In Virginia, emergency warning lights AND continuous, sound-modulating siren are required in conjunction in order to qualify as an "emergency" vehicle, which then opens up the 7 exceptions to the motor vehicle code.
Disregard speed limit while taking due regard for public safety
Pass on the right while taking due regard for public safety (siren not req'd)
Pass in no passing zone while taking due regard for public safety
Pass in an intersection while taking due regard for public safety
Disregard traffic signal devices while taking due regard for public safety
Stop, stand, or park disregarding other provisions of the code, while taking due regard for public safety
Disregard direction of turn restrictive signage with due regard for public safety
Personal vehicles are not allowed to be equipped with a siren, and therefore are not exempt from ANY of the motor vehicle code provisions. Personal vehicles may be equipped with no more than TWO (2) emergency warning flashing lights of red or white color, of a type to be approved by the superintendent of state police. Two emergency warning flashing lights is often practically considered to be two power sources, not bulbs or "light" units.
My fire department uses mostly some variation of MX7000's. My police department uses mostly whelen edge lightbars.
My fire department and rescue squad have limited use of personal lights, probably no more than half have them. Personnel may activate warning lights while en route to an emergency call, however, since neither agency allows personal vehicle response to the scene, only to the station, there's not a whole lot of need for lights. I sold mine years ago to some new squirrel, pocketed the cash, and probably bought guns with it!