The purpose of this act is to permit necessary highways to be constructed, operated and maintained without the expenditure of any city, county or state tax funds, and to thus enable cities and counties and the State Highway Department to conserve available funds for the construction and maintenance of streets and highways that may not be financed under the terms of this act. Provided, however, the provisions of this act shall not apply to public trusts created or to be created for the purpose of financing, constructing, operating and maintaining toll expressways in counties having a population of five hundred thousand (500,000) or more, according to the latest Federal Decennial Census.
Okla. Stat. tit. 69, § 3016