Here's a story for my transportation-geek friends AND my font-geek friends:
The Federal Highway Administration is requiring that new street signs comply with updated standards to use mixed case Clearview.
Mixed-font Clearview was readable from roughly 440 feet away, whereas typical all-cap lettering was readable only at a distance of 384 feet. By expanding the interior spaces of certain letters, Clearview also reduced halanation-the process by which letters blur together late at night. In darkness Clearview became readable at 387 feet, against 331 for the standard highway font style.
More about this
here.