W. Va. Code § 17C-8-9: Signals to be given by hand and arm or signal device.

Any stop or turn signal when required herein shall be given either by means of the hand and arm or by a signal lamp or lamps or mechanical signal device, but when a vehicle is so constructed or loaded that hand-and-arm signal would not be visible both to the front and rear of such vehicle then said signals must be given by such a lamp or lamps or signal device.