自动交通控制系统用红、绿、黄三支共两组发光二极管表示交通信号灯，利用单片机模拟有时间显示的定时交通信号灯控制管理。信号灯的变化规律可如下：

1）放行线：绿灯亮放行25秒，黄灯亮警告5秒，然后红灯亮禁止。

2）禁示线：红灯亮禁止30秒，然后绿灯亮放行。

3）当某一方向的红灯亮时，若该方向有车通过，则用扬声器声报警。（撞红灯信号可用3-5V模拟量表示）-Automatic traffic control system using red, green, yellow light-emitting diodes, said a total of three traffic lights, the use of single-chip analog time display on a regular traffic signal control and management. Changes of lights to be as follows: 1) Release Line: green clearance 25 seconds, the yellow light warning for 5 seconds, then the red light is prohibited. 2) ban shows lines: the red light is prohibited for 30 seconds, then the green light to release. 3) When the red light in one direction, if the direction of the car through, the alarm speaker sound. (Hit the red signal available 3-5V analog representation)