This synthesis will be of interest to geologists; hydrologists; geotechnical, pavement, construction, and maintenance engineers; and researchers. State department of transportation (DOT) program managers and administrators will also find it of interest. The synthesis describes the current state of the practice for the design, construction, and maintenance of pavement subsurface drainage systems. It provides information on the positive effects of good subsurface drainage and the negative effects of poor subsurface drainage on pavement surfaces. This report of the Transportation Research Board presents data obtained from a review of the literature and a survey of the state DOTs. It is a supplemental update to NCHRP Synthesis of Highway Practice 96, Pavement Subsurface Drainage Systems (1982). The synthesis provides a supplement to design issues not found in Synthesis 96, but faced by current designers, e.g., type and quality of aggregate, compaction requirements for open-graded aggregates, asphalt and cement binders, and use of geosynthetics. In addition, it describes the effects of design, construction, and maintenance decisions on the performance of pavement subsurface drainage systems.  The report for this topic can be purchased at  https://www.trb.org/news/blurb_detail.asp?id=3318