Disagree. Very embarrassing mistake. Also very embarrassing that this wasn't caught by whoever signed off on replacing signs (but not surprising, I doubt those

Disagree. Very embarrassing mistake. Also very embarrassing that this wasn't caught by whoever signed off on replacing signs (but not surprising, I doubt those studies are read in detail often and people probably only browse the intro and conclusions). Basically a "you failed science 101" level of embarrassment mistake in my estimation. Testing two brand new signs with the different fonts should be a fairly obvious first idea. The hard/interesting part is taking into account learning effects for the previous font. There's a pretty interesting research question in how you'd age signs in there as well (as you want to know if the gains are positive over the entire lifetime of the sign) and some interesting ethics questions about field testing.