I am from New Jersey. Firefighters, EMS, and SAR can run blue and clear to the front and any color to the rear of the vehicel. police run red and blue Fire chiefs( asst., Deputey) run red or red and clear. Fire and ems appuratis run red , red and blue, red, blue and clear, or red and clear and all non emergency vehicels run amber. no siren in pov unless you are runnig red lights and i think a national standerd would be good
In my area (Wisconsin) law enforcement runs Red & Blue, Fire / EMS / Rescue Runs Red & Red or Red & Clear, Tow Trucks / Wreckers Run Amber & Red, All Non-Emergency Run Amber (Road Crews, Skywarn / Storm Spotters, Fire Photographers [Unless w/ dept. that says red])
NC is RED or RED/WHITE with no siren unless you have a "chief" in you title somewhere.
I like the National standard and think it makes more sense to have lights and siren but that will be hard pressed to change here!