In R5, R6, R7, R8, R9 or R10 Districts, in C1 or C2 Districts mapped within such Residence Districts, or in C1-6, C1-7, C1-8, C1-9, C2-6, C2-7, C2-8, C4, C5, C6 or C7 Districts, for combined school and residences including air rights over schools built on a zoning lot owned by the New York City Educational Construction Fund, the City Planning Commission may permit utilization of air rights; modify the requirements that open area be accessible to and usable by all persons occupying a dwelling unit or rooming unit on the zoning lot in order to qualify as open space; permit ownership, control of access and maintenance of portions of the open space to be vested in the New York City Educational Construction Fund or City agency successor in title; permit modification of yard regulations and height and setback regulations; permit the distribution of lot coverage without regard for zoning lot lines for a zoning lot containing the Co-op Tech High School in Manhattan Community District 11; authorize the total floor area, open space, dwelling units or rooming units permitted by the applicable district regulations on such site to be distributed without regard for district boundaries; and authorize an increase of 25 percent in the number of dwelling units or rooming units permissible under the applicable district regulations. For the purposes of this Section, a zoning lot owned by the New York City Educational Construction Fund may also include a tract of land under single fee ownership or alternate ownership arrangements according to the zoning lot definition in Section 12-10, when such tract of land includes a parcel which was the site of a public school listed in the following table.

The total number of dwelling units or rooming units and residential floor area shall not exceed that permissible for a residential building on the same zoning lot.

The distribution of bulk on the zoning lot shall permit adequate access of light and air to the surrounding streets and properties.

As further conditions for such modifications:

(a)        the school and the residence shall be developed as a unit in accordance with a plan approved by the Commission;

(b)        at least 25 percent of the total open space required by the applicable district regulations, or such greater percentage as may be determined by the Commission to be the appropriate minimum percentage, shall be accessible exclusively to the occupants of such residence and under the direct control of its management;

(c)        notwithstanding the provisions of Section 23-12 (Permitted Obstructions in Open Space), none of the required open space shall include driveways, private streets, open accessory off-street parking spaces or open accessory off-street loading berths; and

(d)        the Commission shall find that:

(1)        a substantial portion of the open space which is not accessible exclusively to the occupants of such residence will be accessible and usable by them on satisfactory terms part-time;

(2)        playgrounds, if any, provided in conjunction with the school will be so designed and sited in relation to the residence as to minimize any adverse effects of noise; and

(3)        all open space will be arranged in such a way as to minimize friction among those using open space of the buildings or other structures on the zoning lot.

The Commission shall give due consideration to the landscape design of the open space areas. The Commission shall also give due consideration to the relationship of the development to the open space needs of the surrounding area and may require the provision of a greater amount of total open space than the minimum amount required by the applicable district regulation where appropriate for the purpose of achieving the open space objectives of the Residence District regulations.

The Commission may prescribe other appropriate conditions and safeguards to enhance the character of the surrounding area.