605 ILCS 5/6-410

All final payments on contracts for the construction or repair of roads, including the constructing or repairing bridges or culverts, shall be made payable as soon as the work under such contract is completed and accepted by the highway commissioner. The highway commissioner shall submit all warrants, bills and orders for such final payments to the township board of trustees or the highway board of auditors within 30 days after the receipt of the bill.