Understanding the Width of National Highways in India as per IRC Standards - Lceted

Understanding the Width of National Highways in India as per IRC Standards

Introduction: IRC  Standards have been laid down for developing highways. Highway forms the lifeline of the nation connecting different states and regions by road. National Highways are administered by the Ministry of Road Transport and Highways and are hence an integral element to ensuring interstate trade and movement of goods and people. In spite of constituting only 2.7% of the total road network, National Highways carry about 40% of road traffic in India. This article stipulates the width of the National Highways in India using the standards set by the Indian Road Congress (IRC).

What is the IRC?

The Indian Road Congress is the ultimate coordinating body of highway engineers in India. It prepares guidelines for the design of roads, and the standards of construction and maintenance for the country. Such guidelines are periodically reviewed in line with evolving requirements and imperatives of technological development.

Why is the Width of National Highways Important?

 The width of a National Highway is of prime importance, as it determines the carrying capacity, safety, and efficiency of the highway. An intelligently designed highway with an adequate width can support more traffic, ease congestion, and bring a decline in the accidents. It also facilitates future widening, which now is mandatory on account of the phenomenal growth of vehicular traffic in the country.

Standard Widths of National Highways

The width of National Highways in India are of varies with the number of lanes. Widely vary with

The usual widths as per IRC standards include not only the carriageway-that means the portion of the highway used by vehicles-but also the shoulders, medians, and the right of way. The right of way is the total land area acquired for the highway and provides space for future expansion.

Here’s a detailed breakdown:

 

Type of Highway	Right of Way (RoW)	Carriageway Width	Shoulder Width	Median Width	Future Expansion Area
2-Lane Highway	30 meters (100 feet)	7 meters (23 feet)	2.5 meters (8.2 feet) on each side	N/A	18 meters (59 feet)
3-Lane Highway	30 meters (100 feet)	10.5 meters (34 feet)	2.75 meters (9 feet) on each side	N/A	14 meters (46 feet)
4-Lane Highway	45 meters (150 feet)	14 meters (46 feet)	4 meters (13 feet) on each side	5 meters (16 feet)	18 meters (59 feet)
6-Lane Highway	60 meters (200 feet)	21 meters (69 feet)	3.5 meters (11.5 feet) on each side	5 meters (16 feet)	27 meters (89 feet)
8-Lane Highway	75 meters (250 feet)	28 meters (92 feet)	4.5 meters (15 feet) on each side	7 meters (23 feet)	31 meters (102 feet)

 

The Key Components Explained

1.    Carriageway Width: This is the width of the highway to be used by vehicles for travel. A standard 2-lane highway has a carriageway width of 7 meters, while an 8-lane highway has a width of 28 meters. Normally, each lane is 3.5 meters wide.

2.    Shoulder Width: The shoulders on the sides of the highway are provided to make emergency stops and laterally support the pavement. Their width will increase with an increasing number of lanes to 2.5 meters on a 2-lane and 4.5 meters on an 8-lane highway.

3.    Median Width: This separates the two opposing streams of circulation and thus saves the occurrence of head-on collisions. The median width may be varying from 5 to 7 meters depending upon the highway.

4.    Right of Way: RoW is the total land area procured for the highway, including a carriageway, shoulder space, median, and space for future expansions. In the case of a 2-lane highway, the RoW will normally be 30 meters; whereas, it is normally 75 meters for an 8-lane highway.

 

Why Consider Future Expansion?

With the rapid increase in road traffic in India, it's crucial to design highways that can accommodate future expansion. The RoW often includes extra space to allow for the addition of more lanes, parking areas, footpaths, and other facilities as needed. This foresight helps avoid the challenges of land acquisition and redesigning the highway later.

Thumb Rules for Highway Design

1.    Lane Width: Think about a standard lane width of 3.5 metres at all times.

2.    Shoulder Width: Here, highways with more than 2 lanes have this part of their design widened to save on safety.

3.    Right of Way (RoW): The RoW should be adequate to accommodate further expansion, mainly on key highways.

Conclusion

The design and construction of National Highways in India follow the stringent guidelines set by the Indian Road Congress (IRC). These standards ensure that highways are built to handle current traffic loads while being ready for future expansions. Understanding the typical widths of National Highways and their components is essential for anyone involved in highway engineering, construction, or maintenance.

As India's road network continues to evolve, adhering to these standards will be critical in maintaining the efficiency, safety, and sustainability of our highways.