A surprisingly interesting brief video about the fonts used on Interstate Highway signs. With quick pacing and excellent graphics, it illustrates the perceptual significance of minor variations in the shapes of letters.
I had to look up "halation" - an entirely new word for me ("the creation of a halo" - duh). I have enjoyed lots of interstate driving, and have always admired the quality of signage on these routes. Here's an example of what happens when you DON'T have good signage (via Neatorama):
I used to drive a lot in rural Kentucky as well, and the clusterfuck filmed above at the interesection of two-way roads doesn't surprise me at all.