路口交通灯的控制是城市交通管理的一个重要内容。如今的交通信号灯系统已经有长足的进步。随着交通路道的不同分工，信号灯要求表达的信息更加细致，信号灯在时间上的控制要求更加精确。 本系统以AT89S52单片机系统为核心，分为中央控制模块、电源模块、交通灯显示模块、传感模块、通行时间显示模块。主要实现了对道路交通指示灯控制、放行时间、时间倒计时的智能控制，从而使放行时间更为精确。由于采用模块化设计,本系统硬件具有良好的可升级性和可扩展性。

The control of the traffic lights at the crossroads is an important content of the urban transportation．Nowadays the system of traffic lamp control has enough advancement. With the different use of the traffic roads, the signal lamp has to put the information more particularity, and the time control on the traffic lamp demand more precise. This system take the AT89S52 Single Chip Microcomputer system as core，divides into the central control module，the power source module，the traffic light display module，the transducer module，the time display module．Mainly realized to the road traffic indicating lamp control，and intelligent control the pass time，the Countdown time, so the pass time will be more exactitude. Because of uses the module design，this system hardware has good may the promotion and may the extension．