The concept
The parking brake is primarily intended to prevent the vehicle from rolling while parked; it brakes the rear wheels.

See also:
2011 BMW X3 Review by Mike Hanley
The BMW X3 may have been a pioneer among compact luxury crossovers, but a
number of competitors — including the Audi Q5, Mercedes-Benz GLK-Class and Volvo
XC60 — have entered the fray since its de ...
BMW TwinPower Turbo technology in the new four-cylinder engine
This new engine is the most powerful in a new generation of four-cylinder
petrol units based on the same reduced-friction core engine, their different
output ratings being achieved principally by ...
Visual warning
The approach of the vehicle to an object can be
shown on the Control Display.
When the distance to an object is small, a red bar
is shown in front of the vehicle, as it is in the PDC
display.
...
