交通灯示意图如图1所示，在东西南北两个方向均安装信号灯，两个方向各6个

交通灯示意图如图1所示，在东西南北两个方向均安装信号灯，两个方向各6个灯，分为红、黄、绿三种颜色。工作时序如图2所示，假设东西向较忙，绿灯时间是南北向的2倍(40s)。按下起动按钮后，南北向绿灯亮维持20s，20s后，南北黄灯闪烁3次，计6S，期间，东西向红灯也亮，并维持26s；26s后，东西方向绿灯亮40s，后东西向黄灯闪烁3次，计6s，期间，南北向红灯也亮，并维持46so接下去周而复始，直到停止按钮被按下为止。

交通灯示意图如图1所示，在东西南北两个方向均安装信号灯，两个方向各6个灯，分为红、黄、绿三种颜色。 工作时序如图2所示，假设东西向较忙，绿灯时间是南北向的2倍(40s)。 按下起动按钮后，南北向绿灯亮维持20s，20s后，南北黄灯闪烁3次，计6S，期间，东西向红灯也亮，并维持26s；26s后，东西方向绿灯亮40s，后东西向黄灯闪烁3次，计6s，期间，南北向红灯也亮，并维持46so接下去周而复始，直到停止按钮被按下为止。

The schematic diagram of traffic lights is shown in Figure 1. Signal lights are installed in the East, West, North and south directions. There are six lights in each direction, which are divided into three colors: red, yellow and green. The working time sequence is shown in Figure 2. Assuming that the east-west direction is busy, the green light time is twice as long as the north-south direction (40s). After pressing the start button, the North-South green light will stay on for 20s, and after 20s, the North-South yellow light will flash for 3 times, 6S in total. During this period, the East-West red light will also stay on for 26S; after 26S, the east-west green light will stay on for 40s, and then the East-West yellow light will flash for 3 times, 6S in total. During this period, the North-South red light will also stay on, and 46so will be kept continuously until the stop button is pressed.<BR>