Visibility at Intersections. No object, including, without limitation, fences, landscaping rocks, hedges, trees and other plantings, buildings, structures, walls and signs, exceeding a height of three feet as measured from the lowest elevation of the curb of any abutting street shall be temporarily or permanently placed, erected or installed within the clear sight triangle required at the intersection of two streets or the intersection of a driveway or alley with a public street. The required clear sight triangle is illustrated in Appendix A, which is an attachment to this chapter.