In the road there are different parts .
the first step is nsl.
NSL the abbreviation of nsl is { natural surface level } natural surface level is the natural surface of earth .
nsl is that area in which no any construction of road it is just surface of earth.
it is unformed road.
After that nsl the second part of road is W.B.M {water bound macadam road}
the road whose wearing course consist of clean crushed aggregates, mechanically interlocked by rolling and bound together with filler material and water laid on a well compacted base course, is called water bound macadam (W.B.M) road.
it is the liquid form of bitchumin we give heat of 500 degree cente greade and change the form of liquid and spread on W.B.Mthen the final part of road is asphalt.