Haven't seen any. Heard about that before. I don't travel much, and what it's worth... I haven't seen any in my area of Columbus or along the route I take from Columbus to Toledo, which is US23 (from Columbus area to Findlay area), and then I-75 (Findlay to somewhat near by neighborhood).
All flat terrain.
Of the 10 places they'd place one, I cannot imagine it would be in my region... nor would I be that lucky. 😉