Traffic light (nonfiction)

LED traffic light.

Traffic lights, also known as traffic signals, traffic lamps, traffic semaphore, signal lights, stop lights, robots (in South Africa), and (in technical parlance) traffic control signals, are signalling devices positioned at road intersections, pedestrian crossings, and other locations to control flows of traffic.

The world's first, manually operated gas-lit traffic signal was short lived. Installed in London in December 1868, it exploded less than a month later, injuring or killing its policeman operator.

Nonfiction cross-reference

• Light (nonfiction)

External links:

• Traffic light @ Wikipedia