How Are The Lights Of Traffic Lights Arranged?

Traffic lights are very common, so I believe that we have a clear meaning for each type of light color, but have we ever thought that its light color ordering has a certain order of order, and today we share it with its light color. Place the rules:
1. When it is not necessary to control the left-turn non-motor vehicle traffic flow alone, the vertical device should be arranged. The order of the traffic lights of the traffic signal lights should be red, yellow and green from top to bottom.
2. When it is necessary to independently control the left-turn non-motor vehicle traffic flow, the traffic signal lights should be vertically arranged and divided into two groups. The left group is the left-turn non-motor vehicle signal, which should be red, yellow and green from top to bottom; the right group is non-motor vehicle signal light, which should be red, yellow and green from top to bottom.
3. The color of the crosswalk signal light shall be arranged in a vertical direction. The order of the signal lights should be red and green.