In order to provide for the payment of all outstanding road district warrants and to liquidate indebtedness against road districts, the county board of any county where such indebtedness exists is hereby authorized and empowered to levy a special tax not exceeding three and five-tenths cents on each one hundred dollars upon the taxable value of all the taxable property in such road districts or so much thereof as may be necessary to pay all the outstanding indebtedness of the character described in this section, except that in no case shall the taxes levied in any one year by the county board in any road district, including the county taxes for all purposes, exceed the aggregate of ten and five-tenths cents on each one hundred dollars upon the taxable value of all the taxable property in such road district unless such additional levy is authorized by a vote of the electors of the county. The levy shall be made by the county board at its regular annual meeting while assembled for the purpose of levying other taxes as provided by law. The tax shall be collected by the county treasurer in the same manner as other county taxes are collected, and all warrants shall be paid by the county treasurer in order in which they appear on his or her register.