The project covers 45.7 kilometres and begins at Karjan near the Bakhtiyarpur–Tajpur bridge in Athmalgola, passing through Barh, Pandarak Mor, Shivnar and Mokama before terminating at Bata Chowk in Mokama Bazaar. The route has been redesigned to provide a more continuous carriageway and to facilitate long distance and regional traffic. Local officials said the alignment was chosen to link key towns and to integrate with existing state and national highways. Traffic management measures will be coordinated with local authorities during the opening phase.
The existing carriageway has been widened from six point five metres to 11 metres, effectively converting it into a four-lane corridor and allowing for higher vehicular capacity. Engineers reported that strengthening works and pavement upgrades were carried out to standards intended to withstand heavier loads and seasonal stresses. Officials said the improvements are expected to alleviate persistent congestion on NH-31 and to shorten journey times for commuters and freight operators.
The total cost of the project stands at approximately Rs 2,498.8 million (mn). Authorities suggested that the widened route will support local economic activity, particularly in agriculture, by improving access to markets and by generating employment opportunities in surrounding areas. The scheme is one of several state initiatives to strengthen road infrastructure and to boost regional mobility. Maintenance schedules and monitoring protocols have been outlined to preserve the upgraded carriageway.