On a motorcycle, a horn:

Your horn can be a useful tool if you need to get someone's attention quickly. However, because a motorcycle's horn is not as loud as a car's, other drivers may not notice that you are sounding your horn. You should never rely only on your horn to deal with a hazard.

• Is useless.
• Usually cannot be heard by others.
• Can be used to get someone’s attention quickly.
• Should not be used.