Haha! Of course a sign would be like this in Michigan...White Lake Township, Oakland County.
Who was the numbskull that thought this idiocy up? Can you imagine driving down the road and approaching this sign? First, you'd have to check the time, precisely...to the minute to ensure your speed is not in excess of 25mph during those to the minute times as opted on the sign. God help you if your clock were a couple minutes off. Second, you'd damn near have to stop first just to read the stupid thing.
I've never been very impressed with anyone that hails from the state of Michigan, and this just further convinces me......their minds are mush.