BMW 5 - Manual (Page 40)

BMW
Media
Information
11/2009
Page 40
sensor technology, a full range radar, to perform its function. This
innovative radar sensor is integrated inconspicuously in the front air dam
of the car, does not require any individual adjustment, and is largely immune
to contamination or dirt from outside. The measuring beam emitted by the
system is sufficiently broad at short distances of up to approximately
50 metres or 165 feet in order to recognise vehicles on adjacent lanes
within certain limits. Whenever another vehicle moves over to the same
lane as the driver’s car, Active Cruise Control with Stop & Go adjusts
the speed of the BMW 5 Series smoothly and softly to the speed of the
new car now ahead.
In combination with Active Cruise Control, the new BMW 5 Series Sedan
is available for the first time with a collision warning incorporating a brake
activation function. While both of these systems may be activated
independently of one another, they are harmonised and matched to
one another in their functions.
Collision warning with its brake activation function triggers an alarm in two
stages. The pre-warning is an optical message presented as a red car symbol
in the instrument cluster and, when fitted, also in the Head-Up Display,
telling the driver to increase his distance from the vehicle ahead. As soon as
this symbol appears, the brakes are pre-loaded, the release thresholds on
the Adaptive Brake Assistant are lowered, and the Brake Standby function
on DSC Dynamic Stability Control is activated. This ensures rapid build-up
of full brake pressure in an emergency, the shorter stopping distance made
possible in this way reducing the risk of a front-to-rear collision.
There is no such pre-warning whenever Active Cruise Control with
Stop & Go is in use, since this sophisticated system automatically maintains
and reinstates an appropriate distance at all times.
The second stage in the collision warning process is activated in the event
of an imminent collision (= greater risk), regardless of the operating status
of Active Cruise Control: whenever the driver is required to intervene very
quickly, the system sends out an acute warning – in this case not only an
optical, but also an acoustic message. It also initiates the braking process
required, slowing down the car with stopping power of up to 3 metres/sec
2
for a maximum of 1.2 seconds. In combination with a signal flashing on
and off in the instrument cluster or, respectively, in the Head-Up Display and
an acoustic warning signal, the driver is urged to act immediately. And with
the brake system again being pre-loaded, the various functions are already
in standby to avoid a collision or, should the worst come to the worst, to
significantly reduce the consequences of an impact.