Illinois: Round Mile Markers, Interpretations and Misinterpretations

[Rothman]

About two-and-a-half months ago, I got into a discussion about alleged "hidden routes" in Illinois somewhere out there on the Interwebs.  Turns out that some people think that markers like this:



can indicate "hidden state routes."

To confirm their suspicions, I reached out to IDOT and asked about the markers and why they have route numbers on them that may not be signed or have routes in IROADS. I referenced a specific example where one of these markers indicated a route 316 where the IROADS indicated it did not exist.  I got a response from their Operations group:

"While the route near Charleston is not officially designated as state route 316, this is what our local IDOT district and residents in the area refer to the road as, so 316 was chosen for display on the reference signs."

Therefore, one should not use such markers as reliable indicators of official Illinois state routes.

[NE2]

If the local IDOT district refers to it as 316, does that not make it at least semi-official?

[74/171FAN]

So IL 905 is still a thing right off of I-474??  (https://www.facebook.com/photo/?fbid=10219520080833154&set=a.10219520161635174)



Exit being referenced to:

[adt1982]

The thing about 316 is that the road actually was marked as IL 316 from 1963 to 1981.

Here in Montgomery County, old US 66 is marked with those signs as 934.

[vdeane]

If the local IDOT district refers to it as 316, does that not make it at least semi-official?

By that logic, NY 7 from I-87 to Troy is actually Alternate NY 7.  And an interstate.

[ilpt4u]

Part of me wants to go knock on the door at IDOT D9 in Carbondale and ask someone on staff if that is accurate. I only see those route/county/mileage reference markers on state maintained roads, whether a shielded highway, old shielded highway, or merely "other" state-maintained routes

Business Highway 13 between IL 149/Walnut and IL 13/127 north of town (follows 11th St north from 149, becomes west on Poplar St, turns north on 14th St, then turns northeast on Ava Rd to reach 13/127) in Murphysboro doesn't have the reference markers at all, but it is IDOT-maintained

That said, D9 is at least decent signing "Begin State Maintenance" and "End State Maintenance" on state-maintained non-shielded roads

[Rothman]

Part of me wants to go knock on the door at IDOT D9 in Carbondale and ask someone on staff if that is accurate. I only see those route/county/mileage reference markers on state maintained roads, whether a shielded highway, old shielded highway, or merely "other" state-maintained routes

Business Highway 13 between IL 149/Walnut and IL 13/127 north of town (follows 11th St north from 149, becomes west on Poplar St, turns north on 14th St, then turns northeast on Ava Rd to reach 13/127) in Murphysboro doesn't have the reference markers at all, but it is IDOT-maintained

That said, D9 is at least decent signing "Begin State Maintenance" and "End State Maintenance" on state-maintained non-shielded roads

State maintained =/= state route.

[ilpt4u]

That is a fine delineation. But for all practical purposes, when state maintained, it at least acts and quacks like a shielded/designated state route

[Rothman]

That is a fine delineation. But for all practical purposes, when state maintained, it at least acts and quacks like a shielded/designated state route

Not really.  You have to define the route for there to be a route.

[ilpt4u]

That is a fine delineation. But for all practical purposes, when state maintained, it at least acts and quacks like a shielded/designated state route

Not really.  You have to define the route for there to be a route.

I was referring more to things like state ROW and permitting requirements, obviously state maintenance, state law enforcement, etc

For navigational and routing purposes, certainly not. Designated/signed routes are such for a reason, even if we sometimes find them ridiculous (the 100% redundant IL 110/336 designation). Unsigned/state-maintained routes are not typically the "major" corridor, more for local and/or business access or "old"/former alignments of realigned highways