Are you allowed in this situation to use a warning sound signal?

In the situation shown, a vehicle pulling out from the right enters traffic directly in front of your vehicle, failing to yield the right of way (the previously visible D-1 'priority road' sign). This creates a direct threat to road safety. According to Art. 29 para. 1 of the Road Traffic Act, an audible signal may be used if it is necessary to warn of a danger.