ABSTRACT
The levels of the top surfaces of the various layers of the pavement are specified in order to ensure that the final structure interacts with the other structures (examples are buildings, overbridges, under-bridges and kerbs) appropriately. The accuracy needed is generally greater for higher layers because most of the interaction is at the surface, although the difference in levels between the top and bottom of any layer can be important in order to ensure that the thickness of the layer is sufficient to work as designed.
