The parking brake auto release function releases the parking brake automatically when you wish to start moving.
Applying the parking brake when stopping
To apply the parking brake, pull the switch 
.
.Releasing the parking brake when driving away
Press the accelerator in the normal way: the parking brake will be released automatically and the Audi A6 will start moving.
You can apply the parking brake when stopping at traffic lights, etc. You do not then have to hold the car with the brake pedal, as the parking brake will stop it creeping forward while a gear is engaged in the automatic transmission. When you press the accelerator in the normal way, the parking brake will be released automatically and the Audi A6 will start moving.
Driving away on a slope
When driving away on a gradient, the parking brake auto release function prevents the Audi A6 from rolling back unintentionally. The braking force of the parking brake is only released when there is enough power at the wheels to make the Audi A6 move in the desired direction.
Note
For safety reasons the parking brake will only release automatically if the driver's seat belt is engaged in its buckle.