Home
Welcome to the Delaware Department of Transportation (DelDOT) Road Design Manual Website. This site was created in conjunction with the updated DelDOT Road Design Manual (RDM) - 2022 Edition. It provides a location for the updated RDM and the reference documents that accompany the manual.
Home
The "Home" page includes the RDM cover page as well as a link where comments or corrections may be suggested (See "Comments" section below). The "Home" page also includes instructions on navigating the RDM website as well as explaining the layout of the website and the material included on the website. It also explains the approach taken in revising the previous RDM.
Manual
The "Manual" page includes a link to the updated RDM with bookmarks for each chapter. It also includes links to the updated Design Control Checklist, Design Criteria Form, Design Exception Request Form, and a newly created process document for determining design controls and criteria and requesting design exceptions.
The intent of the updated version of the DelDOT RDM is to require the use of the AASHTO A Policy on Geometric Design of Highways and Streets ("Green Book") and other industry recognized reference documents, such as AASHTO’s Roadside Design Guide, to provide the design controls, criteria, and elements to be used on DelDOT transportation projects. In addition, the updated manual references DelDOT specific design criteria that when listed supersede the criteria shown in any industry recognized reference document. For emphasis the DelDOT specific criteria are shown in bold text, while the reference documents are shown in italics. (See section 3.1 for an example.)
The updated version also eliminates all references to process related material that appeared in the previous version resulting in a much shorter Road Design Manual. The previous version of the manual has been archived and is available on the Road Design Manual Website on the "References" page. It is intended that the archived version of the manual, in conjunction with the DelDOT Project Development Manual, the Road Design Manual Website, the Design Resource Center, and Design Guidance Memoranda, be used to provide guidance on many design processes and practices.
In conjunction with the update to the Road Design Manual, the Design Control Checklist, the Design Criteria Form, and the Design Exception Request Form have also been updated. Additionally, a document was created to provide guidance on the process of documenting design controls and criteria as well as the process of requesting a design exception. The process document also lays out the timeframes required for completion and approval of each of the forms.
Updates to the forms include a modernized format with fillable data fields, a revised Project Data section requiring project information that is uniform for all three forms, and a revised signature section with updated project titles and revised signature/approval authority. One of the most significant changes is to the Design Criteria form which has been modified to reflect the reduction in FHWA’s Controlling Criteria for Design from 13 criteria to 10 criteria.
References
The "References" page lists the reference documents that are included in the updated RDM as well as some other documents that may be of use including the archived version of the previous RDM. Links to access these references are provided if the reference is available and licensing fees are not required to access the material. If licensing fees are required to access select documents RDM users should be aware that many organizations possess licenses for access to this reference material.
Many sections of the Road Design Manual provide references to specific sections where source material is located in the "Green Book" and the Roadside Design Guide. (See section 2.2 for an example.) Designers should be aware that sections referenced in the manual may only represent areas of the "Green Book" and the Roadside Design Guide where source material is introduced. Designers should investigate all sections of the "Green Book" and Roadside Design Guide to ensure the referenced material is relevant for the type of project being designed.

Comments
Please submit all comments to DOT_RoadDesignManual@delaware.gov.
The Road Design Manual Steering Committee will review all major comments on a quarterly basis and make the necessary changes as deemed necessary by the Committee. The Committee will work with sections within DelDOT and their partners (i.e. FHWA, DNREC, etc.) to provide the most up to date Road Design Manual that is in accordance with policies, regulations, and best practices for the administration of DelDOT contracts. Minor revisions are considered to be spelling and grammar corrections that do not require the review of the Road Design Manual Steering Committee. Minor edits will be made by the Road Design Manual Steering Committee on a more frequent basis.