76.04   TWO ABREAST LIMIT.
Persons riding bicycles upon a roadway shall not ride more than two abreast except on paths or parts of roadways set aside for the exclusive use of bicycles. All bicycles ridden on the roadway shall be kept to the right and shall be operated as near as practicable to the right-hand edge of the roadway.
(Code of Iowa, Sec. 321.236[10])