Classification of Roads

The roads are generally classified into two categories, depending on whether they can be used during different seasons of the year.

i) All-weather Roads

All-weather roads are those which are negotiable during all seasons of the year, except at major river crossings where some interruption to traffic is permissible up to a certain extent, but the road pavement should be negotiable during all weathers.

ii) Fair-weather Roads

Roads which are negotiable only during fair weather are called fair weather roads. On fair weather roads, the traffic may be interrupted during monsoon season at causeways where streams may overflow across the road.

Based on the type of the carriageway or the road pavement, the roads are classified as `paved roads' and `un-paved roads'.

i) Paved Roads

The roads with a hard pavement surface on the carriageway are called 'paved roads'.

E.g. Stones, Water bound macadam (WBM), Bituminous macadam (BM), Concrete roads

ii) Unpaved Roads

The roads without a hard pavement surface on the carriageway are called 'unpaved roads'. Earth roads and gravel roads may be called unpaved roads.

Based on the type of pavement surfacing provided, the roads may be classified as `surfaced roads' and `un-surfaced roads’.

i) Surfaced Roads

Road pavements with any type of bituminous surface or cement concrete are called surfaced roads.

E.g. BM road, Concrete road

ii) Un-Surfaced Roads

The roads which are not provided with a bituminous or cement concrete surfacing are called un-surfaced roads.

E.g. Soil or Gravel road

Methods of Classification of Roads

The roads are generally classified based on the following.

a) Traffic volume

b) Load transported or tonnage

c) Location and function

The classification based on traffic volume or tonnage has been arbitrarily fixed by different agencies and there may not be a common agreement regarding the limits for each of classification group. Based on the traffic volume or flow, the roads are classified as heavy, medium and low volume roads. These terms are relative and so the limits under each class should be clearly defined and expressed as vehicles per day or 'annual average daily traffic'.

The classification based on load or tonnage is also relative and the roads may be classified as class I, II etc. or class A, B etc. and the limits may be expressed in terms of tones per day. The classification based on location and function should therefore be a more acceptable classification method for a country as they may be defined clearly.

Road Classification Based on Location and Function

1) Road Classification as per Nagpur Road Plan

The Nagpur Road Plan classified the roads in India based on location and function into following five categories and are described below.

i) National Highways (NH)

National Highways (NH) are main highways running through the length and breadth of India, connecting major ports, foreign highways, capitals of large states and large industrial and tourist centres including roads required for strategic movements for the defence of India. All of the national highways are assigned the respective numbers. For example, NHI is the national highway connecting Delhi, Ambala, Jalandhar and Amritsar (up to Pakistan border); NH-4 connects Thane, Pune, Belgaum, Hubli, Bangalore, Chittoor and Chennai.

ii) State Highways (SH)

State Highways (SH) are arterial roads of a state, connecting the national highways of adjacent state, district headquarters and important cities within the state and serve as the main arteries for traffic to and from district roads. These highways are considered as main arteries of commerce by road within a state or a similar geographical unit.

iii) Major District Roads (MDR)

Major District Roads (MDR) are important roads within a district serving areas of production and markets and connecting with other major roads or main highways of a district. The MDR has lower speed and geometric design specifications than NH or SH.

iv) Other District Roads (ODR)

Other District Roads (ODR) are roads serving rural areas of production and providing them with outlet to market centres, taluk headquarters, block development headquarters or other main roads. These are of lower design specifications than MDR.

(v) Village Roads (VR)

Village Roads (VR) are roads connecting villages or groups of villages with each other to the nearest road of a higher category. It was specified that these village roads should be in essence farm tracks, but it was desired that the prevalent practice of leaving such tracks to develop and maintain by themselves should be replaced by a plan for a designed and regulated system.

2) Road classification as per third 20-year road development plan, 1981 -2001

The road classification system was modified in the third 20-year road development plan. The roads in the country are now classified into three classes, for the purpose of transport planning, functional identification, earmarking administrative jurisdictions and assigning priorities on a road network.

i) Primary System

ii) Secondary System

iii) Tertiary System or Rural Roads

Primary system consists of two categories of highways.

a) Expressways

b) National Highways (NH)

Expressways are a separate class of highways with superior facilities and design standards and are meant as through routes having very high volume of traffic. The expressways are to be provided with divided carriageways, controlled access, grade separations at cross roads and fencing. These highways should permit only fast-moving vehicles. Expressways may be owned by the Central Government or a State Government, depending on whether the route is a National Highway or State Highway. The National Highways form the other main category of primary system in the country.

The Secondary system consists of two categories of roads.

a) State Highways (SH)

b) Major District Roads (MDR)

(Explained above)

The Tertiary systems are rural roads and these consist of two categories of roads.

a) Other District Road (ODR)

b) Village Roads (VR)

(Explained above)

The roads have classified as follows in the order of increased accessibility and reduced speeds.

1) Freeways

Freeways are access controlled divided highways. Most freeways are four lanes, two lanes each direction, but many freeways widen to incorporate more lanes as they enter urban areas. Access is controlled through the use of interchanges and the type.

2) Expressways

They are superior type of highways and are designed for high speeds (120 km/hr is common), high traffic volume and safety. They are generally provided with grade separations at intersections. Parking, loading and unloading of goods and pedestrian traffic is not allowed on expressways.

3) Highways

They represent the superior type of roads in the country. Highways are of two types - rural highways and urban highways. Rural highways are those passing through rural areas (villages) and urban highways are those passing through large cities and towns, i.e. urban areas.

4) Arterials

It is a general term denoting a street primarily meant for through traffic usually on a continuous route. They are generally divided highways with fully or partially controlled access. Parking, loading and unloading activities are usually restricted and regulated. Pedestrians are allowed to cross only at intersections/designated pedestrian crossings.

5) Local Streets

A local street is the one which is primarily intended for access to residence, business or abutting property. It does not normally carry large volume of traffic and also it allows unrestricted parking and pedestrian movements.

6) Collectors Streets

These are streets intended for collecting and distributing traffic to and from local streets and also for providing access to arterial streets. Normally full access is provided on these streets. There are few parking restrictions except during peak hours.