@burcidi: The National Highways Authority of India is already building some additional roads from the Golden Quadrilateral to some smaller cities and towns. I think that there are just two now, the North-South Corridor and the East-West Corridor.
I have a Golden Quadrilateral map from the NHAI that shows all these roads. The North-South Corridor goes from Srinagar in the very North to Kanyakumari and Cochin in the very South. The East-West Corridor is from Porbandar in the West and Silchar in the East. They are building these additional roads to cover other major cities that the Golden Quadrilateral is not covering. One can literally drive all over India and have a country tour now.