(1) Lots having double Frontage shall not be approved except where necessitated by topographic or other unusual conditions. The width of each block shall be sufficient for an ultimate layout of two tiers of Lots therein of a size required by the provisions of this Title, unless the general layout of the vicinity, lines of Ownership, topographical conditions or locations of Arterial Streets or Freeways justify or make necessary a variation from this requirement.

(2) Blocks shall not exceed 1500 feet in length. In any block over 900 feet in length, there shall be a crosswalk or pedestrian way in accordance with The Transportation and Public Ways Ordinance.