This handbook combines information contained in numerous other documents to assist in the design of freeway signing. In some cases, information from other documents is repeated in this handbook with appropriate citations to the source of the information. This is typically the case where information from several documents is combined in a section of the handbook. In other cases, this handbook refers the user to a specific document for guidance on sign design issues. This is typically the case where a single document contains the necessary design information.

Whenever practical, the handbook refers the reader to other documents so the handbook will not be out of date when these documents are revised. When information from other documents is repeated in the handbook, the reader should check to make sure the source document has not been revised.