A. General Standards:
1. The subdivision shall have adequate off site access providing sufficient capacity to handle all traffic which can be reasonably expected to be generated for the land uses to be located in the subdivision.
2. All streets in the subdivision shall be properly integrated with the existing and proposed street system as established on the official map and comprehensive plan of the village.
3. Major elements of the street system should be used to help define and buffer different land use areas, enhancing their identity and cohesiveness.
4. To the extent feasible, the lineal length of streets, the number of street intersections, and the paved area within intersections should be minimized.
5. The design of the street system of the subdivision shall be in accordance with table 10-1, minimum standards for street design and construction shall be in accordance with the engineering specifications of section 10-10-16 of this chapter.
6. Adequate drainage structures shall be provided. The design, installation, and construction of drainage structures shall comply with specifications of section 10-10-16 of this chapter and with chapter 11, "Floodplain And Storm Water Management", of this ordinance.
TABLE 10-1
MINIMUM STANDARDS FOR STREET DESIGN
Street Type | Right Of Way (Ft.) | Pavement Width* (Ft.) | Radius Of Horizontal Curves Of Center Line (Ft.) | Minimum/ Maximum Gradient (%) | Radius Of Curb Returns At Intersection+++ (Ft.) | Minimum Sight Clear Distance## (Ft.) | Minimum Length Of Vertical Curves++ (Ft.) | Tangent Between Horizontal Reverse Curves (Ft.) |
Street Type | Right Of Way (Ft.) | Pavement Width* (Ft.) | Radius Of Horizontal Curves Of Center Line (Ft.) | Minimum/ Maximum Gradient (%) | Radius Of Curb Returns At Intersection+++ (Ft.) | Minimum Sight Clear Distance## (Ft.) | Minimum Length Of Vertical Curves++ (Ft.) | Tangent Between Horizontal Reverse Curves (Ft.) |
Regional | ||||||||
Arterial | 100** | 48 | 500 | .5/5 | 45 | 500 | 200 | 200 |
Community Arterial | ||||||||
Residential | 80 | 36 | 300 | .5/5 | 35 | 400 | 200 | 200 |
Indst./Com. | 100 | 48 | 500 | .5/2 | 45 | 500 | 200 | 200 |
Neighborhood Arterial | ||||||||
Residential | 70*** | 36*** | 150 | .5/6 | 35 | 300 | 100 | 100 |
Indst./Com. | 80 | 36 | 300 | .5/2 | 45 | 500 | 200 | 200 |
Local | ||||||||
Residential | 66+ | 27 | 150 | .5/6 | 25 | 200 | 100 | --- |
Indst./Com. | 80 | 36 | 300 | .5/2 | 45 | 500 | 200 | 200 |
Cul-De-Sac# | ||||||||
Residential | 66+/100 | 27/75 | 150 | .5/6 | 25 | 200 | 100 | --- |
Indst./Com. | 80/140 | 36/110 | 300 | .5/2 | 45 | 500 | 200 | 200 |
Note:
* Face of curb to face of curb.
** Can also be 80 feet with two 10 foot easements on both sides of the right of way for utility lines, drainage, and landscaping purposes.
*** Can be 60 feet of right of way and 27 feet of pavement width, when there will never be any lots fronting on the street.
# The first dimension of the right of way and pavement width standards refers to the neck of the cul-de-sac; the second to the terminals or "bulb" of the cul-de-sac.
## Along horizontal and vertical curves.
+ Can be reduced to 60 feet with pedestrian walkway system separated from the street right of way laid out throughout the subdivision or planned development.
++ Vertical curves shall not be used in sags and crests where the algebraic difference in gradients recommended by the Village Engineer and approved by the Village Board. Under unusual topographic or site conditions, a longer radius may be required.
< On-street parking not allowed.
7. All pavements shall be designed in accordance with the following references as they apply:
a. "Standard Specifications for Road and Bridge Construction", IDOT, latest edition.
b. "Manual of Structural Design of Portland Cement Concrete Pavement", IDOT, latest edition.
c. "Manual for Instructions for the Structural Design of Flexible Pavements on Projects Involving MFT, FAS and FAUS Funds", IDOT, latest edition.
d. "Design Manual", IDOT, latest edition.
e. "Bureau of Local Roads - Administrative Policies", IDOT, latest edition.
8. Concrete curbs and gutters (type B.6-12) shall be required in all subdivisions.
B. Types And Specifications:
1. Types: The functional definitions of the street classification system for the Village of Western Springs are:
a. Regional Arterial Street: A regional arterial is intended to serve all types of trips, with a significant proportion representing vehicle trips destined beyond the boundaries of the community or neighboring communities. The section of the regional arterial within the community should serve a significant portion of trips generated by land uses within the community, but access should be carefully controlled. This type of street has regional importance because of its alignment, continuity, capacity, and its connections with other regional traffic carriers. Regional arterial streets in urbanized areas can be expected to carry in excess of sixteen thousand (16,000) vehicles per day and require more than one lane in each direction.
b. Community Arterial Street: A community arterial is intended to serve all types of vehicle trips with more emphasis on trips within and between the community and adjacent communities than trips made beyond the community boundaries. This type of street should not serve trips longer than five miles, but is important to the community in terms of traffic capacity and service to abutting land uses. The range of traffic volumes that can be expected on community arterial streets will vary significantly, depending upon the density of development, spacing of regional arterial routes, and the continuity of the street. These volumes will likely vary between six thousand (6,000) and fifteen thousand (15,000) vehicles and will require four (4) lanes in some cases.
c. Neighborhood Arterial Street: A neighborhood community arterial street is intended to serve only vehicle trips generated to and from the subareas (neighborhoods) within the community that it serves. The function of this type of street is to collect and distribute traffic between the neighborhoods and community and regional arterial streets. Neighborhood community arterial streets should not serve through traffic and should not have continuity beyond one and one-half (11/2) miles. These streets typically carry between two thousand (2,000) and five thousand (5,000) vehicles per day and require only one lane in each direction.
d. Local Street: A local street is intended to serve only those vehicle trips generated by land uses abutting the street. The function of this type of street is to provide access to and from individual properties within a neighborhood. Local streets should be designed to discourage through traffic.
e. Cul-De-Sacs: This is a short street ending in a turnaround designed and intended as a permanent terminus. Such streets should be used to discourage through traffic and to increase privacy. Cul-de-sacs should intersect with neighborhood collector streets, not with local streets and other cul-de- sacs, and not with arterial streets. Cul-de-sacs in residential areas should be no longer than five hundred feet (500'). Wherever possible, islands in the center of the bulb of the cul-de-sac should be designed, constructed, and landscaped.
2. Design Criteria: In order to provide for roads of suitable location, width, and improvement to accommodate prospective traffic and afford satisfactory access to police, firefighting, snow removal, sanitation and road maintenance equipment, and to coordinate roads so as to compose a convenient system and to avoid undue hardships to adjoining properties, the following design standards for streets are hereby required. All pavements shall be designed in accordance with the following references as they apply:
a. "Standard Specifications for Road and Bridge Construction", IDOT, latest edition.
b. "Manual of Structural Design of Portland Cement Concrete Pavement", IDOT, latest edition.
c. "Manual for Instructions for the Structural Design of Flexible Pavements on Projects Involving MFT, FAS and FAUS Funds", IDOT, latest edition.
d. "Design Manual", IDOT, latest edition.
e. "Bureau of Local Roads - Administrative Policies", IDOT, latest edition.
C. Design Layout:
1. General Concepts:
a. All streets shall be laid out in conformance with the Official Map and the Comprehensive Plan for the Village. Where such is not shown on the Official Map and Comprehensive Plan, the arrangement of streets within a subdivision shall either:
(1) Provide for the continuation or projection of existing regional arterial or community arterial streets in adjacent areas; or
(2) Conform to a plan for the area or neighborhood recommended by the Plan Commission and approved by the Village Board to meet a particular situation where topographical or other conditions make continuance or conformance to existing streets impracticable.
b. All streets shall be located in relation to existing topographic conditions, to public convenience and safety, and to efficient drainage and utility systems.
c. All streets shall be properly related to special traffic generators such as industrial business districts, school, churches and shopping centers; to population densities, and to the pattern of existing and proposed land uses.
2. Residential Streets:
a. A residential area should be conveniently accessible from arterial streets.
b. Residential streets shall provide safe and convenient access to housing.
c. Local streets shall be so laid out as to discourage high speed or through traffic, but the design shall be logical and comprehensible to a motorist or a pedestrian attempting to travel to and through the subdivision.
d. Curvilinear streets, cul-de-sacs, or U-shaped streets shall be used where such will result in a more desirable layout, or will avoid conformity of lot appearance.
e. Layouts of residential areas should be planned to avoid future need to widen any local street or neighborhood collector street.
f. Local streets and cul-de-sacs should intersect only with neighborhood collector and community arterial streets, unless the physical features of the site do not allow for such a design.
3. Nonresidential Streets:
a. Streets carrying nonresidential traffic, especially truck traffic, shall not normally be extended through adjacent existing or potential residential areas.
b. The streets and other accessways shall be planned in connection with the grouping of buildings, location of rail facilities, and the provision of alleys, truck loading and maneuvering areas, and walks and parking areas, so as to minimize conflict of movement between the various types of traffic, including pedestrian.
c. Streets extending parallel or approximately parallel to a railroad right of way should:
(1) Be at a sufficient distance therefrom to ensure suitable depth for commercial or industrial sites, and
(2) Be at a distance at least one hundred fifty feet (150') from the railroad right of way when intersecting a street which crosses the railroad at grade, or be at such other distance as shall be necessary, when intersecting a street which will be grade separated when crossing the railroad.
4. Half Streets: Half streets shall not be permitted except to complete an existing half street which is dedicated and accepted, or to conform to the Official Map and Comprehensive Plan of the Village of Western Springs.
5. Other Design Criteria:
a. Street jogs with center line off-sets of less than three hundred feet (300') shall be avoided.
b. Tangents shall be used between reverse curves on all regional arterial streets and community arterial streets.
c. Vertical alignment of streets should assure that inclines generally can be negotiated during adverse weather conditions and sight distances are adequate for safety.
d. Extensions of roads shall be provided into all adjacent property as needed. When no such extensions are provided, the extensions of appropriate easements to the boundary of the subdivision for pedestrian traffic, drainage facilities and utility lines shall be required.
e. The terminus of a cul-de-sac should not be lower than the neck of the cul-de-sac.
f. Where a subdivision borders an existing narrow road or when the Official Map or Comprehensive Plan indicates that a road should be realigned or widened which would require use of some of the land in the subdivision, such land shall be reserved and dedicated.
D. Intersections:
1. Streets shall be laid out so as to intersect as nearly as possible at right angles, but in no case shall any intersection be less than seventy five degrees (75o). An oblique street should be curved approaching an intersection and should be approximately at right angles for at least one hundred feet (100') therefrom.
2. Intersections on the inside of a curve, on a hilltop, or a point slightly below a hilltop shall be avoided.
3. An intersection of more than two (2) streets shall not be permitted.
4. Residential local streets and cul-de-sacs should intersect only with neighborhood collector and community arterial streets, not with other residential local streets and cul-de- sacs, and not with regional arterial streets.
5. Center lines of streets at intersections should align or be off-set therefrom by a minimum of three hundred feet (300').
6. In nonresidential areas and along regional arterial streets, proposed new intersections shall, wherever practicable, coincide with any intersections on the opposite side of such street.
7. Where any street intersection will involve earth banks or existing vegetation inside any lot corner that would create a traffic hazard by limiting visibility, the subdivider shall cut such ground and/or vegetation (including trees) in connection with the grading of the public right of way to the extent deemed necessary to provide an adequate sight distance.
8. The pavement cross slopes on street and intersection rights of way shall be three percent (3.0%) or less.
9. Intersections along regional arterial streets shall be at least three hundred feet (300') apart.
E. Other Requirements:
1. Reserve Strips: Reserve ("spite" or "devil") strips controlling access to streets shall not be permitted. Streets roughly parallel to the boundary line of the subdivision shall be located either on that boundary line or not less than one lot depth from said boundary line. All streets intended to provide the subdivision and adjacent parcels of property with means of ingress and egress shall extend to the boundary line of the subdivision.
2. Road Names: The plan commission shall review and the village board shall approve all street names, consulting with the postmaster and the chief of the fire department. Names shall be sufficiently different in sound and in spelling from other road names in the village so as not to cause confusion. A street which is or is planned as a continuation of an existing street shall bear the same name. (Ord. 92-1855, 12-14-1992)