See also:

Malfunction
In the event of a failure or malfunction of the parking brake, secure the vehicle against rolling using a wheel chock, for example, when leaving it. ...

Environmental conditions
Say the commands, numbers, and letters smoothly and with normal volume, emphasis, and speed. Always say commands in the language of the system. The language for the mobile phone voice ...

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