Local planning context
What the regional setting changes—and what it does not
Regional routes may cross Piedmont residual soils and saprolite, Triassic-basin sedimentary materials in some corridors, stream alluvium, weathered rock, and engineered fill.
That context helps a Raleigh project team choose samples, route segments, material zones, and moisture conditions. It does not establish a design thermal rho. The reported value belongs to the tested material and preparation.
