105-441 - Modification of use regulations LAST AMENDED 2/2/2011 In addition to any #use# modifications which may be granted under the provisions of Section 105-701 (Applicability of large- scale residential development regulations), the City Planning Commission may permit #semi-detached# or #attached# #single- family residences# in R2 Districts and #attached# #single-# or #two-family residences# in R3-1 Districts. Furthermore, except in the #Special Natural Area District#-1 (NA-1), the Commission may permit #semi-detached# or #attached# #single-family residences# in R1-2 Districts provided that the #development# or #enlargement# is on a tract of land of at least four acres, and provided the Commission finds that: (a) the preservation of #natural features# requires the permitted #development# to be concentrated to the extent feasible in the remaining portion of the tract; (b) for such concentration of #development#, better standards of privacy and usable #open space# can be and are achieved under the development plan by inclusion of the proposed #residential building# types; (c) the change of housing type constitutes the most effective method of preserving #natural features#; (d) the #aggregate width of street walls# of a number of #residential buildings# separated by party walls shall not exceed 100 feet; (e) the proposed #street# system for the tract of land to be #developed# is so located as to draw a minimum of vehicular traffic to and through #streets# in the adjacent area; and (f) the existing topography, vegetation and proposed planting effectively screen all #attached# #single-family residences# from the #lot lines# along the perimeter of the tract of land to be #developed#.