Following types of roads are generally constructed to meet with the various types of traffic:
1. Earthen Roads
These roads have foundation and wearing surface of one or two layers of an ordinary or stabilized soil. These are the low cost roads. These require very steep camber ranging between 1 in 20 to 1 in 24 to drain off the rain water quickly. For proper drainage of water, a minimum gradient of 1 in 120 is usually recommended. These roads are constructed as village roads. The roads may be ordinary earth roads or stabilized earth roads.
Ordinary earth roads consists of one or two layers of ordinary earth available at site. Foundation and wearing surface is of the same natural soil. These roads become un-serviceable very soon and require frequent repair.
In stabilized earth roads, the foundation and wearing surface consists of stabilized soil. These roads can carry greater traffic loads than ordinary earth roads.
2. Gravel Roads
The roads which consists of one or two layers of compacted gravel mixed with sand and clay are called gravel roads. These roads are as low cost roads are provide better traffic capacity than earth roads. A camber of 1 in 30 is required for these roads. These roads are constructed as villages or other district roads.
3. Water Bound Macadam Roads
These roads are constructed since very ancient days. The roads having its wearing surface consisting of clean, crushed aggregates, mechanically interlocked by rolling and bound together with a filler material and water, laid on a prepared base course is called water bound macadam road. This is constructed as village road and serves as a base for bituminous roads. In most of the roads projects, in the first phase water bound macadam roads are constructed and when the funds are available, the surfacing is done with the premix carpet bituminous macadam or cement concrete. So a water bound macadam road is considered as mother of all types of road construction.
4. Bituminous Roads
Bituminous roads are those which are painted with bituminous materials at its surface. These are high cost roads. Various components of bituminous surface road are as under:
- To make the surface water tight.
- To provide a more desirable surface texture.
- To reduce slipperiness of the surface.
- To obtain an existing dry or weathered surface.
5. Cement Concrete Roads
When the wearing surface of the road consists of cement concrete slab (plan or reinforced), it is called cement concrete road. These roads are said to be all weather roads. These roads are very costly. These roads have pleasing appearance, long life and excellent riding surface. Cement concrete roads are not much popular in India due to their high initial cost through these are much superior than other types of roads.
6. National Highways
All the main highways running through length and breadth of the country. Connecting major ports, capitals of states, foreign highways etc., are known as National Highways. These roads constitute the main arteries of the transport in the country and are also of military importance. These roads should be selected in such a manner that they afford uninterrupted road communication through the country. These National Highways should have carriage way of at-least two lane width i.e., of 8m width. These should have modern type of surfacing. The responsibility of construction and maintenance of these highways lies with the central government.
7. State Highways
It is the highway which important cities and towns in a state or important cities and district head quarter with National Highways. These roads save as the main arteries of traffic to and from District roads within the state. The State Highway should also have two lane width with modern type of surfacing. Thus these should have a carriageway of 8.0m width with 2.0m wide on each side. These responsibility of construction and its maintenance rests with the State Government. The central Government gives grant for the development of these roads.
8. District Roads
The District Roads traverse each district serving areas of production and markets, industries, residential areas, railway stations and airports etc., and connecting these places with each other. The roads take road traffic into the heart of rural areas without any interruption. The responsibility of construction and maintenance of these roads lies with the District Authorities. However, the State Government gives grant for the development of these roads. In the Nagpur plan it was decided that every village in highly populated area should be within about 3km of such area and about 8.0 km or so in the other area.
The district roads are further divided into two types:
- Major District Roads
These are the roads which connect important towns or areas of production and markets with either a National Highway, State Highway or Railway Station. The specification of the major district roads are same as of state or provincial highways. They should have at least single lane metaled carriageway.
- Other District Roads
These roads run within a particular towns connecting a town and village or a town with major district roads or state highway. These roads are of the specifications lower than major district roads. Many of these roads remain closed due to the traffic during monsoon. These should have single lane width of at least stabilized soil, gravel or water bound-macadam surface.
9. Village Roads
Roads connecting the villages or group of villages with each other or with the nearest district road is called a village road. These also sometimes connect towns or railway stations etc. These are generally un metalled with stabilized soil or gravel. These roads allow the transport to carry the rural products to the market. The local district broad authorities are responsible for the construction and maintenance of these roads.