DAF - Adaptive Cruise Control

DAF - Adaptive Cruise Control
Relaxed and safe
Cruise control
Adaptive Cruise Control
Modern commercial vehicles are equipped with cruise control.
Cruise control maintains a set, constant vehicle speed under varying
road conditions and thus is a great relief for the driver, at least on not
too busy motorways.
The limitations of conventional cruise control systems are overcome
by Adaptive Cruise Control (ACC).
If the vehicle catches up with a preceding vehicle, ACC reduces
engine throttle and (if necessary) applies braking force to maintain
a safe distance as preset by the driver. Even in dense traffic and with
other vehicles crossing or joining his lane at various speeds, the driver
is relieved from frequent manual intervention.
What are the benefits of ACC?
Above all, Adaptive Cruise Control reduces the strain on the driver.
Because ACC maintains a safe distance to the vehicle immediately
ahead, the driving is much more relaxed, with reduced symptoms
of fatigue.
ACC includes a Forward Collision Warning (FCW) function to alert
the driver if manual intervention is required.
Advanced Emergency Breaking System (AEBS) further reduces
the risk of a rear-end collision by applying up to the maximum
available brake power if appropriate.
In dense traffic, however, the driver must continually adjust the vehicle
speed to the traffic flow. The benefit of conventional cruise control
systems diminishes as the traffic gets heavier.
DAF | 1
DAF - Adaptive Cruise Control
Relaxed and safe
How does ACC work?
When will ACC react?
A radar sensor behind the grille detects objects ahead of the vehicle
and checks their relative speed and distance. Three radar beams
together with an integrated yaw rate sensor enable the system to
differentiate between vehicles in the same lane and those in other
ACC will react on:
• moving objects ahead that are coming closer, like preceding
vehicles driving at a lower speed.
• stationary objects that have been detected moving before,
like a slowly moving queue that comes to a full stop.
The driver sets a desired cruise speed and following distance to
a vehicle ahead.
ACC will not react on:
• objects that are moving away from the vehicle, like overtaking
• stationary objects, like a traffic jam that is already at complete
stand-still when first detected.
• opposing traffic.
To maintain the set distance the vehicle speed will be adapted by
active intervention from ACC in the vehicle systems:
engine throttle
engine brake
automatic gear shift down
secondary retarder
service brakes
• ACC is intended for use on main roads and motorways.
• The field of view of the radar sensor is limited. In some situations
(for example a motorcycle, or a vehicle driving far off centre)
other traffic can be detected later than expected or not be
detected at all.
• ACC is a supporting system that will contribute to more relaxed
and safer driving. However, ACC is not an autopilot. The driver
himself will at all times remain fully responsible for his vehicle.
How will ACC react?
Maintain a preset distance
If a preceding slower vehicle is detected, ACC will maintain a safe
distance by decelerating the vehicle. If the lane ahead is clear again,
the vehicle will accelerate to the set cruise speed.
ACC alerts the driver if manual intervention is needed to avoid a
collision, Active intervention by FCW and AEBS in the vehicle systems
will follow if the driver does not react properly.
ACC distance alert
• audible distance alert and yellow warning on the central
dashboard display
FCW distance alert
• audible distance alert and red warning on the central dashboard
FCW partial braking phase
• max. deceleration 3 m/s2
AEBS full braking emergency phase
• max. decelaration 6 m/s2
ACC and AEBS can be switched on and off by the driver. FCW will
remain active, even with ACC off.