Images: Although these two typefaces have the same stroke width to height ratio, the Clearview is designed to allow clear reading of letter shapes and word shapes at the furthest point possible for normal vision.
In early 2016, the Federal Highway Administration made a controversial announcement, about fonts. Effective immediately, the agency announced, it would rescind its approval of Clearview, a typeface designed to make highway signs easier to read.
(Note that the bottom terminal of the L curves (to help differentiate between the i) in addition to more open counter forms and more extended descenders on letters like g.)
The Highway Administration, which, among other things, oversees federal funding for highway construction and maintenance, had given the typeface provisional endorsement in 2004. Studies had found it more legible, and therefore safer, than the Standard Alphabets for Traffic Control Devices—more commonly called Highway Gothic—which had gone largely unchanged for more than half a century. Many of America’s highway signs were subsequently updated; if you’ve driven in Pennsylvania, Texas, or some 20 other states, you’ve probably seen the typeface yourself. Clearview has both a classroom kind of simplicity and government-issued authority. Its letterforms are a little taller, a little roomier, and—under certain circumstances—more identifiable than the font it replaced.
In 1997, Penn State researchers subjected Clearview to a range of legibility tests. The results were unambiguously positive, showing that Clearview increased nighttime reading distance by as much as 16 percent. In 2001, a team led by Texas A&M transportation researcher Paul Carlson independently confirmed that Clearview improved the recognition distance of highway signs by as much as 12 percent, a difference of 74 feet over Highway Gothic.
That might not sound like much, but 74 feet provides someone driving 70 mph an extra seven-tenths of a second to react.
“Highway signage is the single most visible manifestation of the government in our day-to-day,” he says. “Everybody knows [the old typeface] looks like a dog’s lunch.”
The Smithsonian Institution’s design museum, the Cooper Hewitt in New York, added the font to its collections and celebrated Clearview as “a beautiful example of design as a form of social activism,” because it made highway signs more readable for older drivers.
The New York Times OpEd (written by a Civil Engineering and Infrastructure Professor at Duke) [link below] argues that font licensing might be the *real* reason that permission to use Clearview has been rescinded. In spite of these massive improvements in legibility, states using it have to pay a onetime fee to the firm that developed the face, whereas Highway Gothic is in the public domain so is free.
Complete article here:
America’s Highway Fonts Got More Drama Than The Bachelor
New York Times: Easy-Reading Road Signs Head to the Offramp
Highway Administration’s Standard Highway Alphabet (originally developed in 1945)
UK’s Transport type for roadways