Okla. Stat. tit. 69, § 603
The board of county commissioners of any county may, under the direction of the Commission, contract for grading, draining or hardsurfacing any street within any municipality where such street is a continuation of or a connecting link in the State or county Highway System.
Laws 1968, HB 501, c. 415, § 603, emerg. eff. July 1, 1968.