Understanding the Width of a 6-Lane National Highway in India and Global Standards

When discussing the width of a 6-lane National Highway in India, it is important to consider both the specific requirements outlined by the Indian government and global standards. This article will delve into the exact specifications and design principles that guide the construction and maintenance of such highways.

Width Requirements in India

In India, the National Highway Authority of India (NHAI) has set strict standards for the width of 6-lane highways to ensure safety, traffic flow, and the potential for future expansion. For a 6-lane National Highway, a minimum right-of-way (ROW) of 60 meters is required. This includes provisions for a median, kerbs, and a reserve for future expansion. The median, which serves to separate the lanes, is a critical component for traffic safety and can be widened as needed.

Design and Components of a 6-Lane National Highway

The design of a 6-lane National Highway includes the following components:

ROW (Right of Way): A minimum ROW of 60 meters is essential. This includes central divisions and medians for safety and separation. Main Carriageway: The ultimate main carriageway is centrally divided with a median. In India, the central median along with the shoulders on either side measure 12 feet, or approximately 3.7 meters, making the total width 88 feet or 30 meters. The remaining 30 meters are allocated for service roads, footpaths, and greenery on either side. Main Carriageway Design: The main carriageway is designed, developed, and maintained by the NHAI, while the service roads and associated infrastructure are the responsibility of the State Government or local authorities.

Global Standards for 6-Lane Highways

Similar to India, global standards for 6-lane highways also have specific requirements. According to the International Road Congress (IRC), the width for a 6-lane highway is as follows:

Right of Way (ROW): The minimum ROW required for a 6-lane highway is 60 meters. This is to allow for the essential elements including the median and reserve for future expansion.

Lane Width of Carriageway: The standard lane width for the project highway should be 3.5 meters. This width is considered appropriate for efficient traffic flow and safety.

Freeways and Truck Traffic

When considering freeways with six or more lanes, additional considerations arise, especially when truck traffic exceeds 250 double-decker highway vehicle (DDHV). In such cases, the minimum width is 22 feet, with a preferred width of 26 feet to accommodate a wider median shoulder. For these minimum median widths, a median barrier is always required to enhance safety and manage traffic flow effectively.

Conclusion

Understanding the width requirements for a 6-lane National Highway in India, as well as global standards, is crucial for both the design and maintenance of these vital transportation infrastructure projects. The NHAI and related authorities ensure that the necessary provisions for safety, traffic flow, and potential future expansion are integrated into the design of these highways, contributing to the efficient and secure movement of people and goods.