Figure 2E-12. Example of Interchange Numbering for Mainline and Circumferential Routes
This figure shows an example of interchange numbering for mainline and circumferential routes.
The figure shows a map of three Interstate routes: a circumferential route labeled Interstate 473, an east-west route labeled Interstate 22, and a north-south route labeled Interstate 73, each of which is shown with several exits to crossing highways. On all three routes, black dots denoting reference location signs (some of which are accompanied by numbers and some of which are not) are depicted spaced at intervals along the route, and each of the exits is shown with an interchange number.
At the top right of the figure, a black capital letter "N" is shown superimposed on an upward-pointing vertical black arrow, denoting the compass direction. A legend is shown at the bottom of the page. It shows a white disc superimposed on a black square, labeled "JUNCTION OF TWO INTERSTATE ROUTES"; the numeral "2" inside a black circle, labeled "INTERCHANGE NUMBER"; the notation "15A," labeled "EXIT NUMBER"; and a black dot superimposed on a vertical black line, labeled "REFERENCE LOCATION SIGN."
The circumferential route, Interstate 473, is shown as roughly circular in shape. The numbering of interchanges along the circumferential route starts at the southern junction of Interstate 73 with Interstate 473 and proceeds clockwise. The circumferential route shows the following interchanges and numbered reference location signs:
- Interchange 2, a partial diamond interchange
- Reference location sign 3
- Interchange 5, a diamond interchange
- Interchange 7, a minor diamond interchange
- Interchange 9, the eastern junction with Interstate 22
- Reference location sign 10
- Interchange 10, a diamond interchange
- Interchange 12, the northern junction with Interstate 73
- Reference location sign 14
- Interchange 15, a diamond interchange
- Reference location sign 17
- Interchange 19, a future diamond interchange, denoted by broken lines
- Reference location sign 20
- Interchange 21, the western junction with Interstate 22
- Reference location sign 22
- Interchange 23, a diamond interchange
- Reference location sign 25
- Interchange 26, a diamond intersection
- Interchange 28, the southern junction with Interstate 73.