Miss. Code Ann. § 65-1-79

The State Highway Commission is authorized to enter into agreements with the United States of America for the purpose of securing federal aid funds when available under the provisions of Title 23, United States Code. The federal aid received under this authorization may be used on roads and streets, either on or off the designated highway system or designated state aid system. The State Highway Commission is given the power and authority to approve the system of roads and streets when the approval of such system(s) establishes the eligibility for these roads and streets for federally funded projects when the necessary matching requirement of the federal aid is supplied by the political subdivision wherein the system or project lies. The State Highway Commission is further vested with full authority to determine the priority of the expenditure of these funds and to approve the priority of improvements financed as a result of such authorization.