Thickness of a pavement may be reduced considerably by?

soil bearing capacity and design years for the road

D. combination of all the above.

Compaction of soil, stabilization of soil and drainge of soil

improving layers underlaying

simply redesign using the reduced value of thickness with the aim of increasing the bearing capacity of the sub-grade. Also, the quality of materials to be used for the pavement should be increased. 

Sabilisation of subbase with either aggregates/cement or/and stabilisation of base material with cement

Drainage of soil

Compaction of soil Stabilization of soil