NHAI sets first design standards for high-speed corridors, mandates boundary wall
NHAI's first standardised guidelines for high-speed corridors require a one-metre boundary wall, median crash barriers and advance signage on upcoming access-controlled national highways.
The National Highways Authority of India has issued its first set of standardised technical and safety guidelines for high-speed corridors, prescribing a one-metre-high wall along the outer edge of such highways to curb unauthorised access and the entry of stray cattle.
The norms will govern all upcoming four- to six-lane greenfield and brownfield high-speed access-controlled national highways. Access-controlled high-speed corridors currently in operation span 3,052 km.
Beyond the perimeter wall, the guidelines tighten median design. Openings in median walls on access-controlled highways are to be prohibited, though collapsible barriers may be permitted every 5 km for emergency and maintenance vehicles. Modular concrete or plastic jersey barriers, used to separate traffic lanes and prevent head-on collisions, are also allowed.
At bridges, tunnels and overpasses, the median wall must carry metal crash barriers on top, with such barriers also provided at the approaches to these structures. Merging points are to be fitted with crash cushions — multi-segment devices that crumple on impact to absorb collision energy.
The guidelines also lay down more detailed signage requirements, including advance direction signs placed 5 km, 2 km, 1 km and 500 metres before exits, depending on the sign configuration.
The move mirrors efforts by Indian Railways, which has fenced stretches to check cattle-related incidents, including metal barrier fencing along the 623-km Mumbai–Ahmedabad route.