PLC Control Traffic Light System

Abstract

A Programmable Logic Controller (PLC)-based Traffic Light System offers an efficient and automated solution for managing traffic at intersections.Traditional traffic light systems operate on fixed timers.Which often struggle to adapt to changing traffic conditions, resulting in congestion and delays. Implementing PLC technology enhances the reliability, flexibility, and responsiveness of traffic control systems. This system utilizes sensors, timers, and PLC programming to control traffic signals dynamically. The use of a PLC ensures high-speed processing, real-time control, and easy modification of traffic rules without requiring major hardware changes. Additionally, emergency vehicle prioritization and pedestrian-friendly crossing mechanisms can be integrated to improve safety and efficiency.

Introduction

Overview

The Automatic Traffic Light System is an advanced, sensor- and AI-driven mechanism designed to optimize vehicle and pedestrian movement. Unlike traditional fixed-timer signals, it dynamically adjusts signal timing based on real-time traffic conditions, improving:

• Traffic flow

• Road safety

• Fuel efficiency

• Urban sustainability

These systems are foundational for smart cities, utilizing technologies like IoT, AI, and cloud computing.

System Components & Technologies

Hardware Design

• Uses components like SMPS, PLC, and Relay Cards.

• A Programmable Logic Controller (PLC), especially the Siemens SIMATIC ET 200S, is central to managing signal changes efficiently.

  • Supports PROFIBUS and PROFINET

  • Allows modular expansion and fast signal processing

  • Widely used in industrial and urban automation settings

Signal Timings (Example Setup)

• Yellow: 10 sec

• Green: 13 sec

• Red: 52 sec

• Total Cycle Time = 75 sec

Duty Cycle & Delay Calculations

• Calculates duty cycle for each light phase

• Computes average vehicle delay to assess traffic efficiency

Design of Traffic Light Monitoring System

Incorporates:

• Timers, Counters, and Comparators

• IoT-based communication to transmit data to central monitoring systems

• Real-time alerts for signal faults, malfunctions, or power failures

Key benefits:

• Emergency vehicle priority

• Integration of V2X (Vehicle-to-Everything) communication

• Enhanced road safety and reduced congestion

Literature Review Highlights

• Real-Time Monitoring Systems: Use IoT and cloud to remotely monitor and control signals

• Smart Traffic Control: Enables adaptive timing and centralized oversight

• Challenges Identified:

  • High installation/maintenance costs

  • Cybersecurity risks in IoT-based systems

  • Inflexibility in traditional fixed-time signals

  • Poor integration for pedestrians and cyclists

Future Research Directions

1. AI-Driven Adaptive Signals – Machine learning to fine-tune light durations.

2. IoT-Integrated Management – Real-time data for smart decision-making.

3. V2X Communication – Lights communicate with vehicles for safety and flow.

4. Sustainable Infrastructure – Solar-powered and energy-efficient LEDs.

5. Cybersecurity – Stronger protocols to prevent system breaches.

Conclusion

The Traffic Light Monitoring System is a crucial component of modern intelligent transportation systems enhance road safety, reduce congestion, and improve traffic flow efficiency. The image depicts a traffic control system at a four-way intersection, featuring traffic signals with green, yellow, and red indicators, along with a monitoring interface featuring ON/OFF controls. Such systems play a vital role in automating and optimizing urban traffic management.By integrating IoT-based sensors, real-time monitoring, and adaptive signal control, these systems enhance decision-making for authorities. The real-time monitoring allows early detection of failures, such as power outages, signal malfunctions, or traffic irregularities, ensuring quick corrective actions. Additionally, smart traffic management reduces vehicle idling time, leading to lower fuel consumption and decreased carbon emissions, supporting sustainable urban mobility.

References

[1] Automatic Accident Alert and Safety System using Embedded GSM Interface, Kajal Nandaniya, Viraj Choksi, International Journal of Computer Applications (0975 – 8887) Volume 85 – No 6, January 2014. [2] Girish H.R, J. Vinay Kumar, Kumara Swamy N.R, Sachin Kumar. M, Sudhakara H M, 2020, A Review: Smart Ambulance and Traffic Controlling System, (April 2020). [3] Xie Keming, Liu Daliang, Xie, Jun. A fuzzy-logic-based traffic light control system. 10th International Symposium on Integrated Circuits, Devices and Systems, ISIC-2004: Integrated Systems on Silicon - Proceedings, 2004, pp. 341-344 [4] Maman Avishay, Goldschlager Sharon, Miller Hillel. Reusable on-chip system level verification for simulation emulation and silicon. 11th Annual IEEE International High-Level Design Validation and Test Workshop, 2006, pp. 119-126 [5] Jaksic, Nebojsa. Improving self-efficacy in engineering students using PLC based traffic light experiments.2002 ASEE Annual Conference Proceedings, 2002, pp. 13409-13414 [6] ItoToshio, Sato Rieko, Shibata Yasuo, etc. Signal Processing Using All-Optical Wavelength Conversion- Application Using Hybrid-integrated XPM Device and SIPAS, NTT Technical Review, April 2003, v 1, n 1, pp. 52-58,

Copyright

Copyright © 2025 Dr. Prabhat Kumar, Er. Umashankar Sharma, Ravi Kumar Sharma, Harsh Modi. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.