Recently opened I-57 interchange at Mattoon

[Revive 755]

The first time IDOT has used a county route shield on a guide sign?

[Brandon]

The first time IDOT has used a county route shield on a guide sign?

Quite possibly.  I've never seen IDOT use one before that I can think of off-hand.

[tdindy88]

So what's the difference between Coles County Road 18 and County Road 1000N?

[3467]

First I have seen.US 34 Cameron Road is Just Cameron road even though it is a county highway
Iowa uses them.

[Alex]

I saw that signage along I-57 southbound two weeks ago and was equally miffed...

[yakra]

So what's the difference between Coles County Road 18 and County Road 1000N?

County Road 1000N is from a grid numbering scheme for section line roads. Many midwest states have similar schemes on county roads, often varying by county. Dig 900N a mile south and 1100N a mile north, with 1000E also nearby. Evidently this county also has county highways, which are spiffier. Spiffy enough for a shield at least.
The same way US302 is carried on Forest Ave, CR18 is carried on 1000N.

[US71]

Must be a new subdivision or a new factory in the area: Google maps shows 1000N doesn't even cross I-57, though streetview, though I can't see anything that would justify a new interchange.

Oh wait: searching Google News, I find the interchange is for a new zero emission coal plant.

*sigh* You move away from a place and it all goes to hell. 

[misterdeez]

The I-57 interchange (Exit 192) serves the factories in Mattoon (Mars, RR Donnelly).  Work is being done on the sections east of the interchange where it will eventually connect to IL Route 130 in Charleston and the factories in that town.  County Road 1000 (County Highway 18) starts at IL Route 121 (at the Coles/Moultrie County line) and goes east.  I believe that in my travels along Illinois' highways that the use of a county highway sign on an exit sign is unheard of in the state, so this sign would be a first in Illinois.