§ 153.22  PRINCIPLES AND STANDARDS OF DESIGN.
   The final plat of the subdivision shall conform to the following principles and standards of design.
   (A)   General. The subdivision plan shall conform to the principles and standards which are generally exhibited in the Master Plan.
   (B)   Streets.
      (1)   The street and alley layout shall provide access to all lots and parcels of land within the subdivision, and where streets cross other streets, jogs shall not be created.
      (2)   Proposed streets shall be adjusted to the contour of the land, so as to produce usable lots and streets of reasonable gradient
      (3)   Certain proposed streets, where appropriate, shall be extended to the boundary line of the tract to be subdivided so as to provide for normal circulation of traffic within the vicinity.
      (4)   Wherever there exists a dedicated or platted portion of a street or alley adjacent to the proposed subdivision, the remainder of the street or alley to the prescribed width shall be platted within the proposed subdivision.
      (5)   Widths of arterial and collector streets shall conform to the width specified in the Official Thoroughfare Plan.
      (6)   The minimum right-of-way of residential streets or culs-de-sac shall be 50 feet. All culs-de-sac shall terminate in a circular right-of-way with a minimum diameter of 100 feet, or other arrangement for the turning of all vehicles conveniently within the right-of-way, and shall not exceed 500 feet in length.
      (7)   Alleys shall be discouraged in residential districts but should be included in commercial and industrial areas where needed for loading and unloading or access purposes, and where platted shall be at least 20 feet in width.
      (8)   The centerlines of streets should intersect at 90 degrees or closely thereto and in no case at less than 80 degrees.
      (9)   At intersections of streets and alleys, property line corners shall be rounded by arcs of at least 20 feet radii or by chords of such arcs.
      (10)   At intersections of streets the property line corners shall be rounded by arcs with radii of not less than 15 feet, or by chords of such arcs.
      (11)   Intersections of more than two streets at one point shall not be permitted.
      (12)   Where parkways or special types of streets are involved, the Commission may apply special standards to be followed in their design.
      (13)   Whenever the proposed subdivision contains or is adjacent to a railroad right-of-way, a major arterial or minor arterial street, provision shall be made for a marginal access street, or a parallel street adjacent to such railroad right-of-way or major arterial or minor arterial street. As a general principle, intersections of such marginal access streets or parallel streets shall not exist at less than one-quarter mile intervals with major arterial streets or at less than one-eighth mile intervals with minor arterial streets.
      (14)   Horizontal visibility on curved streets and vertical visibility on all streets must be maintained along the centerlines as follows.
         (a)   Arterial streets: 500 feet.
         (b)   Collector streets: 300 feet.
         (c)   Residential streets: 150 feet.
      (15)   Curvature measured along the centerline shall have a minimum radius as follows.
         (a)   Arterial streets: 500 feet.
         (b)   Collector streets: 300 feet.
         (c)   Residential streets: 200 feet.
      (16)   Between reversed curves on arterial streets there shall be a tangent of not less than 100 feet, and on collector and residential streets, such tangent shall be not less than 40 feet.
      (17)   Maximum grades for streets shall be as follows.
         (a)   Arterial streets, not greater than 6%.
         (b)   Collector and residential streets and alleys, not greater than 6%.
      (18)   The minimum grade of any street gutter shall not be less than 0.3%.
   (C)   Blocks.
      (1)   Blocks should not exceed 1,250 feet in length.
      (2)   Blocks shall be of sufficient width to permit two tiers of lots of appropriate depth, except where an interior street parallels a limited access highway or arterial street or collector street or a railroad right-of-way.
      (3)   Blocks shall not be less than 500 feet long.
   (D)   Lots.
      (1)   All lots shall abut on a street or a place.
      (2)   Side lines of lots shall be at approximately right angles to straight streets and on radial lines on curved streets. Some variation from this rule is permissible, but pointed or very irregular lots should be avoided.
      (3)   Double frontage lots should not be platted, except that, where desired along limited access highways or arterial streets or collector streets, lots may face on an interior street and back on such thoroughfares. In that event a planting strip for a screen, at least 20 feet in width shall be provided along the back of each lot.
      (4)   Widths, depths and areas of lots shall be not less than that provided in the zoning ordinance for single-family dwellings for the district in which the subdivision is located, except, that when a water main supply system or a sanitary sewer system are not available, the lot area necessary to install a private water supply or private sewage disposal on the lot in accordance with the State Board of Health regulations shall become the required minimum lot area.
      (5)   The depth-to-width ratio of the usable area of a lot shall be a maximum of three to one.
      (6)   Wherever possible, unit shopping centers, based upon sound development standards, should be designed in contrast to the platting of lots for individual commercial use.
      (7)   Corner, residential lots shall be wider than normal in order to permit appropriate setbacks from both streets.
   (E)   Easements. Where alleys are not provided, easements for utilities shall be provided. Such easements shall have minimum widths of 12 feet, and where located along lot lines, one-half the width shall be taken from each lot. Before determining the location of easements the plan shall be discussed with the local public utility companies to assure their proper placing for the installation of such services.
   (F)   Building line. Shall be as provided in the zoning ordinance.
   (G)   Public open spaces.
      (1)   Where sites for parks, schools, playgrounds or other public uses are located within the subdivision area as shown on the Master Plan, the Commission may request their dedication for such purposes, or their reservation for a period of one year following the date of the final approval of the plat.
      (2)   In the event a governmental agency concerned passes a resolution expressing its intent to acquire the land so reserved, the reservation period shall be extended for an additional six months.
(Ord. 478, passed 5-5-1970)