§ 14-1-71. Street construction standards

(a) General Requirements.

(1) Construction Standards. All roadway construction and materials used shall be performed in accordance with the construction methods as listed in the appropriate sections of the "State of Wisconsin Department of Transportation Standard Specifications for Road and Bridge Construction" and its supplements, and this Chapter, whichever is more restrictive. The design requirements of this Section and Section 14-1-70 shall be applicable to all streets and roads that are to be dedicated to the City, regardless of whether such streets or roads are part of a new subdivision or land division. Design requirements for the pavement shall be adequate for the zoning classification of the area served by the subject street. A street which divides areas with different zoning classifications shall be constructed in accordance with the requirements of the area requiring the higher quality pavement. Any variation of this must have prior approval of the City Engineer. Combination concrete curb and gutter is required on all streets. (Refer to the Section describing requirements for curbs and gutters.) A copy of all design assumptions and computations on which the proposed design is based shall be submitted to the City Engineer.

(2) Preliminary Consultation. Prior to the design, preparation and construction of any roadway to be dedicated to the City of Greenwood, the applicant shall notify the City Engineer. An on-site meeting will then be arranged to be attended by the City Engineer and the applicant. Plans must be provided in order for the City Engineer to check the design and the drainage.

(3) Material Slips. Copies of material slips for all materials furnished for the road construction projects shall be delivered to the City before the City approves the final construction.

(4) Required Inspections. Prior to the commencement of any street construction, the subdivider shall notify the City Engineer, at least three (3) workdays in advance, as to the nature of the work being done. The City Engineer shall be contacted for required inspections during the following phases of construction:

a. Subbase grading;

b. Crushed aggregate base course;

c. Concrete gutter, curb and sidewalks;

d. Bituminous surface course; and

e. Shouldering.

Any deficiencies found by the City Engineer shall be corrected before proceeding to the next phase of construction.

(5) Tests of Materials. The City shall be provided with a sample of the roadway base material prior to placement on the roadway. The City shall also be provided with copies of test reports performed by an independent testing lab indicating test results for material gradation and soundness.

(6) Pavement Samples. Samples of bituminous concrete will be taken by the City during pavement construction operations for purposes of determining that the material meets specifications.

(b) Construction Standards. All streets and highways constructed in the City or to be dedicated to the City shall fully comply with the following construction standards, and shall be adequate for the zoning classification or projected use of the area served by the street:

(1) General. After completion of the underground utilities and approval thereof, the streets shall be constructed. Unless excepted, building permits shall not be issued prior to the installation of the street improvements and the approval of an individual lot grading plan that conforms to the guidelines of the master site grading plan, as determined by the City Engineer, or his/her designee.

(2) Temporary Streets. Construction of temporary streets shall require authorization of the Common Council.

(3) Standard Street Improvements.

a. Standard street improvements shall include street lights, crushed stone base course, concrete curb and gutter, bituminous binder and surface course and, when required, walkways.

b. The construction of standard street improvements can begin only when the construction of underground utilities has been completed and mechanical compaction test reports have been approved by the City Engineer.

c. Standard street improvements shall be installed to the boundary line of the subdivision unless the street culminates in a cul-de-sac, the topography or other physical conditions make it impossible to do so, or unless this requirement is waived, in writing, by the City Engineer.

(4) Roadway Base Standards.

a. After the installation of temporary block corners monuments by the subdivider and establishment of street grades by the City Engineer, the City shall grade the full width of the right-of-way of all streets proposed to be dedicated in accordance with plans and standard specifications approved by the City Plan Commission, upon the recommendation of the City Engineer. The roadbeds in the street rights-of-way shall be graded to subgrade.

b. Cut and filled lands shall be graded to a maximum slope of one (1) on four (4) or the soils angle of repose, whichever is the lesser and covered with permanent vegetation.

c. Residential streets shall have a minimum nine (9) inch thick, compacted in-place, crushed stone roadway base. Roadway base shall consist of four (4) inch minimum depth of compacted, crushed stone conforming to requirements of Gradation No. 2 of Section 304 - Crushed Aggregate Base Course of "State of Wisconsin, Standard Specifications For Road and Bridge Construction," latest edition, in top layer over five (5) inch minimum depth of compacted, crushed stone in bottom layer.

d. On commercial, arterial or other heavy-use streets, as determined by the City Engineer, a ten (10) inch minimum depth base course shall be constructed upon an inspected and approved subgrade, with crushed rock approximately six (6) inches in depth conforming to the specifications in Subsection (b)(4)b above and overlaid with one (1) four (4) inch layer of crushed stone conforming to Gradation No. 2 as specified in Subsection (b)(4)b above.

e. In the case of commercial, arterial or other heavy-use roads, the Common Council may, in the alternative to the above standards, have the City Engineer provide specifications for such roads after researching the site(s) and conducting a soil analysis for separate pavement design analysis.

f. In any case, the Common Council shall have the sole discretion in determining the use and construction classification to be adhered to.

g. In all cases, the base course shall be compacted to the extent necessary to produce a condition so that there will be no appreciable displacement of material laterally and longitudinally under traffic and shall conform to line, grades and shape shown on the approved plans, profiles and cross sections. Compaction shall be to ninety-five percent (95%) modified Proctor ASTM D1557. Testing shall be conducted by nuclear density meter or as otherwise approved by the City Engineer.

h. The subdivider shall furnish drawings which indicate the proposed grades of streets shown on the plat and, after approval of those grades by the City Engineer and adoption by the Common Council, the streets shall be graded to full width of the right-of-way of the proposed street to the subgrade elevations shown on the typical cross-section. The grading is to be completed prior to installation of utilities. All stumps and trees which cannot be saved, boulders and other similar items shall be removed by the subdivider.

(5) Roadway Subgrade Quality. All subgrade material shall have a minimum California Bearing Ratio (CBR) of three (3). Subgrade material having a CBR less than three (3) shall be removed and replaced with a suitable fill material, or the pavement must be designed to compensate for the soil conditions. The soil support CBR values selected for use by the designer should represent a minimum value for the soil to be used.

(6) Roadway Sub-Base. Stable and nonorganic sub-base material is required. Unstable and organic material must be subcut, removed and replaced with a suitable granular or breaker-run material approved by the City Engineer.

(7) Street Width; Pavement Thickness; Surfacing.

a. After the installation of all utility and storm water drainage improvements, the City shall surface all roadways in streets proposed to be dedicated to the widths prescribed by these regulations and the comprehensive plan or the comprehensive plan components of the City.

b. All roadways shall be surfaced with a three and one-half (3½) inch hot mix bituminous concrete pavement, made up of a two (2) inch binder course and a one and one-half (1½) inch surface course, placed on an eight (8) inch thick gravel base. The bituminous pavement shall be constructed in stages.

c. The binder course being placed initially upon completion of the utilities, and the surface course being placed at such time that seventy-five percent (75%) of the lots within the subdivision have been developed, but not sooner than one (1) year after the date the binder course was placed. All failures in the binder course shall be repaired and no bituminous surface shall be laid later than October 1 of any given year. Said surfacing shall be done in accordance with plans and standards specifications approved by the City Plan Commission, upon the recommendations of the City Engineer.

d. The entire cost of surfacing will be paid for by the City.

(8) Roadway Culverts and Bridges. Roadway culverts and bridges shall be constructed as directed by the City Engineer and sized utilizing the methods listed in Chapter 13, entitled "Drainage," of the "Facilities Development Manual" of the Wisconsin Department of Transportation. All roadway culverts shall be provided with concrete or metal apron endwalls. All culverts shall be designed to pass a ten (10) year, twenty-four (24) hour duration storm event.

(9) Driveways.

a. Curbs shall not be interrupted by openings for driveways or other accessways to private property unless the number and location of such interruptions have been approved by the City Engineer.

b. When allowed, curb openings for driveways within the public service area shall be no less than fourteen (14) feet nor more than twenty-four (24) feet in width unless the opening is intended to afford access to a commercially zoned parcel. The width of any driveway opening intended to afford access to commercial property shall not be more than thirty-five (35) feet, unless otherwise prescribed by the City Engineer.

c. Driveways outside of the public service area shall be no less than twelve (12) feet in width, shall have a culvert at the ditch line, and shall, in all other respects, comply with the requirements of any ordinance regulating driveways adopted by the pertinent adjacent town.

d. The culverts shall be placed in the ditch line at elevations that will assure proper drainage, and they shall be provided with concrete or metal endwalls.

(10) Topsoil, Grass, Seed, Fertilizer and Mulch. All disturbed areas (ditches, backslopes) within the road right-of-way not provided with pavement and shouldering material shall be restored utilizing four (4) inches of topsoil and good quality grass seed, fertilizer and mulch. Ditches along the roadway with greater than a two percent (2%) slope shall be protected by erosion control materials such as hay bales, sod, erosion control mats, etc.

(11) Drainage Improvements. All new roads and streets shall be provided with storm water retention areas and storm sewers in order to provide for proper drainage.

(12) Continuity and Transitions.

a. All street pavement widths on streets continued from previously developed or platted streets shall, wherever practical, provide for the greater of either the existing or required pavement type, width, grade and cross slope.

b. Where it is necessary to provide for a transition of pavement width and/or type between new and existing streets, the transition shall occur in a safe manner at an intersection. In width transitions, the ratio of the transition length to width shall not be less than forty to one (40:1) unless the City Engineer determines that special circumstances prevent use of such ratio, in which case the minimum transition ratio shall be twenty to one (20:1).

(13) Curb and Gutter. Combination concrete curb and gutter is required on all streets. Refer to Section 14-1-54 describing requirements for curbs and gutters.

(14) Post-Construction Traffic Limited. No vehicular traffic shall be permitted on the pavement for a minimum period of between twenty-four (24) and seventy-two (72) hours following paving, as determined necessary by the City Engineer to protect the new pavement.

(15) Rural Street Sections.

a. When permanent rural street sections have been approved by the Common Council, the City shall finish grade all shoulders and road ditches, install all necessary culverts at intersections and, if required, surface ditch inverts to prevent erosion and sedimentation in accordance with plans and standard specifications approved by the City Plan Commission, as recommended by the City Engineer and as set forth in this Chapter.

b. The cost of rural street sections will be paid for by the City. Any work to be done must be requested the year before the work is to be completed for budgetary purposes.