347.06 BACKING A VEHICLE.
   No vehicle shall be backed without the driver first indicating by some sign or signal his intention to back, and no vehicle shall be backed in any street if, by so doing, any other vehicle is impeded or any pedestrian is endangered. No vehicle shall in any event or on any street be backed a greater distance than twenty-five feet, unless it is necessary to relieve a traffic jam or on orders from a police officer.
(1947 Code §19.52)