Okla. Stat. tit. 47, § 12-213
A. Whenever the load upon any vehicle extends to the rear four (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 time specified in subsection B of Section 12-201 of this title:
2. One red light facing to each side positioned to indicate maximum overhang.
The required lights and reflectors may be mounted in combination at each side of the vehicle and shall be visible from a distance of one thousand (1,000) feet.
Laws 1961, HB 556, p. 396, § 12-213, § 12-202, eff. September 1, 1961; Amended by Laws 2003, SB 633, c. 411, § 31, eff. November 1, 2003 (superseded document available).