The operator of a bicycle emerging from an alley, driveway or building shall upon approaching a sidewalk or the sidewalk area extending across an alleyway or driveway, yield the right-of-way to all pedestrian approaching on said sidewalk or sidewalk area and upon entering the roadway shall yield the right-of-way to all vehicles approaching on said roadway.
(1991 Code, § 74.21) Penalty, see § 70.99