The provisions of Section 37-40 (OFF-STREET RELOCATION OR RENOVATION OF A SUBWAY STAIR) may be waived by joint certification of New York City Transit and the Chairperson of the City Planning Commission that major construction problems or operating design considerations render the stair relocation infeasible. In such event, the stair relocation requirement may be satisfied by retention of the existing stair and the provision on the zoning lot of an open area, qualifying under the provisions of Section 37-50 (REQUIREMENTS FOR PEDESTRIAN CIRCULATION SPACE), that accommodates pedestrian traffic passing the existing stair entrance.