Highway Design Manual (HDM)
The 7th Edition Highway Design Manual (HDM) establishes uniform policies and procedures to carry out the state highway design functions of the California Department of Transportation. Refer to the "Foreword" section of the HDM for more information.
When a chapter is updated, the date on the header of the updated pages is changed and a vertical line added on the outside margin beside the changed text. Implementation of the current version of the HDM shall be applied to on-going projects in accordance with HDM Index 82.5, unless otherwise noted on the Manual Change Transmittal memo or by separate Design Memo.
No matter which of the formats is used to download and/or print, if the HDM Holder chooses to do so, the Holder is responsible for keeping their electronic and/or paper copy up to date and current. For this reason, HDM Holders are encouraged to use the on-line version of the HDM for the most current design guidance.
Design Information Bulletins (DIBs) and Design Memoranda may supersede this manual.
HDM Manual Change Transmittals
Highway Design Manual Change Transmittal memorandums are issued summarizing the significant changes and are posted by change date.
View recent HDM Manual Change Transmittals here.
Propose a Revision to the HDM
Changes can be proposed by submitting a HDM Revision Request Form to firstname.lastname@example.org
Sign Up For Email Notifications of Changes
Request to be notified automatically of any changes or updates to the Highway Design Manual (or unsubscribe) here.
Table of Contents
Combined HDM Chapters
The individual files in the HDM Table of Contents above are the official accessible version of the Highway Design Manual. The combined HDM chapters are available below for user convenience.
All HDM Chapters - Complete Download Version (Updated 05/20/2022) (PDF)