Improving Vehicular Traffic Light Control in a Developing Country Using On-Road Wireless Sensors Networks (WSN)
Chapter One
OBJECTIVES OF STUDY
The aim of this thesis is to develop and analyzethe on-roads wireless sensor network prototype for improving traffic control in a given road network under real-time constraints. The following objectives are set to meet the requirements of the thesis:
- Collectionof vehicular movement record or traffic data using on-road wireless sensors network
- Design and development of the system prototype
- Cost effective deployment of on-road WSN
CHAPTER TWO
LITERATURE REVIEW
TECHNOLOGY BASE
A sensor is a device or transducer that is able to detect a given phenomenonsuch as motion or transform some physical process such as vibration within a specific location or environment into an electrical or optical signal,which can be measured by a digital processor [8]. Transducer converts energy from one domain to another [9]. The usefulness of sensors lies in their ability to communicate such detection or transformation to. Data gathered by sensors are obtained by users in different ways. These include physical change in their appearance, texture, size, taste, etc. The transformation can be transmitted to remote location by means of electrical or optical signals for processing or to initiate an action.
- SENSORNETWORK
A sensor network (SN) is composed of sensor nodes which are small in size, low in cost, and have short communicationrange. In general, someenvironmental conditions are measured by the sensor nodes deployed with a spatial densityand at a sampling rate specified by the application [8].A sensor node usually consists of four components or sub-systems:
- A processor (microcontroller) or computing subsystem: this is responsible for functions such as execution of the communication protocols andcontrol ofsensors,
- A sensing subsystem: this subsystem is responsible forsensing the environmental characteristics, such as usingtemperature, humidity, or acousticsensor,
- A radio or communication subsystem: this consists of a short radio range used to communicate with neighbouring nodes,
- A power source or power supply subsystem: this includes a battery whichprovides energy to sensor node.[10]
The sensing subsystem comprise of sensor(s) and analogue circuit [11]. Composition of a sensor node is depicted as in Figure 2.1. Figure 2.2 depicts three main types of deployment of sensors in any given facility or area, viz: – (a) triangular sensor deployment (b) square sensor deployment and (c) irregular sensor deployment.
Energy ratings of possible power sources and drawback in adoption of each presented in [8] reveals the following:
- Zinc-based batteries have high energy density but high leakage, so they are only good for use in short-durationapplications
- Lithium batteries offer higher energy density with fewermemory effects1, but require longer rechargetimes
- polymer-based batteries have excellent energy density with flexible form factor, but relatively expensive (e.g. $20 /1500mAh)
- developing battery technology using micro fuel cell, has 10 times larger energy density than the commonly used alkalinebattery
- active research aimed at collecting renewable energy from wind or solar panelson-going
TYPES OF SENSORS
Sensors in a sensing subsystem are made from the following sensing technologies [12]:
- Micro-electromechanical systems (MEMS) – gyroscopes, accelerometers, magnetometers, pressure sensors, pyroelectric effect sensors, acousticsensors
- CMOS-based sensors – temperature, humidity, capacitive proximity, chemicalcomposition
- LED sensors – ambient light sensing, proximity sensing, chemical composition
The sensing subsystem/technologies are further classified as intrusive, non-intrusive and off-roadway technologies [8]. Intrusive technologies refer to those that require installation directly onto the pavements, in saw-cut, holes or tunnelling under the surfaces. Drawbacks include the disruption of traffic for installation and repair, failures induced by poor road conditions, and system reinstallation caused by road repairs or resurfaces. Examples include inductive loop,pneumatic road tube, and piezoelectric cable, among others.
Non-intrusive technologies do not need any installation on or under the pavement.The installation and repair of such a system can be done without disrupting the traffic. Examples include microwave radar, infrared, Video Image Processing (VIP), ultrasonic and passive acoustic array.Off-Roadway Technologies refer to others that do not require any hardware to be setup under the pavement or on the roadside. Example includes probe vehicle technologies with GlobalPositioning System (GPS) and mobile phones; Automatic Vehicle Identification (AVI); andremote sensing technologies that make use of images from aircraft or satellite.
CHAPTER THREE
IMPROVED VEHICULAR TRAFFIC CONTROL SYSTEM DESIGN
INTRODUCTION
Traffic situation in some cosmopolitan cities in Nigeria, such as Lagos, Port Harcourt and Abuja are becoming chaotic and resulting in needless wastage of man-hour and loss of innocent lives. The situation has further become worrisome in terms of economic loss to individuals and country at large. Government response to dealing with the situation included installation of traffic light at major intersections, provision of mass transport system, regulation of vehicular movement in certain areas and certain days, among others.
The use of traffic light to control vehicular movement aims at avoiding vehicular collision, orderly passage of vehiclesarriving the intersection from different routes. But it should also address concern of road users in terms of minimising travelling time by eliminating unnecessary delay. It relies on assignment of time slots to traffic approaching a given junction or intersection in sequence based on pre-programmed time allotment designed to allocate right of way to vehicles or pedestrians arriving the intersection from a particular route.An improvement desired is to alter the sequence and time allotment based on flow of traffic from different route. The system design takes cognizance of vehicle counts and speeds from different route, and allot right of way to vehicles arriving the intersection based on an adaptive algorithm.
DESIGN SPECIFICATION
Given the objectives of this design, which aim at improving vehicular traffic control in a developing country using on-road WSN, the design took into consideration the need to avoid vehicular collision or traffic jam, ensure safety of road users, eliminate or minimise delay at intersections or road junctions.
This is achieved by utilising the enormous potential of WSN to detect, count, compare or analyse the number of vehicles and the speed at which they are arriving a road junction from different routes to determine the right of way granted at the junction. In order to reduce travelling times, the algorithm for granting right of way must take cognisance of traffic conditions in adjoining intersections.
The requirements to be satisfied by the system proposed in this study include the following:
- an intersection of roads carrying traffic to and from four routes as depicted in Figure1
- each of the routes has two lanes
- the routes are separated and protected such that traffic from one route cannot cross to the other route, whereas vehicles on a given route are free to change lane at any
- Right of way given to traffic from any route apply to vehicles on both lanes of the givenroute
- Theright of way is such as to avoid vehicular collision or traffic jam,
i.e. no two routes are given right of way in a manner that could lead to collision
CHAPTER FOUR
IMPLEMENTATION AND SYSTEM TESTING
The system design was subjected to test vide partial implementation and simulation control. The KashimIbrahim /Aminu Kano intersection at Wuse II district of Abuja, the Federal Capital Territory (FCT) of the Federal Republic of Nigeria was selected for the purpose. Figure 4.1 describes or depicts the sketch of the intersection with sensors positioned along the routes. The choice of the road is influenced by observed flow of traffic, which when compared with other two lane roads in the area, records high levelof vehicular movement.
CHAPTER FIVE
CONCLUSION AND FUTURE WORK
CONCLUSION
The study have shown that it is possible to improve on the existing vehicular traffic light control using on-road wireless sensor network (WSN) thereby enhance safety, minimise accidents and loss of lives, reducing travel time of road users, and contribute to economic development of the developing nations.
RECOMMENDATION FOR FUTUREWORK
The need to put the design to work cannot be over-emphasised. The design can be improved upon to link adjacent intersections, such that traffic conditions in adjacent conditions are taken into consideration in determining routes that are granted right of way. The effect of this will further improve vehicular traffic and safety.
A GSM module and a sever may be integrated into the system to provide road users traffic situations ahead of each intersection with a view to taking decisions as to which direction to follow to achieve maximum reduction in travel time.
CONTRIBUTION TO EXISTING KNOWLEDGE
This study has made significant contribution to existing through the introduction of a unique algorithm to determine the best route to grant rite of way at any particular intersection, with the attendant improvement over the existing system.
REFERENCES
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