The subdivider shall conform to the following principles and standards of land subdivision in the design of each subdivision or portion thereof.
(A) General. The subdivision plan shall conform to design standards that will encourage good development patterns and particularly to the principles and standards which are generally exhibited in the Comprehensive Plan. The streets, drainage rights-of-way, school sites, public parks, playgrounds and other public facilities shown on the officially adopted Comprehensive Plan or Official Map, shall be considered in the approval of subdivision plats.
(B) Streets.
(1) The street and alley layout shall provide access to all lots and parcels of land within the subdivision. Street jobs of less than one hundred and twenty-five feet (125’) shall be avoided. Cul-de-sacs shall not exceed five hundred feet (500’) in length, unless necessitated by site topography.
(2) Neighborhood streets shall be designed so as to discourage through traffic.
(3) Proposed streets shall be adjusted to the contour of the land so as to produce usual lots and streets of reasonable gradient.
(4) Certain proposed streets, where appropriate, shall be extended to the boundary of the tract to be subdivided so as to provide for normal circulation of traffic within the vicinity.
(5) 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 shall be platted to the prescribed width within the proposed subdivision.
(6) Reserve strips controlling access to streets shall be prohibited except where their control is definitely placed in the City Council under conditions approved by the Plan Commission.
(7) Widths of major and collector street rights-of-way shall conform to the widths specified in Plat 1. These widths may be increased or decreased or varied upon approval of the Plan Commission and the City Engineer.
(8) The minimum right-of-way of local streets, including marginal access streets and cul-de-sacs, shall be fifty feet (50’). All cul-de-sacs shall terminate in a circular right-of-way with a minimum diameter of one hundred feet (100’) and a minimum diameter of seventy-five feet (75’) for the vehicle turn around (i.e. paved area). The City may require a wider right-of-way in order to comply with typical street cross section with minimum drainage swell and blank slopes.
(9) Subdivisions that adjoin or include existing streets that do not conform to the required widths shall dedicate additional width along either or both sides of said street.
(10) Streets shall be laid out so as to intersect as nearly at right angles as possible.
(11) If the smaller angle of intersection of two streets is less than sixty degrees (60°), the radius of the arc of the intersection of the property lines shall be determined by the Plan Commission.
(12) At the intersection of other streets the property line corners shall be rounded by arcs with radii of not less than twenty feet (20’), or chords of such arcs.
(13) At intersections of streets and alleys the property lines corners shall be rounded by arcs with radii of not less than fifteen feet (15’) or chords of such arcs.
(14) Intersections of streets and alleys, the property line corners shall be rounded by arcs with radii of not less than fifteen feet (15’) or chords of such arcs.
(15) Where parkways or special types of streets are involved, the Plan Commission may apply special standards to be followed in the design of such parkways. or streets.
(16) Whenever the subdivision contains or is adjacent to a railroad right-of-way or a highway designated as a “Limited Access Highway”, by the appropriate highway authorities, provision shall be made for a Marginal Access Street, or a parallel street. at a distance acceptable for the appropriate use of the land between the highway or railroad and such streets.
(17) Horizontal visibility on curved streets and vertical visibility on all streets shall be maintained along the center line as follows:
(a) Major streets: Five hundred feet (500’).
(b) Collector streets and parkways: Three hundred feet (300’).
(c) Local streets: One hundred fifty feet. (150’).
(18) Horizontal curvature measured along the center line shall have a minim radius as follows:
(a) Major streets: Five hundred feet (500’).
(b) Collector streets and parkways: Three hundred feet (300’).
(c) Local streets: One hundred fifty feet (150’).
(19) All changes in grade shall be connected by vertical curves of sufficient radii to provide smooth transitions and required sight distances.
(20) Between reversed curves on major streets there shall be a tangent of not less than one hundred feet (100’) and on collector and local streets such tangent shall be not less than forty feet (40’).
(21) Maximum grades for streets shall be as follows:
(a) Major streets, not greater than six percent (6%), or as approved by the City Engineer and the Plan Commission.
(b) Other streets and alleys, not greater than ten percent (10%), or as approved by the City Engineer and the Plan Commission.
(22) The minimum grade of any street gutter shall be not less than three-tenths of one percent.
(23) No street shall have a name which will duplicate or so nearly duplicate as to be confused with the name of an existing street; unless, the proposed street is an extension of or in alignment with an existing street, in which case the duplication shall be mandatory.
(24) Alleys shall be discouraged in residential areas but shall be included in commercial and industrial areas where needed for loading and unloading or access purposes; and, where platted, shall be at least twenty feet (20’) in width.
(25) Dead-end alleys shall be avoided where possible, but if unavoidable, shall be provided with adequate turn-around facilities at the dead-end, as determined by the Plan Commission.
(C) Blocks.
(1) Blocks shall not normally exceed twelve hundred fifty feet (1250’) in length, unless unusual circumstances justify greater 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, major street or railroad right-of-way.
(3) Blocks shall fit easily into the overall plan of the subdivision and their design must evidence consideration of lot planning, traffic flow and public areas.
(4) (a) Within blocks of over seven hundred feet in length, the Planning Commission may require, at or near the middle of the block, a public walk connecting adjacent streets or other public areas, shopping centers.
(b) Width of right-of-way for such walks shall be at least ten feet (10’) and shall be intended for the use of pedestrians only.
(D) Lots.
(1) All lots shall abut on a street, except lots within a Planned Business Development established pursuant to the Planned Business District Zoning Classification of the Schedule of District Regulations of Chapter 161 herein which lots shall abut either 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. Pointed or irregular lots shall be avoided.
(3) Double frontage lots shall not be platted, except that where desired along major streets, lots may face on an interior street and back on such thoroughfare. In that event a planting strip or a planting screen at least twenty feet in width should be provided along the rear of the lot.
(4) Minimum lot areas, widths and building setback lines shall be provided in the Zoning Ordinance for the district in which the subdivision is located within the jurisdiction, except that where a main supply system or a sanitary system is not available, the lot area necessary to install a private water supply or sewage disposal system on the lot, in accordance with the Illinois Department of Public Health, shall become the minimum lot area.
(5) Wherever possible, a unit shopping center, based on sound development standards, shall be designed in contrast to the platting of lots for individual commercial use.
(6) Corner residential lots shall be wider than normal to permit appropriate setbacks from both streets.
(E) Easements.
(1) (a) Where alleys are not provided, easements for utilities shall be provided. Such easements shall have a minimum width of fifteen feet and where located along interior lot lines, one-half the width shall be taken from each lot, except, however, perimeter easements located on the perimeter of the subdivision adjacent to private property outside the limits of the proposed subdivision may have a minimum width of ten feet (10’) where no water, sewer, or gas facilities are to be located within perimeter easement.
(b) Before determining the location of easements, the plan shall be discussed with the local utility companies to assure proper placing for the installation of services.
(2) Whenever a subdivision is traversed by a water course, drainage way channel or stream there shall be provided a drainage right-of-way which shall be for the purpose of widening, improving or protecting the stream at the subdivision’s expense. The width of the drainage right-of-way shall be adequate for any necessary channel relocations and straightenings and shall be reviewed by the City Engineer and shall relate as closely as possible to the requirements of the Comprehensive Plan. Parallel streets or parkways may be required in connection therewith.
(F) Public Use Areas. Where sites for parks, schools, playgrounds or other public use areas as shown in the Comprehensive Plan or Official Map are located within the subdivision area, the City Council shall require that such areas be so designated on the Final Plat. Within one year after the approval of the Final Plat, the authority having jurisdiction shall acquire the designated land or commence proceedings to acquire it by condemnation; otherwise, the owner may make any other permitted use of the site as permitted by the Zoning District within which it lies.
(G) Topography, Natural Vegetation and Flooding.
(1) In the subdividing of any land within the jurisdiction, due regard shall be shown for all natural features, such as tree growth, water courses, or other similar elements which, if preserved, would add attractiveness to the proposed development.
(2) The natural topography shall be retained wherever possible in order to reduce excessive run-off onto adjoining property and to avoid extensive re-grading of the site.
(3) Floor elevations of all buildings shall be carefully studied in relation to existing topography, proposed street grades, existing 12” and over caliper trees, and other pertinent site features.
(4) Where there is a question as to the suitability of a lot or lots for their intended use due to factors such as rock formations, flood conditions or similar circumstances, the Commission shall consider withholding approval of such lots.
(Prior Code, Art. 17, § 17.6)