It’s a good attempt but it doesn’t make sense! On signage system, nobody mix numerals and lowercases on same words just to confuse people!? Numerals form a different system mostly used separately specially on such context. In Paris, numerals are used in circles for the line numbers, rarely mixed with the text itself too. And never they use the non aligned numerals that you show in your image but the capitals aligned numerals.

because every road sign has Illinois Illustrator 1011 on it. And people get confused. Kris Sowersby

So what is your point? Back in 2012, I have wrote a little funny paragraph about a similar topic. I think this unlegible o-zero story is maybe relevant for monospace typefaces used for coding as the code will be buggy if used wrongly but definitely not a problem in signage. Even if someone (and during production process see it) use a zero on a word to remplace a o, the word will still be legible right?!

Last but not least minus this detail, the rest of your article is very good and I have already suggested it as great reference for transport system typography to my students.