In the districts where billboards are permitted, each billboard may have two faces, provided that the faces are parallel to each other and facing opposite directions. The maximum visible display structure area of a billboard shall be 300 square feet, and the maximum height above grade at the top of the sign shall be thirty feet. Billboards may not be placed within ten feet of any right-of-way, and any billboard that is greater than 100 square feet in area shall be set back from the right-of-way an additional three feet for each twenty square feet, or portion thereof, of additional sign area. No billboard shall be placed closer than 250 feet from any Residence District. (Ord. 4320. Passed 11-15-93.)