In evaluating porous pavement, what soil condition should be assessed as part of the site analysis?

• A. Soil color
• B. Whether there are poorly performing soils present
• C. pH level
• D. Soil depth

Answer: (B)

Determining whether poorly performing soils are present is essential when evaluating porous pavement. Porous pavement depends on water infiltrating through the surface into the soil below, so the infiltration capacity of the subgrade is a critical factor. If the site has poorly performing soils—such as high clay content, dense compaction, or very low permeability—water may not infiltrate effectively, leading to surface ponding, overflow, or clogging of the pore space. Identifying these soils early helps decide if the site is suitable as-is or if remedies are needed, like soil amendments, a drainage or treatment layer, or choosing a different pavement approach.

Soil color, pH level, or simple soil depth don’t directly indicate the infiltration performance that porous pavement relies on, though they can be part of a broader soil assessment.