Alternate Interstate Highways

[roadman65]

Originally the I-695 Beltway in Baltimore was signed using "ALT ROUTE TO I-95" along its eastern loop for Hazmats and other restricted vehicles that were not allowed in the Harbor Tunnel before I-95 got completed in Baltimore.  Now I would imagine that they are still there, as the Fort McHenry Tunnel uses the same restrictions as the Harbor Tunnel and that those were never lifted.

Whether the term "ALT TO" is still used to help navigate Hazmats and restricted cargo vehicles, or some other type of trailblazing now implemented is I have no clue as I have not been that way in a while.

[1995hoo]

For many years there were orange signs all over Bay Ridge saying "ALT RTE TO [I-278 shield] EAST." The one on the Belt Parkway's NB Exit 2 BGS necessitated a second arrow because the original arrow was obscured and it led to a weird-looking situation of two arrows when the orange banner finally came down.

[Sykotyk]

Ohio has some for I-76 along Mahoning Ave (County Route 18) that parallel's I-76 for a bit. Though their isn't much in the way of guide signs leaving the interstate to get to Mahoning Ave.

[TheHighwayMan3561]

Minnesota has none of their own, but they do have the courtesy to sign Wisconsin's alternate routes where they need to follow Minnesota routes to reconnect to the primary route. You can see these on US 10/61 between Hastings and St. Paul and I think on MN 95 in Afton as well.

[silverback1065]

465 is sometimes signed as alt i-65 (on 65 only approaching the city on either side) in indianapolis