Okla. Stat. tit. 47, § 47-12-203.3: Headlamps with single distribution of light - Farm

tractors and certain other motor vehicles.

Headlamps arranged to provide a single distribution of light

shall be permitted on farm tractors and motor vehicles manufactured

and sold prior to September 1, 1962, 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 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 (25) feet ahead project higher than a level

of five (5) inches below the level of the center of the lamp from

which it comes, and in no case higher than forty-two (42) inches

above the level on which the vehicle stands at a distance of

seventy-five (75) feet ahead.

2. The intensity shall be sufficient to reveal persons and

vehicles at a distance of at least three hundred (300) feet.