Uses located on the ground floor or entered by stairs from a sidewalk entry, except for uses with no street frontage and accessible only through a lobby, shall be limited as follows:

(a)        On any wide street, at least 80 percent of any wide street front lot line ground level frontage shall be allocated to uses indicated in Section 81-722 (Use Group T).

(b)        On any narrow street, at least 50 percent of any narrow street front lot line ground level frontage shall be allocated to uses indicated in Section 81-722.

(c)        For zoning lots between 43rd and 50th Streets with street frontage on Broadway and/or Seventh Avenue, at least 50 percent of any length of narrow street front lot line ground level frontage within 100 feet of Broadway or Seventh Avenue shall be allocated to uses permitted only on wide street frontages in Section 81-722.

Where a stairway entrance into a subway is relocated onto a zoning lot pursuant to Section 81-46 (Off-street Relocation or Renovation of a Subway Stair), up to, but not more than, 40 feet of the narrow street front lot line ground level frontage occupied by that stairway may be excluded from the length of narrow street frontage to which the requirements of this Section apply.