The Hindu. The NHAI invites bids for a Rs 821.49 crore project to improve NH-75 in Karnataka by constructing grade separators at accident blackspots along 25.6 km, with a 2-year timeline and 5-year maintenance. The National Highways Authority of India (NHAI) has undertaken a series of road safety measures, including installing blinkers at Vadaputhupatti junction, regarded as a ‘black spot’ or.