§ 155.092  STREET DESIGN.
   The following requirements shall be incorporated into the design of all streets:
   (A)   Vertical alignment.  Grades.  The maximum grade on a major or minor arterial shall be five percent.  The maximum grade on all other streets shall be eight percent.  The minimum grade on all streets shall be 0.40 percent.  All street-grades shall be subject to the approval of the village's consulting engineer.
   (B)   Horizontal alignment.
      (1)   Horizontal curves.  When a center line deflection angle is greater than one degree, the following curves shall be required in the street:  major and minor arterials and collector streets shall have a minimum center line radius of 300 feet and a minimum length of curve of 100 feet; arterials and collectors having a design speed and/or expected posted speed greater than 30 miles per hour shall be consistent with the latest revision of the horizontal curvature requirements of ASSHTO.  A Policy on Geometric Design of Highways and Streets for the appropriate roadway classification; all other types of streets shall have a minimum center line radius of 100 feet.  The pavement in all cases shall be wide enough to allow the movement of a WB-50 Design vehicle, as described in the State of Illinois, Department of Transportation Design Manual.
      (2)   Intersections.  Intersections of major and minor arterials and collectors with roadways of the same classes shall not be closer than one-quarter of a mile from any other such functionally classed roadways' intersections.  These intersections shall be located at the quarter mile grid points.
      (3)   Street offsets.  Street centerline offsets shall not be less than 125 feet, unless otherwise warranted to the satisfaction of the village's consulting engineer.
      (4)   Curb corners.  All curb corners shall have a minimum radius of 25 feet.
   (C)   All local and collector streets shall be installed in accordance with the following pavement standards:
      (1)   Subgrade:
         (a)   Subgrade shall be processed and compacted in accordance with Section 301 of the IDOT standard specifications
      (2)   Base Course:
         (a)   geotextile fabric for ground stabilization, meeting the requirements of AASHTO M288
         (b)   6" Compacted Aggregate Sub base (CA-6). For Asphalt Alternate.
         (c)   4" Compacted Aggregate Sub base (CA-6). For Concrete Alternate.
      (3)   Asphalt: pavement alternate:
         (a)   The pavement design will consist of 4" of bituminous concrete binder course and 2" of bituminous concrete surface course, in accordance with the latest edition of the IDOT Standard Specifications for Road and Bridge Construction. Mix designs shall be submitted to the subdivider's engineer and the village's engineer for approval prior to paving, and shall be appropriate mix designs for the forecasted traffic volume and anticipated vehicle composition.
         (b)   All subgrades shall be inspected by the village’s consulting engineer. If the engineer deems necessary, subgrades will be proof rolled prior to paving,
         (c)   If the street is a minor arterial, the above binder and surface shall be increased to six inches and two inches. All major arterial roadways will be designed in accordance with Illinois DOT pavement design standards and as described in the division (4), Pavement design, below.
         (d)   All asphalt material testing shall conform to the latest Illinois DOT quality control/quality assurance procedures for documentation.
      (4)   Concrete: pavement alternate:
         (a)   A minimum of six-inch, un-reinforced Portland cement concrete pavement, according to Section 420 of IDOT specifications, shall be employed.  All transverse contraction joints shall be 15 feet and sealed per ASTM D3405.
         (b)   If the street is a minor arterial, the pavement shall be increased to eight inches.  All transverse contraction joints shall be 20 feet and sealed per ASTM D3405.
      (5)   Pavement design.
         (a)   All major arterial pavements shall be designed in accordance with the requirements contained in the latest, revised edition of the State of Illinois DOT Design Manual, and shall be designed for a 20-year period.  The minimum requirements listed in the tables of the Design Manual shall govern at all times.
         (b)   An Illinois Bearing Ratio of 3.0 (IBR = 3.0) shall be used in pavement design unless the subdivider’s engineer submits soil tests justifying a different IBR.
         (c)   Vehicular traffic volumes and vehicle classification percentages used in the design shall be approved by the village’s consulting engineer, based on approved traffic projections for the design year.
         (d)   In all cases the minimum street will govern if the above major arterial design is less.
   (D)   Pavement width.
      (1)   All streets shall be improved with pavements to an overall width in accordance with the following general guidelines, which are subject in every case to the discretion of the Village.
   Type of Street            Pavement Width
                  (edge of pavement to edge of pavement)
   Major Arterial            40 feet minimum and
                    as required by IDOT
   Minor Arterial            32 feet minimum
   Collector Street         27 feet minimum
   Local Street            27 feet minimum
      (2)   The minimum pavement width shall be 27 feet from the edge of pavement to edge of pavement, not including the curb and gutter.  Different widths may be used depending on the anticipated traffic volumes and parking demand.  These widths of pavement shall be determined by the Planning Commission and the village’s consulting engineer in consultation with the engineer for the subdivider.  If a pavement width narrower than the above stated minimum results from this consultation, the subdivider shall install "No Parking" signs at his expense.
   (E)   Curb and gutter.
      (1)   The standard curb and gutter required adjacent to flexible pavement shall be a valley gutter type constructed of Portland cement concrete with the following dimensions:  24" wide, 8" thick on the front face (pavement side), 10" thick on the back face, 7" thick at center line (flow line), and a 10" radius in the flow line, in accordance with Appendix A-12.  The curb and gutter adjacent to concrete pavement, if poured monolithically, may be limited to the thickness of the pavement.
      (2)   All arterial roadways shall be constructed with a barrier type curb and gutter similar to Type B6.18 as described in the State of Illinois, Department of Transportation Highways Standards.  Other locations where a barrier type curb and gutter are required shall be determined by the engineer for the subdivision and the village's consulting engineer.
      (3)   Expansion and contraction joints shall be constructed at the intervals identified and in accordance with the provisions of the Illinois DOT standard specifications.
   (F)   Pavement crown.  The minimum crown used on all pavements shall be one quarter inch per foot measured from the edge of the pavement to the centerline of the street.
   (G)   Cul-de-sac streets.  Local streets that are also cul-de-sac streets shall be no more than 600 feet long unless necessitated by topography in which case they shall be no longer than 1,000 feet unless provision is made for an interim turnaround with a radius sufficient to accommodate emergency vehicles and/or a median entrance (See division (J) of this section).  A turnaround shall be provided at the closed end having an outside roadway diameter of at least 86 feet edge to edge of pavement and a street right-of-way diameter of 110 feet.  No obstructions shall be permitted in the cul-de-sac turnaround.
   (H)   Corner "Knuckles".  Widened areas or "knuckles" constructed at the corners of local streets shall have a minimum edge of pavement radius of 45 feet.
   (I)   Stub streets.  Access shall be provided to adjoining property not yet subdivided.  Proposed streets shall be extended by dedication to the boundary of such unsubdivided property.  At the end of all temporary stub streets, a barricade meeting the provisions of the Illinois Manual on Uniform Traffic Control Devices shall be installed by the subdivider.  Stub streets in excess of 250 feet shall be provided with a temporary cul-de-sac with an outside roadway diameter of at least 90 feet.  The type of construction shall be determined by the village's consulting engineer.  The subdivider shall dedicate a temporary easement to the appropriate street authority in the amount needed in excess of the normally required right-of-way for the temporary turnaround.  When the street is extended in the future, the extra turnaround pavement shall be removed and curb and gutters and sidewalks constructed by the subdivider who constructed the temporary pavement or by the subsequent lot owner.
   (J)   Multiple access.  Any area of development containing 70 or more single family lots (or equivalent population) shall be served by two functioning points of access.  Where higher densities of development are proposed, a divided type entrance roadway may suffice with a median of adequate width to ensure continued emergency access lanes on one side.  Depending on location and height of nearby poles or trees, the required median width shall range between 12 and 30 feet.  This type of roadway construction is intended to accommodate higher density developments and not to lengthen the overall length of a cul-de-sac.
   (K)   Restriction of access.  When a subdivision or a portion of it adjoins a major or minor arterial, no lot shall have direct access to the arterial.  The lot shall have adequate depth for screen planting on the portion of the lot contiguous to the major or minor arterial.
   (L)   Street names and street signs.
      (1)   A proposed street that is in alignment with and/or joins an existing named street shall bear the name of the existing street.  In no case shall the proposed name of a street duplicate the name of an existing street within the plat jurisdiction of this chapter.  The use of the suffix "street", "avenue", "boulevard", "driveway", "place", "court" or similar description shall not be a distinction sufficient to constitute compliance with this requirement.
      (2)   Street names signs shall be erected at all intersections within the village's jurisdiction at the expense of the subdivider and shall be subject to the specifications of the Illinois Manual on Uniform Traffic Control Devices.  The actual costs to install the street sign assemblies will be collected from the developer at the time the developer requests village acceptance of the streets.
   (M)   Private streets.  There shall be no private streets platted in any subdivision.  Every subdivision lot shall be served from a publicly dedicated street.
   (N)   Alleys.  Alleys are not recommended in residential subdivisions unless deemed necessary by the Planning Commission.
   (O)   Ramps.  Where sidewalks cross a barrier type curb and gutter as described in division (G) of this section, ramps shall be constructed to accommodate the handicapped.  These ramps shall be constructed to the lines and grades shown on the standard sidewalk ramp example as shown in Appendix A-5.  Inlets for storm drainage shall not be located so that a pedestrian way will be interrupted by the inlet grates. 
   (P)   Typical street section.  Refer to Appendix A-5 for typical residential street section. For non-residential streets, a pavement design shall be provided based on the anticipated loads based on the projected average annual traffic volume.
   (Q)   Medians and islands.
      (1)   Where medians or islands are proposed they shall be constructed with barrier curbing.  All medians and islands shall be the responsibility of the subdivider and/or a subdivision association to maintain.  No sign may be installed in the median which blocks the sight distance at the intersection.  If such a sign is to be installed, detailed plans for the sign shall be submitted with the construction plans for approval.  In no case shall an island or median contain any other sign or structure except as may be placed for traffic control under the direction of the village's consulting engineer.
      (2)   The subdivider or subdivision association may landscape medians or islands.  Ground cover may not exceed a maximum height of 12".  Any additional living plant material must be maintained to allow visibility across, over or through medians and islands at a height of 3-10 feet above the adjacent roadway pavements.
(Ord. 94-01, passed 1-25-94; Am. Ord. 94-60, passed - -96; Am. Ord. 05-05, passed 2-22-05; Am. Ord. 10-01, passed 1-12-10; Am. Ord. 15-03, passed 1-27-15; Am. Ord. 16-35, passed 6-28-16)