Audi A8 2019 Service Training page 89

Response to pedestrian or cyclist
Audi pre sense city responds to pedestrians and cyclists in
the same lane as the vehicle or moving into the same lane
as the vehicle.
The following preconditions must be met in order to acti-
vate the system:
› Audi pre sense front is active at a speed of approximately
6.2 mph (10 km/h) or higher.
› Audi pre sense front can warn against pedestrians and
cyclists up to a speed of 52.8 mph (85 km/h).
› Audi pre sense front can initiate braking up to a speed of
52.8 mph (85 km/h).
Advance warning phase
If the vehicle is traveling at speeds of between approxi-
mately 6.2 and 52.8 mph (10 - 85 km/h) and a pedestrian
or cyclist is in the same lane as the vehicle or moving into
the same lane as the vehicle resulting in a critical driving
situation, the instrument cluster alerts the driver by issuing
audible and visual warnings. These warnings are given
within a certain time frame ahead of the last braking
opportunity for braking or collision avoidance before the
actual collision occurs. The timing of warnings depends on
the driver's activity level.
Acute warning phase
If driver does not respond to the warnings, however, J104
generates an acute warning by initiating a brake warning.
At the same time, a visual warning is issued via the instru-
ment cluster display. The brake warning is a very brief but
easily noticeable braking impulse which does not slow the
vehicle down directly.
Automatic brake intervention phase
If the driver fails to respond to the brake warning or only
takes his foot off the accelerator, ABS/ESP Control Module
J104 initiates automatic braking. Depending on the speed
at which the vehicle is traveling, braking power may
increase progressively to maximum level (emergency
braking).
Depending on the situation, the following additional
actions may be initiated:
› Closing the panoramic sunroof.
› Closing of the side windows apart from a residual gap.
› Partial tensioning of the electrically reversible seat belt
tensioners.
› Display of corrective action by Audi pre sense in the
instrument cluster.
Depending on steering, pedal and turn signal inputs, the
system classifies the driver as active or inactive and, conse-
quently, as attentive or inattentive. If the driver is deemed
to be "attentive", warnings are issued later than for a driver
deemed to be "inattentive". At the same time, ABS/ESC
Control Module J104 initiates prefilling of the brake
system, and hydraulic brake assist is reconfigured. Hydrau-
lic brake assist reacts more sensitively to pedal operations
by the driver.
It alerts the driver to the traffic situation and indicates to
the driver that he must react immediately in order to
prevent an impending collision. Depending on how atten-
tive the driver is deemed to be, the brake warning is pro-
duced within a certain time window ahead of the last
opportunity to brake or take evasive action in order to avoid
a collision.
If the vehicle automatically brakes itself to a standstill
without driver intervention, a driver take-over prompt
appears in the instrument cluster and further audible
signals sound. These signals will alert the driver to the fact
that he must actively take control of the vehicle (for
example, by applying braking). If the driver fails to take
control of the vehicle, the system will release the brake and
the vehicle will start to move.
85