NHAI lays down uniform design standards for high speed controlled access highways

New Delhi: The National Highways Authority of India (NHAI) has introduced a uniform design framework for controlled access high-speed state highways in a bid to standardize how such corridors are planned and designed as India expands its expressway network.

The directives, issued on Monday, apply to the planned four- and six-lane state highways with controlled access on greenfields and brownfields, excluding expressways. They are significant as the government, under its Viksit Bharat 2047 roadmap, aims to develop 50,000 km of high-speed controlled access corridors.

So far, there were no separate standards governing the planning and design of access-controlled high-speed national highways, except for expressways, NHAI said. This has led to differences in the technical standards used to prepare Detailed Project Reports (DPRs) across different corridors.

Consistency is sought

The new framework seeks to ensure consistency in DPR preparation, road geometry and safety provisions while improving operational efficiency and reducing disruption to high-speed corridors.

One of the key changes is the introduction of additional safety measures suitable for high speed roads. The guidelines prescribe early notification of motorway exits and entrances to give motorists sufficient time to anticipate and safely negotiate access and exit points, the Ministry of Road Transport and Highways (MoRtH) said in a statement.

The plan proposes highways based on how many vehicles will use them. Corridors carrying up to 15,000 vehicles will have four-lane highway and four-lane structures with a proposed corridor width of 60 meters, the guidelines said. Corridors carrying 15,000 to 25,000 vehicles will have four-lane highways and six-lane 70-meter-wide structures, she added.

For traffic between 25,000 and 40,000 vehicles, the directives prescribe a six-lane highway and six-lane constructions, also in the 70-meter-wide corridor.

Limiting direct access

The directive also seeks to limit direct access to high-speed highways by requiring interchanges and ramps at important road intersections. These will be provided at intersections with expressways, state highways, state highways and important arterial roads that generate significant traffic.

Connectivity to major traffic-generating destinations – including ports, airports, multimodal logistics parks, industrial areas and major tourist destinations – will also be provided through interchanges.

NHAI has also prescribed a physical barrier to strengthen access control. A 1 meter high boundary wall will be constructed along the outer edge of the corridor to prevent foreign objects, unauthorized entry and stray cattle on the highway.

The new framework will apply to both greenfield projects and existing motorway sections being upgraded to controlled access corridors. By setting common parameters for traffic assessment, lane configuration, structure, intersection and access control, NHAI aims to bring greater consistency to project planning while supporting the expansion of India’s high-speed highway network and the government’s Viksit Bharat 2047 roadmap.