PLC based 4 Way Traffic Light Control System

We most often come across a four-way traffic jam in our city. This PLC ladder logic gives the solution to control city traffic using programmable logic control.

4 Way Traffic Light Control

This project is for a junior-level VLSI class at the Bijoy Sarani and it outlines a simple traffic light controller design project. It necessitates the creation of a state machine-based traffic signal controller for a four-way intersection. There are two lanes in each way at this intersection: east, west, north, and south. This assignment emphasizes the differences between DSCH and Cad writing.

A four-phase signal intersection must be managed by the traffic light controller. If only straight-line traffic is considered while Bijoy Sarani street is open, traffic flows north to south or south to north alternately. The EW street traffic is stopped by a red signal during this time. Following the completion of NS street, East to West or West to East traffic now follows EW street.

Microcontrollers are used in traditional traffic light systems, which are inconvenient to use on a daily basis. In addition, microcontrollers must be maintained on a regular basis to ensure that they continue to function properly. Costs of future investments will rise.

So this is where smart traffic comes in Light management is a long-term solution for reliving the past. Microcontrollers are also simple to adapt and maintain circumstances of temperature.

We are employing traffic density control in this project to monitor the traffic density and control the delay of the traffic signals automatically. Proximity sensors that work inductively are used to determine the volume of traffic.

The SCADA system is in charge of the overall progress. Supervisory control and data acquisition (SCADA) is an acronym for supervisory control and data acquisition. That is to say, it can be employed in a variety of applications control and surveillance As a result, it keeps an eye on the process.

PLC monitors what’s going on and gives a reaction to the SCADA system. As a result, if traffic intensity changes, the intensity is displayed of the traffic.

The main goal of this project is to regulate and monitor the status of traffic lights, as well as to alter the intensity automatically. A relay is used in the suggested model card and an SMPS to a PLC with a digital extension module and a step-down and regulates the PLC’s power supply and the indices of outputs.

There are 12 indications here that depict real-time traffic lights, as well as a proximity sensor that determines the intensity. The one that is more significant in the Com Cable is the project model (Communication Cable) which sends the information to the SCADA system.

We use a 3rd party intermediary driver called KEPSERVER to connect the SCADA and the PLC. As a result, this keyserver will construct a virtual server in which PLC and other software can be installed. SCADA will be implemented.

So that each of them can communicate with one another. RS232 is the communication protocol utilized. This refers to communication between two points.

List of Inputs and Outputs

RUNG 0002

Turning on North Yellow and East Yellow. Parallel circuits are added to turn ON/OFF the output in up next sequence.

Rung 0003

Turn on East Red and North Green.

Rung 0004-0005-0006-0007

Same procedures were followed to turn on further outputs. ( Refer to Above Tabular column for a sequence of operation)

RUNG 0008

The done bit of the timer (T4:7) is utilized to restart the cycle from the beginning.

Until STOP PB is pushed, the program will execute indefinitely.

Function Description

According to the actual situation, this paper selects the main road traffic signal model of travel Binzhou Polytechnic as the research object. this place. has an extensive business district Schools, kindergartens, and large shopping malls.

The road is huge and planned. The transport facilities are in conformity with the latest traffic construction standards. However, due to The existence of schools and shopping malls, the traffic volume is large and the traffic jam is easy. How to develop a set of traffic light control systems that can effectively solve its traffic control, to realize the intelligent traffic guidance function of peak time, improve the efficiency of Transport, be the research problem in this paper.


The Intelligent Traffic Light Control System developed in this research is designed and programmed by JINGYI’s network learning software. Through the debugging of subsequent simulations, the function is Reached the development and design requirements, which can reduce the traffic jam.

Important The features of this control are: To fit the actual situation and analyze the problems of traffic lights control system, to promote a way of improvement. Its function is flexible. It can simulate a variety of Actual working statuses of traffic light control. And it is easily installed.


The design of intelligent traffic light control system based on PLC, mechanical electrical integration wangxiaojuan,

[2]  The design and implementation of an intelligent traffic light experimental device is based on
PLC, Research and Exploration in the Laboratory, Feng Gui-sheng

[3] Design and simulation of urban traffic signal control systems. Journal of the Mianyang General University Zhoumingchen.

[4]  Traffic light signal system based on PLC control, agriculture, equipment, and vehicle Engineering, Jin Hui.

[5] Design of intelligent control system of traffic signal based on PLC, industrial equipment, and automation equipment.

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