CHAPTER ONE
INTRODUCTION
1.1 Background of the study.
The monitoring and control of vehicular
traffic and pedestrians pose a major challenge to transport authorities
around the world. The escalating number of vehicles in cities not only
has a huge environmental impact, but also results in loss of lives on
the road. This situation demands a comprehensive approach involving a
system in which both the traffic controls for vehicles and pedestrians
are coordinated so that road users are safe and traffic is smoothly
flowing. Currently, pedestrian crossings pose a significant hazard in
many countries, both in developed and developing countries due to the
increase in the number of vehicles. Each year a staggering figure of
500,000 pedestrians are killed all over the world and in China alone
from 2000-2004, half a million pedestrians were killed (Zhen Liu,
Simulation of Pedestrians in Computer Animation in Proceedings of ICICIC
(2) 2006. pp. 229~232.).
The European Transport Safety Council
(ETSC) claims that 15 to 30 percent of the transportation mode used is
walking. According to a telephone survey conducted by the Royal
Automobile Club of Spain in the year 2000, walking is highly recommended
as part of a healthy lifestyle with no negative side effects. However,
it has been the victim of badly controlled traffic, thus increasing the
mortality rates of road users. In the large cities of Europe, especially
in Spain, people walked to their destinations but this is being seen as
dangerous as pedestrians are more vulnerable to road accidents than
passengers and drivers of cars (European Transport Safety
Council(ETSC),http://www.etsc.be/stats3.ppt.). In a conventional traffic
light controller, the traffic lights change at a constant cycle time
which is clearly not the optimal solution. The system calculates the
cycle time based on average traffic load and disregards the dynamic
nature of the traffic load, which aggravates the problem of congestion.
Consequently, we see an urgent need to
optimize traffic control algorithms to accommodate the increase in
vehicles in urban traffic that experience long travel times due to
inefficient traffic light controls and to improve pedestrian’s safety.
In this paper, we propose an optimal
control of traffic lights using a genetic algorithm (GA), in a four-way,
two-lane junction with a pedestrian crossing. The innovative design of
the pedestrian crossing is also based on such algorithm, which includes
pedestrians as one of the parameters. The specific genetic algorithm
used in this work is a standard genetic algorithm. A Genetic Algorithm
is an adaptive and efficient heuristics that is able to solve
optimization problems. This is a stochastic search technique to look for
optimal solution. Most genetic algorithms are used in research and
science related works to look for optimal solutions. They usually run on
powerful computers as genetic algorithms generally are resources taking
in terms of CPU time and memory size. Some methods a genetic algorithm
uses are selection, crossover and mutation inspired from evolution in
the real nature. Genetic algorithm is introduced in the traffic control
system to provide an intelligent green interval response based on
dynamic traffic load inputs, thereby overcoming the inefficiencies of
conventional traffic controllers. In this way, the challenges are
resolved as the numbers of vehicles are read from sensors put at every
lane in a four-way, two-lane junction and pedestrians are monitored at
the road junction.
The features inherent in genetic
algorithm play a critical role in making them the best choice for
practical applications, namely optimization, computer aided design,
scheduling, economics and game theory. It is also selected because it
does not require the presence of supervisor or observer.
However, genetic algorithms, without
prior training, continuously allow permanent renewal of decisions in
generating solutions. Instead of trying to optimize a single solution,
they work with a population of candidate solutions that are encoded as
chromosomes. Within these chromosomes are separate genes that represent
the independent variables for the problem at hand.
There are a number of specific
attributes of genetic algorithms that give them an edge over other
traditional optimization techniques. These are:
- A genetic algorithm works from a population, not a single point, and hence it is likely to be trapped at a local optimum.
- Derivative freeness, i.e., a genetic algorithm does not need the objective function’s derivative to do its work.
- Flexibility, i.e., a genetic algorithm can function just fine
regardless of how complex the objective function is; the only thing it
requires of the function is that it is executable (i.e., its value can
be calculated given the values of the decision variables).
- Because of its implicit parallelism, a genetic algorithm can handle
combinatorial problems efficiently. It has been shown that as the size
of the search space or number of solutions increases exponentially, the
time requirements for the genetic algorithm to reach a solution only
grows linearly. This feature is particularly useful for on-line
optimization of transportation problems such as traffic control.
- A genetic algorithm naturally lends itself to parallel implementation. This follows from its functional components structure.
- Genetic algorithm is, for the most part, based on intuitive notions and concepts.
The preliminary review of the literature
indicates that genetic algorithm has not been tested on pedestrian
crossings. This work has, therefore, attempted to implement this
algorithm and study its effects on this problem.Ayad Mashaan Turky, Mohd
Sharifuddin Ahmad and Mohd Zaliman Mohd Yusoff, Use of Genetic
algorithm for Traffic Light and Pedestrian Crossing Control, (2009).
pp.1-2.
From a recent analytical
statistics of the Nigerian Ministry of Transportation 2010, it is
estimated that roughly half of the congestion is what is known as
recurring congestion, which is caused by recurring demands that exist
virtually every day, where roads use exceeds existing capacity and bad
roads. The other half is due to non-recurring congestion caused by
temporary disruptions. Four main reasons of non-recurring congestion
are: traffic incidents (ranging from disabled vehicles to major
crashes), work zones, weather and special events. Expert systems with
Application systems dramatically reduce available capacity and
reliability of the entire transportation system. Therefore, researchers
have carried out many researches to increase capacity and remove
bottlenecks. Schaefer, Upchurch and Ashur (2008) developed a simulation
model for evaluating freeway lane control signing. The simulation
results show that the lane control has little influence on congestion.
However, the region between heavy and medium traffic flow is sensitive
to lane control. This is why the Genetic algorithm has been proposed to
solve this major problem, because by making use of this algorithm,
traffic quality can be improved and operation costs can be reduced.
1.2 Statement of the Problem
Port Harcourt and indeed Nigeria
alongside other developing countries are facing serious traffic
congestion problem due to rapid motorization and rapid population growth
in their cities. Infrastructure development could not match the rapid
motorization. As a result, serious congestion occurs almost at every
intersection during peak hours mainly because of the inability of signal
system to provide optimum flows, either due to the imbalance green time
split or optimum band width for progressive flows. Thus this project
work has come with the view of designing an expert system to check this
difficulty in the urban and sub-urban metropolitan areas of our country.
1.3 Objectives of the Study
The aim of this project is to
develop and design an effective traffic control system that can monitor
and regulate traffic congestions within the road network in our cities.
Aims include:
- To design a traffic system that is not only time based but traffic based on highly packed junctions.
- To design a traffic control system that will be available round-the-clock
- To design a system that coordinates traffic flow using the appropriate programming language.
1.4 Significance of the Study
The uniqueness of the project
is not only for clearing the traffic but it shares time slot equally
between two sides of a junction. It is going to be a useful project for
traffic police to prevent road accidents and promote safety on the road
for road users. Since automotive technologies are gaining ground in
modern day traffic-control systems and the number of vehicles and
passengers is rapidly growing, traffic control systems are needed to
ensure the safety of all parties involved which include, pedestrians who
obediently wait for traffic signal to interrupt traffic so they can
cross and drivers who also patiently wait for their turn to move.
1.5 Scope of Study
This work is essentially
intended to design an efficient traffic control system to control
traffic in the urban areas and industrial estates across the country. It
looks at controlling traffic in a four-way, two lane junction.
1.6 Limitations of the Study
This study was limited by some factors which include:
- Limited materials: due to some materials being inaccessible, I only had to work with the few I could get.
- Technical issues: owing to the fact that my system’s battery had expired, I could only work on my project when there was power supply.
- Time factor: because of the challenges mentioned above and others, the time given to finish my project work was not enough.
1.7 Definition of terms
It’s pertinent to highlight and define properly some important terms that are used in this work. They include:
Algorithm: a process or set of rules to be followed in calculations or other problem-solving operations, especially by a computer.
Congestion: the state of being overcrowded, especially with traffic or people.
Control: this is the
action necessary to ensure that plans and objectives are being achieved.
Control as applied to road traffics is the act of directing vehicles
(motorists) and pedestrian traffic around a construction zone in order
to be free from accidents and other road disruptions.
Genetic: of or relating to genes or origin.
Traffic: this is defined as the vehicles that are travelling in an area at a particular time.
Traffic light: which is
also known as ‘stop light, traffic lamps, traffic signal, signal light,
robot or semaphore’ is a signalling device which is positioned at road
intersections, pedestrian crossings and other locations to control
competing flows of traffic. Traffic lights alternate the right of way of
road users by displaying lights of standard colours (red, amber and
green) using a universal colour code.
Transportation: the action of transporting someone or something or the process of being transported.