主、支两条交叉道路上的车辆交替行走，主道上通行的时间为30s，支道上通行的时间为25s。 在绿灯转为红灯时，要求绿灯先闪烁3秒，黄灯亮5秒，才能变换运行车道。-Lord, vehicles on the road supporting two intersecting alternating walking passage of time is the main trail 30s, supported the passage of time trail 25s. When the gree