An overview about the Traffic light

A traffic light or traffic signal is a signaling machine positioned at a road intersection or pedestrian crossing to point out when it is secure or safe to drive, ride or walk, using a worldwide color code.

The Traffic lights for common vehicles or pedestrians for all time have two main lights, a red one that means stop and a green one that means go. Generally, the red light contains some orange in its hue, and the green light has some blue, to give some support for people with red-green color blindness. In nearly all countries there is also a yellow (or amber) light, which when on and not flashing means halt if able to do so securely. In some systems, flashing amber means that a motorist can go ahead with care if the road is clear, giving way to pedestrians and to other road vehicles that possibly will have priority. A flashing red basically means the same as a regular stop sign. There can be added lights (generally a green arrow or "filter") to approve turns (called a lead light in the U.S., because it is generally leading the main green light). Traffic lights for particular vehicles (like buses or trams) may perhaps use other systems, like vertical vs. horizontal bars of white light.