TRANSPORTATION
ENGINEERING
UNIT :- 01
OVERVIEW OF HIGHWAY
ENGINEERING
NGP PATNA -13
CIVIL ENGG.
❑ ROLE OF TRNSPORTATION
The roles of transportation in society can be classified according to economic, social, political and
environmental roles. The social role of transport has caused people to live in permanent settlements
and has given chances of sustainable developments. Regarding political role, large areas can now be
very easily governed with the help of good transportation system.
❖ Economic role of transportation
1.Transport extends the range of sources of supply of goods to be consumed in an area, making it
possible for user to get resources at cheap price and high quality.
2.The use of more efficient systems of supply results in an increase in the total amount of goods
available for consumption.
3.Since the supply of goods is no longer dependent on the type of mode, items can be supplied by
some alternative resources if usual source cannot supply what is needed.
❖ Social role of transportation
Transportation has always played an important role in influencing the formation of urban societies.
Although other facilities like availability of food and water, played a major role, the contribution of
transportation can be seen clearly from the formation, size and pattern, and the development of
societies, especially urban centers.
❑ Formation of settlements
From the beginning of civilization, the man is living in settlements which existed near banks of major
river junctions, a port, or an intersection of trade routes. Cities like New York, Mumbai and Moscow are
good examples.
❑ Size and pattern of settlements
The initial settlements were relatively small developments but with due course of time, they grew in
population and developed into big cities and major trade centers. The size of settlements is not only
limited by the size of the area by which the settlement can obtain food and other necessities, but also by
considerations of personal travels especially the journey to and from work. The increased speed of
transport and reduction in the cost of transport have resulted in variety of spatial patterns.
❑ Growth of urban centers
When the cities grow beyond normal walking distance, then transportation technology plays a role in the
formation of the city. For example, many cities in the plains developed as a circular city with radial
routes, where as the cities beside a river developed linearly. The development of automobiles, and other
factors like increase in personal income, and construction of paved road network, the settlements were
transformed into urban centers of intense travel activity.
Political role of transportation
The world is divided into numerous political units which are formed for mutual protection,
economic advantages and development of common culture. Transportation plays an important
role in the functioning of such political units.
1 Administration of an area
The government of an area must be able to send/get information to/about its people. It may include
laws to be followed, security and other needful information needed to generate awareness. An efficient
administration of a country largely depends on how effectively government could communicate these
information to all the country. However, with the advent of communications, its importance is slightly
reduced.
2 Political choices in transport
These choices may be classified as communication, military movement, travel of persons and
movement of freight. The primary function of transportation is the transfer of messages and
information. It is also needed for rapid movement of troops in case of emergency and finally movement
of persons and goods. The political decision of construction and maintenance of roads has resulted in
the development of transportation system.
➢ MODES OF TRANSPORTATION
Modes of transportation are designed to carry both the passengers and goods from one place to
another & the different modes of transportation are used for the physical movement across the border
or transport of goods and most modes of transportation can carry a combination of both passengers
and goods.
MODES OF TRANSPORT:
There are many modes of transportation as discussed below;
1.Road Transportation
2.Rail Transportation
3.Air Transportation
4.Water or Maritime Transportation
Road transportation
The road is one of the common modes of transportation and provides a seamless movement of goods
even across various countries and states. Road transportation uses certain types of vehicles such as
automobiles, bicycles, vans or trucks, and buses, etc.
BENEFITS OF ROAD TRANSPORTATION:
1.Scheduled and quick delivery.
2.Cost-effectiveness.
3.Deliveries in local, over the border, even in rural areas.
4. Flexible service.
5.Compared to other modes of transportation this mode saves the packing cost.
6.Complete door to door service and more economical.
RAIL TRANSPORTATION:
Rail transportation is also one of the commonly used modes of transportation and rails burn less fuel per
ton-mile than road vehicles. With rail transportation systems heavy industries are traditionally linked and
rail is a land transportation mode which offers the highest capacity with 23,000 tons.
The railways are constructed on the lands and used for the transportation of goods or people but at the
end of the rail transit, a road delivery will be needed and there will be a lift cost which transfers the
container between the road vehicle and the train.
➢ BENEFITS OF RAIL TRANSPORTATION:
There are following benefits of rail transportation such as;
1.Reliable schedules and transit times.
2.Most efficient form of land transportation.
3.Over long distance fast and cost-effective.
4.The safety record of rail is strong.
5.It helps in alleviating road congestion.
❖ AIR TRANSPORTATION:
World air cargo traffic to meet the demand for growth and air transport is the critical mode of transport
and serves the demand speed of markets and supply chains.
➢ BENEFITS OF AIR TRANSPORTATION:
There are following benefits of air transportation such as;
1.Quick transit & less handling of cargo.
2.Less documentation.
3.Reliable departures and arrival.
4.For cargo enhanced level of security.
WATER OR MARITIME TRANSPORTATION:
Water or maritime transportation is the most effective mode to transport large quantities of cargo over
long distances and the main routes of maritime are oceans, seas, channels, rivers, & lakes. The
transportation of goods or passengers via water-ways is called maritime transportation and this type of
transport is cheaper than air transport.
BENEFITS OF WATER TRANSPORTATION:
There are following benefits of water or maritime transportation such as;
1.It can transport large volumes at low cost.
2.They can transport heavy loads.
3.More eco-friendly.
4.Reduces the distance compared to land transport.
❖ Classification of Roads
The classification of roads is mostly based on following conditions :
•According to traffic.
•According to transported tonnage.
•According to Importance.
•According to location and function.
Classification of Roads According to Traffic :
Based on traffic volume the roads are classified as follows :
Types of Roads Vehicles Per Day
Very heavy traffic roads Above 600
Heavy traffic roads 251 to 600
Medium traffic roads 70 to 250
Light traffic roads Below 70
Classification of Roads According to Tonnage :
Based on total tonnage per day, the roads are classified as follows :
Types of Road Vehicles Per Day
Very heavy traffic roads Above 1524
Heavy traffic roads 1017 to 1524
Medium traffic roads 508 to 1017
Light traffic roads Below 508
3. Classification of Roads According to Importance :
According to importance of connecting holy places, stations or major cities etc, roads are classified as follows :
•Class 1 Roads.
•Class 2 Roads.
•Class 3 Roads.
❖ Classification of Roads by Nagpur Road Plan
Different Road categories according to this classification are discussed below :
➢ National Highways (NH) :
The main highways running through the length and breadth of India, joining major parts, capital of states, large
industrial and tourist centers, foreign highways including roads required for strategic movements for the defence of
India etc. are known as National Highways (NHs).
All the national highways are assigned with the respective numbers.
For example:
•Amritsar- Ambala- Delhi Road- NH1
The responsibility of construction and maintenance of these roads lies with the central government.
➢ State Highways (SH) :
The highways linking up with the national highways of adjacent states, district headquarters and important cities
with the states are known as State Highways (SHs).
The geometric design specifications and design speed for NH and SH are same. These highways serve as arterial
routes of traffic from district road within the state.
The responsibility of construction and maintenance of these roads lies with state government. However, the central
government gives grant for development.
➢ Major District Roads (MDR) :
The important roads within a district serving areas of production and markets and connecting these places with
each other or with the main highways are known as Major District Roads (MDRs).
The responsibility of construction and maintenance of these roads lies with District Authorities. However, the state
government gives grant for development of these roads.
➢ Other District Roads (ODR) :
The roads serving rural areas of production and providing them with outlet to market centers, tahsil headquarters,
block development headquarters, railway stations etc. are known as Other District Roads (ODRs). This have lower
design specification than MDR.
➢ Village Roads (VR) :
The roads connecting villages or group of villages with each other or with the nearest road of higher category are
known as village roads.
These roads are very important from the rural area development point of view. They are generally un-metalled with
single lane width of stabilized soil or gravel. The responsibility of construction and maintenance of these roads lies
with the local district authorities.
❖ Classification of Road System by Third Road Development Plan (1981-2001)
According to the third road development plan, the roads in the country are classified into three classes, for the
purpose of transport planning, functional identification and assigning priorities on a road network :
•Primary System.
•Secondary System.
•Tertiary System.
1. Primary System :
•Express Ways
•National Highways (NH)
(a) Express Ways :
Express ways are a separate class of highways with superior facilities and design standard and are meant as through
routes having very high volume of traffic. These highways should permit only fast moving vehicles.
Express way may be owned by central government or a state government depending on whether the route is a
national highway or state highway.
2. Secondary System :
The secondary system consists of two categories of roads
•State Highways (SH)
•Major District Roads (MDR)
3. Tertiary System :
The tertiary system are rural roads and these consists of two categories of roads :
•Other District Roads (ODR)
•Village Roads (VR)
❖ Classification of Urban Roads :
The road system within urban areas are classified as urban roads. The urban authorities are responsible to take care
of these roads.
Generally the urban roads other than the express ways are classified as :
•Arterial Roads.
•Sub- Arterial Roads.
•Collector Streets.
•Local Streets.
➢ Arterial Roads :
The streets primarily for through traffic on a continuous route, but with high level of traffic mobility are known as
arterial roads.
➢ Sub- Arterial Roads :
The streets primarily for through traffic on a continuous route but have a lower level of traffic mobility than the
arterials are known as sub-arterial roads.
➢ Collector Street :
The streets which provides access to arterial streets and they collect and distribute traffic from and to local streets
is known as collector streets.
➢ Local Street :
The streets which provides access to abutting streets are known as local streets.
What is Highway Alignment?
The position of the central line of the highway or the layout of the planned highway line on the
ground is called HighwayAlignment.
Highway Alignment is generally phrased as two types on Highway plans
The ideal Highway alignment should meet the following criteria :
•The alignment should be designed in such a way that the distance between the start point and the endpoint
of the road should be short and straight with fewer curves.
•The alignment is selected in such a way that it should be very easy to construct and maintain. A good
alignment should be linear and have fewer gradients and slopes. To achieve this, a small deviation in
alignment is permitted.
•The alignment should be considered only when the operation cost, initial cost and maintenance cost is least.
•The selected alignment should be safe during construction, especially at embankments, slopes, hilly areas
and at gradients.
❖ Factors controlling the Highway alignment:
➢ 1. Obligatory Points:
The control points governing highway alignment are called obligatory points. These points decide where
the alignment should pass and where the alignment should not pass.
➢ Alignment Should pass:
Roads are constructed for the development of the areas. A small deviation in alignment can be acceptable
if highway passes through the towns, villages, cities etc.
If the alignment passes through the mountain, it is recommended to relook the best alternatives, either to
construct the tunnel or go round the hills. The selection of the choice depends on factors like topography,
site conditions and construction and operation cost,
➢ Alignment should not pass:
It is always recommended to avoid the alignment on small lakes and ponds and deviate the alignment upto
some extent where required, construction of bridges on these lakes and ponds requires more funds.
The alignment should not pass through the places which are developed or having expensive buildings or
high rise buildings acquisition of land at these places incurs huge initial cost and demolishing these
structures takes more time.
➢ The volume of traffic:
The volume of traffic and an increase in the traffic volume per year and peak traffic is analyzed and
alignment is finalized by considering all previous data of traffic respectively.
➢ Type of Traffic:
If the traffic is of vehicular type and for fast-moving vehicles, it is advised to keep the alignment as
straight as possible with fewer curves. Separate lanes for fast-moving vehicles are recommended.
➢ Earthwork and backfilling:
Earthwork and backfilling to level the land constitutes huge costs after the land acquisition. The
alignment has deviated wherever required to avoid the excessive cutting of earthwork and backfilling.
➢ Railway Crossing:
Road alignment should cross a rail lane ideally at 90Degrees.
For fast-moving lanes or national highways or expressways, it is advisable to construct the bridge
over rail lane to avoid the traffic jams.
➢ Sight Distance:
To avoid accidents, minimum sight distance should always be available for the drivers. The alignment
should not obstruct the visibility of drivers, especially during nights.
➢ Proper Drainage:
Proper water drainage is provided at the edges of the alignment to avoid water logging during monsoon.
➢ Stability of Slopes:
Special care is to be taken for road alignment in hilly areas, the problem with the hilly areas is landslides.
The road should be aligned to the side of the hill which is stable. Excessive earthwork cutting and
backfilling affect stability.
➢ Monotony:
Straight and even road alignment are possible for flat terrain but it monotonous for driving which may lead
to accidents for a sudden curve. It is recommended to keep the slight bend for every few miles to alert the
driver.
.
➢ Economy:
The initial cost, operating cost and maintenance cost should be minimum for the finalized alignment.
Avoid High embankments and deep cutting to reduce the cost of construction.
➢ Formation bed:
The alignment should go through the good soil having enough strength, to achieve this a slight change in
alignment is acceptable
➢ THANK YOU
