On a corner lot in any Residential, Commercial or Industrial District, except the C-4 Central Business District nothing shall be erected, placed or allowed to grow in such a manner as materially to impede vision between a height of two and one-half feet (21/2') and ten feet (10') above the centerline grades of the intersecting streets in the area bounded by the street lines of such corner lots and a line joining points along said street lines twenty five feet (25') from the point of intersection of right-of-way lines. (1983 Code § 11-1-9A)