The fact that we have the feds dictating font and capitalization rules to local governments on how they sign their streets and roads is what drives me nuts.
I think the federal government was justified in handing down the new requirement for mixed case legends on street name blade signs. Previous all caps designs were often legibly deficient.
Unfortunately, mixed case street name signs require taller sign blanks to accommodate the descenders of the lowercase letters. A 4" legend would need an 8" tall panel if the lettering was going to be vertically centered on the panel. Even with that layout there might not be enough room to add things like white borders.
I actually suspect some cities and towns have deliberately misinterpreted the MUTCD spec, shrinking lowercase letters to 75% of their normal size, just so they can keep using the shorter, cheaper sign panels.
Ultimately, I think cutting costs also has something to do with the misuse and ultimate dismissal of Clearview. There really is no question Clearview, when used properly, is more legible than FHWA Series Gothic. IMHO, these new claims of Clearview having little if any more legibility than Series Gothic stinks of political spin.
The true problem is Clearview requires longer, more expensive sign panels. A 10" tall legend set in Clearview 5W is going to require a significantly longer sign panel than a 10" legend set in Series Gothic E. The lowercase letters in Clearview are nearly 7/8 the height of the uppercase letters. Series Gothic letters are just under 3/4 the cap height.
State agencies are searching for any way to cut costs, including replacing large, aging traffic signs with smaller, cheaper, harder to read panels. There's a bunch of new ones around Lawton that are a joke.
How about this? You can choose any font but it can't be deemed silly. Ideally, you would send the typeface to some sort of approval center. That way, you could use basically any sans-serif font but it would filter out the silly "I can't tell if it's serif or sans-serif" type of fonts (such as posted above).
The approval center can't be a city council, either. They'll choose comic sans because they thinks it cute or something.
There's a couple problems with that. The big one is its very difficult or just plain impossible to legislate good taste. I'm an experienced sign designer, but at the same time I'm about as harsh a critic as there is over badly designed signs. I hate it when people distort typefaces out of their normal proportions or do obviously silly things like setting script typefaces in all capitals. The only thing local governments can do is draft sign ordinances that control size, location and certain functional features of signs.
The other problem is typefaces designed for print or electronic display use often don't work well for traffic sign use. Typefaces meant for traffic sign use have little variance in weight, but need a great variety of widths. Some "super font" families come close to satisfying the variety of widths, but usually fall short in the most condensed forms. Letter spacing in traffic sign typefaces has to be more loosely tracked.
There is plenty of room for improvement with Series Gothic (or room for it to be replaced with something better). Unfortunately we're stuck in a chicken vs. egg scenario where both the fonts and traffic sign software are badly outdated in their capabilities. Both need to improve.