§ 154.191  DESIGN STANDARDS.
   (A)   Blocks.
      (1)   Block length. In general, intersecting streets, determining block lengths, shall be provided at such intervals so as to serve cross-traffic adequately and to meet existing streets. Where no existing plats control, the blocks in residential subdivisions should not exceed 1,200 feet nor be less than 400 feet in length, except where topography or other conditions justify a departure from this maximum. In blocks longer than 800 feet, pedestrian ways and/or easements through the block may be required near the center of the block.
      (2)   Block width. The width of the block shall normally be sufficient to allow two tiers of lots of appropriate depth. Blocks intended for business or industrial use shall be of a width as to be considered most suitable for their respective use, including adequate space for off-street parking and deliveries.
   (B)   Lots.
      (1)   Area. The minimum lot area, width and depth shall not be less than that established by the zoning regulations in effect at the time of adoption of the final plat.
      (2)   Corner lots. Corner lots for residential use shall have additional width to permit appropriate building setback from both streets as required in this chapter.
      (3)   Side lot lines. Side lines of lots shall be approximately at right angles to street lines or radial to curved street lines.
      (4)   Frontage. Every lot must have the minimum frontage on a City approved street other than an alley, as required in this chapter.
      (5)   Setback lines. Setback or building lines shall be shown on all lots intended for residential use and shall not be less than the setback required by this chapter, as may be amended.
      (6)   Watercourses. Lots abutting a watercourse, wetland, ponding area or stream shall have additional depth and width, as required under the provisions of this chapter.
      (7)   Features. In the subdividing of any land, due regard shall be shown for all natural features, such as tree growth, watercourses, wetlands, historic locations or similar conditions which if preserved will add attractiveness and stability to the proposed development.
      (8)   Lot remnants. All remnants of lots below minimum size left over after subdividing of a larger tract must be added to adjacent lots, rather than allowed to remain as unusable parcels.
      (9)   Political boundaries. No singular plat shall extend over a political boundary or school district line without document notification to the affected units of government.
      (10)   Frontage on two streets. Double-frontage, or lots with frontage on two parallel streets, shall not be permitted, except where lots back on arterial streets or highways, or where topographic or other conditions render subdividing otherwise unreasonable. The double-frontage lots shall have an additional depth of at least 20 feet in order to allow space for screen planting along the back lot line.
      (11)   Turn-around access. Where proposed residential lots abut a collector or arterial street, they should be platted in a manner as to encourage turn-around access and egress on each lot.
   (C)   Streets and alleys.
      (1)   Streets, continuous. Except for cul-de-sacs, streets shall connect with streets already dedicated in adjoining or adjacent subdivisions, or provide for future connections to adjoining un-subdivided tracts, or shall be a reasonable projection of streets in the nearest subdivided tracts. The arrangement of streets shall generally adhere to the City’s transportation plan, and implement a grid system as directed by the City. The arrangement of arterial, collector and local streets shall be considered in their relation to the reasonable circulation of traffic, to topographic conditions, to run-off of storm water, to public convenience and safety and in their appropriate relationship to the proposed uses of the area to be served.
      (2)   Local streets and dead-end streets. Local streets should be so planned as to discourage their use by non-local traffic. Dead-end streets are prohibited, but cul-de-sacs shall be permitted where topography, design constraints or other physical conditions justify their use. Cul-de-sacs shall generally not be longer than 600 feet, including a terminal turn-around, which shall be provided at the closed end, with a right-of-way radius of not less than 60 feet.
      (3)   Street plans for future subdivisions. Where the plat to be submitted includes only part of the tract owned or intended for development by the subdivider, a tentative plan of the proposed future street system for the unsubdivided portion shall be prepared and submitted by the subdivider. Street plans shall be in conformance with the City’s transportation plan, and shall provide for connectivity to adjoining neighborhoods as determined by the City Engineer.
      (4)   Temporary cul-de-sac. In those instances where a street is terminated pending future extension in conjunction with future subdivision, a temporary turn-around facility shall be provided at the closed end, in conformance with cul-de-sac requirements.
      (5)   Provisions for re-subdivision of large lots and parcels. When a tract is subdivided into larger than normal building lots or parcels, such lots or parcels shall be so arranged as to permit the logical location and openings for future streets and appropriate re-subdivision, with provision for adequate utility connections for the re-subdivision.
      (6)   Street intersections. Under normal conditions, streets shall be laid out so as to intersect as nearly as possible at right angles, except where topography or other conditions justify variations. Under normal conditions, the minimum angle of intersection of streets shall be 80 degrees. Street intersection jogs with an offset of less than 150 feet shall be avoided.
      (7)   Subdivisions abutting major rights-of-way. Wherever the proposed subdivision contains, or is adjacent to the right-of-way of a U.S. or state highway, or a county road or thoroughfare, provision should be made for a marginal access street approximately parallel and adjacent to the boundary of the right-of-way; provided that, due consideration is given to proper circulation design, or for a street at a distance suitable for the appropriate use of land between the street and the right-of-way. The distance shall be determined with due consideration of the minimum distance required for approach connections to future grade separations or for lot depths. Design considerations should include avoidance of rear yards abutting the subject right-of-way.
      (8)   Sidewalks. Sidewalks shall be required on one side of any platted local street, both sides of collector or arterial streets, and both sides of cul-de-sac streets including the turn-around. In those cases where the Council deems appropriate and necessary, additional sidewalks of not less than five feet in width shall be provided. In all cases where sidewalks are provided, provision shall be made for handicapped access.
      (9)   Service access, alleys. Service access shall be provided in commercial and industrial districts for off-street loading, unloading and parking consistent with and adequate for the uses proposed. Alleys, where provided, shall not be less than 30 feet wide. Dead-end alleys shall be avoided wherever possible, but if unavoidable, the dead-end alleys may be approved if adequate turnaround facilities are provided at the closed end.
      (10)   Half streets. Dedication of half streets shall not be considered for approval, except where it is essential to the reasonable development of the subdivision and in conformity with the other requirements of these regulations, or where it is found that it will be practical to require the dedication of the other half when the adjoining property is subdivided.
      (11)   Street grades. Except when upon the recommendation of the City Engineer, where the topography warrants a greater maximum, the grades of all local streets and alleys in any subdivision shall not be greater than 10%. The maximum grade of collector streets, thoroughfares and arterials shall not be greater than 6%. In addition, there shall be a minimum grade on all streets, arterials and thoroughfares of not less than 0.5%.
      (12)   Curb radius. The minimum curb radii for thoroughfares, collector streets, local streets and alleys shall be as follows:
         (a)   Arterial and collector streets: 50 feet;
         (b)   Local streets: 15 feet; and
         (c)   Alleys: five feet.
      (13)   Reverse curves. Minimum design standards for collector and arterial streets shall comply to state aid standards.
      (14)   Reserve strips. Reserve strips controlling access to streets shall be prohibited, except under conditions accepted by the Council.
      (15)   Street right-of-way width. Street right-of-way widths shall generally conform with the following standards:
Functional Classification
Jurisdictional Classification
Typ. Posted Speed (mph)
R.O.W. Typ.
Functional Classification
Jurisdictional Classification
Typ. Posted Speed (mph)
R.O.W. Typ.
Regional arterial
County
40 - 45 mph urban
80 - 150 feet
Regional arterial
County
45 - 55 mph rural
120 - 150 feet for 4-lane
Local arterial
City
30 - 40 mph urban
80 - 120 feet
Local arterial
City
40 - 50 mph urbanizing
80 - 120 feet
Regional collector
County
30 - 40 mph urban
80 - 120 feet
Regional collector
County
40 - 45 mph urbanizing
80 - 120 feet
Regional collector
County
45 - 55 mph rural
80 - 120 feet
Local collector
City
30 - 40 mph urban
66 - 100 feet
Local collector
City
40 - 50 mph urbanizing
66 - 100 feet
Local street
City
30 mph
50 - 66 feet (varies)
 
      (16)   Access management. To provide access to land development while preserving safety, capacity and operation of the transportation system.
Functional Classification
Area Type
Intersection Spacing
Private Access
Full Mvmt.
Condit. Mvmt.
Functional Classification
Area Type
Intersection Spacing
Private Access
Full Mvmt.
Condit. Mvmt.
Local arterial
Urban Core
300’ - 660’ dep. on block length
Subj. to Condit.
Local arterial
Urban/Urbanizing
1/4 mile
1/8 mile
By Exception
Local arterial
Rural
1/2 mile
1/4 mile
Subj. to Condit.
Local collector
Urban Core
300’ - 660’ dep. on block length
Subj. to Condit.
Local collector
Urban/Urbanizing
1/8 mile
Not Applic.
Subj. to Condit.
Local collector
Rural
1/2 mile
1/4 mile
Subj. to Condit.
Local street
City
Not Applic.
Not Applic.
Regional arterial
Urban Core
300’ - 660’ dep. on block length
Subj. to Condit.
Regional arterial
Urban/Urbanizing
1/4 mile
1/8 mile
By Exception
Regional arterial
Rural
1/2 mile
1/4 mile
Subj. to Condit.
Regional collector
Urban Core
300’ - 660’ dep. on block length
Subj. to Condit.
Regional collector
Urban/Urbanizing
1/8 mile
Not Applic.
Subj. to Condit.
Regional collector
Rural
1/2 mile
1/4 mile
Subj. to Condit.
 
   (D)   Easements.
      (1)   Width and location. An easement for utilities at least ten feet wide shall be provided along all lot lines. If necessary for the extension of main water or sewer lines or similar utilities, easements of greater width may be required along lot lines or across lots.
      (2)   Continuous utility easement locations. Utility easements shall connect with easements established in adjoining properties. These easements, when approved, shall not thereafter be changed without the approval of the Council after a public hearing.
      (3)   Guy wires. Additional easements for pole guys should be provided, where appropriate, at the outside of turns. Where possible, lot lines shall be arranged to bisect the exterior angle so that pole guys will fall along side lot lines.
   (E)   Erosion and sediment control.
      (1)   The development shall conform to the natural limitations presented by topography and soil so as to create the least potential for soil erosion.
      (2)   Erosion and siltation control measures shall be coordinated with the different stages of construction. Appropriate control measures shall be installed prior to development when necessary to control erosion.
      (3)   Land shall be developed in increments of workable size such that adequate erosion and siltation controls can be provided as construction progresses. The smallest practical area of land shall be exposed at any one period of time.
      (4)   When soil is exposed, the exposure shall be for the shortest feasible period of time.
      (5)   Where the topsoil is removed, sufficient arable soil shall be set aside for re-spreading over the developed area. Top soil shall be restored or provided to a minimum depth of six inches and shall be of a quality at least equal to the soil quality prior to development.
      (6)   Natural vegetation shall be protected wherever practical.
      (7)   Runoff water shall be diverted to a sedimentation basin before being allowed to enter the natural drainage system.
   (F)   Storm drainage. All subdivision design shall incorporate adequate provisions for storm water runoff and be subject to review and approval of the City Engineer.
   (G)   Protected areas.
      (1)   Where land proposed for subdivision is deemed environmentally sensitive by the City, due to the existence of wetlands, drainage ways, watercourses, floodable areas or steep slopes, the design of the subdivision shall clearly reflect all necessary measures of protection to ensure against adverse environmental impact.
      (2)   Based upon the necessity to control and maintain certain sensitive areas, the Council, based upon the review of the City Engineer, shall determine whether said protection will be accomplished through lot enlargement and redesign, or establishment of those sensitive areas in the form of outlots, or conservation easements.
      (3)   In general, measures of protection shall include design solutions which allow for construction and grading involving a minimum of alteration to sensitive areas. Where these areas are to be incorporated into lots within the proposed subdivision, the subdivider shall be required to demonstrate that the proposed design will not require construction on slopes over 18%, or result in significant alteration to the natural drainage system such that adverse impacts cannot be contained within the plat boundary.
(Ord. passed 3-20-2002, § 30.13)