Miss. Code § 65-11-9
The State Highway Commission shall determine what proportion of the funds allotted to the State of Mississippi for the improvement of secondary and feeder roads under subsection (b), Section 3, of the Federal Aid Highway Act of 1944 [53 U. S. Stat. 838, ch. 626], shall be expended upon the improvement of highways on the county federal aid highway system; however, not less than fifty percent (50%) of the amount so apportioned to Mississippi under said act shall be apportioned for expenditure among the counties for the improvement of roads on the county federal aid highway system; if the amount apportioned by the state to the state highway fund to carry out the purposes of Sections 65-11-1 through 65-11-37 should be less than fifty percent (50%) of the amount apportioned to Mississippi for secondary and feeder roads under said act, then the amount of federal funds apportioned to the counties for the improvement of roads on the county federal aid highway system may be less than fifty percent (50%) of such federal funds, but shall not be less than the amount of such state appropriation.
Miss. Code § 65-11-9