The provisions of this article with respect to equipment on vehicles shall not apply to implements of husbandry, road machinery or farm tractors except as herein made applicable. Every farm tractor equipped with an electric-lighting system shall at all times mentioned in § 56-5-4450 display a red tail lamp and either a multiple-beam or single-beam road-lighting equipment meeting the requirements of §§ 56-5-4510 to 56-5-4530, 56-5-4770 and 56-5-4790, respectively.