When is it appropriate to use your horn while approaching a blind curve?

Using your horn while approaching a blind curve is primarily done to warn others of your approach. This is crucial in situations where visibility is limited, and other road users, such as pedestrians or vehicles, may not see you coming. Sounding your horn alerts them to your presence, allowing them to take necessary precautions, such as yielding right of way or being more aware of their surroundings.

In contrast, greeting other drivers, indicating a lane change, or expressing frustration are either inappropriate or less effective uses of the horn in this context. Greeting other drivers may not convey an important message and can be ignored. Indicating a lane change is typically done with turn signals, which are a more accepted form of communication on the road. Expressing frustration through the horn is not only unhelpful but can escalate tension and create unsafe driving conditions. Therefore, using the horn to warn others is the most effective and responsible reason to utilize this feature while navigating a blind curve.