In this situation, can you use an audible warning signal when you see pedestrians walking on the road?

In the photo, you are entering a residential area in the town centre in the evening - on the corner you can see sign D-40 and a plate "Nie dotyczy" (does not apply) with bicycles under sign B-22; pedestrians are walking across the square in front of you. You cannot use the horn at them. The answer is: no.

The Road Traffic Act states that in a residential area a pedestrian may use the full width of the road and has right of way over vehicles, and that the horn may be used only when it is necessary to warn of danger; in a built-up area this is allowed only in connection with immediate danger, and misusing signals is prohibited. Pedestrians walking on the roadway in a residential area are doing nothing wrong - it is their right, and you are a guest here and must drive at no more than 20 km/h, giving way to them. So the horn would serve only to hurry them out of your way, and that is misuse of the signal and a petty offence. There is also no immediate danger: the pedestrians can see you, and you are driving slowly. The correct behaviour is to slow down to walking pace, keep your distance and wait patiently until the pedestrians make room - or drive around them if there is enough width.

Legal basis: Art. 11 para. 5, Art. 20 para. 2 and Art. 29 para. 1 and 2 of the Road Traffic Act (Prawo o ruchu drogowym); § 58 para. 1 of the Regulation on road signs and signals