Okla. Stat. tit. 47, § 7-311
The provisions of Section 47-7-310 shall not apply with respect to any such judgment arising out of an accident caused by the ownership or operation, with permission, of a vehicle owned or leased to the United States, this state or any political subdivision of this state or a municipality thereof.
Laws 1961, HB 556, p. 359, § 7-311, eff. September 1, 1961.