When should you use your horn?

Answer: B — To alert another driver of your presence if necessary

Using your horn to alert another driver of your presence is an important safety measure on the road. It serves as a warning signal in situations where visibility or awareness may be compromised, ensuring that other drivers, pedestrians, or cyclists are alerted to your vehicle's presence. This action can help prevent accidents, particularly in scenarios where another vehicle may change lanes, run a stop sign, or when approaching intersections where visibility is limited. The other options do not reflect appropriate or safe uses for your horn. For instance, signaling that you are leaving is not a standard practice, as other drivers typically do not need to be alerted in this manner. Employing the horn in heavy traffic can lead to unnecessary confusion or aggravation among drivers, and using it to express frustration could escalate tensions rather than contribute to safe driving. Therefore, using the horn primarily as a safety alert reflects proper driving etiquette.