New Delhi, Oct. 13 -- The National Highways Authority of India (NHAI) has mandated independent proof-checks of designs and drawings by empanelled IITs, government technical institutions and reputed firms to improve safety checks for bridges, viaducts, tunnels and other complex structures from December 1. The new rules will apply to all NHAI projects where design-setting and proof-checking have not begun before December. Contractors or concessionaires must appoint an independent design proof-checking consultant to review design calculations, structural drawings and, where applicable, hydrological and hydraulic studies, before the designs are sent for approval. NHAI said proof-checking costs for EPC, HAM and BOT projects would be borne by the...