The AASHTO Drainage Manual provides transportation agencies with guidelines for establishing state-specific policies and procedures for the design of highway drainage facilities. This manual has been developed to provide hydraulics engineers with a basic working knowledge of hydrology and hydraulics. All basic design elements are included such that the hydraulics engineer can design highway drainage with minimal assistance. However, this manual cannot provide guidance on complex hydrologic or hydraulic problems. Volume One provides states with guidelines or examples for drainage design policies, criteria, and standards. Volume Two provides hydrologic and hydraulic design procedures that are frequently used by highway hydraulics engineers. 2014. Both volumes are included on a single CD-ROM in both PDF and Microsoft Word formats, to facilitate easy incorporation into state drainage manuals. This publication supersedes the 2005 AASHTO publication, Model Drainage Manual.