Lane Keeping Assist
98
Driving assistance systems
Introduction of the New E-Class, Model Series 212 Sedan
b
The Lane Keeping Assist helps the driver by warning
him if the vehicle is about to leave its lane unintention-
ally. The warning comes in the form of steering wheel
vibrations that are barely noticeable to the other occu-
pants of the vehicle.
The Lane Keeping Assist is activated in the instrument
cluster by means of the buttons on the multifunction
steering wheel.
The Lane Keeping Assist monitors the area in front of
the vehicle with the multifunction camera which is
mounted to the top of the windshield. The assistance
from the Lane Keeping Assist is available at speeds
above approximately 60 km / h. The system takes
measurements of the lane markings on the road. From
the recorded image sequences and the measure-
ments of the road markings it calculates the position
of the vehicle within the lane and the path of the lane
itself. If there are multiple markings on the road, the
innermost marking acts as the reference point. On the
basis of this data the multifunction camera can deter-
mine whether the driver is crossing a road marking.
When the Lane Keeping Assist detects that one of the
front wheels is touching or crossing a road marking, it
warns the driver that he is leaving the lane uninten-
tionally. The warning is given by actuating a vibration
motor in the steering wheel which provides the driver
with a haptic warning by intermittently vibrating the
steering wheel.
In order to provide the correct warning in the right
situation, the warning time can be shifted forward or
backward and warnings that are obviously undesirable
can be suppressed. To do this the system evaluates
the driver's actions on the primary controls, such as
the steering wheel, brakes and accelerator pedal.
Shifting of the warning time
• If the lanes are narrow, the warning occurs slightly
later
• When negotiating a bend in the road, the warning
occurs later on the inside of the curve depending
on the lateral acceleration; on the outside of the
curve the warning occurs earlier
• If the lanes are very wide, on freeways in particular,
the warning occurs slightly earlier
• When unbroken lane markings are detected, the
warning again occurs earlier because it is more
dangerous if these lines are crossed (e.g. due to
the hard shoulder or crash barriers beyond the
markings)
Suppression of the warning
• Under strong acceleration, heavy braking and
sudden steering
• When turn signaling
• When the active and passive safety systems are
activated
P54.32-7360-00
Representation in multifunction display (example)
1 Lane Keeping Assist active
i
Note
Ambiguities in the lane recognition can occur
when there are multiple markings, e.g. at road-
works. If the system is unable to make a reliable
decision about the lane to be followed, the Lane
Keeping Assist shuts down.
– This printout will not be recorded by the update service. Status: 01 / 2009 –
