A motorcyclist tapping the top of their helmet typically indicates a signal or message to other riders or drivers. It is commonly used as a sign to alert fellow riders of potential hazards or police presence ahead. When a motorcyclist taps the top of their helmet, it's a way of telling others to be cautious and attentive. It is often accompanied by other gestures, such as pointing or waving, to indicate the specific nature of the hazard or the direction of the police presence.
This form of communication among motorcyclists is informal and not universally recognized or understood. However, it has become a common practice in many motorcycle communities, particularly in certain regions or among groups of riders who have established this gesture as part of their riding culture.