Has anyone seen this before?

Yep... they do those specifically to draw your attention to them so you'll note the speed.

Mind games.

 

You mean they actually do replace them just because they have an unplanned hole?

 

Was it in Trenton,TN?

 

I have seen a 17 MPH sign off of I-44 in Oklahoma at the Chandler on-ramp for the eastbound side. It is because people pay more attention to the odd speed.

I think it was Knute Rockne who would call team meetings at odd times so his players would be more likely to remember the time. It's just so it sticks in your mind.

 

I always ask Google before I ask truck drivers. That way I only get 1,000,000 replies and still get the right answer. None of which were correct so far in this thread.

It has been that way since the 1960s.

Trenton TN's 31 MPH Speed Limit

Wikipedia says its been that way since the 1950s
Trenton, Tennessee - Wikipedia

Trenton, TN - 31 MPH Speed Limit

 

not as bad as some speed limits in scale houses ,like; 8 1/2 MPH.
no 8 on the dial or 1/2 mark. lol

 

Many moons ago in a past life I passed through this town. I remember that strange speed limit and actually somewhere in my old photo collection have a photo of one of those signs. I was working for a recovery company and did a tractor repo several miles north. I never did ask why the strange speed limits, but those websites are interesting.