The operator of a bicycle emerging from an alley, driveway, bicycle path, building or otherwise approaching upon a sidewalk or a sidewalk area extending along any such area shall yield the right of way to all pedestrians approaching on such sidewalk or sidewalk area, and upon entering a bicycle lane, shall yield the right of way to all bicycles approaching on such lane, and upon entering the roadway shall yield the right of way to all vehicles or bicycles approaching on such roadway. (Ord. No. 633, § 2; Ord. No. 839, § 4.)