Driveways built on prep that lasts, not a thicker mat over a bad base.
Call For A Carolinas EstimatePiedmont red clay shrinks in drought and swells when saturated, so pavement built straight on it moves seasonally. The fix is a properly thick stone base with drainage that actually leaves the site, not a heavier mat.
NCDOT Standard Specifications for Roads and Structures (and SCDOT for South Carolina scopes)