Okla. Stat. tit. 69 § 1714
The exercise of the powers granted by this article will be in all respects for the benefit of the people of the state, for the increase of their commerce and prosperity, and for the improvement of their health and living conditions, and as the operation and maintenance of turnpike projects by the Authority will constitute the performance of essential governmental functions, the Authority shall not be required to pay any taxes or assessments upon any turnpike project or any property acquired or used by the Authority under the provisions of this article or upon the income therefrom, and the bonds issued under the provisions of this article, their transfer and the income therefrom (including any profit made on the sale thereof) shall at all times be free from taxation within the state. The Authority is hereby limited in its power to acquire property to the acquisition of property which is necessary to the construction and operation of the turnpike. And all property, both real and personal, belonging to the Authority that is leased for concessions, such as filling stations and restaurants, shall be subject to taxation, the same as other privately owned property.
Okla. Stat. tit. 69, § 1714