316.228  Lamps or flags on projecting load.--Whenever the load upon any vehicle extends to the rear 4 feet or more beyond the bed or body of such vehicle, there shall be displayed at the extreme rear end of the load, at the times specified in s. 316.217, two red lamps visible from a distance of at least 500 feet to the rear, two red reflectors visible at night from all distances within 600 feet to 100 feet to the rear when directly in front of lawful lower beams of headlamps and located so as to indicate maximum width, and on each side one red lamp visible from a distance of at least 500 feet to the side and located so as to indicate maximum overhang. There shall be displayed at all other times on any vehicle having a load which extends beyond its sides or more than 4 feet beyond its rear, red flags, not less than 12 inches square, marking the extremities of such load, at each point where a lamp would otherwise be required by this section.