The National Highways Authority of India (NHAI) has tightened safety requirements for metal beam crash barriers after flagging the use of installations that did not conform to prescribed specifications on some of its highway projects. The requirements cover the dimensions and thickness of rails, posts and spacers, as well as the materials and protective coating to be used.

The authority issued the provisions through a policy circular amending its policy of December 17, 2024, on the approval and installation of metal beam crash barriers. It has made the relevant requirements of the Manual of Specifications and Standards and IRC:119-2015 mandatory for all future projects, as well as projects where the barriers have not yet been installed.

For three-beam barriers, the rail and steel posts must each be 3 mm thick. The posts and blocking-out spacers must be made from a 75 mm by 150 mm channel section with a thickness of 5 mm. Posts must be installed at 2-metre centres and have an overall length of 2,100 mm.

The specifications for W-beam barriers also require rails and steel posts to be 3 mm thick. Their posts and blocking-out spacers must use a 75 mm by 150 mm channel section that is 5 mm thick. Posts must be placed at 2-metre centres and have an overall length of 1,800 mm.

NHAI has specified E350-grade steel conforming to IS 2062 (Part 1):2025 for the barriers. Posts, spacers and fasteners must be hot-dip galvanised, with a minimum zinc coating of 0.55 kg per square metre. The revised provisions are intended to ensure that safety barriers installed across highway projects meet consistent structural and material standards.