The driver of a vehicle within a business or residence district
emerging from an alley, driveway or building shall stop such vehicle
immediately prior to driving onto a sidewalk or onto the sidewalk area
extending across any alleyway or driveway, and shall yield the
right-of-way to any pedestrian as may be necessary to avoid collision,
and upon entering the roadway shall yield the right-of-way to all
vehicles approaching on said roadway.