Numbered routes that should be merged?

[jbnv]

I-10 and I-12. Can we go back to suffixing again?

Nah. I would replace the entirety of I-12 with I-10. Current I-10 between I-12 at Baton Rouge and I-55 at Laplace becomes I-710. I-55 takes over I-10 between Laplace and downtown New Orleans. I-59 takes over the rest of I-10 between NOLA and Slidell. 

Edit: that would also mean renumbering I-510 and I-610. I-510 becomes I-159 and I-610 becomes I-559, which makes sense because I-559 would connect I-55 and I-59.

Wouldn't I-810 make more sense than I-710, as it connects two interstates? Similar issue regarding I-559; while logical, I doubt AASHTO would approve of that.

Doesn't matter, since any idea of renumbering or extending every interstate in southeast Louisiana is fantasy land.

[hobsini2]

US 641, KY 91, Cave-in-Rock Ferry, IL 1

I actually love this idea. I assume to make it all US 641. I would have it go straight up IL 1, IL 394, I-94, Stony Island Ave and Cornell Dr to end at Lake Shore Dr (US 41) at 57th Dr right by the Museum of Science and Industry in Chicago.

[ilpt4u]

US 641, KY 91, Cave-in-Rock Ferry, IL 1

I actually love this idea. I assume to make it all US 641. I would have it go straight up IL 1, IL 394, I-94, Stony Island Ave and Cornell Dr to end at Lake Shore Dr (US 41) at 57th Dr right by the Museum of Science and Industry in Chicago.

That is one of my potential Chicagoland routings to get US 641 (back) to US 41, and probably my favorite

Other possibilities:
-Go up IL 394, enter 80/94 EB into Indiana and cross the border to the Calumet Ave/US 41 exit
-Go up IL 394, enter the Tri-State/I-294 NB, and follow the Tri-State to its Northern terminus where US 41/I-41 joins I-94
-Go up IL 1, keep US 641 signed on Halsted St, then Clarendon Ave in Chicago to its termination at Lawrence, then over to US 41/LSD there
-Go up IL 394, then follow I-94 via the Bishop Ford, Dan Ryan, Kennedy, Edens until Skokie Blvd/US 41 joins the Edens

[Phoenix1867]

I-49 and I-29 into I-49