Ohio Rev. Code § 5521.09: Tax levy by county commissioners authorized.

For the purpose of providing a fund for the payment of the county's proportion of the cost and expense of co-operating with the department of transportation, the board of county commissioners may levy a tax, not exceeding one and one-half mills, upon all taxable property of the county. The proceeds of such levy shall be used for the purpose of paying the county's proportion of the cost and expense of any work conducted by the department in co-operating with such county.