Okla. Stat. tit. 47, § 1-102
Any U.S. or state-numbered route, controlled-access highway, or other major radial or circumferential street or highway designated by local authorities within their respective jurisdictions as part of a major arterial system of streets or highways.
Laws 1961, HB 556, p. 315, § 1-102, eff. September 1, 1961.