Active Cruise Control; Principles Of Operation - CITROËN C4 Picasso Owner's Handbook Manual

Driving

Active cruise control

This systems allows, in addition to maintaining
your vehicle's speed at a value that you
have defined, the inter-vehicle time you have
selected between your vehicle the the one
ahead to be maintained (2 seconds by default,
on activating the function).
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Principles of operation

Using a radar with a range of about 100 metres,
located at the front of the vehicle, this system
detects a vehicle running in front of your
vehicle.
It automatically adapts the speed of the vehicle
to that of the vehicle in front.
If the vehicle in front is running more slowly,
the system progressively reduces the speed of
your vehicle using just engine braking (as if the
driver had pressed the "- " button).
If your vehicle is too close to or approaching too
quickly the vehicle in front, the cruise control
is automatically deactivated. The driver is then
alerted by an audible signal, accompanied by a
message.
If the vehicle in front accelerates or changes
lane, the active cruise control progressively
accelerates your vehicle to return to the
programmed speed.
If the driver operates a direction indicator to
the left (left hand drive) or the right (right hand
drive), to overtake a slower vehicle, the active
cruise control allows your vehicle to temporarily
approach the vehicle in front to assist the
overtaking manoeuvre, though never exceeding
the programmed speed.
The active cruise control operates by
day and at night, in fog or in moderate
rainfall.
The activation of this system
deactivates the function of inter-vehicle
time.
The system does not act on the braking
system, but works only with engine
braking.
The regulation range is limited: there will
no longer be any adjustment of speed if the
difference between the programmed speed
setting and the speed of the vehicle in front
becomes too high (18 mph (30 km/h).
If the difference between the
programmed speed setting and the
speed of the vehicle in front is too
great, the speed cannot be adjusted:
the cruise control is automatically
deactivated.