Traffic lights have phases. The time and process after the straight and left turns in two directions at the intersection are called phases.

The phase is calculated according to the traffic flow at each intersection, so the phase at each intersection is different.

Firstly, the traffic flow is measured, and the traffic flow and peak flow of various traffic flows (pedestrians, non-motor vehicles and motor vehicles) in all directions in a period of time are measured. Then calculate the time required for them to run according to the traffic flow law, then determine the red light and green light time at each intersection, and then determine the phase.

According to twd 6349- General Force 1 1 level, you can set up traffic lights at will. Then imagine that setting every green light at the intersection of your city to 10 second will definitely cause traffic congestion. The phase of traffic lights must be calculated scientifically according to the traffic flow.