In cities, traffic lights on roads can be seen everywhere, especially on busy roads where all four sides of the road will have traffic lights. Now there are already solar-powered street lamps, but relative to the high cost of solar panels, the investment payback period is very long. Moreover, it is estimated that the efficiency of solar panels absorbing sunlight is not so high, and the solar energy absorbed during the day may be enough for night use. I wonder if this solar-powered traffic light can work independently without additional electricity. There is a solar panel at the top of this solar-powered traffic light, which is the source of energy for the traffic light. Of course, the traffic light can normally display all three colors. Only in one unit, it can display red, green, and yellow colors.