Va. Code Ann. § 46.2-1037

Any vehicle parked or stopped on a highway, whether attended or unattended, between sunset and sunrise shall display at least one light projecting a white or amber light visible in clear weather from a distance of 500 feet to the front of such vehicle and projecting a red light visible under like conditions from a distance of 500 feet to the rear. No lights, however, need be displayed upon any such vehicle when legally parked.