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

See also:
Maintenance
The battery is maintenance-free, i.e., the electrolyte
will last for the life of the battery.
Your service center will be glad to advise you on
questions regarding the battery. ...
For US customers
The following only applies to vehicles owned and operated in the US.
If you believe that your vehicle has a defect which could cause a crash or could
cause injury or death, you should immediately i ...
Child seat security
Child seat security
The rear safety belts
▷ BMW X5: all safety belts of the 2nd and 3rd row seats
▷ BMW X6: all safety belts of the 2nd row seats
And the safety belt for the front ...
