The operator of a bicycle emerging from an alley, driveway or building shall, upon the approaching of a sidewalk or the sidewalk area extending across any alleyway, yield the right-of-way to all pedestrians approaching on such sidewalk or sidewalk area, and upon entering the roadway shall yield the right-of-way to all vehicles approaching on such roadway.
(`90 Code, § 6-6) Penalty, see § 73.99