Every motor vehicle, combination of motor vehicle and towed equipment, every self-propelled unit of equipment, self-propelled implement of husbandry, or towed implement of husbandry normally operating at speeds not in excess of twenty-five miles per hour on public streets and roads at all times shall be equipped with a slow moving vehicle emblem as follows:
(1) Where the towed unit or any load thereon obscures the slow moving vehicle emblem on the towing unit, the towed unit shall be equipped with a slow moving vehicle emblem.
(2) Where the slow moving vehicle emblem on the towing unit is not obscured by the towed unit or its load, then either or both may be equipped with the required emblem, but it shall be sufficient if either has it.
(3) The emblem required shall comply with current standards and specifications as established by the American Society of Automotive Engineers and approved by the commissioner.