The following regulations shall govern the design and layout of blocks:
(a) The arrangement of blocks shall be such alto conform to the street planning criteria set forth in Sections 1117.05 to 1117.12 hereof, and shall be arranged to accommodate lots and building sites of the size and character required for the district as set forth in these subdivision regulations or zoning regulations and to provide for the required community facilities.
(b) Irregularly shaped blocks, those intended for cul-de-sacs or loop streets, and those containing interior parks or playgrounds, may be approved by the Planning Commission if properly designed and located and if the maintenance of interior public spaces is covered by agreements.
(c) No block shall be longer than 1, 320 feet and the block width shall accommodate two tiers of lots, except where unusual topography or other exceptional physical circumstances exist.
(d) Where blocks are over 900 feet in length a crosswalk easement not less than ten feet in width at or near the halfway point may be required by the Commission if necessary to provide proper access to schools, recreational areas, shopping center and other facilities.