The warning triangle is an essential bit of safety equipment for all drivers and should ideally be kept as part of a larger breakdown kit. The warning triangle is used if a vehicle breaks down and is particularly useful should you break down in the dark as it’s reflective so keeps you visible and alerts other drivers of your presence at the roadside.
There is no legal requirement to carry a warning triangle whilst driving in the UK, but it is a legal necessity in various parts of Europe including Italy, France, Germany, Belgium, Poland, Switzerland, Austria and Ireland. In Spain, it is a legal requirement to carry two warning triangles whilst driving (check local driving rules).
If you do use one when you break down in the UK, you should remember that you should never place a warning triangle on a motorway as it’s dangerous to do so. You should also be aware that when placing a warning triangle you need to position it 45 metres (147ft) behind your broken down vehicle on the same side of the road to give other drivers plenty of time to notice you.