No private driveway shall be constructed which has a grade of fourteen (14) percent or more at any point thereon lying within forty (40) feet of the intersection of such drive and the right-of-way line of the public street it intersects; provided, however, that such requirements shall not apply if no portion of the drive lying within twenty (20) feet of the intersection of the drive and the public street exceeds a grade of four percent. (Prior code § 9.060)