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Driving and operating215Note
Speed limit signs which are
combined with add-on signs, e.g.
time, weather or vehicle type
limitations, are not considered by
this system.
Note
The driver stays fully responsible for
driving conform to speed limits and
has to supervise any automatic set
speed change performed by this
system.
Due to system limitations and
latencies, the set speed might be
changed after entering the road
section with the new speed limit.
Speed limit signs between 30 km/h
and 150 km/h are considered.
Switching on the system
The function can be activated or
deactivated in the vehicle settings
menu of the Driver Information Centre
3 112. Furthermore, adaptive cruise
control has be to switched on as
described above.Usage
Even if adaptive cruise control is
inactive, the set speed is updated
automatically at each new detected
speed limit as described in the next
section. Press RES+ to re-activate
adaptive cruise control, using the
memorised set speed.
Note
Adaptive cruise control has to be
initiated once by pressing SET- after
ignition or just adaptive cruise
control has been is switched on.
If adaptive cruise control is active, the detected speed limit will be displayed in the Driver Information Centre. The
driver can accept or decline the
detected new set speed while the
display message is shown.
Press SET- on the steering wheel to
accept the detected speed limit and
take over as new set speed.
Press RES+ to decline detected
speed limit and keep the current set
speed.
If no action is performed when the
message is displayed, the detected
speed limit is taken over as new setspeed automatically after 3 seconds.
The message disappears and is
followed by the offset message:
If a new set speed was defined, a confirmation message is displayed.
During this time, the offset from the
set speed can be adjusted.
Press SET- or RES+ to adjust the
offset.
If no action is performed while the
message is displayed, the last set
offset will be used and the message
disappears after 3 seconds.
The new set speed including offset is displayed in the Driver Information
Centre.
System limitations
Intelligent adaptive cruise control has
the same limitations as the traffic sign assistant 3 240.
Implicit speed limits may be
considered with a delay, e.g. city entry, city exit, or highway entry signs.
The system may ignore a particular
traffic sign or use a wrong speed limit.
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216Driving and operatingA new speed limit from the navigationmay be taken over automatically after
a certain distance since the last
detected traffic sign or when entering
a new road segment, e.g. road exits
or round-abouts.
Forward collision alert
The forward collision alert is part of
the forward collision system 3 124. It
can help to avoid or reduce the harm
caused by front-end crashes.
A vehicle ahead is indicated by the
control indicator A.
Additionally, the status of the forward
collision alert is indicated on the
Driver Assistance page in the Driver
Information Center 3 112.
If the vehicle is equipped with
conventional cruise control, the
forward collision alert uses the front
camera in the windscreen to detect a
vehicle directly ahead, in your path.
If the vehicle is equipped with
adaptive cruise control, the forward
collision alert uses the radar sensor
and front camera to detect a vehicle
directly ahead, in your path.A precondition is that forward collision
alert in the vehicle personalisation
menu is not deactivated 3 124.
Activation
Forward collision alert with front
camera detects vehicles to distances
of approximately 60 metres and
operates automatically at all speeds
above walking speed.
Forward collision alert with radar
sensor detects vehicles to distances
of approximately 150 metres and
operates automatically at all speeds
above walking speed.
Alerting the driver
The vehicle ahead control indicator
A illuminates green in the instrument
cluster when the system has detected
a vehicle in the driving path. On
vehicles with head-up display, A is
projected on the windscreen.
The control indicator A changes to
amber when the distance to a
preceding moving vehicle gets too
small.Caution
The colour lighting of this control
indicator does not correspond to
local traffic laws on following
distance. The driver bears full
responsibility for maintaining safe
following distance according to
applicable traffic rules, weather
and road conditions etc. at all
times.
When the time to a potential collision
with a vehicle in front gets too small
and a collision is imminent, the
collision alert symbol pops-up in the
Driver Information Centre and the
driver gets notified by a flashing red
LED stripe or the pop-up symbol in
the head-up display which is
projected on the windscreen in the
driver's field of view.
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Driving and operating217
Simultaneously a warning chime
sounds. Depress the brake pedal and
steer the vehicle, if it is required by the
situation.
Indication on Driver Assistance page
A symbol of a preceding vehicle
appears in grey when a vehicle was
detected.
The symbol turns amber when the
distance gets too small.
The symbol turns red if a collision is
imminent.
Selecting the alert sensitivity Press K to set the alert sensitivity to
near, medium or far.
The first button press shows the
current setting on the Driver
Information Centre. Additional button
presses will change this setting. The
chosen setting will remain until it is
changed. The alert timing will vary
based on vehicle speed. The faster the vehicle speed, the farther awaythe alert will occur. Consider traffic
and weather conditions when
selecting the alert timing.
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218Driving and operating
Note that the alert timing sensitivity
setting is shared with the following distance setting of the adaptive cruise control. So changing the alert timing
sensitivity changes the adaptive
cruise control following distance
setting.
Indication on Driver Assistance page
Deactivation
The system can be deactivated in the
personalisation menu, 3 124.
If the forward collision alert was
deactivated, alert sensitivity is set to
"medium" when ignition is switched on next time.
The last selected setting will be stored
when the ignition is switched off.
General information9 Warning
Forward collision alert is just a
warning system and does not
apply the brakes. When
approaching a vehicle ahead too
rapidly, it may not provide you
enough time to avoid a collision.
The driver accepts full
responsibility for the appropriate
following distance based on traffic, weather and visibility conditions.
The complete attention of the
driver is always required while
driving. The driver must always be
ready to take action and apply the
brakes.
System limitations
Forward collision alert is designed to warn on vehicles only, but may reactalso to other objects.
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Driving and operating219In the following cases, Forward
collision alert may not detect a vehicle
ahead or sensor performance is
limited:
● Driving on winding or hilly roads.
● During nighttime driving.
● Weather limits visibility, such as fog, rain, or snow
● The sensor in the windscreen is blocked by snow, ice, slush, mud,dirt, windscreen damage or
affected by foreign items, e.g.
stickers.
Following distance indication
The following distance indication
displays the distance to a preceding
moving vehicle. The front camera in
the windscreen is used to detect the
distance of a vehicle directly ahead in
the vehicle's path. It is active at
speeds above 40 km/h.
When a preceding vehicle is detected
ahead, the distance is indicated in
seconds, displayed on a page in the
Driver Information Centre.On Baselevel display, choose Info
Menu ? via MENU on the turn
signal lever and turn the adjuster wheel to choose following distance
indication page, 3 112
On Mid- and Uplevel display, select
Info menu via steering wheel buttons
and press å to select following
distance indication 3 112.
The minimum indicated distance is 0.5 seconds.
If there is no vehicle ahead or the vehicle ahead is out of range, two
dashes will be displayed: -.- sec.
If Adaptive cruise control is active,
this page shows the alert sensitivity
setting instead of following distance
setting. 3 206.
System limitations In the following cases, following
distance indication sensor
performance is limited:
● Driving on winding or hilly roads.
● During nighttime driving.
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220Driving and operating● Weather limits visibility, such asfog, rain, or snow.
● The sensor is blocked by snow, ice, slush, mud, dirt, windscreen
damage or affected by foreign
items, e.g. stickers.
Active emergency braking
Active emergency braking is part of
the forward collision system 3 124. It
can help to reduce the damage and
injury from crashes with vehicles,
pedestrians and obstacles directly
ahead, when a collision can no longer be avoided either by manual braking
or by steering. Before the active
emergency braking applies, the driver is warned by the Forward collision
alert 3 216 or the Front pedestrian
protection alert 3 223.
The feature uses various inputs (e.g.
camera sensor, radar sensor, brake
pressure, vehicle speed) to calculate
the probability of a frontal collision.9 Warning
This system is not intended to
replace the driver responsibility for driving the vehicle and looking
ahead. Its function is limited to
supplemental use only to reduce
the vehicle speed before a
collision.
The system may not react to
animals. After a sudden lane
change, the system needs a
certain time to detect the next
preceding vehicle.
The driver must always be ready
to take action and apply the brakes and steer to avoid collisions.
Functionality
If equipped only with front camera the
active emergency braking operates in forward gear above walking speed up
to 85 km/h.
With radar sensor active emergency
braking operates in forward gear
above walking speed at all speeds.
A precondition is that forward collision
alert with front camera system is not
deactivated in the vehicle
personalisation menu 3 124.
The system includes: ● brake preparation system
● emergency automatic braking ● forward looking brake assist
● intelligent brake assist (only with radar sensor)
● front pedestrian protection system
Brake preparation system
When approaching a vehicle ahead
or a pedestrian so quickly that a
collision is likely, the brake
preparation system slightly
pressurizes the brakes. This reduces
the response time, when a manual or automatic braking is requested.
The brake system is prepared so that braking can occur more rapidly.
If equipped only with front camera the
system operates up to a speed of 80
km/h.
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Driving and operating221Emergency automatic brakingAfter activation of brake preparation
system and just before the imminent
collision, this function automatically
applies limited braking to reduce the
impact speed of the collision or
prohibit a crash. Depending on the
situation, the vehicle may
automatically brake moderately or
hard. This front automatic braking can
only occur if a vehicle ahead is
detected, indicated by the vehicle
ahead indicator A 3 216 . On vehicles
with front pedestrian protection, front automatic braking can also occur
when a pedestrian ahead is detected,
indicated by the pedestrian ahead
indicator 7.
If equipped only with front camera the system operates up to a speed of 80
km/h.
Below a speed of 40 km/h the system
can apply full braking.
Emergency automatic braking may
slow the vehicle to a complete stop to
try to avoid a potential crash. If this
happens, emergency automatic
braking may engage the electricparking brake to hold the vehicle at a
stop. To release press the electric
parking brake button or firmly press
the accelerator pedal.9 Warning
Emergency automatic braking is
an emergency crash preparation
feature and is not designed to
avoid crashes. Do not rely on the
system to brake the vehicle.
Emergency automatic braking will
not brake outside of its operating speed range and only responds to
detected vehicles and
pedestrians.
Forward looking brake assist
In addition to the brake preparation
system and emergency automatic
braking, the forward looking brake
assist function makes the brake assist more sensitive. Therefore, pressing
the brake pedal less strongly results
in immediate hard braking. This
function helps the driver brake
quicker and harder before the
imminent collision.
If equipped only with front camera the
system operates up to a speed of 85
km/h.9 Warning
Active emergency braking is not
designed to apply hard
autonomous braking or to
automatically avoid a collision. It is designed to reduce the vehicle
speed before a collision. It may not
react to animals. After a sudden
lane change, the system needs a
certain time to detect the next
preceding vehicle.
The complete attention of the
driver is always required while
driving. The driver must always be
ready to take action and apply the brakes and steer to avoid
collisions.
The system is designed to work with
all occupants wearing their seat belts.
Intelligent Brake Assist
If the vehicle is equipped with radar
sensor Intelligent brake assist may
activate when the brake pedal is
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222Driving and operatingapplied quickly by providing a boost
to braking based on the speed of approach and distance to a vehicle
ahead.
Minor brake pedal pulsations or pedal movement during this time is normal
and the brake pedal should continue to be applied as needed. Intelligent
brake assist will automatically
disengage only when the brake pedal is released.9 Warning
Intelligent brake assist may
increase vehicle braking in
situations when it may not be
necessary. You could block the
flow of traffic. If this occurs, take
your foot off the brake pedal and
then apply the brakes as needed.
Front pedestrian protection
3 223.
Deactivation
Active emergency braking can be
deactivated in the personalisation
menu 3 124. If deactivated a
message is displayed in the Driver
Information Centre.
We recommend to deactivate the
system in the vehicle personalisation
in the following cases:
● when the vehicle is being towed
● before using an automatic car wash with ignition switched on
● if the windscreen has been damaged close to the camera
● if the front bumper has been damaged
System limitations In some cases, the active emergencybraking system may provide an
automatic braking in situations that
seem to be unnecessary, for instance
in parking garages, due to traffic signs
in a curve or due to vehicles in
another lane. This is normal
operation, the vehicle does not need
service. Firmly apply the acceleratorpedal to override the automatic
braking if the situation and the
surroundings permit.
In the following cases, Active
emergency braking performance is
limited:
● Driving on winding or hilly roads.
● Detecting all vehicles, especially vehicles with a trailer, tractors,
muddy vehicles, etc.
● Detecting a vehicle when weather limits visibility, such as in
fog, rain, or snow.
● During nighttime driving.
● Weather limits visibility, such as fog, rain, or snow.
● The sensor in the windscreen is blocked by snow, ice, slush, mud,dirt, windscreen damage or
affected by foreign items, e.g.
stickers.
To avoid malfunction keep the areas
of the camera sensor in the
windscreen and the radar sensor in
the radiator grille always clean from
dirt, dust, ice and snow.