to train and employ local surveyors, engineers and overseers, to perform the work, and to maintain the roads. This programme resulted in an estimated of metalled roads being constructed by the 1850s. In December 1934, the Indian Road Congress (IRC) was formed, on the recommendations of the Indian Road Development Committee (Jayakar Committee) of the Government of India. In 1943, they proposed a twenty-year plan to increase the road network from to by 1963, to achieve a road density of 16 km per 100 km2 of land. The construction was to be paid in part through the duty imposed, since 1939, on petrol sales. This became known as the Nagpur Plan. The construction target was achieved in the late 1950s. In 1956, a Highways Act was passed, and a second twenty-year plan proposed for the period 1961–1981, with the ambition of doubling road density to 32 km per 100 km2. This second plan became known as the Bombay Road Plan. In 1988, an autonomous entity called the National Highways Authority of India (NHAI) was established by an Act of Parliament and came into existence on 15 June 1989. The Act empowered NHAI to develop, maintain and manage India's road network through National Highways. However, little happened until India introduced widespread economic liberalization in the early 1990s. Since 1995, NHAI has increasingly privatized road network development in India. In 1998, National Highways Development Project (NHDP) was started by the then Prime Minister Atal Bihari Vajpayee. The flagship project of the NHDP is the Golden Quadrilateral, a total of of four-to-six-lane highways connecting the four major cities of Delhi, Mumbai, Chennai and Kolkata. The total cost of the project is , funded largely by the government's special petroleum product tax revenues and government borrowing. In January 2012, India announced that the four-lane GQ highway network was complete. Another important road project of the NHDP is the four-to-six-lane North–South and East–West Corridor, comprising national highways connecting four extreme points of the country. The project aims to connect Srinagar in the north to Kanyakumari in the south (including a spur from Salem to Kanyakumari, via Coimbatore and Kochi), and Silchar in the east to Porbandar in the west. As of 31 October 2016, 90.99% of the project had been completed, 5.47% of the project work is under implementation and 3.52% of the total length is remaining. As of May 2017, under NHDP, about of