Whenever the height of the curb is more than 200 millimeters, driveways may be constructed across the entire width of the sidewalk, provided that the driveway shall be joined to the sidewalk by means of a ramp of rough finish have a slope of not more than 1/8. The driveway and the ramp shall be made of the same materials as that of the sidewalk. (Figs. VIII.G.19., VIII.G.20., and VIII.G.21.)