"One in a million" signs.

[RobbieL2415]

These are signs that are only used once or twice in any given state that you'd swear aren't even in the DOT spec book.

Example: CT 15 North and South.  Southbound pictured.  This is for the approach to the West Rock tunnel, the state's only tunnel and the only one in New England bored above-ground.  Thus it's only been used here.

https://goo.gl/maps/nNNDfXMReDr

[hotdogPi]

Don't have a photo, but near Exit 39 on MA 2, there's a sun glare warning.

[kphoger]

So....  this thread is for unique, odd, or interesting signs, then?

[wanderer2575]

M-113 in Kingsley, MI -- I almost expect to see an old man in a trenchcoat standing on the corner.

[machias]

Don't have a photo, but near Exit 39 on MA 2, there's a sun glare warning.

I remember signs that used to warn of "Solar Glare".