Solution de système de sécurité et de surveillance MCCTV Actualités de CCTUNG — traffic Light

Traffic lights are very important for keeping people safe (安全) on the road. They help control (控制) when vehicles (车辆) and people should stop or go. A traffic light has three colors: red, yellow, and green. The red light means stop. When the red light is on, vehicles and people must wait. They cannot move. The yellow light means slow down (减速). It tells drivers (司机) the light will change soon. The green light means go. When the light is green, vehicles can drive, and people can walk if it is safe. The first traffic light was used in 1868...