When can you sound a car horn in Australia?

In Australia, you can sound a car horn to alert other road users of your presence to avoid a collision or when necessary for safety. It's typically prohibited to use the horn in a non-emergency situation, such as to express frustration or as a form of greeting. Additionally, using the horn unnecessarily or in a way that causes annoyance may result in fines. Always check local regulations, as specific rules can vary by state or territory.