Okla. Stat. tit. 69 § 1710
In the discretion of the Authority any bonds issued under the provisions of this article may be secured by a trust agreement by and between the Authority and a corporate trustee, which may be any trust company or bank having the powers of a trust company within or without the state. Such trust agreement may pledge or assign the tolls and other revenues to be received from the project constructed by the use of the proceeds of the bonds, but shall not convey or mortgage any turnpike project or any part thereof. Such trust agreement or resolution providing for the issuance of such bonds may contain such provisions for protecting and enforcing the rights and remedies of the bondholders as may be reasonable and proper and not in violation of law, including convenants setting forth the duties of the Authority in relation to the acquisition of property and the construction, improvement, maintenance, repair, operation and insurance of the turnpike project in connection with which such bonds shall have been authorized, and the custody, safeguarding and application of all monies, and provisions for the employment of consulting engineers in connection with the construction or operation of such turnpike project or projects. It shall be lawful for any bank or trust company incorporated under the laws of the state which may act as depository of the proceeds of bonds or of revenues to furnish such indemnifying bonds or to pledge such securities as may be required by the Authority. Any such trust agreement may set forth the rights and remedies of the bondholders and of the trustee, and may restrict the individual right of action by bondholders as is customary in trust agreements or trust indentures securing bonds and debentures of corporations. In addition to the foregoing any such trust agreement may contain such other provisions as the Authority may deem reasonable and proper for the security of the bondholders. All expenses incurred in carrying out the provisions of such trust agreement may be treated as a part of the cost of the operation of the turnpike project or projects.
Okla. Stat. tit. 69, § 1710