What is Road?
A road may be defined as a thoroughfare or a pavement that steers you to your desired destination by using feet or vehicles (land-compatible vehicles). In this article, different types of roads are briefly discussed.
Types Of Roads
The types of roads are mainly classified based on certain factors as follows:
- Accessibility & Speed.
- Construction materials used.
- Nagpur road classification.
- Usage of road.
- Traffic volume, and
- Type of traffic.
Out of these above-listed factors, we will see some most important factors, based on which the roads are classified, in detail below.
Classification Of Road Based On Accessibility & Speed
Based on accessibility & speed, roads are further classified as given below:-
- Freeways or Controlled-access highways.
- Local streets, and
- Collector roads.
Let’s learn about each one of them briefly.
1. Freeways Or Controlled-Access Highways
A freeway, also known as a motorway or a controlled-access highway is a type of route that is specially developed for the movement of high-speed moving vehicle traffic.
Freeways are free from any kind of obstructions such as signals, parking spaces, intersections, footpaths, rails, etc. So it allows an undisturbed movement of traffic.
Freeways normally consist of two or four lanes on each side of their roads. Bifurcation of the freeway is commonly done at road intersections using the slip roads which are also known as ramps.
Highways are one of the most important types of road with a high density of traffic. Highways do not have any kind of restrictions on vehicles, but still, the majority of traffic on highways includes heavy as well as fast-moving vehicles such as cars, buses, and trucks.
A highway connects villages, cities, and states with each other. Unlike freeways, highways have more than one entry point as well as exit points. Also, highways do consist of some primary services like petrol stations, food plazas, and toll points.
The highway may be divided or sometimes not, in case of state highways. Each of its sides comprises of minimum two lanes. Highways are further classified as national highways and state highways.
Arterials also referred to as urban roads, are the types of roads normally seen inside the cities. Urban roads usually carry a majority of traffic volume throughout the day inside the city itself from one place to another.
These roads possess signals, footpaths, and other services like pedestrian crossings (zebra crossings) also. All types of land vehicles are generally allowed on these types of roads.
4. Local Streets
Streets are generally smaller roads as compared to urban roads. Streets usually comprise of low traffic density and that too of smaller and slow-moving vehicles as well as pedestrians.
Local streets do not have any specific point for crossing the road. Pedestrians can cross the road at any point. Streets are divided with the help of white break lines.
5. Collector Roads
The primary function of collector roads is to collect & distribute the traffic from local streets to the arterial roads. Collector roads allow entry & exit to and from arterial roads. The speed limit on collector roads is usually lowered than arterial roads.
Classification Of Road Based On Construction Materials Used
Based on construction materials used, roads are further classified as follows:-
- Earthen road
- Gravel road
- Murram road
- Kankar road
- Water Bound Macadam (WBM)
- Bituminous road, and
- Cement concrete road
1. Earthen Roads
It is the type of road constructed from the ordinarily available soil. The foundation, as well as the pavement of the earthen road, is constructed out of one or two layers of compacted soil.
After laying each layer of soil, that layer is compacted with the help of a rammer or compactor to remove the unnecessary voids from it. Earth roads are the cheapest of all. Also, they are known as temporary roads.
2. Gravel Roads
Gravel roads are mostly similar to earthen roads in terms of quality as well as cost. The pavement surface of gravel road consists of a mixture of gravel and soil which is compacted with the help of a compactor or rammer.
Gravel roads are easily built with lesser consumption of resources such as time & money. Generally, these types of roads are seen in villages and rural areas.
3. Murram Roads
A specific material is obtained when the disintegration of igneous rocks takes place due to weathering effect. This particular material is known as Murram.
The road constructed with primary material as Murram is better known as Murram road. Murram road gives a better finish than that of earth & gravel roads.
4. Kankar Roads
The impure form of limestone is commonly known as kankar. Kankar roads are generally constructed where the limestone is available in an adequate quantity & also of good quality. The quality of the kankar road is not considered as good, but still better than earth & gravel roads.
5. Water Bound Macadam (WBM) Roads
The water bound macadam (WBM) road is a type of road which is constructed using the layer of crushed stone aggregates as a base course.
After the crushed stone aggregates are laid, water is sprinkled on it & is compacted using a heavy and smooth wheeled roller, which gives a better finish.
The aggregates are bound together with filler materials which are also known as screenings. The thickness of every layer of WBM road is usually 10 cm.
6. Bituminous Roads
Bituminous roads are the most common types of roads which are usually seen all around the globe. During distillation of petrol, a black viscous & adhesive material is obtained.
It is known as bitumen. Bitumen is also known as asphalt. These are high-quality roads providing a smooth surface. The pavement of a bituminous road is considered a flexible pavement.
The cost of construction of bitumen road is way higher as compared to an earth road, kankar road, murram road & water-bound macadam road. The average lifespan of a bituminous road is 8 – 10 years.
The process of construction of the bituminous roads is comparatively easy and also consumes a lesser period of time. One of the disadvantages of the bituminous road is that it needs to get repaired at frequent intervals. Hence its maintenance cost shall also be considered.
7. Concrete Roads
The concrete roads are constructed where the volume of traffic is heavy. Like the bituminous roads, the pavement of concrete road is also considered a rigid pavement.
These are not used as much as bituminous roads because the concrete roads, despite great quality of surface & strength, are very costly. They are the costliest of all.
The construction of concrete roads is usually a time-consuming process. The reason behind it is that concrete needs a lot of curing to gain the perfect amount of strength. Sometimes, the concrete roads are also seen as internal roads of large societies of bungalows.
Concrete roads have the longest lifespan as compared to any other type of road due to their superior strength and built quality. The average lifespan of a concrete road is nearly forty to fifty years.
Despite a long life, the concrete roads are maintenance-free. They do not require maintenance at certain intervals like the bituminous roads.
Classification Of Roads Based On Nagpur Road Classification.
In this category, the roads are classified as:-
- National highway
- State highway
- District roads, and
- Village roads
1. National Highways
These are major highways running through the length and width of the country. National highways connect the majority of states and large cities with each other.
The national highways are assigned with specific numbers as an identification factor for any particular route. For e.g. NH-48 – starts at Delhi & terminates at Chennai.
2. State Highways
The highway which links up with the national highways of adjacent states, district headquarters & important cities is called state highways. Generally, the state government is responsible for the construction and maintenance of state highways.
3. District Roads
The roads which allow the conveyance of traffic within the district are known as district roads. The district authorities are responsible for the construction and maintenance of district roads.
4. Village Roads
The road which connects different villages with each other is known as village road. Village roads are usually single-track roads, with a smaller width.
Classification Of Road Based On Rigidity.
Based on rigidity, the roads are further classified:
- Flexible roads, and
- Rigid roads.
1. Flexible Roads
These are the types of roads that consist of a flexible pavement surface. The pavements are not strong enough to withstand heavy loads. If these roads are not maintained properly, then they might get damaged within a short period of construction. All the roads, except the concrete road, fall under this category.
2. Rigid Roads
Unlike flexible roads, the pavement of rigid roads is hard & strong enough to withstand heavy traffic loads. The initial cost of construction of rigid roads is way too higher than that of flexible roads.
Classification Of Road Based On Topography.
Based on the topography, the roads are further classified as:-
- Plain area roads, and
- Hilly area roads.
1. Plain Area Roads
The roads which are laid on plain areas where the frequency of steep slopes, bends and ups & downs is very less are called plain area roads.
2. Hilly Area Roads
The roads which are usually seen in hilly areas such as in mountains or hills are commonly known as hilly roads. Steep bends, ups & downs, and slops are seen in these roads due to the topographical nature of hills and mountains.
Classification Of Road Based On Traffic Volume
Based on the volume of traffic, the roads are further classified as:-
- Light traffic roads
- Medium traffic roads, and
- Heavy traffic roads
1. Light Traffic Roads
The roads which carry less than 400 vehicles per day are known as light traffic roads. These are usually seen in villages where the population is less.
2. Medium Traffic Roads
The roads carrying a number of vehicles ranging from 400 to 1000 vehicles per day are known as medium traffic roads.
3. Heavy Traffic Roads
The roads that carry more than 1000 vehicles a day are known as heavy traffic roads