Traffic lights, which may also be known as stoplights, traffic lamps, traffic signals, stop-and-go lights, robots or semaphore, are signaling devices positioned at road intersections, pedestrian crossings and other locations to control competing flows of traffic. Traffic lights have been installed in most cities around the world. They assign the right of way to road users by the use of lights in standard colors (Red - Amber - Green), using a universal color code (and a precise sequence, for those who are color blind).
Typically traffic lights consist of a set of three colored lights: red, amber and green. In a typical cycle,
* Illumination of the green light allows traffic to proceed in the
* Illumination of the amber light denoting if safe to, prepare to stop short of the intersection, and
* Illumination of the red signal prohibits any traffic from proceeding.
Usually, the red light contains some orange in its hue, and the green light contains some blue, to provide some support for people with red-green color blindness.
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