1. In addition to other levies authorized by law, the township board of directors of any township in their discretion may levy an additional tax not exceeding thirty-five cents on each one hundred dollars assessed valuation in their township for road and bridge purposes. Such tax shall be levied by the township board, to be collected by the collector-treasurer and turned into the county treasury, where it shall be known and designated as a special road and bridge fund.

2. The county commission of any such county may in its discretion order the county treasurer or collector-treasurer to retain an amount not to exceed five cents on the one hundred dollars assessed valuation out of such special road and bridge fund and to transfer the same to the county special road and bridge fund; and all of said taxes over the amount so ordered to be retained by the county shall be paid to the treasurers of the respective townships from which it came as soon as practicable after receipt of such funds, and shall be designated as a special road and bridge fund of such township and used by said townships only for road and bridge purposes, except that amounts collected within the boundaries of road districts formed in accordance with the provisions of sections 233.320 to 233.445 shall be paid to the treasurers of such road districts; provided that the amount retained, if any, by the county shall be uniform as to all such townships levying and paying such tax into the county treasury; provided further, that the proceeds of such fund may be used in the discretion of the township board of directors in the construction and maintenance of roads and in improving and repairing any street in any incorporated city, town or village in the township, if said street shall form a part of a continuous highway of the township running through said city, town or village.