On what grounds would a driver use a light tap of the horn?

Using a light tap of the horn is appropriate as a way to alert other road users, particularly when overtaking a bicycle or pedestrian. This action serves as a warning that the driver is passing and to ensure the safety of those more vulnerable road users. A gentle tap is less aggressive than a prolonged honking, making it a courteous way to signal without causing alarm.

Maintaining a safe distance while also being aware of the presence of cyclists and pedestrians is crucial, and a light tap of the horn can help communicate the driver's intention. This approach fosters a safer environment for everyone on the road and reinforces the importance of being cautious and considerate while driving near those who might be more at risk.