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

See also:
BMW Maintenance System
The maintenance system directs you to required
maintenance measures and thereby supports
you in maintaining road safety and the operational
reliability of the vehicle. ...
Vehicle information
Owner's Manual
Computer
Vehicle
...
BMW X5 xDrive35d: Maintaining the Benchmark with BMW Advanced Diesel
Technology.
The BMW Advanced Diesel X5 xDrive35d was introduced to the United States as a
2009 model, and despite increased competition remains the fastest, most fuel
efficient diesel-powered vehicle in its c ...
