When should you not sound your horn near bicycles?

When approaching from the rear, it's important to avoid sounding your horn as it can startle the cyclist and lead to dangerous situations. A sudden noise can cause a cyclist to lose balance or react unpredictably, which may result in an accident. This is especially critical given that cyclists often have less visibility than motor vehicles and may not expect to hear a horn from behind them.

In contrast, there are other contexts where a horn might be more appropriate, such as when passing at speed, as long as it's done at a safe distance. When cyclists are turning, they may be more aware of their surroundings, and communication through a horn in this case could be seen as a reminder of your presence on the road. However, generally, caution is emphasized when dealing with cyclists, making it important to understand when not to use your horn to ensure their safety.