Bahami,

Thank you for your comment. I am not sure why Salt Lake City sent you our way. In the Utah Administrative Code Rule R918-6-4 under section (9) it states who is responsible for signs on our roads. At the end of the paragraph it talks about street name signs. It says "The local government is responsible for street name signs, except those mounted on signal mast arms."
I would call Salt Lake City and tell them about this code. It can be found at this website. https://rules.utah.gov/publicat/code/r918/r918-006.htm#T2