Color of flashing lights has specific meaning though in many states. Amber was reserved for utility vehicles, tow-trucks and such. Red for emergency vehicles like ambulances and fire trucks and blue for law enforcement. White was typically everyone else not already covered. There does seem to be a green flasher showing up for road repair crews now.
Side note: I like that here, law enforcement only uses blue. However surrounding states seem to have overthunk it and decided that law enforcement also respond to emergencies and therefore run both red and blue lights as well as white. I personally don't like that as it makes it difficult to plan whats ahead of you when you see every color light and it winds up only being a single cop car.