Access to any lot other than one- and two-family dwellings shall be had by means of driveways twenty-four (24') feet wide, with not more than one such driveway permitted for each two hundred (200') feet or fraction thereof of street frontage, except that, where more than one such driveway is provided for any lot, the width of such driveway may be reduced to twelve (12') feet, and each such driveway shall be used as a one-way entrance or exit. The entire street frontage opposite any residential zone shall be landscaped so as to prevent any use from hindering or discouraging the development and use of adjacent land and buildings or the impairment of the value thereof, and such landscaping shall be properly maintained throughout the life of any use.