In which situation is it required to use your vehicle's horn?

Using your vehicle's horn is primarily intended as a safety measure to alert others to your presence, especially in situations where there is a potential risk of collision. In the context of warning pedestrians, this use of the horn becomes crucial. When you see pedestrians near or on the road, especially if they might not be aware of your vehicle approaching, using the horn ensures that they know you are coming and can react accordingly. This helps in preventing accidents and promoting safety for both drivers and pedestrians.

In other scenarios like greeting a friend or changing lanes, using the horn may not only be inappropriate but could also be distracting for other road users and lead to confusion regarding your intentions. Therefore, reserving the horn for situations that enhance safety, such as warning pedestrians, is essential for responsible driving.