warning
Rnot give a warning
There is a risk of an accident.
Always pay particular attention to the traffic
situation and stay in lane, in particular if
warned by Lane Keeping Assist.
GWARNING
The Lane Keeping Assist warning does not
return the vehicle to the original lane. There is
a risk of an accident.
You should always steer, brake or accelerate
yourself, in particular if warned by Lane Keep-
ing Assist.
If you fail to adapt your driving style, Lane Keep-
ing Assist can neither reduce the risk of an acci-
dent nor override the laws of physics. Lane
Keeping Assist cannot take into account the
road, traffic and weather conditions. Lane Keep- ing Assist is merely an aid. You are responsible
for the distance to the vehicle in front, for vehi-
cle speed, for braking in good time and for stay-
ing in your lane.
The Lane Keeping Assist does not keep the vehi-
cle in the lane.
The system may be impaired or may not function
if:
Rthere is poor visibility, e.g. due to insufficient
illumination of the road, or due to snow, rain,
fog or spray
Rthere is glare, e.g. from oncoming traffic, the
sun or reflections (e.g. when the road surface
is wet)
Rthe windshield is dirty, fogged up, damaged or
covered, for instance by a sticker, in the vicin-
ity of the camera
Rthere are no, several or unclear lane markings
for a lane, e.g. in areas with road construction
work
Rthe lane markings are worn away, dark or cov-
ered up, e.g. by dirt or snow
Rthe distance to the vehicle in front is too small and the lane markings thus cannot be detec-
ted
Rthe lane markings change quickly, e.g. lanes
branch off, cross one another or merge
Rthe road is narrow and winding
Rthere are strong shadows cast on the road
Switching on Lane Keeping Assist
XSwitch on Active Lane Keeping Assist using
the on-board computer; to do so, select
Standard
or Adaptive(Ypage 205).
If you drive at speeds above 40 mph
(60 km/h) and lane markings are detected,
the lines in the assistance graphics display
Driving systems189
Driving and parking
Z
(Ypage 203) are shown in green. Lane Keep-
ing Assist is ready for use.
Standard
If Standardis selected, no warning vibration
occurs if:
Ryou have switched on the turn signals. In this
event, the warnings are suppressed for a cer-
tain period of time.
Ra driving safety system intervenes, such as
ABS, BAS or ESP®.
Adaptive
When Adaptiveis selected, no warning vibra-
tion occurs if:
Ryou have switched on the turn signals. In this
event, the warnings are suppressed for a cer-
tain period of time.
Ra driving safety system intervenes, e.g. ABS,
BAS or ESP®.
Ryou accelerate hard, e.g. kickdown.
Ryou brake hard.
Ryou steer actively, e.g. swerve to avoid an
obstacle or change lanes quickly.
Ryou cut the corner on a sharp bend.
In order that you are warned only when neces-
sary and in good time if you cross the lane mark-
ing, the system recognizes certain conditions
and warns you accordingly.
The warning vibration occurs earlier if:
Ryou approach the outer lane marking on a
bend.
Rthe road has very wide lanes, e.g. a highway.
Rthe system recognizes solid lane markings.
The warning vibration occurs later if:
Rthe road has narrow lanes.
Ryou cut the corner on a bend.
Active Driving Assistance package
General notes
The Active Driving Assistance package consists
of DISTRONIC PLUS (Ypage 155), Active Blind
Spot Assist (Ypage 190) and Active Lane Keep-
ing Assist (Ypage 193).
Active Blind Spot Assist
General notes
Active Blind Spot Assist uses a radar sensor
system, pointed toward the rear of the vehicle,
to monitor the area to the sides of the vehicle
which the driver is unable to see. A warning dis- play in the exterior mirrors draws your attention
to vehicles detected in the monitored area. If
you then switch on the corresponding turn sig-
nal to change lane, you will also receive an opti-
cal and audible warning. If a risk of lateral colli-
sion is detected, corrective braking may help
you avoid a collision. Before a course-correcting
brake application, Active Blind Spot Assist eval-
uates the space in the direction of travel and at
the sides of the vehicle. For this, Active Blind
Spot Assist uses the forward-facing radar sen-
sors.
Active Blind Spot Assist supports you from a
speed of approximately 20 mph (30 km/h).
Important safety notes
Active Blind Spot Assist is only an aid and is not
a substitute for attentive driving.
GWARNING
Active Blind Spot Assist does not react to:
Rvehicles overtaken too closely on the side,
placing them in the blind spot area
Rvehicles which approach with a large speed
differential and overtake your vehicle
As a result, Active Blind Spot Assist may nei-
ther give warnings nor intervene in such sit-
uations. There is a risk of an accident.
Always observe the traffic conditions care-
fully, and maintain a safe lateral distance.
iUSA only:
This device has been approved by the FCC as
a "Vehicular Radar System". The radar sensor
is intended for use in an automotive radar
system only. Removing, tampering with, or
altering the device will void any warranties,
and is not permitted by the FCC. Do not tam-
per with, alter, or use in any non-approved
way.
Any unauthorized modification to this device
could void the user’s authority to operate the
equipment.
190Driving systems
Driving and parking
iCanada only: This device complieswit h
RSS -210 of Industry Canada. Operation is
subject to the foll owing two conditions:
1. This device may not cause harmful inter-
ference, and
2. This device must accept any interference
receive d,inc ludin g interference that may
cause undesired operation of the device.
Removal, tampering, or altering of the device
will void any warranties, and isnot permitte d.
Do not tamper with, alter, or use inany non-
approved way.
Any unauthorized mod ification to th isdevice
could void the user's authority to operate the equipm ent.
Radar sensors
The Active BlindSpo t Assist radar sensors are
integrated into the front and rear bumpers and
behind a cover inthe radiator trim. Make sure
that the bumpers and the cover inthe radiator
grill are free of dirt, ice or slush. The rear sensors
must not becovered, for example bycyc leracks
or overhanging cargo. Fol lowing a severe impact
or inthe event of damage to the bumpers, have
the function of the radar sensors checked at a
qualif ied specialist workshop.ActiveBlindSpo t
Assist may otherwise no longer work properly.
Monitoring area
GWARNING
Active Blind Spot Assist does not detect all
traff icsituations and road users. There isa
risk of an acc ident.
Alwa ys make sure that there issuff icientdis-
tance on the side for other traff icor obstacles.
The detection of obstacles can beimpaired in
the case of:
Rthere is dirt on the sensors or anything else
covering the sensors
Rpoor vis ibility, e.g. due to rain, snow or spray
Vehicles inthe monitoring range are then not
indicated or indicated with a delay.
Active Blind Spot Assist may not detect narrow
vehicles, such as motorcycles or bicycles, or
may only detect them too late.
If the lanes are narrow, vehicles driving in the
lane beyond the lane next to your vehicle may be
indicated, especially if the vehicles are not driv- ing inthe midd le of their lane. This may be the
case ifthere are vehicles at the edge of their
lane.
Due to the nature of the system:
Rwarnings may be issued inerror when driving
close to crash barriers or similar solid lane
borders.
Rthe warning is canceled when driving for an
extended period next to long vehicles, such as
trucks.
Driving systems191
Driving and parking
Z
RESP®is switched off.
Ra loss of tire pressure or a defective tire is
detected.
Switching on Active Blind Spot Assist
XMake sure that Active Blind Spot Assist
(Ypage 205) is activated in the on-board
computer.
XTurn the SmartKey to position 2in the ignition
lock.
Warning lamps :in the exterior mirrors light
up red for approximately 1.5 seconds and
then turn yellow.
Active Lane Keeping Assist
General notes
Active Lane Keeping Assist monitors the area in
front of your vehicle by means of multifunction
camera :at the top of the windshield. Various
different areas to the front, rear and side of your
vehicle are also monitored with the aid of the
radar sensor system. Active Lane Keeping
Assist detects lane markings on the road and
can warn you before you leave your lane unin-
tentionally. If you do not react to the warning, a
lane-correcting application of the brakes can
bring the vehicle back into the original lane.
This function is available in the range between
40 mph and 120 mph (60 km/h and 200 km/h).
For Active Lane Keeping Assist to assist you
when driving, the radar sensor system must be
operational
Important safety notes
If you fail to adapt your driving style, Active Lane
Keeping Assist can neither reduce the risk of
accident nor override the laws of physics. Active
Lane Keeping Assist cannot take account of
road and weather conditions. It may not recog- nize traffic situations. Active Lane Keeping
Assist is only an aid. You are responsible for the
distance to the vehicle in front, for vehicle
speed, for braking in good time and for staying in
you
r lane.
Active Lane Keeping Assist cannot continuously
keep your vehicle in its lane.
GWARNING
Active Lane Keeping Assist cannot always
clearly detect lane markings.
In such cases, Active Lane Keeping Assist
can:
Rgive an unnecessary warning and then
make a course-correcting brake application
to the vehicle
Rnot give a warning or intervene
There is a risk of an accident.
Always pay particular attention to the traffic
situation and keep within the lane, especially
if Active Lane Keeping Assist alerts you. Ter-
minate the intervention in a non-critical driv-
ing situation.
The system may be impaired or may not function
if:
Rthere is poor visibility, e.g. due to insufficient
illumination of the road, or due to snow, rain,
fog or spray
Rthere is glare, e.g. from oncoming traffic, the
sun or reflections (e.g. when the road surface
is wet)
Rthe windshield is dirty, fogged up, damaged or
covered, for instance by a sticker, in the vicin-
ity of the camera
Rthe radar sensors in the front or rear bumpers
or the radiator trim are dirty, e.g. obscured by
snow
Rthere are no, several or unclear lane markings
for a lane, e.g. in areas with road construction
work
Rthe lane markings are worn away, dark or cov-
ered up, e.g. by dirt or snow
Rthe distance to the vehicle in front is too small
and the lane markings thus cannot be detec-
ted
Rthe lane markings change quickly, e.g. lanes
branch off, cross one another or merge
Driving system s193
Driving an d parking
Z
Rthe road is narrow and winding
Rthere are strong shadows cast on the road
If no vehicle is detected in the adjacent lane and
broken lane markings are detected, no lane-cor-
recting brake application is made.
Warning vibration in the steering wheel
A warning may be given if a front wheel passes
over a lane marking. It will warn you by means of
intermittent vibration in the steering wheel for
up to 1.5 second s.
Lane-correcting brake application
GWARNING
A lane-correcting brake application cannot
always bring the vehicle back into the original lane. There is a risk of an accident.
Always steer, brake or accelerate yourself,
especially if Active Lane Keeping Assist warns
you or makes a lane-correcting brake appli-
cation.
GWARNING
Active Lane Keeping Assist only detects traf-
fic conditions or road users to a limited
extent. In very rare cases, the system may
make an inappropriate brake application, e.g. after intentionally driving over a solid lane
marking. There is a risk of an accident.
An inappropriate brake application may be
interrupted at any time if you steer slightly in
the opposite direction. Always make sure that
there is sufficient distance on the side for
other traffic or obstacles.
If you leave your lane, under certain circumstan-
ces the vehicle will brake briefly on one side.
This is meant to assist you in bringing the vehicle
back to the original lane.
If a lane-correcting brake application occurs,
display :appears in the multifunction display. A lane-correcting brake application can be made
after driving over a lane marking recognize as
being solid or broken. Before this, a warning
must be given by means of intermittent vibration
in the steering wheel. In addition, a lane with
lane markings on both sides must be recog-
nized.
In the case of a broken lane marking being
detected, a lane-correcting brake application
can only be made if a vehicle has been detected
in the adjacent lane. The following vehicles can
have an influence on brake application: oncom-
ing traffic, vehicles that are overtaking and vehi-
cles that are driving parallel to your vehicle.
iA further lane-correcting brake application
can only occur after your vehicle has returned
to the original lane.
No lane-correcting brake application occurs if:
Ryou clearly and actively steer, brake or accel-
erate.
Ryou cut the corner on a sharp bend.
Ryou have adopted a sporty driving style with
high cornering speeds or high rates of accel-
eration.
Ryou have switched on the turn signal.
Ra driving safety system intervenes, e.g. ESP®,
PRE-SAFE®Brake or Active Blind Spot Assist.
RESP®is switched off.
Rthe transmission is not in position D.
Ran obstacle has been detected in the lane in
which you are driving.
Rwhen a loss of tire pressure or a defective tire
has been detected and displayed.
There is a possibility that the Active Lane Keep- ing Assist could misjudge the given traffic sit-
uation. An inappropriate brake application may
be interrupted at any time if you:
Rsteer slightly in the opposite direction.
Rswitch on the turn signal.
Rclearly brake or accelerate.
A lane-correcting brake application is interrup-
ted automatically if:
Ra driving safety system intervenes, e.g. ESP®,
PRE-SAFE®Brake or Active Blind Spot Assist.
Rlane markings can no longer be recognized.
194Driving systems
Driving and parking