Every vehicle other than a school bus, motorcycle, motor-driven cycle, or moped operated upon a street or highway within this municipality at any time from sunset to sunrise or during fog, smoke, rain, or other unfavorable atmospheric conditions, or at any other time when there is not sufficient light to render clearly discernible persons and vehicles on the street or highway at a distance of 500 feet ahead shall display lighted head lamps and illuminating devices as hereinafter respectively required for different classes of vehicles, subject to exceptions with respect to parked vehicles as provided for in § 72.166(C) of this subchapter. Every school bus, motorcycle, motor-driven cycle, and moped shall display lighted head lamps at all times when upon the street or highway. Lighted lamps and other lighting devices that consist of multiple light-emitting diodes (LEDs) or other illuminating components that function as a single lighting unit are deemed to be functional so long as at least 66% of the LEDs or other illuminating components are functional; provided, that the lighted lamps or lighting devices must still project sufficient illumination to satisfy all other requirements contained in this subchapter.
(W. Va. Code § 17C-15-2)