S.C. Code § 57-5-760
The Department of Transportation is hereby authorized to enter into reimbursement agreements with the several counties of the State for the construction of farm-to-market and secondary roads financed through the issuance of bonds and reimbursed from funds accruing under the provisions of Section 12-27-400.
This reimbursement shall be made in annual installments, in amounts not exceeding the annual maturity principal on the bonds to be issued by the county, out of the apportionment of funds accruing for construction in the county under the Department of Transportation's farm-to-market construction program, if so much thereof shall accrue for such construction in the county. The Department of Transportation shall not be obligated to the repayment to the county for any installment due under its reimbursement agreement unless sufficient amounts for such installments shall accrue to the credit of the county under the state farm-to-market construction program. The Department of Transportation shall not be required to pay any interest to the county for funds turned over to the department pursuant to the provisions of this section. If, during any year hereafter, the apportionment to which farm-to-market construction in the county is entitled exceeds the sum required to meet the annual installment of principal of the bonds in that year, then such excess shall be applied by the department as if no reimbursement agreement had been entered into.
The reimbursement agreement shall be upon such other terms and conditions as may be mutually agreed upon by the department and the governing bodies of the several counties.
S.C. Code § 57-5-760