Where a lot in the General Commercial, Regional Economic Development or Light Industrial District abuts a lot in a residential district, there shall be provided along such abutting line on the nonresidential district lot a buffer at least equal in width to that required in the abutting residential district, but in no instance less than 75 feet, which shall be in addition to any required yard. The buffer area shall remain undisturbed and shall be not be used for storage of any material or goods, parking area, road, driveway, or other improvements, and the Planning Board, in its discretion, may require that the buffer area be suitably landscaped with year-round plantings no less than six feet in planting height. The Planning Board may also require a solid fence no less than six feet in height. The Planning Board shall establish the location of the landscape materials and fence within the buffer, and the buffer shall extend the full length of the shared property line of the two lots. The Planning Board may modify the requirement that the fence or hedge be extended the length of the common lot line to ensure adequate sight distance is maintained.