The 1999 Highway Design Manual will be used as a working document until all chapter rewrites have been completed. Many hours have and are being spent rewriting this manual with the goal of creating a user-friendly, accurate document. As chapters are finalized, they will be posted to this page. If you are in possession of a hardcopy of the 1999 manual, the Department asks that you exchange the existing chapter with the rewrite. As you use the chapter rewrites, please note and submit any changes or corrections to the e-mail address listed below.
The chapters of these manuals are in Portable Document Form (PDF). To view PDF files, you will need the Adobe Acrobat Reader which is available for free from Adobe at www.adobe.com
Please e-mail any suggestions, additions, revisions, etc. to the Highway Design Webmaster.
Purpose: The primary functions of the New Hampshire Department of Transportation (NHDOT) Highway Design Manual (HDM) are to provide requirements and guidance on current highway design methods and policies, and to assure uniformity of design practice throughout the NHDOT in conjunction with the American Association of State Highway and Transportation Officials (AASHTO) and the Federal Highway Administration (FHWA). Our mission is to plan, construct, and maintain the best possible transportation system and State facilities in the most efficient and economical manner utilizing quality management techniques consistent with available resources and mandated controls. This manual should not supersede the application of sound engineering principles by experienced design professionals.
This manual does not eliminate the need for other references. Directives from the NHDOT office and FHWA, books, publications and other related material may need to be referred to for further details, clarification, or interpretations. Subsequent Official Issuances by the NHDOT may supersede portions of the material in this manual. Known holders of the bound 1999 Version of the Highway Design Manual will be notified, as changes are made available.
Variations from this manual will be necessary for special or unusual conditions, or between the issuances of new or revised source documents and any corresponding updates of the HDM. Consequently, instructions in this document are not intended to preclude the exercise of individual initiative and engineering judgment in reaction to site-specific conditions. It is important that there be consistency statewide in the application of this manual. The objective is uniformity of design for the same or similar conditions. Justifications for variations from this manual are to be appropriately documented.
WARNING: Web site information is subject to periodic change and/or updating without notice. Anyone relying on such information must bear the risk that the information downloaded previously may not be the most current version available. It is the user's responsibility to check often for updates.