See also:

ConnectedDrive or BMW Assist
...

The concept
The automatic engine start-stop function helps save fuel. The system switches off the engine during a stop, e. g., in a traffic congestion or at traffic lights. The ignition remains switched on. ...

Signal tones
When approaching an object, an intermittent tone is sounded that indicates the position of the object. For example, if an object is detected to the left rear of the vehicle, a signal tone sounds ...