(1) On any vehicle having a load that extends more than four inches beyond its sides or more than four feet beyond its rear, there must be displayed red or orange fluorescent warning flags, not less than eighteen inches square, marking the extremities of such loads.
(2) Whenever the load upon any vehicle extends to the rear four feet or more beyond the bed or body of the vehicle, there must be displayed at the extreme rear end of the load at the times specified in RCW 46.37.020:
(a) Two red lamps, visible from a distance of at least five hundred feet to the rear;
(b) Two red reflectors, visible at night from all distances within six hundred feet to one hundred feet to the rear when directly in front of lawful lower beams of headlamps, and located so as to indicate maximum width; and
(c) A red lamp on each side, visible from a distance of at least five hundred feet to the side, and located so as to indicate maximum overhang.