I'm sure we all know what a "u-turn" is. However, people seem to go from the top of the U. Wouldn't an "n-turn" make more sense, because driving logistics force you to go in more the shape of a lowercase "n", from your perspective.
Most critical traffic instruction signs are written in capital letters, such as
- LEFT TURN
- DEAD END
- MERGE RIGHT etc.
This is so that it can be clearly seen from a distance.
As mentioned by Chris Sunami upper case "u" is still "U" making it unambiguous, whereas n becomes N which is ambiguous, irrespective of the sign looking like a "n" however in written form it is U.