说明：  利用单片机的定时器定时，令十字路口的红绿灯交替点亮和熄灭，实现主支路路口的交通信号灯控制（尽可能保持主线的畅通，即在通常情况下，保持主线的放行，只有在支线到达时，才放行支线），同时采用LED数码管或LCD显示倒计时时间。
(The use of single-chip timer timing, make the turn at the crossroads of the traffic lights lit and extinguished realize the main traffic lights at the junction of the slip control (as much as possible to maintain the smooth flow of the main line, that is, in normal circumstances, to maintain the main line of the release, only in the Line arrived, before the release Line), while the use of LED digital tube or LCD display countdown time.)