CE 6504 - HIGHWAY ENGINEERING UNIT I HIGHWAY PLANNING AND ALIGNMENT Significance of highway planning – Modal limitations towards sustainability - History of road development in India – Classification of highways – Locations and functions – Factors influencing highway alignment – Soil suitability analysis - Road ecology - Engineering surveys for alignment, objectives, conventional and modern methods. Road: A road is a route, or way on land between two places that has been paved or otherwise improved to allow travel by some conveyance, including a horse, cart, bicycle, or motor vehicle etc., Roads consist of one or two carriageways, each with one or more lanes and any associated sidewalks. Roads that are available for use by the public may be referred to as public roads or as highways. Road transport is one of the most common mode of transport. Roads in the form of trackways, human path ways etc., were used even from the pre-historic times. Since then many experiments were going on to make the riding safe and comfort. Thus road construction became an inseparable part of many civilizations and empires. The different means of transport that we commonly use in our life can be divided into three main categories: 1. Land transport 2. Water transport 3. Air transport Mr.P.BALAMURUGAN.ME, AP/CIVIL DEPARTMENT OF CIVIL ENGINEERING/DSIT 1
1. Land Transport: All Vehicles those move on road like scooters, cars, truck etc., included in Land Transport. But Land transport can be subdivided in two more type: Roadways and Railways Roadways / Highways: -All states of a country are connected to each other by roads and highways. These highways are well-constructed and different types of vehicles used for different distances. Scooters, bikes and auto etc. used for short distances while cars, buses and trucks used for covering long distances. Buses is the main carrier for travellers, where as for carrying raw material and finished good from factories to market, Trucks are most useful. Railways: In all countries of the world, all major cities are connected with railways. Even some countries are also connected by railway. Trains carry people and bulky goods over long distances. India has the second largest network of railways in the world. Metro is the latest and improved railway system which is most comfortable. 2. Water Transport: Boats, ships, steamers and submarine are included in water transport. Boats and ships are used as carriage of people and goods. In early days people used rafts and simple boats as water transport. Boats are used for short distances while ships are used for covering longer distances. Cargo ships are used to transport tones of goods like oil tankers for carrying goods, internationally. Submarine is used for naval forces of the nations. It is mainly used for naval operation in war or for rescue operation of sinking ships in the oceans. They mostly remain submerged in water, hence fit for deep seas and oceans only. 3. Air Transport: Air Transport includes airplanes and helicopters which are very fast means of transport. Today, almost all nations of our earth are interconnected by air transport. However, air transport is more expensive as compared to other means of transport.
Highway: A highway is any public road or other public way on land. It is used for major roads, but also includes other public roads and public tracks. Highway engineering: Highway engineering is an engineering discipline branching from civil engineering that involves the planning, design, construction, operation, and maintenance of roads, bridges, and tunnels to ensure safe and effective transportation of people and goods. Highway planning: Road planning is part of community planning. It is part of a planning system in which plans for traffic, land use and areas are all integrated. SIGNIFICANCE OF HIGHWAY PLANNING: Roads and highways have a pervasive effect on social, economic, energy, environmental and land-use issues. Planning for roads therefore begins within a broader planning and policy framework, in which the inter-connectivity between roads and other factors is established. The importance or necessity of highway transportation can be easily judged from the following purposes or advantages of roads: They facilitate conveyance of people, goods, raw-materials, manufactured articles, etc. speedily and easily in the different parts of a country. They act as the only source of communication in regions of high altitude i.e in mountainous regions. They help in growth of trade and other economy activities in and outside the villages and towns by establishing contact between towns and villages. They help in providing efficient distribution of agricultural products and natural resources all over the country. They help in price stabilization of commodities due to mobility of products all over the country. Mr.P.BALAMURUGAN.ME, AP/CIVIL DEPARTMENT OF CIVIL ENGINEERING/DSIT 3
They help in social and cultural advancement of people and making the villagers active and alert members of the community. They help in promoting the cultural and social ties among people living in different part of a country and thus strengthen the national unity. They help in providing improved medical facilities quickly to human beings, especially to those who live in rural areas. They provide more employment opportunities. They enhance land value and thus bring better revenue. They serve as feeders for Airways, Waterways and Railways. They help in reducing distress among the people, caused due to famine, by supplying them food and clothing quickly. Objectives of Highway Planning: Every highway planning is done with the following objectives. 1. To establish an integrated highway network with minimum cost capable of encompassing all highway travel in a most safe, efficient, economical and orderly manner. The minimum cost should include initial cost of construction, maintenance cost, renewal cost of pavement layers and the vehicle operation costs. 2. To plan a highway system this could be constructed within the available resources during the proposed plan period with maximum utility. 3. To forecast the future requirements of road needed and improvements of roads. 4. TO phase out the entire highway development during the plan period by identifying the priorities keeping in view utility as the main criterion. 5. To workout financing system.