Okla. Stat. tit. 47 § 157.1
The Department of Transportation, the Board of Agriculture, and the Department of Human Services of the state are hereby authorized to carry insurance on vehicles, motorized machinery, or equipment owned and operated by the Department of Transportation, the Board of Agriculture, and the Department of Human Services, such insurance to be of the following kinds and in amounts not exceeding the following:
Such insurance shall be on standard policy forms approved by the State Insurance Commissioner and with companies authorized to do business in Oklahoma, and shall be paid for out of administrative funds of such departments. Such insurance may cover not only the department or state agency purchasing the insurance but also the personal liability of the operator. The ownership, maintenance, operation and use of motor vehicles and motorized movable equipment owned, leased, used or operated by such departments or state agencies named in this section is hereby declared to be a public governmental function. An action for damages may be brought against such department or state agency, but the governmental immunity of such department or state agency shall be waived only to the extent of the amount of insurance purchased. Such department or state agency shall be liable for negligence only while such insurance is in force, but in no case in any amount exceeding the limits of coverage of any such insurance policy. No attempt shall be made in the trial of any action brought against any such department or state agency to suggest the existence of any insurance which covers in whole or in part any judgment or award which may be rendered in favor of the plaintiff, and if the verdict rendered by the jury exceeds the limits of the applicable insurance, the court shall reduce the amount of said judgment or award to a sum equal to the applicable limits stated in the policy. To the extent that the insurer has provided indemnity in the contract of insurance to a department or state agency described in this section, the said insurer may not plead as a defense in any action involving insurance purchased by the authority of this section, the governmental immunity of either the state or of any department or agency thereof purchasing insurance pursuant to this section. Venue of all actions provided for herein shall be in the county of the residence of the plaintiff or where the cause of action arose, but summons may be served upon the director, head or governing board or body of the department or state agency being sued and alleged to come within the purview of this section, wherever that person may be found. Such policies shall be filed in the office of the Secretary of State as a public record.
Okla. Stat. tit. 47, § 157.1