The City Planning Commission may permit a parking facility listed in paragraph (a) of Section 13-45 (Special Permits for Additional Parking Spaces), where such parking facility serves the parking needs of a predominantly residential development or enlargement, provided that, in addition to the conditions and findings set forth in Section 13-45, the Commission shall find that either:

(a)        the number of off-street parking spaces in such proposed parking facility is reasonable and not excessive in relation to recent trends in close proximity to the proposed facility with regard to:

(1)        the increase in the number of dwelling units ; and

(2)        the number of both public and accessory off-street parking spaces, taking into account both the construction, if any, of new off-street parking facilities and the reduction, if any, in the number of such spaces in existing parking facilities. In making this determination, the Commission may take into account off-street parking facilities for which building permits have been granted, or which have obtained City Planning Commission special permits pursuant to Section 13-45; or

(b)        the proposed ratio of parking spaces to dwelling units in the proposed development or enlargement does not exceed:

(1)        20 percent of the total number of dwelling units, where such units are located within Community District 1, 2, 3, 4, 5 or 6; or

(2)        35 percent of the total number of dwelling units, where such units are located within Community District 7 or 8.

The Commission may prescribe appropriate conditions and safeguards to minimize adverse effects on the character of the surrounding area.