In this situation, are you required to use a sound signal to alert children that you are approaching the pedestrian crossing?

In the video you are approaching a pedestrian crossing in town marked with sign D-6; a group of children with carers is walking across the zebra crossing, and on the right there is B-33 "30". You are not required to use the horn to warn the children. The answer is: no.

The Road Traffic Act allows you to use the horn only when it is necessary to warn of danger, prohibits overusing it, and in a built-up area prohibits using the horn at all, unless it is necessary because of immediate danger. The children are crossing at a marked crossing, supervised by adults - they have right of way here, and you are required to exercise particular caution, reduce speed and give way to them; sounding the horn would mean hurrying the pedestrians, which is misuse of the horn, and it could frighten a child so much that they stop in the middle of the roadway or start running. You stop before the crossing and wait until the whole group has left the roadway, also watching the pavements, because stragglers often run to catch up with the others. In town you save the horn for a situation when someone really is stepping in front of your car and does not see the danger.

Legal basis: Art. 29 para. 1 and para. 2 point 1 and 2 and Art. 26 para. 1 of the Road Traffic Act (Prawo o ruchu drogowym)