On application, the City Planning Commission may grant an authorization modifying the building setback requirements of Section 107-241 (Special provisions for arterials), provided that the Commission finds that:

(a)        the area of that portion of the zoning lot which is designated as designated open space on the District Plan in Appendix A of this Chapter, is at least equal to the area of the required building setback front yard or yards, or portion thereof, which is waived;

(b)        along any front lot line abutting an arterial, a front setback shall be provided having a depth to be determined by the Commission and which shall be improved in accordance with a landscape plan approved by the Commission; and

(c)        building placement leaves adequate spaces for the provision of street trees.