2009 Edition Part 2 Figure 2E-20. Example of Interchange Numbering for Mainline, Loop, and Spur Routes
Figure 2E-20. Example of Interchange Numbering for Mainline, Loop, and Spur Routes
This figure shows an example of interchange numbering for mainline, loop, and spur routes.
The figure shows a map of three Interstate routes: a mainline labeled Interstate 3, a loop labeled Interstate 203, and a spur labeled Interstate 103, each of which is shown with several exits to crossing highways. On all three routes, black dots denoting reference location signs accompanied by numbers 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 horizontal dashed black line at the bottom of the figure is labeled "STATE LINE." 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 "11" inside a black circle, labeled "INTERCHANGE NUMBER"; the notation "9A," labeled "EXIT NUMBER"; a black dot superimposed on a vertical black line next to the numerals "115," labeled "REFERENCE LOCATION SIGN," and an Interstate route shield with the numeral "203," labeled "INTERSTATE ROUTE NUMBER."
The mainline route, Interstate 3, is shown as running roughly north-south from the state line to the top of the figure. The numbering of interchanges along the Interstate 3 mainline starts at a diamond interchange at the southern end of Interstate 3 and proceeds north. The mainline route shows the following interchanges and numbered reference location signs:
- Reference location sign 1
- Interchange 1, a diamond interchange
- Reference location sign 2
- Reference location sign 3
- Reference location sign 4
- Interchange 4, the southern junction with the Interstate 203 loop. This is interchange 1 at the beginning of the Interstate 203 loop. An enlargement of this interchange, shown inside a circle, shows this interchange as a partial cloverleaf interchange. On Interstate 3, it shows reference location sign 4, Exit 4 from Interstate 3 North to Interstate 203, Exit 4 from Interstate 3 South to Interstate 203, and reference location sign 5. On Interstate 203, it shows Exit 1A to Interstate 3 South, Exit 1B to Interstate 3 North, and reference location sign 1.
- Reference location sign 5
- Interchange 5, a diamond interchange, and reference location sign 6
- Reference location sign 7
- Interchange 7, a partial diamond interchange
- Reference location sign 8
- Reference location sign 9
- Interchange 9, a cloverleaf with Exits 9A and 9B in each direction, and reference location sign 10. In the northbound direction, Exit 9A is shown preceding 9B. In the southbound direction, Exit 9B is shown preceding 9A.
- Reference location sign 11
- Interchange 11, the northern junction with the Interstate 203 loop. This is interchange 15 at the end of the Interstate 203 loop. An enlargement of this interchange, shown inside a circle, shows this interchange as a partial cloverleaf interchange. On Interstate 3, it shows reference location sign 11, Exit 11 from Interstate 3 North to Interstate 203, Exit 11 from Interstate 3 South to Interstate 203, and reference location sign 12. On Interstate 203, it shows Exit 15A to Interstate 3 South, Exit 15B to Interstate 3 North, and reference location sign 15.
- Reference location sign 12
- Reference location sign 13
- Interchange 13, the junction with the Interstate 103 spur. This is interchange 1 on the spur. An enlargement of this interchange, shown inside a circle, shows this interchange as a partial cloverleaf interchange. On Interstate 3, it shows reference location sign 13, Exit 13 from Interstate 3 North to Interstate 103, Exit 13 from Interstate 3 South to Interstate 103, and reference location sign 14. On Interstate 103, it shows Exit 1A to Interstate 3 South, Exit 1B to Interstate 3 North, and reference location sign 1.
- Reference location sign 14
- Interchange 14, a diamond interchange
- Reference location sign 15.
The loop route, Interstate 203, is shown running in a semicircular direction beginning at the junction of Interstate 3 with Interstate 203 near the bottom of the figure, looping to the east of the mainline, and then circling back to the west and joining the mainline farther north. The numbering of interchanges along the Interstate 203 loop starts at the junction with the Interstate 3 mainline and proceeds along its path back to the mainline:
- The Interstate 203 loop starts at interchange 4 of the Interstate 3 mainline. This is interchange 1 on the Interstate 203 loop. It is a partial cloverleaf interchange. A note states: "The freeway/freeway interchange where the beginning of the loop or spur route intersects with the mainline route may be called either Exit 1 or Exit 0 on the loop or spur route."
- Reference location sign 1
- Reference location sign 2
- Interchange 2, a diamond interchange
- Reference location sign 3
- Reference location sign 4
- Reference location sign 5
- Interchange 6 and reference location sign 6. Interchange 6 is a cloverleaf with Exits 6A and 6B in each direction. In the northbound direction, Exit 6A is shown preceding 6B. In the southbound direction, Exit 6B is shown preceding 6A.
- Reference location sign 7
- Interchange 9, reference location sign 8, and reference location sign 9. Interchange 9 is a major diamond interchange across a divided highway.
- Reference location sign 10
- Reference location sign 11
- Interchange 12, a diamond interchange, and reference location sign 12
- Reference location sign 13
- Reference location sign 14
- Reference location sign 15
- Interchange 15 on the loop. This is interchange 11 on the Interstate 3 mainline and is the northern junction with Interstate 3. This is a partial cloverleaf interchange.
The spur route, Interstate 103, is shown as running roughly east-west. The Interstate 103 spur is shown as beginning at Interchange 13 on the Interstate 3 mainline and running east of the mainline. The Interstate 103 spur shows the following interchanges and numbered reference location signs:
- Interchange 1, the junction with the Interstate 3 mainline. This is a partial cloverleaf interchange. A note states: "The freeway/freeway interchange where the beginning of the loop or spur route intersects with the mainline route may be called either Exit 1 or Exit 0 on the loop or spur route."
- Reference location sign 2
- Interchange 2, a through interchange in both directions, and reference location sign 3
- Interchange 4, a cloverleaf, with Exits 4A and 4B in both directions. In the eastbound direction, Exit 4A is shown preceding 4B. In the westbound direction, Exit 4B is shown preceding 4A.
- Reference location sign 5
- Reference location sign 6.
