Approved single-beam headlamps 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. The intensity shall be sufficient to reveal persons and vehicles at a distance of at least two hundred feet.