Transport is the life of a city and choices on public transit options are fundamental decisions about a city’s future growth and development. An efficient transportation system increases accessibility and improves quality of life. The main mode of public transport in the country is the bus. The transport sector in Dhaka is composed of many different modes of travel - both motorized and non-motorized. These diverse modes often use the same road space, resulting in a high level of operational disorder. The deteriorating traffic conditions of the country are causing increasing delays and worsening air pollution. This situation compromises the ability of the transport sector to serve and sustain economic growth and provide an acceptable quality of life. Much needs to be done to serve existing transport needs better, much more will be required to serve the transport needs of a rapidly expanding population in the coming decades. The challenge is to establish an overall framework for a multi-modal transport system that effectively serves current and future land uses. The first full legal document for the transport sector is the Strategic Transport plan(STP). Urban transport Planning is defined in the following way:
Why do people travel?
•
People do not normally travel or move
their possessions for the sake of movement but in order to accomplish something
else, for example, to go to school, to work, to shop, or to visit with friends.
By the same token, workers do not place themselves in the middle of the morning
and evening rush hours because they enjoy traffic congestion but because their
work schedules require it.
•
Therefore, transportation is a derived
demand. The concerns of the transportation experts are the accommodation of
social activities to satisfy the people’s need for mobility.
1.0
Traffic Engineering
The Institute of Traffic Engineers
defines traffic Engineering as “that phase of engineering which deals with
planning, geometric design and traffic operations of roads and streets and
highways, their networks, terminals, abutting lands, relationships with other modes of transportation for
achievement of safe, efficient and convenient movement of persons and goods.”
(Ref. 1)
The definition contained in the
Glossary on Traffic Engineering Terms of the PIARC (Ref. 2) is:
“That phase of engineering which
deals with the planning and geometric design of streets, highways and abutting
lands, and with traffic operation thereon, as their use is related to the safe,
convenient and economical transportation of persons and goods.”
Traffic Engineering is a comparatively new branch of engineering and has grown with the increase in
traffic in recent years. As vehicular traffic began to increase, the congestion
on streets began to hamper the safe and efficient movement of traffic. More and
more accidents were caused, and serious problems of parking and environmental
pollution began to felt. It was, therefore, necessary to give increasing attention
to the operational characteristics of highway transportation and study the need
for better geometric design, capacity, intersections, traffic regulation,
signals, traffic signs, and roadway markings, parking facilities, design of bus
stands, truck terminals, and street lighting.
3.1.1
Collection and Analysis of Factual Data
One of the principal objectives of
the traffic engineer is to replace opinions with facts in various traffic
situations. The work of every traffic engineer will entail a substantial effort
in the collection and analysis of traffic facts.
The simpler types of surveys
include those having to do with traffic volumes (vehicular and pedestrian),
speeds, and accidents.
Physical and economic data are
acquired by the traffic engineer to measure existing conditions and to provide
a basis for estimating future characteristics and needs.
3.1.2
Traffic Regulation
The traffic engineer is the logical
person to supervise the application of many traffic regulations, such as
one-way streets, curb-parking controls, pedestrian controls, turning
restrictions, through streets and regulation of mass transportation.
In dealing with traffic
regulations, the traffic engineer must consider the close relationship of the
controls to enforcement and must work closely with police in planning and
applying most regulations.
3.1.3
Control Devices
There is general agreement that the
traffic engineer should have primary supervision over the application of signs,
signals, markings and traffic control islands. Many public officials also agree
that the traffic engineer should have close supervision and control over street
and highway lighting because of the close relationship of lighting to safety.
3.1.4
Traffic Design
The traffic engineer is primarily
concerned with the operational qualities of roadway design.
Experiences have shown that there
is much that the traffic engineer can contribute from his studies and knowledge
of traffic characteristics and future traffic needs that will be helpful in the
work of design departments, and also in administrative decisions relative to
the reconstruction and new construction of public ways.
3.1.5
Cooperative Activities
Because traffic engineering is so
broad in its interests and applications, the traffic engineer must participate
in many cooperative activities. The needs of traffic engineer must be evaluated
in terms of the needs of other traffic agencies.
3.1.6
Administrative Functions
In addition to basic functions of
business management and personnel relations the traffic engineer must undertake
in the operation of his own department, there are numerous ways in which he or
she can assist in key administrative decisions.
3.1.7
Other Functions
Traffic engineers and traffic
engineering bureaus engage in other activities than those already enumerated.
Almost all have a direct interest in traffic laws and ordinances.
Some traffic engineering
departments are given the responsibility of issuing various types of permits; for
example, controlling the movement of overloaded and oversized vehicles on the
public ways, road openings, and access controls.
Definition of Transportation System:
A transportation system may be
defined as consisting of the fixed facilities, the flow entities and the control system that permit people and goods to overcome the friction of
geographical space efficiently in order to participate in a timely manner in
some desired activity.
Functional
Components of a Transportation Systems:
·
Fixed
facilities: Fixed facilities are the physical components of the system that are fixed in space and constitute a network of links (e.g., roadway
segments, railway tracks, tunnels) and nodes (e.g., intersections,
interchanges, transit terminals, harbors, airports) of the transportation
system. The development of fixed facilities needs capital investment.
·
Flow
entities: Flow entities are the units that traverse the fixed
facilities. They include vehicles, container units, railroad cars, etc. In
highway design, fixed facilities are expected to accommodate a variety of
vehicle types, ranging from bicycles to large tractor-trailer combinations. The
operating cost of the transportation mode depends on the flow entities.
·
Control Systems:
Ø The the control system consists of vehicular control and flow control.
Ø Vehicular
control refers to the technology in which individual vehicles are guided on the
fixed facilities.
Ø Such
control can be manual or automated. The control system determines the
efficiency of the system.
Ø The the flow control system consists of the means that permit the efficient and smooth
operation of streams of vehicles and reduction of conflicts between vehicles.
This system includes signing, marking, and signal systems.
Usually a
transportation system is formed with the combination of two or more modes. The efficiency of a transportation system of a region is judged on the basis of the following criteria:
· 1. Safety
· 2. Adequacy
· 3. Comfort
· 4. Per head Cost
· 5. Fuel Efficiency
Major
Transportation Subsystems
Four major
subsystem
Land Transportation
·
Highway
·
rail
Air Transportation
·
Domestic
·
International
water Transportation
·
Inland
·
coastal
·
Ocean
Continuous transportation
·
Pipeline-Oil,
gas and other
·
Ropeway
Impacts
of transportation
•
Land development
–
Change in land
value
–
Inappropriate
land development
•
Pollution
–
Air quality
–
Noise pollution
•
Social impact
•
Transportation
and land use
