The National Highways Development Project is a project to upgrade, rehabilitate and widen major highways in India to a higher standard. The project was implemented in 1998 under the leadership of Atal Bihari Vajpayee. "National Highways" account for only about 2% of the total length of roads, but carry about 40% of the total traffic across the length and breadth of the country. This project is managed by the National Highways Authority of India (NHAI) under the Ministry of Road, Transport and Highways. The NHAI has invested US$71 billion for this project, as of 2006. The NHDP represents 49,260 kms of roads and highways work and construction in order to boost economic development of the country.