Exit numbers on Wisconsin freeways help orient drivers to their location. Wisconsin uses a reference location approach to identify exit numbers, which means the exit numbers relate to the mile reference sign, or mile marker, at that location.
Mile markers used on freeways begin at 0 on the west or south termini of the route within Wisconsin and progress to the east or north. On freeways where more than one numbered route exists on the same roadway, one highway will be used to establish the mile reference.
Generally the lower numbered Interstate highway takes precedence in the numbering scheme, but that may vary depending on the history of the route, or other factors.
When more than one exit occurs within the same mile, the first exit will be identified with the number and the letter A, the second exit B, and so on. Each exit will have an exit sign, with the exit number, at the point where the ramp diverges from the freeway.
Exit numbers are also used on the top of exit direction signs. When exit numbers appear on top of exit direction signs or on top of interchange guide signs, the placement of the exit number plaque will confirm whether the exit is a right exit or a left exit.
The Exit 4A sign is located on the left-hand side of the interchange guide sign, indicating the exit uses the left-hand lane.
Likewise, the Exit 240 sign is positioned in the center of the interchange guide sign, indicating travelers should use the center lanes to enter WIS 30 West.
The Exit 142A sign is positioned on the right-hand side of the interchange guide sign. Therefore this exit will use the right-hand lane.
Exit numbers and reference mile numbers are useful information when reporting highway incidents.
Listing of exit signs along Wisconsin's freeways (printer friendly)
Links on 511