The first system of traffic signals, which was a semaphore traffic signal, was installed as a way to replace police officer control of vehicular traffic outside the Houses of Parliament in London on 9 December 1868. This syste… See more

A set of lights, known as a signal head, may have one, two, three, or more aspects. The most common signal type has three aspects facing the oncoming traffic: red on top, amber (yellow) below, and green below that. Additi… See more

Pedestrian signals are used to inform pedestrians when to cross a road. Most pedestrian signal heads will have two lights: a 'walk' light (normally a walking human figure, typically coloured green or white) and a 'don'… See more