AASHTO HDG-4-M, Highway Drainage Guidelines, 4th Edition (2007), provides a consolidated overview of highway hydraulic design. The guidelines discuss possible hydrology problems across a set of subject areas treated in separate chapters. Topics covered include hydraulic considerations in highway planning and location, hydrology, and erosion and sediment control. Additional chapters carry the treatment of drainage subjects through the remaining areas of highway hydraulic design. The publication consolidates drainage guidance of interest to highway agencies in a single reference. Highway design engineers and hydraulics staff can use the guidelines as an overview of drainage planning and design for highway projects.