For any development, enlargement or site alteration:

(a)        the City Planning Commission may authorize variations in the requirements for private roads and driveways on any Tier II site as set forth in Section 105-35 (Tier II Site Requirements for Driveways and Private Roads), as well as the requirements of Sections 25-621 (Location of parking spaces in certain districts) and 25-631 (Location and width of curb cuts in certain districts) provided that:

(1)        the development or enlargement is not feasible without such modification, or that the requested modification will permit a development, enlargement or site alteration that satisfies the purposes of this Chapter;

(2)        such modification is the least modification required to achieve the purpose for which it is granted;

(3)        the modification will not disturb the drainage pattern and soil conditions of the area;

(4)        the modification has minimal impact on the existing natural topography and vegetation and blends harmoniously with it; and

(5)        such modification will enhance the quality of the design of the development, enlargement or site alteration; or

(b)        located on a zoning lot containing historic buildings designated by the Landmarks Preservation Commission within the New York City Farm Colony-Seaview Hospital Historic District, as shown on Map 2 in Appendix A of this Chapter, the City Planning Commission may authorize modifications or waivers of the requirements for private roads as set forth in Section 26-20 (SPECIAL REQUIREMENTS FOR LOTS WITH PRIVATE ROADS) through Section 26-27 (Waiver of Bulk Regulations Within Unimproved Streets), inclusive, and Section 26-30 (SPECIAL REQUIREMENTS FOR LOTS WITH PRIVATE ROADS IN LOWER DENSITY GROWTH MANAGEMENT AREAS) through 26-35 (Screening), inclusive, provided that such modification or waiver:

(1)        results in greater environmental conservation or preservation of existing natural features;

(2)        results in a superior site and landscape plan that will not unduly disturb the drainage pattern and soil conditions of the area;

(3)        results in greater preservation of historic buildings or other architectural elements of the Historic District designated by the Landmarks Preservation Commission;

(4)        enhances vehicular and pedestrian connections between buildings on the site and the surrounding neighborhood;

(5)        will not impair the essential character of the Historic District and the surrounding area;

(6)        is the least required to achieve the purpose for which it is granted; and

(7)        will not reduce the required minimum width of the private road to a width less than 34 feet unless the Fire Department has approved such reduction and determined that emergency vehicles can adequately access and move within the site.