The operator of a bicycle emerging from an alley, driveway, or building shall, upon approaching a sidewalk or the sidewalk area extending across any alleyway, yield the right-of-way to all pedestrians approaching on the sidewalk or sidewalk area, and upon entering the roadway shall yield the right-of-way to all vehicles approaching on the roadway.
('75 Code, § 44.6) Penalty, see § 75.99