What is the horn for?
Any vehicle horn is to alert others to your presence. Most vehicles, whether they are cars, lorries, ships or even trains are equipped with a horn.
A car horn tends to be electric. It works with a steel diaphragm that has an electromagnet attached to it. Both are in turn connected to a connector which allows the current to be interrupted. When you hit the horn, the current flows through and the horn makes a noise.
There are different kinds of horns with various tones. Although horns can be used singly, generally there are two to created two tones.
The use of your horn is determined by the Highway Code. Bear in mind that you are only allowed to sound your horn when your car is moving. You cannot use your horn when stationary on the road or in built-up areas between 11:30pm and 7:00am unless another road uses poses a danger. Your horn must never be used agressively