RCW 46.61.770 Riding on roadways and bicycle paths

Every person operating a bicycle upon a roadway at a rate of speed less than the normal flow of traffic at the particular time and place shall ride as near as near to the right side of the right through lane as is safe except as may be appropriate while preparing to make or while making turning movements, or while overtaking and passing another bicycle or vehicle preceding in the same direction. A person operating a bicycle upon a roadway or highway other than a limited-access highway, which roadway or highway carried traffic in one direction only and has two or more marked traffic lanes, may ride as near to the left side of the left through lane as is safe. A person operating a bicycle upon a roadway may use the shoulder of the roadway or any specially designated bicycled lane if such exists.
Persons riding bicycles upon a roadway shall not ride more than two abreast except on paths or part of the roadway set aside for the exclusive use of bicycles.