The objectives of this project were to (1) assess the feasibility of using data available in the LTPP SPS-1 and SPS-2 experiments to evaluate the effects of subsurface drainage on the performance of asphalt and concrete pavements, (2) recommend additional field data collection (e.g., inspection of drainage function) needed to complement the available SPS-1 and SPS-2 data in support of the first objective, and (3) develop a plan for analysis of the SPS-1 and SPS-2 data to quantify the effects of subsurface drainage on pavement performance.

The project final report was published as NCHRP Report 499, Effects of Subsurface Drainage on Performance of Asphalt and Concrete Pavements.