traffic light

An LED 50-watt traffic light in Portsmouth, United Kingdom Traffic lights, traffic signals, or stoplights – also known as robots in South Africa, Zambia, and Namibia – are signalling devices positioned at road intersections, pedestrian crossings, and other locations to control the flow of traffic.

Traffic lights usually consist of three signals, conveying meaningful information to road users through colours and symbols, including arrows and bicycle symbols. The usual traffic light colours are red to stop traffic, amber to signal a change, and green to allow traffic to proceed. These are arranged vertically or horizontally in that order. Although this is internationally standardised, variations in traffic light sequences and laws exist on national and local scales.