One of those rules refers to "changeable message signs," or CMS, which are the electronic signs that Arizona uses to display the funny messages, along with travel times, traffic alerts and more.

MICHAEL FLOOD WITH MDOT TOLD US...ONLY THREE LINES WITH 21 MESSAGES EACH CAN FIT ONTO THESE SIGNS... <"WE'VE HAD SUCH A GOOD TURN OUT WITH PEOPLE SUBMITTING MESSAGES OVER THE YEARS SO WE FIGURED WE ...