Driving
Rear cross traffic alert (RCTA) Fig. 198
Schematic representation of the rear
cr oss tr
affic alert assistant: zone monitored
around the vehicle while leaving a parking
space. Park Assist uses the radar sensors on the rear
bumper
››
› page 244
to monitor the traffic
crossing behind the vehicle as it backs out of
a parallel parking space or as it is being man-
oeuvred, for example in very low visibility con-
ditions.
When the system detects a relevant vehicle
on the road that is approaching the rear of
the vehicle ››› Fig. 198
, an acoustic alarm
may sound if the relevance so requires it.
In addition to the acoustic alarm, the driver is
also informed by means of a visual signal on
infotainment system display. This signal is dis- played in the form of a red or yellow strip at
the back of the image of the vehicl
e on the in-
fotainment system screen. This strip displays
the side of the vehicle towards which traffic is
approaching in transverse direction 1)
.
Automatic braking to reduce damages
If the rear cross traffic alert detects that
someone else on the road is approaching the
rear of the vehicle and the driver does not
step on the brake, the system will engage the
brakes automatically.
The parking system helps the driver by auto-
matically engaging the brakes to reduce any
damage. The automatic intervention on the
brakes takes place when driving in reverse at
approx. 1-12 km/h (1-7 mph). After detecting
that the vehicle is stationary, the system
keeps it that way for around 2 seconds.
After automatically braking to reduce dam-
age, the system will not be able to automati-
cally brake again for approximately 10 sec-
onds.
You can interrupt the automatic braking by
stepping hard on the accelerator pedal or
the brake pedal in order to regain control of
the vehicle. WARNING
The smart technology incorporated into
the r ear cr
oss traffic alert cannot over-
come the limits imposed by the laws of
physics; it only works within the limits of the
system. The parking assistant function
should not tempt you into taking any risks.
The system is not a replacement for driver
awareness.
Braking and parking
If the running gear or brake system is modi-
fied, the eff ectiv
eness of the ABS could be se-
verely limited.
Hydraulic Brake Assist (HBA)
The brake assist system can reduce the re-
quired braking distance. The braking force is
automatically boosted if you press the brake
pedal quickly in an emergency. You must
keep pressing the brake pedal until the dan-
ger has passed.
Traction control system (ASR)
In the event of the wheels spinning, the ASR
reduces the engine torque to adapt to the
road condition. This helps the car to start
moving, accelerate or climb a gradient.
Electronic differential lock (EDL)
When the EDL detects wheelspin, it brakes
the spinning wheel and directs the power to
the other driven wheel. This function is active
up to approximately 100 km/h (62 mph).
To prevent the disc brake of the braked wheel
from overheating, the EDL cuts out automati-
cally if subjected to excessive loads. The ve-
hicle can still be driven. The EDL will switch on
again automatically when the brake has
cooled down. Tractor-trailer sway mitigation*
If the vehicl
e is pulling a trailer, it will control
the following: tractor-trailers tend to sway.
When the swaying of the trailer is felt by the
vehicle and detected by the ESC, it will auto-
matically brake the towing vehicle within the
limits of the system and mitigate the sway.
Tractor-trailer sway mitigation is not available
in all countries ››› page 312
.
Electronic engine torque management
(XDS)
When taking a curve, the driveshaft differen-
tial allows the outer wheel to turn at a higher
speed than the inner wheel. In this way, the
wheel that is turning faster (outer wheel) re-
ceives less drive torque than the inner wheel.
This may mean that in certain situations the
torque delivered to the inner wheel is too
high, causing the wheels to spin. On the other
hand, the outer wheel is receiving a lower
drive torque than it could transmit. This can
cause a loss of grip on the drive axle, in this
case the front axle, which results in under-
steer or “lengthening” of the trajectory.
The XDS can detect and correct this effect
via the sensors and signals of the ESC.
Via the ESC, the XDS will brake the inside
wheel and counter the excess driving torque of that wheel. This means that the requested
traject
ory is much more precise.
XDS works in combination with the ESC and is
always active, even when ASR is switched off,
or when the ESC is in Sport mode or discon-
nected.
Multi-collision brake
The multi-collision brake consists of automat-
ic braking activated by the Airbag control
unit. It is activated when, in the event of an
accident, the Airbag control unit detects de-
celerations above the activation level, and
braking is managed by the ESC system.
In the event of an accident, the multi-collision
brake can help the driver by braking to avoid
the risk of skidding during the accident and
causing other collisions.
The following actions control automatic brak-
ing during the accident: