The following requirements shall be incorporated into the design of all streets.
(A) Vertical alignment.
(1) Grades. The maximum grade on a major street shall be 5%. The maximum grade on all other streets (other than a major highway) shall be 8%. The minimum grade on all streets shall be 0.40%. All street grades shall be subject to the approval of the Village Engineer.
(2) Vertical curves. All grade changes shall be connected by vertical curves. The length of vertical curves shall not be less than 30 times the algebraic difference in rates of grade for crest curves and 35 times the algebraic difference for sag curves. When speed limits are to be posted greater than 30 mph, vertical curvature standards shall be used as contained within the latest revision of A Policy on Geometric Design of Highways and Streets (AASHTO) for urban local, collector and arterial streets by the respective classification. The minimum length of vertical curves on all types of streets shall be ten feet.
(B) Horizontal alignment.
(1) Horizontal curves. When a centerline deflection angle is greater than one degree, the following curves shall be required in the street: major and collector streets shall have a minimum centerline radius of 300 feet and a minimum length of curve of 100 feet; major and collector streets having a design speed and/or expected posted speed greater than 30 mph shall be consistent with the latest revision of the horizontal curvature requirements of AASHTO, 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 Department of Transportation Bureau Design and Environmental Manual.
(2) Intersections. Intersections of major and collector streets 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 Engineer.
(4) Curb corners. All curb corners shall have a minimum radius of 25 feet.
(C) Collector and local streets; installed in accordance with pavement standards. All collector and local streets shall be installed in accordance with the following pavement standards.
(1) Subgrade. At the option of the subdivider, 12 inches lime stabilized soil per current IDOT Standard shall be employed within the street area (omit curb).
(2) Asphalt - pavement alternatives.
(a) Alternate A: If the subgrade is treated as in above, the pavement design will consist of five inches of bituminous concrete binder course, Class I (A Binder), and two inches of bituminous concrete surface course, Class I (Gradation of coarse aggregate to be CA 16).
(b) Alternate B: If the subgrade is not lime treated, the pavement shall consist of five inches bituminous concrete binder course, Class l (A Binder), and two inches of bituminous concrete surface course, Class I (Gradation of coarse aggregate to be CA 16).
(c) All subgrades shall be inspected by the Village Engineer and, if he or she deems necessary, proof rolled prior to paving.
(d) If the street is a major street, the above binder and surface shall be increased to six inches and two inches for the lime treated and eight inches and two inches to the non-lime treated subgrade.
(3) Concrete - pavement alternate.
(a) A minimum of six inches unreinforced portland cement concrete pavement, according to § 420 of IDOT specifications, and a minimum of four inches of Subbase Granular Material, according to § 311 of IDOT specifications, shall be used.
(b) If the street is a major street, the P.C.C. pavement shall be increased to eight inches. All transverse contraction joints shall be 20 feet and sealed per ASTM D3405.
(4) Pavement design. In all cases, the minimum street will govern if the above major street design is less.
(a) All major street pavements shall be designed in accordance with the requirements contained in the latest, revised edition of the State IDOT BDE Manual and shall be designed for a 20-year period. The minimum requirements listed in the tables of the BDE 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 classifications percentages used in the design shall be approved by the Village Engineer.
(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) |
Alley | 20 feet minimum |
Collector street | 36 feet minimum |
Cul-de-sac | 90 feet diameter |
Local street | 27 feet minimum |
Major highway | As required by IDOT or applicable agency |
Major street | 40 feet minimum |
(2) Different widths may be used depending on the anticipated traffic volumes and parking demand. These widths of pavement shall be determined by the Village Board and the Village 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 or her expense.
(E) Curb and gutter.
(1) The standard curb and gutter required adjacent to flexible pavement shall be a mountable type constructed of portland cement concrete with the following dimensions: 24 inches wide, eight inches thick on the front face (pavement side); ten inches thick on the back face; seven inches thick at center line (flow line); and a ten-inch radius in the flow line. The curb and gutter adjacent to concrete pavement, if poured monolithically, may be limited to the thickness of the pavement.
(2) In subdivisions proposed to have streets with an anticipated daily traffic volume of 2,500 or more, a barrier type curb and gutter similar to Type B6.18, as described in the State Department of Transportation Highway Standards, shall be used. Other locations where a barrier type curb and gutter are required shall be determined by the engineer for the subdivision and the Village Engineer.
(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 (I) below). A turnaround shall be provided at the closed end having an outside roadway diameter of at least 90 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) 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 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 is constructing the street extension.
(I) 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.
(J) Restriction of access. When a subdivision or a portion of it adjoins a major street, no lot shall have direct access to the major street. The lot shall have adequate depth for screen planting on the portion of the lot contiguous to the major street.
(K) 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 name 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 current Illinois Manual on Uniform Traffic Control Devices.
(L) Private streets. There shall be no private streets platted in any subdivision. Every subdivision lot shall be served from a publicly dedicated street.
(M) Alleys. Alleys are not recommended in residential subdivisions unless deemed necessary by the Village Board.
(N) Ramps. Where sidewalks cross a barrier type curb and gutter, as described in division (E) above, ramps shall be constructed to accommodate the handicapped. These ramps shall be constructed to the lines and grades shown on the standard sidewalk ramp standards. Ramps shall comply with the latest ADA or IAC Standards. In case of conflict, the more restrictive specifications shall apply. Inlets for storm drainage shall not be located so that a pedestrian way will be interrupted by the inlet grates. Other locations where these ramps are required shall be determined by the Village Engineer.
(O) Typical street section.
(P) Median and islands.
(1) Where medians or islands are proposed, they shall be constructed with barrier or 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 Engineer.
(2) The subdivider or subdivision association may landscape medians or islands. Ground cover may not exceed a maximum height of 12 inches. Any additional living plant material must be maintained to allow visibility across, over or through medians and islands at a height of three to ten feet above the adjacent roadway pavements.
(Prior Code, § 153.132) (Ord. 06-01-01, passed 1-9-2006) Penalty, see § 153.999