智能控制交通灯。分主路辅路，当辅路无车时主路保持绿灯，当辅路有车通过时辅路亮绿灯，并且在最短五秒钟之后或者20秒之内返回原来的状态。-Intelligent control of traffic lights. At the main road and side roads, as roads without the green light when the main road to maintain, when the roads w