No person shall operate any vehicle upon a highway without bumpers of a type specified by regulations of the department in both the front and rear unless the vehicle was originally designed and manufactured to be used without bumpers. This section shall not apply to any special mobile equipment, commercial implement of husbandry or implement of husbandry that is not so equipped by the original manufacturer. The driver of a commercial implement of husbandry equipped with vehicular hazard signal lamps shall use the signals when the vehicle is traveling below the speed limit on any highway if the vehicle is not equipped with a rear bumper.
75 Pa.C.S. § 4536