Erroneous road signs

[Dirt Roads]

Oakland Avenue in Crest Hill, IL:  Seem to be a couple additional railroad crossings that are invisible?
Southbound
Northbound

Fascinating.  It looks like the Sealed Corridor application (in this case, soft bollards down the middle stripes with standard flashing light signals and gates) also included these signs as a reminder to folks that have already cleared the crossing not to stop downstream of the crossing such that a car could get trapped on the railroad.  Or otherwise, you might need to [stop, look and listen] for those invisible trains on those invisible tracks with invisible gates.

[Revive 755]

^ I meant to reference the circular warning signs (W10-1) with the No Train Horn plaques.  It's standard practice in Illinois to try to have as many 'Do Not Stop On Tracks' signs as possible at a crossing, even if they start blocking other important devices and/or leading to an overload of signing.  A great example is Euclid Avenue at the UP Northwest Line in Arlington Heights (good luck seeing the arrow indications on the pre-signal).

[Great Lakes Roads]

Marshall, MI- a business route erroneously signed as if I-94 was concurrent with I-69

[roadman65]

https://maps.app.goo.gl/ZqNZiQwgHfiV2UjP8?g_st=ac

Kinda sorta. FL 417 should have a FL Toll Road shield.

[74/171FAN]

US 421 Business (signed without banners) is signed east-west instead of north-south here for some reason.

US 421 BUS NORTH AT NC 87 SOUTH (1) by Mark Moore, on Flickr

[Dirt Roads]

US 421 Business (signed without banners) is signed east-west instead of north-south here for some reason.

US 421 BUS NORTH AT NC 87 SOUTH (1) by Mark Moore, on Flickr

Neat find!  Your byline might be erroneous too, as this appears to be on the east end of Sanford between US-421/NC-87 where US-421 drops off and heads [east] at the interchange.  If so, that J-cut is not yet on the imagery on AppleMaps and you are looking ahead at where this Bus US-421 merges with Bus NC-87.  No need to change your byline.

[74/171FAN]

A couple of incorrect rectangles along SR 613 in Fairfax County.  First should be SR 842 instead of SR 843 (probably have to zoom in on Flickr to see for both).  Second should be SR 8400 instead of SR 8000.

SR 613 NORTH AT SR 842 by Mark Moore, on Flickr

SR 613 SOUTH AT SR 8400 by Mark Moore, on Flickr

[roadman65]

https://maps.app.goo.gl/boG9Cb9ysVBFw7Qc6

Dont think there are any circle shields in AL for any class route.

[interstatefan990]

https://maps.app.goo.gl/boG9Cb9ysVBFw7Qc6

Dont think there are any circle shields in AL for any class route.

And then they use the correct shield at the intersection not even a few hundred feet further down.

[freebrickproductions]

https://maps.app.goo.gl/boG9Cb9ysVBFw7Qc6

Dont think there are any circle shields in AL for any class route.

And then they use the correct shield at the intersection not even a few hundred feet further down.

Going back to ye olde days with that shape. The current (and correct) shape has gained a few pounds in the decades since.