Basic Concept of Transportation Planning (1)

 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.”

2.0 Why it is necessary for Urban Planning?

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.

3.0 Theoretical Discussion

3.1 The function of Traffic Engineering

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