Accessory off-street parking spaces are not required in Zone C. However, a maximum of 300 public parking spaces are permitted in subzones C-1 and C-2 combined, provided that:
(a) such spaces shall be completely enclosed;
(b) no portion of the parking facility, other than entrances and exits, shall be visible from adjoining zoning lots, streets, parks or the Esplanade ;
(c) no exhaust vents shall open onto any street or park; and
(d) the parking facility shall not be more than 23 feet above curb level.