In this chapter, we shall discuss about an introductory part of Highway Engineering which is considered as an important branch of transportation engineering so as to have the basic knowledge about importance of highway transportation, history of development of roads in India, classification of roads, organization of the state highway department etc.
What is highway engineering?
Highway engineering is one of the branches of civil engineering. It deals with the process of design, construction and maintenance of different types of roads in India.
Scope of Highway engineering:
Apart from the design, construction and maintenance of different types of roads, highway engineering also includes the study of the following topics:
· Development, planning and locations of roads;
· Materials required for their construction
· Highway traffic performance and its' control
· Drainage of roads etc.
Important technical terms related to roads:
Some important terms having immediate concern with highway engineering are discussed below:
A public through fare over which vehicles, cyclists, pedestrians etc. may lawfully move from one place to another is called a road or highway.
Usually, the term highway is used for an important road of national or state importance in a country.
The vehicles, cycles, carts, pedestrians etc. traveling together on a road constitute the traffic.
The portion of roadway of an urban road reserved only for pedestrians is called foot path, side walk or foot way. The minimum width of side walk should be 1.5 meters.
The portion of roadway of an urban road reserved only for bicycles is called cycle track. The minimum width of cycle track should be 2 meters.
The portion of roadway of an urban road reserved for use only by high speed and power driven vehicles is called motor way, express way or super highway.
The land width for an express way is recommended as 50 to 60 meters. The function of express way is to cater for movement of heavy volumes of motor traffic at high speeds.
Importance of highway transportation:
Considering the utility of roads anywhere in the different parts of a country; they can be rightly compared to arterials in a human body.
Just as arteries maintain man's health by providing circulation of blood; similarly Roads promote nation's wealth by keeping its people and goods moving. Thus, we see that progress and well-being of a nation depends much on roads. In fact, roads are the life lines of nation's economy.
The importance or necessity of highway transportation can be easily judged from the following purposes or advantages of roads:-
Highway development in India:
Excavations in the sites of Indus valley, Mohenjo-dero and Harappan civilizations revealed the existence of planned roads in India as old as 2500-3500 BC. The Mauryan kings also built very good roads. Ancient books like Arthashastra written by Kautilya, a great administrator of the Mauryan times, contained rules for regulating traffic, depths of roads for various purposes, and punishments for obstructing traffic.
During the time of Mughal period, roads in India were greatly improved. Roads linking North-West and the Eastern areas through gangetic plains were built during this time.
After the fall of the Mughals and at the beginning of British rule, many existing roads were improved. The construction of Grand-Trunk road connecting North and South is a major contribution of the British. However, the focus was later shifted to railways, except for feeder roads to important stations.
Modern developments
The first World war period and that immediately following it found a rapid growth in motor transport. So need for better roads became a necessity. For that, the Government of India appointed a committee called Road development Committee with Mr.M.R. Jayakar as the chairman. This committee came to be known as Jayakar committee.
Jayakar Committee
In 1927 Jayakar committee for Indian road development was appointed. The major recommendations and the resulting implementations were:
Central Road Fund (CRF), 1929
Indian Road Congress (IRC), 1934
The Indian Roads Congress (IRC) is the Apex Body of Highway Engineers in the country. The IRC was set up in December, 1934 on the recommendations of the Indian Road Development Committee best known as Jayakar Committee set up by the Govt. of India with the objective of Road Development in India.
Nagpur road congress 1943
The Second World War saw a rapid growth in road traffic and this led to the deterioration in the condition of roads. To discuss about improving the condition of roads, the government convened a conference of chief engineers of provinces at Nagpur in 1943. The result of the conference is famous as the Nagpur plan.
A twenty year development programme for the period (1943-1963) was finalized. It was the first attempt to prepare a co-ordinated road development programme in a planned manner.
The roads were divided into four classes:
The committee planned to construct 2 lakh kms of road across the country within 20 years.
They recommended the construction of star and grid pattern of roads throughout the country.
One of the objectives was that the road length should be increased so as to give a road density of 16kms per 100 sq.km.
Central road research institute:
In 1950, Central Road Research Institute (CRRI) was started at New Delhi. This institute is considered as one of the National laboratories of the Council of Scientific and Industrial Research in India. This institute is mainly engaged in applied research and offers technical advice to state governments on various problems concerning to roads.
National highway act:
In 1956, the National Highway Act was passed. According to this act, the responsibility of development and maintenance of National Highways was given provisionally to the central government.
Bombay road congress 1961:
The length of roads envisaged under the Nagpur plan was achieved by the end of it, but the road system was deficient in many respects. The changed economic, industrial and agricultural conditions in the country warranted a review of the Nagpur plan. Accordingly a 20-year plan was drafted by the Roads wing of Government of India, which is popularly known as the Bombay plan. The highlights of the plan were:
Lucknow road congress 1984:
This plan has been prepared keeping in view the growth pattern envisaged in various fields by the turn of the century. Some of the salient features of this plan are as given below:
Classification of roads:
Roads are classified into different categories as under:-
Classification of roads according to location:
According to location and financial responsibility, non-urban roads in India are classified into the following five categories:-
This classification of roads was done as per recommendations made in the Nagpur plan finalized the Indian Roads Congress in 1943. This classification is, therefore, popularly known as IRC classification of road.
The different categories of roads according to this classification are discussed below:-
1. National highways:
The main highways running through the length and breadth of the country connecting major parts, foreign highways and capitals of states etc. are known as National Highways (NH's).
These highways constitute the main arteries of transport in the country and are also of military importance. National highways should have the carriageway of atleast two lane widths. They should have the modern type of surfacing. The responsibility of construction and maintenance of these roads lies with the central govt.
2. State highways:
The highways linking the district headquarters and important cities within the state or connecting them with National highways or with highways of the neighboring states are known as state highways (SH's).
These highways are also called provincial highways. These highways serve as arterial routes of traffic to and from district roads within the state. State highways should preferably be of two lane width. They should also have a modern type of surfacing. The responsibility of construction and maintenance of these road lies with state governments. However, the central government gives grant for the development of these roads.
3. Major district roads:
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 (MDR's).
4. Other District Roads:
The roads serving rural areas of production and providing them with outlet to market centers, Tehsil head quarters, block development headquarters, railway stations etc. are known as Other District Roads (ODR's).
5. Village Roads:
The roads connecting villages or group of villages with each other or with the nearest road of higher category are known as Village roads.
Road Patterns:
Road network can be laid in various patterns. These patterns in which the road network is laid could be
Road Alignment
The position of the layout of the centre line of highway on the ground is called the alignment.
There are two type of alignment:
1. Horizontal alignment
2. Vertical Alignment
The alignment of road should be carefully decided before the construction of road is started. Improper alignment would result in one or more of the following disadvantages:
Requirement of Good alignment:
The basic requirement of an ideal alignment are:
1. Short
2. Easy
3. Safe
4. Economical
Short:
It is desirable to have a short alignment between two terminal stations. A straight alignment would be the shortest. Such a route will be cheap in construction and will reduce the time of travel.
Easy:
The alignment should be such that it is easy to construct and maintain the road with minimum problems. Also the alignment should be easy for the operation of vehicles with easy curves and gradients.
Safe:
The alignment should be safe enough for construction and maintenance. Also it should be safe for the traffic operation with safe geometric feature.
Economical:
The highway alignment should be selected in such a way that the total cost including initial cost, maintenance cost and operation cost is brought down to the minimum level.
Factors affecting road alignment:
Highway Project:
In a new highway project, engineer has to plan, design and construct either a network of new roads or a road link. It should contain information such as..
The following drawings are usually prepared in a highway project;