Where a lot in a B-H Highway and Regional Business District abuts a lot in any residential district, there shall be provided along such lot lines on such business lot a planted buffer strip at least equal to the width or depth of that required in the residential district, but in no case shall such yard be smaller than that required for the district in which such lot is located, and in said yard a strip of twenty (20) feet abutting the residential district shall not be utilized for roadway or parking and shall be landscaped and planted so as to create an effective evergreen visual screen.