RCW 46.37.240: Single-beam road-lighting equipment.

Head lamp systems which provide only a single distribution of light shall be permitted on all farm tractors regardless of date of manufacture, and on all other motor vehicles manufactured and sold prior to one year after March 18, 1955, in lieu of multiple-beam road-lighting equipment herein specified if the single distribution of light complies with the following requirements and limitations:

(1) The head lamps shall be so aimed that when the vehicle is not loaded none of the high intensity portion of the light shall at a distance of twenty-five feet ahead project higher than a level of five inches below the level of the center of the lamp from which it comes, and in no case higher than forty-two inches above the level on which the vehicle stands at a distance of seventy-five feet ahead;

(2) The intensity shall be sufficient to reveal persons and vehicles at a distance of at least two hundred feet.