Hi, you have surely finished this project by now but I just wanted to add my own expertise. I solely make road and traffic signs for the 3 surround states including the one I live it. Printhog said earlier that state-to-state and city-city/county-county standards and specifications are varied, this is correct absolutely.
Also, I can brag that our products have been superior compared to those surrounding us in other businesses who don't know how to use these types of materials: we use Electrocut film, all colors, on 3M DG, HIP and EGP sheeting, dry application. We finally got a 54" cold laminator roller, takes the pressure off my shoulder rotator cuff repetitive injury issue from using a 4" hand roller; I make roughly 200 signs a week out of our little 1.5 person ran sign shop here. Most everything is EC on Retro-reflective sheeting. I make a LOT of street signs, road signs, TTC signage, TTC for federal interstate applications, and they are picky! A good general rule is know what city or county boundaries the signs are going to be installed in and it never hurts to ask the roads/engineering department of that city or county entity what they prefer. Resources are at the tip of your fingers. I have a book of all the specs for surround cities etc. FHWA MUTCD has downloadble files with both EPS and PDF's for several signs. I almost always recommend to customers who order signs in private communities to follow the standards of the surrounding entity, or follow standards set by the MUTCD in which ever state DOT you're working within. An email asking is always generally welcome, they appreciate that you want to know and if you know the site will have an inspection, find out who is performing it and ask them. They have the final say. UDOT is different than ADOT, different from NDOT in types of materials that can be used. I almost always have to clear my materials list with the Mohave gov entity for ADOT, they are very picky also (inks vs films etc). I've been learning about these things and have connections with almost all city and county entities now for the past 2 years, they are your friends! (Beware, engineers NO OFFENSE TO ANY HERE, will change their mind about their construction plans at any given time so, be ready to jump).
Just wanted to add my two cents even though it has been a few months.
Thank you!!!