Historically used in the planning and development of roadway projects, straight-line diagrams are graphic illustrations of the construction history of North Carolina's Interstate, U.S., and N.C. route systems for a particular period.
In 2004, the N.C. Department of Transportation discontinued the creation and updates of diagrams and other geometric information on the diagrams (pavement type, width, shoulders, etc.) no longer accurately reflect current road information.
The most accurate geometric information is now available in the latest release of the
NCDOT Road Characteristics Arcs.
The latest Interstate diagrams are listed below in PDF format.
For additional historic and other current roadway information, including U.S. and N.C. route diagrams, contact Getaneh Admasu at