Soil compaction is one of the most critical factors in the construction of highway pavements. The load carrying capacity of a pavement is highly dependent on the proper compaction of the subgrade and the subgrade compaction profile (i.e., variability of the subgrade modulus).It is thus proposed to use the LWD to determine the stiffness modulus of the subgrade and the variability of the subgrade profile. Additionally, the LWD will be used to determine the moduli of cement-treated and asphalt-treated bases for use in pavement design. Other tests (and equipment) will be used: GeoGauge™, DCP (dynamic cone penetrometer), and the FWD. The analysis will compare and contrast the results obtained from the different tests.