Design and development of sensor based traffic light system

Abstract: The main object of this study was to design and implement a suitable algorithm and its simulation for an intelligent traffic signal simulator. The system developed is able to sense the presence or absence of vehicles within certain range by setting the appropriate duration for the traffic signals to react accordingly. By employing mathematical functions to calculate the appropriate timing for the green signal to illuminate, the system can help to solve the problem of traffic congestion. The simulation of the algorithm of the traffic signal system was done using MATLAB software. Hardware simulation tests were successfully performed on the algorithm implemented into a controller. The new timing scheme that was implemented promises an improvement in the current traffic light system and this system is feasible, affordable and ready to be implemented especially during peak hours. A countdown timer interfacing according to the traffic system using Lab VIEW software was also created.

Key words: Traffic signal system, sensor based traffic light system, traffic congestion

INTRODUCTION

Many traffic light systems operate on a timing mechanism that changes the lights after a given interval. An intelligent traffic light system senses the presence or absence of vehicles and reacts accordingly. The idea behind intelligent traffic systems is that drivers will not spend unnecessary time waiting for the traffic lights to change. An intelligent traffic system detects traffic in many different ways [1].

The older system uses weight as a trigger mechanism [2]. Current traffic systems react to motion to trigger the light changes. Once the infrared object detector picks up the presence of a car, a switch causes the lights to change. In order to accomplish this, algorithms are used to govern the actions of the traffic system. While there are many different programming languages today, some programming concepts are universal in Boolean Logic.

We need to understand the function of traffic signals so that we can improve driving habits by controlling the speed in order to reduce the number of associated traffic accidents. The more number of drivers who know about the operation of traffic signals, the less frustrated they are going to be while waiting for the lights to change. The main aim in designing and developing of the Intelligent Traffic Signal Simulator is to reduce the waiting time of each lane of the cars and also to maximize the total number of cars that can cross an intersection given the mathematical function to calculate the waiting time.

The traffic signal system consists of three important parts. The first part is the controller, which represents the brain of the traffic system. It consists of a computer that controls the selection and timing of traffic movements in accordance to the varying demands of traffic signal as registered to the controller unit by sensors [3]. The second part is the signal visualization or in simple words is signal face. Signal faces are part of a signal head provided for controlling traffic in a single direction and consist of one or more signal sections. These usually comprise of solid red, yellow, and green lights. The third part is the detector or sensor. The sensor or detector is a device to indicate the presence of vehicles. One of the technologies, which are used today, consists of wire loops placed in the pavement at intersections. They are activated by the change of electrical inductance caused by a vehicle passing over or standing over the wire loop. Recent technology utilization is video detection. A camera feeds a small computer that can "see" if a vehicle is present.

Experimental setup: In order to implement the Intelligent Traffic Signal Simulator, one needs to setup and assemble the hardware components and write a program to control the intelligent traffic signal simulator.

The layout of the Intelligent Traffic Signal Simulator is displayed in Figure 1. The blocks, which are labeled N1, N2, N3, E1, E2, E3, S1 and W1 are the infrared object detectors.

Hardware components: The traffic light system consists of four important components: the controller which is the brain to the system, the sensors which detect the presence of vehicles, the light emitting diodes (LED) which act as the actuator and the countdown timers which is displayed in Lab VIEW.

BASIC STAMP 2 (BS2) is used as the microcontroller of the traffic signal. The BS2, which needs to be plugged to the Board of Education (BoE), is directly attached to the computer in order to program it. The wiring for the output and input signals is done from this board. Figure 2 shows the Board of Education to which a 9V DC power is supplied. There is also a DB9 connector, that is connected to the COM port of computer using RS-232 serial cable, for BS2 programming and serial communication during runtime. Next to the BS2, there is a breadboard. The breadboard has many strips of copper, which run underneath the board in a horizontal fashion. These strips connect the sockets to each other.

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