These traffic signs remind me of a lawsuit brought maybe 50 years ago where a guy sued the city and won over their "No Parking From 12:00PM-5:00PM" sign. He successfully (and correctly) argued that there is no such time as 12:00PM or 12:00AM.
AM=Anti Meridiem (before midday) PM=Post Meridiem (after midday) So you go from 11:59 AM-->Noon-->12:01PM Or you go from 11:59 PM-->Midnight-->12:01AM Some people would say 12 Noon or 12 Midnight. 12 is the meridiem. So signs should say Noon or Midnight.
The legal system can be that way. Shall we discuss the fools people who celebrated the "New Millennia" on 12/31/1999 instead of 12/31/2000?
We had a tack shop just off of HWY 41 that used a full sized fiber glass quarter horse to indicate where it was. The horse was chained to the fence to prevent someone from 'borrowing' it. One day a call went into the sheriffs dept about this poor horse that was chained to a fence with no water, day after day....