My take on this would be if it was possibly to put it in the /extras menu. This way I believe it could be possible to select certain /extra options to display certain messages, albeit they wouldn’t flash or cycle, they would display a more relevant message.
Common used message such as “police slow” could be set on all boards as default that would cycle to attract attention, but things such as “Follow Me”, “Road Closed”, “Do not pass” and other more common phrases put in the /extras menu to be static messages on the board would be brilliant for more functionality with our boards.
This doesn’t have to be exclusive to RTPC/MET either, I believe National Highways would really benefit from it alongside all specialised police divisions.
I appreciate this would be a lot of work, if even viable, but it would mean a lot and be a huge advancement for our policing ability on the server.