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

See also:
Tire inflation pressures X5 xDrive50i with three rows of seats
...
Entering a street and intersection
1. Select "Street" or the displayed street.
2. Enter a street and intersection in the sameway as you would
enter a town/city.
If there are several streets with the same name:
1. Change ...
Releasing the parking brake manually
In the event of an electrical power loss or electrical
malfunction, you can release the parking
brake manually.
Secure the vehicle against rolling
Before releasing the parking brake manually, ...
