(A) General.
(1) No subdivision shall be approved unless the area to be subdivided includes frontage on or access from an existing street as designated by the town street map and providing such street has existing public right-of-way allowing public access to the subdivided area.
(2) Streets shall be graded and improved in accordance with the construction standards, the approved construction plans, and as provided herein.
(B) Topography and arrangement.
(1) Streets shall be related appropriately to the topography. All streets shall be arranged so as to obtain as many as possible of the building sites at, or above, the grades of the streets. Grades of streets shall conform as closely as possible to the original topography. A combination of steep grades and sharp curves shall be avoided.
(2) All arterials and collector streets shall be properly related to special traffic generators such as industries, business districts, schools, churches, and shopping centers; to population densities; and to the pattern of existing and proposed land uses.
(3) Local streets shall be laid out to conform as much as possible to the topography to discourage use by through traffic, to permit efficient drainage and utility systems, and to require the minimum number of streets necessary to provide convenient and safe access to the property.
(4) In business and industrial developments, the streets and other access ways shall be planned in connection with the grouping of buildings, location of rail facilities, and the provision of alleys, truck loading and maneuvering areas, walkways, bikeways, and parking areas so as to minimize conflict of movement between the various types of vehicular and pedestrian traffic
(C) Street extensions.
(1) The street layout of the proposed subdivision shall provide for the continuation or projection of streets and alleys already existing in areas adjacent to the area being subdivided.
(2) Where, at the determination of the Plan Commission, it is desirable to provide street access to adjoining properties, proposed streets shall be extended by dedication to the boundaries of such properties. Where the Plan Commission deems it necessary, such dead-end streets shall be provided with a temporary turn around approved by the Plan Commission.
(3) The street system for the proposed subdivision shall provide for extending existing streets at the same or greater width, but in no case shall a street extension be of less width than the minimum width required in these regulations for a street in its category.
(D) Dedication of right-of-way for new streets.
(1) The dedication of right-of-way for new streets measured from lot line to lot line shall be as shown in Table IV-1.
(2) All streets classified as arterial streets by the Transportation Plan shall have all points of access approved by the Plan Commission. The Commission may require marginal access streets or frontage roads for subdivisions fronting on arterial streets.
(3) Through business areas, street widths shall be increased ten feet on each side if needed to provide parking without interfering with normal traffic patterns.
Table IV-1 Design Standards for Streets | ||||
Arterial Streets | Collector Streets | Local Streets | Cul-de-Sacs | |
Table IV-1 Design Standards for Streets | ||||
Arterial Streets | Collector Streets | Local Streets | Cul-de-Sacs | |
Curve length(2) SAG Crest | 70 x A 80 x A | 40 x A 30 x A | 40 x A 30 x A | 40 x A 30 x A |
Horizontal curve minimum radius | 400 ft. | 100 ft. | 100 ft. | 100 ft. |
Maximum grade | 5% | 7% | 10% | 7% |
Minimum angle for intersection | 90 degrees | 80 degrees | 70 degrees | 70 degrees |
Minimum corner radius | 30 ft. | 20 ft. | 20 ft. | 20 ft. |
Minimum grade | 0.5% | 0.5% | 0.5% | 0.5% |
Minimum street width(1) | 28 ft. | 24 ft. | 24 ft. | 24 ft. |
Minimum tangent length between reverse curves | 200 ft. | 100 ft. | 100 ft. | 100 ft. |
Right-of-way width | 120 ft. | 80 ft. | 50 ft. | 100 ft. diam. |
Vertical curve minimum sight distance | 500 ft. | 200 ft. | 100 ft. | 100 ft. |
(1) Street width is defined as the distance from back of curb to back of curb. Where curb and gutter is not required, minimum street width can be reduced by two feet. (2) Vertical curve length is defined by multiplying the algebraic difference in grade (A) by the value shown in the Table. | ||||
(E) Dedication of right-of-way for existing streets. Subdivisions platted along existing streets after the effective date of this chapter shall dedicate additional right-of-way if necessary to meet the minimum street width requirements set above for new subdivision streets.
(1) The entire minimum right-of-way width shall be dedicated where the subdivision is located on both sides of the existing street. When the subdivision is located on only one side of an existing street, one-half the required right-of-way width, measured from the centerline of the existing roadway, shall be dedicated.
(2) Dedication of one-half of the rights-of-way for proposed streets along the boundaries of land proposed for subdivision shall be prohibited.
(F) Street grades and elevations.
(1) All streets shall be designed so as to provide for the discharge of surface water from the pavement and right-of-way by grading and drainage. Street grades and curvatures shall be as listed in Table IV-1.
(2) The Plan Commission will not approve any streets that will be subject to inundation or flooding. All streets must be located at elevations that will make them flood free in the event of a 100-year flood. Fill may be used in areas subject to flooding in order to provide flood-free streets if such fill does not unduly increase flood heights and where allowed by and in accordance with any applicable rules and regulations of the state’s Department of Natural Resources.
(3) Drainage openings under any streets shall be designed so as not to restrict the flow of water, thereby unduly increasing flood heights.
(G) Intersections.
(1) In general, all streets shall join each other so that for a distance of at least 100 feet the street is approximately at right angles to the street it joins.
(2) Intersections shall be designed with a flat grade wherever practical. In hilly or rolling areas, at the approach to an intersection, a leveling area shall be provided having 2% maximum grade at least 60 feet in distance measured from the nearest right-of-way line of the intersecting street.
(3) No lot or other parcel of land which abuts on and has access to either a collector or a local access street shall have a service drive, curb cut, or other means of access to an arterial street within 50 feet of the right-of-way of any street which intersects such arterial street on the side on which such lot or parcel is located.
(H) Gutters and curbs.
(1) Gutters and curbs shall not be required for streets in subdivisions designed for two dwelling units or less per acre of ground within the boundaries of the plat.
(2) Gutters and curbs shall be required for all streets in subdivisions as designed for more than two dwelling units per acre of ground within the boundaries of the plat.
(3) Gutters and curbs may be required in the case of marginal access streets.
(4) Gutters and curbs may be integral concrete curb or combined gutter and curb type and may be designed with either straight or rolled curb section.
(I) Dead-ends and cul-de-sacs.
(1) Dead-end streets shall not be allowed unless specifically approved by the Plan Commission. Where allowed, dead-end streets shall not exceed 800 feet in length.
(2) Minor terminal streets or courts (cul-de-sacs) which are designed so as to have one end permanently closed shall not be longer than 800 feet. Such streets shall be provided at the closed end with a turnaround having a radius at the outside of the pavement of at least 40 feet and a radius at the outside of the right-of-way of at least 50 feet. The cul-de-sac shall be a geometric shape so as to contain an 80-foot diameter minimum circle.
(J) Names. Street names shall not duplicate any existing street name within the area covered by these regulations, except where a new street is a continuation of an existing street. Street names that may be spelled differently but sound the same as existing street names shall not be used. The Plan Commission shall coordinate with 911 services and have final authority to approve the names of streets, which shall be determined at the time of sketch plan approval.
(K) Private streets, reserve strips, and alleys.
(1) There shall be no private streets, nor any alleys, platted within a subdivision.
(2) There shall be no reserve strips in a subdivision except where their control is rested in the town or county under conditions approved by the Plan Commission as authorized in these regulations.
(L) Access to collector streets. Where possible, lots in single-family residential subdivisions fronting on collector streets shall be avoided, and lots at the corners of intersections between local and collector streets shall front on the local street and have driveway access to it only and not to the collector street. In multiple-family residential areas, entrances to group parking lots shall have access only to local streets (where possible) and such entrances shall be widely spaced.
(M) Access to principal arterials. Where a subdivision borders on or contains an existing or proposed principal arterial, the Commission may require that access to it be limited by one of the following means:
(1) Design of the subdivision lots so as to have the rear yards adjacent to the principal arterial and frontage onto a parallel local street. No access shall be provided from the principal arterial and screening shall be provided within a strip of land along the rear property line of such lots;
(2) A series of cul-de-sacs, or loop streets entered from, and designed generally to be at right angles to, an access street that is at some distance from and parallel to arterial street, with the rear yards of the terminal lots adjacent to the arterial; or
(3) A marginal access or service road (separated from the principal arterial by a landscaped and/or decoratively fenced grass strip and having access thereto at widely spaced suitable points).
(N) Street regulatory signs. A street name sign shall be provided at every street intersection within a subdivision. All necessary stop, speed limit, and other traffic-control devices and signs shall be provided and be in conformance with the Manual on Uniform Traffic-Control Devices. The town shall inspect and approve all street signs.
(O) Street lights. A lighting plan drawn up by developer and submitted with the construction plans shall require streetlights at all intersections, dead-ends, and entrances to platted subdivisions.
(P) Railroads and limited access highways. Railroad rights-of-way and limited access highways, where so located as to affect the subdivision of adjoining lands, shall be treated as follows.
(1) In residential districts a buffer strip at least 25 feet in depth in addition to the normal depth of the lot required in the district shall be provided adjacent to the railroad right-of-way or limited access highway. This strip shall be part of the platted lots and shall be designated on the plat: “This strip is reserved for screening. The placement of structures hereon other than earth berms, walls, fences, and other landscape screening devices approved by the Commission is prohibited.”
(2) In districts zoned for business, commercial, or industrial uses, the nearest street extending parallel or approximately parallel to a railroad shall, wherever practical, be at a sufficient distance from there to ensure a suitable depth for commercial or industrial sites.
(3) Streets parallel to a railroad when intersecting a street, which crosses the railroad at grade, shall, to the extent practicable, be at a distance of at least 150 feet from the railroad right-of-way. Such distance shall be determined with due consideration of the minimum distance required for future separation of grades by means of appropriate approach gradients.
(Q) Construction standards for streets.
(1) The base course for streets and alleys shall contain a minimum of 12 inches of compacted crushed stone or creek gravel with voids filled by sand or limestone screenings. Subgrade soil conditions shall be evaluated by the Building Inspector. Where drainage and soil conditions warrant, additional depth shall be required at the discretion of the Plan Commission or the Building Inspector. Subgrade shall be compacted to 90% of maximum density for a depth of 12 inches as determined by proctor needle test.
(2) All hot-mix asphalt pavement shall have 220 pounds per square yard bituminous with 110 pounds per square yard bituminous wearing surface. Other types of pavements used shall be approved by the Plan Commission or Building Inspector as equivalent to the just-described hot-mix asphalt.
(Ord. 2005-5, passed 6-7-2005)