Welcome to Edukum.com

Introduction to Transportation Planning and Engineering

Introduction
A transportation system may be defined as consisting of the fixed facilities, the flow entities, and the control systems 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.
The transportation system as defined by ITE-Institute of Transportation Engineers can be summed up as the application of technology and scientific principles to the planning, functional design, operation and management of facilities for any mode of transportation to provide safe, rapid, comfortable, convenient, economical and environmentally compatible movement of people and goods.

  • Role of Transportation in Society
    Transportation is an inseparable part of a society. In fact, the measure of the development of any society is characterized by how developed transportation system is. Advancement in transportation has made a vast change in the quality of life of people. Impact of transportation can be summarized as below:
    • Economic Role
      Transportation plays an important role in developing the economic aspect of a society. Economics involves production, distribution, and consumption of goods and services which are inevitable without the transportation facility.In a country like Nepal which has a wide gap between production and consumption, an effective mode of transportation can always be helpful for its economic growth.
    • Social Role
      Development of transportation system influences the formation of urban society. It links rural areas with urban ones transporting goods from one place to other, eventually helping in overall development.
    • Political Role
      The world being divided into different political units is linked by transportation of both people and goods through different modes. Transportation plays a vital role in functioning of these political units.
    • Environmental Role
      The environment is highly affected by transportation. It's harmful aspect is more prominent than its useful aspects. Air pollution, noise pollution, overuse of non-renewable energy etc. are some of its impacts on the environment.
  • Components of Transportation System
    A transportation system consists of different components which together allow people and goods to overcome the hindrance of geography. The different components are:
    • Fixed Facilities
      These are the physical components of the system which are fixed. Road, railway track, ocean or waterways, airports harbor etc. are fixed facilities of their respective modes.
    • Flow Entities
      These are the components that travel through fixed facilities. They mainly include vehicles and are considered on the basis of shape, size, weight, acceleration and deceleration abilities. For example road vehicles, trains, aircraft, ships etc.
    • Control System
      This system consists of vehicle control and flow control.
      1. Vehicle control refers to the technological way in which the vehicles are guided either automatically or manually.
      2. Flow control refers to the efficient way of allowing vehicles to flow in their respective modes. For example, traffic control using traffic lights, at the intersection, road signs and markings, air traffic control etc. help in the smooth flow of vehicles.

Modes of Transportation
On the basis of mediums (mode of transportation) on which the flow entities are supported transportation system is classified as below:

Modes of Transportation

Comparison Between Various Modes Of Transportation
The description and comparison between different modes are briefly described below:

  • Primary Mode
    • Land Transportation
      • Highway
        The major advantage of the highway is that it has high accessibility to almost all potential destinations, direct service with very low door-to-door travel times, moderate speeds and capacities. Capital cost for physical facilities is also moderate. Vehicles are small and readily available at a low cost. However operating cost tends to be higher. Environmental impacts of the system as a whole are high and are a major social concern.
      • Railway
        The railway system provides moderate speeds and levels of accessibility but traditional operating practices lead to high and unreliable door-to-door travel times. A heavy capital must be invested in both physical facilities and flow entities. However for transportation of a lot of goods, if not possible through oceans and airways, railway comes in very handy. Accessibility is only limited to railway stations.
    • Air Transportation
      The main advantage of air transport is its high speed and less time consumption. Accessibility is limited but is of less importance as greater lengths of trips are made. Capital investment as well as operating and maintenance cost for both fixed and flow entities are higher than other modes. Environmental impacts are significant, air and noise pollution of commercial aviation but are of less concern than that of highways.
    • Water Transportation
      Water transportation provides low speed and relatively low accessibility, but extremely high capacities. The capital cost of vehicles, especially ships are very high but operating cost is low for a large distance. So if a lot of goods is required for transportation, this mode can be used for best results. Environmental effects are relatively low but the chances of water pollution due to leakage of oil and petroleum products are high.
    • Pipeline Transportation
      The transport of daily use products and wastes to the desired location encompass pipeline transportation. They provide very low speed, but the high capacity constant flow and involves a large amount of working storage. Environmental impacts are generally low.
  • Secondary Mode
    A variety of other modes also exists although they do not contribute in major transportation, however, are inevitable. Cable and belt are systems extensively used in industries. Canals are also used in transportation for irrigation system in rural areas. Ropeways are another important transportation in hilly terrain.
    In the Context of Nepal, Nepal is a landlocked country. The possibility of waterways is less due to the presence of fast flowing rivers. So water transport is only limited to small distances for fishing and crossing the rivers. Also, most of the area is covered by hills and mountains. So the potentiality of any mode of transport becomes less. But road transport is the best option Nepal has carried out so far. However, there is a lot of potential for rope ways and railways. Although it is difficult to provide railways at every place it can be a useful mode of transport. The government of Nepal has established a Department of Railways giving more priority on the development of railway tracks. Similarly, rope ways program is also being started at different places in Nepal.
    • Private and Public Transportation
      Transportation system can also be classified as for-hire and not-for-hire services. These are also known as public and private transportation respectively. They refer to availability rather than their ownership.For-hire systems can be further classified into contract carriers and common carriers. Contract carriers provide service to public under individual contract whereas common carriers offer scheduled services and are open to all who are willing to use it.
  • Historical Development of Roads and Road Construction In Nepal
    The history of road making is related to the development of human civilization. People’s desire to choose an easy path for hunting and fishing became the sole purpose for the development of roads back then which later on gave a platform for the development of roads. The most outstanding works towards the development of modern roads are as follows:
    • Roman Road
      Roman Roads
      Road construction was extensively developed during the Roman Empire. During this period roads were constructed on a large commercial scale. The roman road network built during seven centuries extended over a total length of 90000 km. of which about 14000 km still exist in present day. They were constructed using large foundation stones and kerb stone placed at 0.75 to 1.2 m deep trench from the existing ground level. Although these roads were not made with good engineering practice, these roads were very strong and can even handle modern day traffic as a lot of investment was done on it.
    • Tresaguet Construction
      Tresaguet Roads
      Tresaguet in 1775 developed an advanced method of construction with total depth of only 30 cm maximum. He was the first man to realize the importance of surface drainage and its methodical maintenance. However his construction did not confirm the present day theory of soil science. His proposal was much cheaper than Roman Road.
    • Telford Construction
      Telford Roads
      While Tresaguet developed his typical pavement detail in France in 1764 and implemented in 1775 Telford in England started his work independently and proposed a similar type of construction. Sub-grade was however kept horizontal and sloping surface on the top was achieved. As the lateral confinement Telford used a block made of broken stones in lime mortar. This construction also did not confirm the theory of soil science.
    • Macadam Construction
      Macadam Roads
      John Macadam (1756-1836), a Scottish road builder, is considered as the pioneer of modern road construction. He was the first man to realize the importance if sub-grade drainage in addition to surface drainage. He also was the first person to notice the baseless use of hard stones in the base. Stress below the wheel will be reduced as the depth increases. The theory of soil science was first realized by Macadam. His construction has influenced the road construction so profoundly that most of the modern road construction bears his name. The total thickness of the pavement suggested by him was 25 cm stability and strength of pavement structure was assumed to be the result of internal friction between the aggregate and cohesion created by stone powder formed by attrition of stones under the traffic.
    • Modern Roads
      The type of road discussed above with granular surfacing completely satisfied the requirement of animal driven transport. The engineering science and technique of construction improved appreciably, the practice of laying surfacing with the uniform grain size compacted by vehicles being superseded by surfacing in which the granular material was blended during rolling with loose fine soil aggregates. With the advantage of mechanically propelled vehicles at the beginning of this century it was necessary to alter radically the construction of road pavements.

Road construction in Nepal

  • 70,000 km distance road is constructed in Nepal.
  • Local roads contribute to distance more than 52000 km.
  • Headquarters of Dolpa and Humla are not connected with roads.
  • 400 villages are devoid or roads. 15000-20000 km roads are to be constructed to overcome this.
  • Out of Bhaktapur, Kathmandu and Lalitpur, Bhaktapur is highly fascilated with roads.
  • 60% of National Highways are black topped.
  • 40-50% of Feeder roads are black topped.

Bibliography
Marsani A. and Shrestha D.K. (2071), Transportation Engineering Volume - I, Divine Print Support, Lagan Tole, Kathmandu
Parajuli P.M. (1999), Course Manual of Transportation Engineering - I, IOE, Pulchowk Campus, Lalitpur, Nepal.
Nepal Road Standard 2070
Nepal Rural Road Standard 2071

 


© 2019 EDUKUM.COM ALL RIGHTS RESERVED


#Things To Remember



1047 Views