Johnston City Zoning Code

CHAPTER 196

SUBDIVISION DESIGN STANDARDS

196.01 GENERAL DESIGN AND DEVELOPMENT STANDARDS

Conformance Required. No subdivision plat shall be approved by the Council unless it conforms to all applicable minimum standards and requirements of this Ordinance, except those plats referred to as auditor’s plats.

Suitability.

A.
No land shall be developed which is held unsuitable for such use due to steep slopes, flooding, inadequate drainage, adverse soil or rock formation, unfavorable topography or any of the feature likely to be harmful to the health, safety, or welfare of the community.
B.
When slopes over 14% are proposed to be disturbed, a slope stability analysis shall be submitted to demonstrate that the area may be disturbed without risk of ongoing erosion and detailing if any protective measures shall be incorporated to reduce the risk of erosion during disturbance or post-disturbance.
C.
Areas deemed unsuitable for development shall be protected through the use of unbuildable outlots or conservation easements.

Waivers Allowed. Whenever the tract proposed to be subdivided is of such unusual size or shape or is surrounded by such development or unusual conditions that the strict application of the requirements contained in this Ordinance would result in less desirable use of the land, the City may waive such requirements to the end that the subdivider is allowed to develop property in a reasonable manner. The waivers granted shall be in harmony with the intended spirit of this Ordinance and granted with the view toward protecting the public welfare and interest of the City and surrounding area.

Creation of Lots with Some Services not Available. It is the policy of the City to prohibit the creation of lots where adequate services are not provided. Adequate services would include (but are not limited to) availability of water service adequate to serve fire protection needs, sanitary sewer service as opposed to individual sewer disposal systems, adequate streets to serve the proposed use without creating safety concerns and maintenance liabilities for the City. However, there are areas of the City where service levels are currently deficient and may remain deficient for several years to come. Where it is unlikely that services will be provided in an economically practical and timely fashion, the creation of the subdivision via the platting procedure is dependent upon satisfactory evidence that:

A.
The lots created would be an appropriate division of land and shall not hinder the future upgrade of public services to a level as envisioned in the Comprehensive Plan.
B.
Any on-site wastewater treatment system must be approved by Polk County or the Iowa Department of Natural Resources.
C.
The existing street system has the capacity and is in satisfactory condition to support the increased development.
D.
The proposed subdivision is an infill project within an existing neighborhood.
E.
The subdivision shall create no more than four (4) lots accessing a shared driveway.
F.
The property owner seeking to develop the subdivision shall acknowledge through a petition and waiver (voluntary assessment) that they will be in full support of any future capital improvement project in that neighborhood. The project will be one that is financed all or partially by special assessment and built to the City’s subdivision regulations and standard specifications. In addition, the City Council may interpret the vote for that property and/or subsequent lots as votes in support of the project.

Large Lot Subdivision. Whenever the area is divided into lots containing one (1) or more acres and there are indications that such lots will eventually be re-subdivided into smaller building lots, consideration shall be given to the street and lot arrangement of the original subdivision so that additional minor streets can be opened which will permit a logical arrangement of smaller lots.

General Subdivision Design. The layout of streets shall discourage through traffic on local streets and channel traffic onto collector and arterial streets. The layout should also conform to the topographical character of the site through the use of curvilinear streets. The street circulation system shall be established to achieve economical use of land for building sites, minimize the cost of roadway construction, and provide uniform, efficient, and safe traffic conditions. The layout of streets shall also be consistent with the general character desired as defined in the City’s Comprehensive Plan and other policies and guidelines of the City.

Vertical Datum Plane. The NOAA (National Oceanic and Atmospheric Administration)’s NGS (National Geodetic Survey) NAVD88 (North America Vertical Datum) Plane is established and adopted as the City of Johnston datum plane and shall be used as the primary vertical reference plane in establishing all elevations and grades within the City. City established vertical benchmarks reference the NGS point “PID-MH0677” or the “DODGE” monument on the ground at the Northeast corner of NW Beaver Drive and NW 78th Avenue within Johnston. Character of Development. The Council shall have the right to agree with the subdivider regarding the type and character of development that will be permitted in the subdivision, and may require that certain minimum regulations regarding this matter be incorporated in deed restrictions. Such regulations shall be intended to protect the character and value of the surrounding development and shall also tend to secure the most appropriate development of the property being subdivided.

Subdivisions immediately adjacent to Camp Dodge. Any property immediately adjacent to Camp Dodge or which is within a Camp Dodge Noise Zone shall at the time of subdivision:

A.
Include a statement in the deed that notes the property’s proximity to Camp Dodge and that there may be impacts from adjoining Camp Dodge activities.
B.
Provide a landscape buffer at least 50 feet wide along any shared property line with Camp Dodge. The buffer shall contain plant materials as described for a 50-foot wide buffer in Section 182.04.

Effective on: 5/1/2023

196.02 BLOCKS & LOTS

Blocks

A.
Blocks shall not be greater than 1,320 feet in length, except if necessary due to unusual topographic conditions, water frontage, or other circumstances.
B.
Blocks for commercial and industrial areas may vary from the elements of design contained in this Section if the nature of the use requires other treatment. In such cases, off-street parking for employees and customers shall be provided along with safe and convenient limited access to the street system. Space for off-street loading shall also be provided with similar access. Extension of roads, railroad access right-of-way and utilities shall be provided as necessary.
C.
Blocks shall be wide enough to allow for two (2) tiers of lots, except lots adjoining a lake, stream, railroad, or arterial, or where one (1) tier of lots is necessary because of topographic conditions.

Lots

A.
The minimum dimensions for lots shall be in accordance with the bulk regulations of the Zoning Ordinance for the district within which the subdivision is located; provided, corner lots shall be of such width as to permit the maintenance of all yard requirements as required by the Zoning Ordinance.
B.
Street Frontage Required.
1. 1.
  No lot shall be created for residential purposes and no building permit shall be issued for a residential structure unless:
  1. a.
    The lot abuts for at least 40 feet on a public street; or
  2. b.
    An exclusive unobstructed private easement of access or private right-of-way of a least 25 feet wide to a public street is provided up to and including the lot being created.
  3. c.
    The subdivision of land into lots not meeting the provisions of 1.a and 1.b above may be permitted if the Council determines the lot cannot be included as part of adjoining vacant land to create a subdivision in compliance with this Ordinance.
2. 2.
  If a shared driveway will provide access for two (2) to four (4) single-family dwellings, the shared driveway easement shall be at least 50 feet wide from the public street up to and including the lot being created. A lot served by a shared driveway shall not be created until the Council can make a determination that:
  1. a.
    The shared driveway easement is a reasonable and necessary means of access in lieu of a public street;
  2. b.
    A shared maintenance agreement has been established between the property owners served by the shared driveway; and
  3. c.
    The shared driveway improvements are adequate for their intended use and comply with fire code requirements.
3. 3.
  Private streets. For any subdivision that does not meet the provisions of B.1 or B.2 above, a private street shall be created to serve those lots. The private street shall be located on a separate outlot or parcel and encumbered within an easement. A homeowners association shall be established to maintain ownership of the private street parcel.
C.
All side lot lines shall be substantially at right angles or radial to street centerlines, unless the Council agrees that a variation to this requirement will provide for a better street and lot arrangement. Double frontage lots shall be avoided except where essential to provide separation of residential development from major arterial streets or to overcome specific disadvantages of topography.
D.
The minimum required lot width for corner lots shall be increased by a minimum of 10 feet to allow for the additional required corner yard setback. For example, if the minimum lot width is 60 feet, the minimum width of a corner lot shall not be less than 70 feet.
E.
All lots at street intersections shall have a radius of not less than 15 feet at the street corner. A greater radius shall be required for intersections involving one (1) or more major streets. A cutoff or chord may be substituted for the circular arc.

Effective on: 5/1/2023

196.03 EASEMENTS

Easements for utilities, trails, sidewalks, and stormwater management

A.
Easements for public and private utilities, open space, trails, sidewalks, conservation, and stormwater management shall be provided as determined necessary based upon the subdivision design and as required in the Comprehensive Plan, Parks and Trails Master Plan, or Watershed Assessment and Stormwater Management Plan.
B.
Easement Widths
1. 1.
  Easements for private utilities only shall be a minimum of 10 feet wide.
2. 2.
  Easements for sidewalks only shall be a minimum of 10 feet wide.
3. 3.
  Easements for trails only shall be a minimum of 20 feet wide.
4. 4.
  Easements for dedicated public utilities shall be a minimum of 10 feet wide on either side of the centerline of the utility.
5. 5.
  Combined private utility and sidewalk easements shall be a minimum of 15 feet wide, while combined private utility and trail easements shall be a minimum of 20 feet wide.
6. 6.
  Public utility easements (PUE) shall be a minimum of 10 feet on the rear or side lot line except where impractical due to physical constraint.
7. 7.
  Drainage easements may vary in width depending upon drainage requirements as specified in the site’s stormwater management plan.
C.
The applicant shall provide and dedicate to the City an easement along each side of any stream or major surface watercourse in sufficient width to meet the requirements of CHAPTER 183 Stream Buffer Protection. Easements identified on the preliminary and final plats shall be by separate written document approved by the City Attorney and Zoning Administrator and filed in conjunction with the final plat.
D.
Proper coordination shall be established between the subdivider, Department of Community Development, and the utility companies for the establishment of utility easements.

In compliance with CHAPTER 88, Erosion and Sediment Control and whenever any stream or major surface watercourse is located in an area that is being subdivided, the applicant shall, at the applicant’s expense, make any required modifications to existing storm drainage channels to properly carry the surface water, address erosion control issues to ensure the protection of all improvements within the proposed subdivision.

Effective on: 5/1/2023

196.04 STREET DESIGN

General

A.
Relationship to Adjoining Street System. The arrangement of streets in new subdivisions shall make provision for the continuation or proper intersection of existing streets in adjoining subdivisions. Proposed streets shall be extended to the boundary lines of the tract to be subdivided, unless prevented by topography, or unless, in the opinion of the City Engineer, such extension is not necessary or desirable for the coordination of the layout of the subdivision with the most advantageous future development of adjacent tracts. The width of such streets in new subdivisions shall not be less than the minimum street widths established herein. The street arrangement shall cause no hardship to owners of adjoining property and its ability to be platted consistent with this chapter.
B.
Half-Streets. The platting of half-streets shall be discouraged. Whenever there exists a dedicated or platted half-street or alley adjacent to the tract to be subdivided, the other half of the street or alley shall be platted.
C.
Minimum Curvature of Streets. The minimum radius of curvature for streets shall be established according to the most current version of SUDAS as adopted by the City.
D.
Maximum Grade. The maximum grade for any street shall be established according to the most current version of SUDAS as adopted by the City as well as the most current versions of ADA and PROWAG.
E.
Street lights and city utilities, including but not limited to hydrants and watermains, shall be located on the north and east side of all public roads unless otherwise approved by the City Council.
F.
Fire hydrants shall be spaced at a maximum of 450 feet in residential areas; 300 feet in multi-family, commercial, and industrial areas, and not greater than 250 feet from major structures.

Street Right-of-Way and Pavement Dimensions

A.
The design standards for street right-of-way and pavement dimensions listed in Table 196.1 shall be considered minimum standards for the design of subdivisions in the City and shall be based upon the street’s functional classifications.
B.
Right of way and pavement width dimensions for major collector and arterial streets may be increased or decreased after consideration of traffic safety and performance by the City Engineer.

Table 196.1 Summary of Street Classification System
Street Designation	Volume¹	Right-of-Way Width	Pavement Width²
Local loop	Less than 250 average daily trips (ADT) or serving fewer than 24 dwelling units	60 feet	26 feet
Cul-de-sac	Less than 250 ADT or serving fewer than 24 dwelling units	90 feet diameter	80 feet diameter
Local	Less than 1,500 ADT Or serving 25 or more dwelling units	60 feet	29 feet
Minor collector - residential	Less than 2,500 ADT	70 feet	31 feet
Minor collector - commercial	Less than 2,500 ADT	80 feet	34 feet
Major collector	Less than 5,000 ADT	80 feet	40 feet
Minor Arterial3	Greater than 5,000 ADT	100 feet	64 feet (5-lane) 2-26 feet (4-lane divided)
Major Arterial3	Greater than 12,000 ADT	120 feet	Determined by traffic impact study
1. Traffic generation will be based upon actual traffic counts or upon trip generation surveys of the Institute of Traffic Engineers. 2. Pavement width is measured from back of curb to back of curb. 3. Arterial street rights-of-way with greater widths than listed above shall be required to maintain an adequate area between the street pavement and the right-of-way boundary to accommodate desired corridor area of a minimum of 15 feet for utilities and public sidewalks, unless a greater width is required by other ordinances or standards of the City.

Table 196.1 Summary of Street Classification System
Street Designation	Volume¹	Right-of-Way Width	Pavement Width²
Local loop	Less than 250 average daily trips (ADT) or serving fewer than 24 dwelling units	60 feet	26 feet
Cul-de-sac	Less than 250 ADT or serving fewer than 24 dwelling units	90 feet diameter	80 feet diameter
Local	Less than 1,500 ADT Or serving 25 or more dwelling units	60 feet	29 feet
Minor collector - residential	Less than 2,500 ADT	70 feet	31 feet
Minor collector - commercial	Less than 2,500 ADT	80 feet	34 feet
Major collector	Less than 5,000 ADT	80 feet	40 feet
Minor Arterial3	Greater than 5,000 ADT	100 feet	64 feet (5-lane) 2-26 feet (4-lane divided)
Major Arterial3	Greater than 12,000 ADT	120 feet	Determined by traffic impact study
1. Traffic generation will be based upon actual traffic counts or upon trip generation surveys of the Institute of Traffic Engineers. 2. Pavement width is measured from back of curb to back of curb. 3. Arterial street rights-of-way with greater widths than listed above shall be required to maintain an adequate area between the street pavement and the right-of-way boundary to accommodate desired corridor area of a minimum of 15 feet for utilities and public sidewalks, unless a greater width is required by other ordinances or standards of the City.

3.
Residential Streets
1. A.
  Residential streets shall be laid out so that use by through-traffic will be discouraged. Traffic-calming techniques such as diverters, neck-downs, street gardens, and curvilinear alignments to reduce speeds and cut-through traffic are encouraged.
2. B.
  To the maximum extent practicable, streets shall be arranged to follow the natural contours of the site.
3. C.
  Should topography or other constraints require the use of streets that extend more than 660 feet without being punctuated by cross streets, an oblong median, traffic-calming device, or similar feature shall be used to slow traffic and break-up the “runway” appearance. Location, dimensions, and design of such features shall be coordinated with required mid-block pedestrian connections to maximize pedestrian safety.
4.
Cul-de-Sacs
1. A.
  Cul-de-sac streets are discouraged when through streets are practical.
2. B.
  Cul-de-sac streets are limited for health and safety purposes to provide adequate fire protection and suitable ingress/egress for emergency vehicles and for occupants.
3. C.
  Cul-de-sacs shall be limited to land uses which generate less than 250 average daily trips which rely entirely upon the roadway for ingress/egress to their property. For the purposes of this section, a single-unit residence would generate 10 ADT.
4. D.
  Cul-de-sacs serving 250 ADT or more or extending 1,000 feet or more in length may be permitted by the Council if the following two (2) provisions have been demonstrated to the Council’s satisfaction:
  1. 1.
    The terminated roadway cannot be extended further due to:
    a.
    The presence of (but not limited to) unique or excessive slopes or drainage ways which would require substantial cuts and fills, the extension of which may cause adverse visual and environmental effects, blockage of natural drainage ways, disturbance of natural areas, or other adverse environmental impacts; or
    b.
    Unique configurations of land ownership or existence of public land ownership where the extension of the roadway is not consistent with the purpose of the open space.
  2. 2.
    One (1) or more of the following innovative design measures that suitably mitigate the intent to maintain fire protection and emergency vehicle ingress/egress and satisfy all other City standards and specifications shall be incorporated:
    a.
    Median divided boulevards
    b.
    Additional roadway width beyond required minimums
    c.
    Parking restrictions
    d.
    Alternate vehicular access designed to accommodate the size and weight of rescue equipment
    e.
    Required fire suppression systems
5.
Temporary Dead-End Streets
1. A.
  All temporary dead-end streets serving four (4) or more lots or exceeding 150 feet in length shall terminate in a temporary turn-around by fire code standards and shall be constructed of temporary concrete or alternate approved by the Jurisdictional Representative.
2. B.
  The normal development of subdivisions may result in only one (1) means of ingress/egress for a period of time until a later phase of development occurs or until an abutting property extends the roadway. Temporary dead-end streets that serve land uses that generate more than 500 ADT shall provide an alternative access or make other necessary accommodations for safe ingress and egress to the satisfaction of the Council.
6.
Street Names and Lot Addresses
1. A.
  Names of new streets within a subdivision shall be shown on the preliminary plat and shall be subject to review by City staff and approval by the Council. Address designations for all buildable lots created shall be provided by the Zoning Administrator and shown on the final plat and shall be subject to approval by the Council.
  1. 1.
    All newly platted streets shall be named in a manner conforming to the prevailing street naming system.
  2. 2.
    Proper names of individuals shall not be considered acceptable as street names, except upon approval of the Council. The Council may commemorate or honor an individual who has made a significant contribution of high recognition to the community, State or nation by requiring that name to be shown on the plat.
  3. 3.
    The last name of all streets in the City shall be determined as follows:
    a.
    North and south streets shall end with Street or Court
    b.
    East and west streets shall end as Drive, Avenue, Place, Circle, or Lane
    c.
    Major arterial or collector streets that run in any direction will be named as Boulevard, Way, or Road.
  4. 4.
    Streets which are looped, with their two (2) accesses from the same street and whose predominant street alignment is perpendicular to the street from which its access is obtained, shall have a minimum of two separate street name identifications; if a significant segment of such looped street has an alignment generally parallel to the street from which access is obtained, a third street name within the loop may be permitted.
  5. 5.
    A looped street may have only one (1) name if its predominant alignment is parallel to the street from which access is obtained, and provided the segments of the loop street not parallel to the street from which access is obtained are not significant in length and have few lot frontages.
  6. 6.
    Addresses for buildable lots shall be reviewed by City staff and approved by the Commission and Council as part of their review of the final plat. Addresses shall be designated based upon a grid system with intervals of eight (8) blocks of approximately 660 feet per block in the north-south alignment, and 14 blocks of approximately 380 feet per block in the east-west alignment.
2. B.
  As a general policy for numeric addressing of lots, addresses shall be sequenced in increments of four (4) per lot for north-south streets and increments of eight (8) per lot for east-west streets. Variations from this number sequencing may be required for subdivisions with large lots. Addresses on the north and east sides of a street shall be odd numbers, and addresses on the south and west sides of a street shall be even numbers.

Effective on: 5/1/2023

196.05 NON-MOTORIZED CONNECTIONS

Dedication of Land or Easements for Trails. Where bike/pedestrian or recreational trails are indicated in the Comprehensive Plan or Parks and Trails Master Plan, the developer shall be required to dedicate land or easements at least 20 feet in width and construct the identified trail.

Mid-Block Pedestrian Crossings

A.
A mid-block pedestrian crossing shall be installed when a new street extends more than 990 feet without an intersection. This shall also apply when an existing street is extended.
B.
Mid-block pedestrian crossings shall:
1. 1.
  Be located approximately equidistant from either intersection in the pair;
2. 2.
  Be located along property boundaries wherever possible;
3. 3.
  Be located at least 10 feet from the nearest driveway curb-cut, measured edge to edge;
4. 4.
  At a minimum, the crossing shall be marked with signage per the Manual on Uniform Traffic Control Devices (MUTCD). Crossings may be improved with a treatment determined by average daily traffic, road speed, and roadway width as referred to in the Federal Highway Administration (FHWA) Guide for Improving Safety at Uncontrolled Pedestrian Crossings. The following uncontrolled pedestrian crossings shall be prohibited:
  1. a.
    Raised pedestrian crossings
5. 5.
  Connect at both ends to either:
  1. a.
    A public sidewalk or similar pedestrian feature; or
  2. b.
    Another public off-street pedestrian pathway;
6. 6.
  Not conflict with utility structures, manhole covers, and storm sewer grates.
C.
The City Council may waive any of the mid-block crossing requirements if one (1) or more of the following circumstances have been demonstrated to their satisfaction:
1. 1.
  The average daily trips on the roadway to be crossed is less than 1,000 vehicles per day; or
2. 2.
  Pedestrian safety concerns exist from diminished sight lines or other physical constraints; or
3. 3.
  The crossing would encroach on a significant natural feature (e.g., stream channel, wetland, steep slope); or
4. 4.
  The crossing would not serve to connect to a trail, sidewalk, or destination.

Bicycle and Pedestrian Connections

A.
Provisions shall be made in all new developments to encourage the use of bicycle and pedestrian travel through the integration of bicycle and pedestrian paths, trails, and/or bicycle lanes that connect to parks, open spaces, schools, public transit, and shopping areas. Within new subdivisions, bicycle and pedestrian paths, trails, and/or bicycle lanes shall also connect to collector and minor arterial streets.
B.
Easements and/or rights-of-way shall be provided for bicycle/pedestrian paths/trails between and within developments as necessary to provide pedestrian and bicycle linkages between developments, unless waived by the City Council based upon the applicant demonstrating that to do so would be infeasible based on topography or constraints posed by the site layout of pre-existing development.

Trail Linkages

A.
All development, either at the time of platting or during site plan approval, shall be required to demonstrate that the design of the proposed development includes open space and trail linkages pursuant to the City’s Comprehensive Plan and Parks and Trails Master Plan.
B.
In residential areas, blocks longer than 990 feet shall be provided with 10-foot wide trails extending between residential lots in locations deemed necessary to allow for residents to safely connect to neighboring streets or neighborhoods. Suitable easements, setbacks, paving, landscaping, or fencing may be required.

Figure 196.1 Mid-block Trail Linkages

1. C.
  Trails shall be constructed at the time of development in accordance with City Policy.

Effective on: 5/1/2023

Johnston City Zoning Code

CHAPTER 196

SUBDIVISION DESIGN STANDARDS

196.01 GENERAL DESIGN AND DEVELOPMENT STANDARDS

Suitability.

A.
No land shall be developed which is held unsuitable for such use due to steep slopes, flooding, inadequate drainage, adverse soil or rock formation, unfavorable topography or any of the feature likely to be harmful to the health, safety, or welfare of the community.
B.
When slopes over 14% are proposed to be disturbed, a slope stability analysis shall be submitted to demonstrate that the area may be disturbed without risk of ongoing erosion and detailing if any protective measures shall be incorporated to reduce the risk of erosion during disturbance or post-disturbance.
C.
Areas deemed unsuitable for development shall be protected through the use of unbuildable outlots or conservation easements.

A.
The lots created would be an appropriate division of land and shall not hinder the future upgrade of public services to a level as envisioned in the Comprehensive Plan.
B.
Any on-site wastewater treatment system must be approved by Polk County or the Iowa Department of Natural Resources.
C.
The existing street system has the capacity and is in satisfactory condition to support the increased development.
D.
The proposed subdivision is an infill project within an existing neighborhood.
E.
The subdivision shall create no more than four (4) lots accessing a shared driveway.
F.
The property owner seeking to develop the subdivision shall acknowledge through a petition and waiver (voluntary assessment) that they will be in full support of any future capital improvement project in that neighborhood. The project will be one that is financed all or partially by special assessment and built to the City’s subdivision regulations and standard specifications. In addition, the City Council may interpret the vote for that property and/or subsequent lots as votes in support of the project.

Subdivisions immediately adjacent to Camp Dodge. Any property immediately adjacent to Camp Dodge or which is within a Camp Dodge Noise Zone shall at the time of subdivision:

A.
Include a statement in the deed that notes the property’s proximity to Camp Dodge and that there may be impacts from adjoining Camp Dodge activities.
B.
Provide a landscape buffer at least 50 feet wide along any shared property line with Camp Dodge. The buffer shall contain plant materials as described for a 50-foot wide buffer in Section 182.04.

Effective on: 5/1/2023

196.02 BLOCKS & LOTS

Blocks

A.
Blocks shall not be greater than 1,320 feet in length, except if necessary due to unusual topographic conditions, water frontage, or other circumstances.
B.
Blocks for commercial and industrial areas may vary from the elements of design contained in this Section if the nature of the use requires other treatment. In such cases, off-street parking for employees and customers shall be provided along with safe and convenient limited access to the street system. Space for off-street loading shall also be provided with similar access. Extension of roads, railroad access right-of-way and utilities shall be provided as necessary.
C.
Blocks shall be wide enough to allow for two (2) tiers of lots, except lots adjoining a lake, stream, railroad, or arterial, or where one (1) tier of lots is necessary because of topographic conditions.

Lots

A.
The minimum dimensions for lots shall be in accordance with the bulk regulations of the Zoning Ordinance for the district within which the subdivision is located; provided, corner lots shall be of such width as to permit the maintenance of all yard requirements as required by the Zoning Ordinance.
B.
Street Frontage Required.
1. 1.
  No lot shall be created for residential purposes and no building permit shall be issued for a residential structure unless:
  1. a.
    The lot abuts for at least 40 feet on a public street; or
  2. b.
    An exclusive unobstructed private easement of access or private right-of-way of a least 25 feet wide to a public street is provided up to and including the lot being created.
  3. c.
    The subdivision of land into lots not meeting the provisions of 1.a and 1.b above may be permitted if the Council determines the lot cannot be included as part of adjoining vacant land to create a subdivision in compliance with this Ordinance.
2. 2.
  If a shared driveway will provide access for two (2) to four (4) single-family dwellings, the shared driveway easement shall be at least 50 feet wide from the public street up to and including the lot being created. A lot served by a shared driveway shall not be created until the Council can make a determination that:
  1. a.
    The shared driveway easement is a reasonable and necessary means of access in lieu of a public street;
  2. b.
    A shared maintenance agreement has been established between the property owners served by the shared driveway; and
  3. c.
    The shared driveway improvements are adequate for their intended use and comply with fire code requirements.
3. 3.
  Private streets. For any subdivision that does not meet the provisions of B.1 or B.2 above, a private street shall be created to serve those lots. The private street shall be located on a separate outlot or parcel and encumbered within an easement. A homeowners association shall be established to maintain ownership of the private street parcel.
C.
All side lot lines shall be substantially at right angles or radial to street centerlines, unless the Council agrees that a variation to this requirement will provide for a better street and lot arrangement. Double frontage lots shall be avoided except where essential to provide separation of residential development from major arterial streets or to overcome specific disadvantages of topography.
D.
The minimum required lot width for corner lots shall be increased by a minimum of 10 feet to allow for the additional required corner yard setback. For example, if the minimum lot width is 60 feet, the minimum width of a corner lot shall not be less than 70 feet.
E.
All lots at street intersections shall have a radius of not less than 15 feet at the street corner. A greater radius shall be required for intersections involving one (1) or more major streets. A cutoff or chord may be substituted for the circular arc.

Effective on: 5/1/2023

196.03 EASEMENTS

Easements for utilities, trails, sidewalks, and stormwater management

A.
Easements for public and private utilities, open space, trails, sidewalks, conservation, and stormwater management shall be provided as determined necessary based upon the subdivision design and as required in the Comprehensive Plan, Parks and Trails Master Plan, or Watershed Assessment and Stormwater Management Plan.
B.
Easement Widths
1. 1.
  Easements for private utilities only shall be a minimum of 10 feet wide.
2. 2.
  Easements for sidewalks only shall be a minimum of 10 feet wide.
3. 3.
  Easements for trails only shall be a minimum of 20 feet wide.
4. 4.
  Easements for dedicated public utilities shall be a minimum of 10 feet wide on either side of the centerline of the utility.
5. 5.
  Combined private utility and sidewalk easements shall be a minimum of 15 feet wide, while combined private utility and trail easements shall be a minimum of 20 feet wide.
6. 6.
  Public utility easements (PUE) shall be a minimum of 10 feet on the rear or side lot line except where impractical due to physical constraint.
7. 7.
  Drainage easements may vary in width depending upon drainage requirements as specified in the site’s stormwater management plan.
C.
The applicant shall provide and dedicate to the City an easement along each side of any stream or major surface watercourse in sufficient width to meet the requirements of CHAPTER 183 Stream Buffer Protection. Easements identified on the preliminary and final plats shall be by separate written document approved by the City Attorney and Zoning Administrator and filed in conjunction with the final plat.
D.
Proper coordination shall be established between the subdivider, Department of Community Development, and the utility companies for the establishment of utility easements.

Effective on: 5/1/2023

196.04 STREET DESIGN

General

A.
Relationship to Adjoining Street System. The arrangement of streets in new subdivisions shall make provision for the continuation or proper intersection of existing streets in adjoining subdivisions. Proposed streets shall be extended to the boundary lines of the tract to be subdivided, unless prevented by topography, or unless, in the opinion of the City Engineer, such extension is not necessary or desirable for the coordination of the layout of the subdivision with the most advantageous future development of adjacent tracts. The width of such streets in new subdivisions shall not be less than the minimum street widths established herein. The street arrangement shall cause no hardship to owners of adjoining property and its ability to be platted consistent with this chapter.
B.
Half-Streets. The platting of half-streets shall be discouraged. Whenever there exists a dedicated or platted half-street or alley adjacent to the tract to be subdivided, the other half of the street or alley shall be platted.
C.
Minimum Curvature of Streets. The minimum radius of curvature for streets shall be established according to the most current version of SUDAS as adopted by the City.
D.
Maximum Grade. The maximum grade for any street shall be established according to the most current version of SUDAS as adopted by the City as well as the most current versions of ADA and PROWAG.
E.
Street lights and city utilities, including but not limited to hydrants and watermains, shall be located on the north and east side of all public roads unless otherwise approved by the City Council.
F.
Fire hydrants shall be spaced at a maximum of 450 feet in residential areas; 300 feet in multi-family, commercial, and industrial areas, and not greater than 250 feet from major structures.

Street Right-of-Way and Pavement Dimensions

A.
The design standards for street right-of-way and pavement dimensions listed in Table 196.1 shall be considered minimum standards for the design of subdivisions in the City and shall be based upon the street’s functional classifications.
B.
Right of way and pavement width dimensions for major collector and arterial streets may be increased or decreased after consideration of traffic safety and performance by the City Engineer.

Table 196.1 Summary of Street Classification System
Street Designation	Volume¹	Right-of-Way Width	Pavement Width²
Local loop	Less than 250 average daily trips (ADT) or serving fewer than 24 dwelling units	60 feet	26 feet
Cul-de-sac	Less than 250 ADT or serving fewer than 24 dwelling units	90 feet diameter	80 feet diameter
Local	Less than 1,500 ADT Or serving 25 or more dwelling units	60 feet	29 feet
Minor collector - residential	Less than 2,500 ADT	70 feet	31 feet
Minor collector - commercial	Less than 2,500 ADT	80 feet	34 feet
Major collector	Less than 5,000 ADT	80 feet	40 feet
Minor Arterial3	Greater than 5,000 ADT	100 feet	64 feet (5-lane) 2-26 feet (4-lane divided)
Major Arterial3	Greater than 12,000 ADT	120 feet	Determined by traffic impact study
1. Traffic generation will be based upon actual traffic counts or upon trip generation surveys of the Institute of Traffic Engineers. 2. Pavement width is measured from back of curb to back of curb. 3. Arterial street rights-of-way with greater widths than listed above shall be required to maintain an adequate area between the street pavement and the right-of-way boundary to accommodate desired corridor area of a minimum of 15 feet for utilities and public sidewalks, unless a greater width is required by other ordinances or standards of the City.

Table 196.1 Summary of Street Classification System
Street Designation	Volume¹	Right-of-Way Width	Pavement Width²
Local loop	Less than 250 average daily trips (ADT) or serving fewer than 24 dwelling units	60 feet	26 feet
Cul-de-sac	Less than 250 ADT or serving fewer than 24 dwelling units	90 feet diameter	80 feet diameter
Local	Less than 1,500 ADT Or serving 25 or more dwelling units	60 feet	29 feet
Minor collector - residential	Less than 2,500 ADT	70 feet	31 feet
Minor collector - commercial	Less than 2,500 ADT	80 feet	34 feet
Major collector	Less than 5,000 ADT	80 feet	40 feet
Minor Arterial3	Greater than 5,000 ADT	100 feet	64 feet (5-lane) 2-26 feet (4-lane divided)
Major Arterial3	Greater than 12,000 ADT	120 feet	Determined by traffic impact study
1. Traffic generation will be based upon actual traffic counts or upon trip generation surveys of the Institute of Traffic Engineers. 2. Pavement width is measured from back of curb to back of curb. 3. Arterial street rights-of-way with greater widths than listed above shall be required to maintain an adequate area between the street pavement and the right-of-way boundary to accommodate desired corridor area of a minimum of 15 feet for utilities and public sidewalks, unless a greater width is required by other ordinances or standards of the City.

3.
Residential Streets
1. A.
  Residential streets shall be laid out so that use by through-traffic will be discouraged. Traffic-calming techniques such as diverters, neck-downs, street gardens, and curvilinear alignments to reduce speeds and cut-through traffic are encouraged.
2. B.
  To the maximum extent practicable, streets shall be arranged to follow the natural contours of the site.
3. C.
  Should topography or other constraints require the use of streets that extend more than 660 feet without being punctuated by cross streets, an oblong median, traffic-calming device, or similar feature shall be used to slow traffic and break-up the “runway” appearance. Location, dimensions, and design of such features shall be coordinated with required mid-block pedestrian connections to maximize pedestrian safety.
4.
Cul-de-Sacs
1. A.
  Cul-de-sac streets are discouraged when through streets are practical.
2. B.
  Cul-de-sac streets are limited for health and safety purposes to provide adequate fire protection and suitable ingress/egress for emergency vehicles and for occupants.
3. C.
  Cul-de-sacs shall be limited to land uses which generate less than 250 average daily trips which rely entirely upon the roadway for ingress/egress to their property. For the purposes of this section, a single-unit residence would generate 10 ADT.
4. D.
  Cul-de-sacs serving 250 ADT or more or extending 1,000 feet or more in length may be permitted by the Council if the following two (2) provisions have been demonstrated to the Council’s satisfaction:
  1. 1.
    The terminated roadway cannot be extended further due to:
    a.
    The presence of (but not limited to) unique or excessive slopes or drainage ways which would require substantial cuts and fills, the extension of which may cause adverse visual and environmental effects, blockage of natural drainage ways, disturbance of natural areas, or other adverse environmental impacts; or
    b.
    Unique configurations of land ownership or existence of public land ownership where the extension of the roadway is not consistent with the purpose of the open space.
  2. 2.
    One (1) or more of the following innovative design measures that suitably mitigate the intent to maintain fire protection and emergency vehicle ingress/egress and satisfy all other City standards and specifications shall be incorporated:
    a.
    Median divided boulevards
    b.
    Additional roadway width beyond required minimums
    c.
    Parking restrictions
    d.
    Alternate vehicular access designed to accommodate the size and weight of rescue equipment
    e.
    Required fire suppression systems
5.
Temporary Dead-End Streets
1. A.
  All temporary dead-end streets serving four (4) or more lots or exceeding 150 feet in length shall terminate in a temporary turn-around by fire code standards and shall be constructed of temporary concrete or alternate approved by the Jurisdictional Representative.
2. B.
  The normal development of subdivisions may result in only one (1) means of ingress/egress for a period of time until a later phase of development occurs or until an abutting property extends the roadway. Temporary dead-end streets that serve land uses that generate more than 500 ADT shall provide an alternative access or make other necessary accommodations for safe ingress and egress to the satisfaction of the Council.
6.
Street Names and Lot Addresses
1. A.
  Names of new streets within a subdivision shall be shown on the preliminary plat and shall be subject to review by City staff and approval by the Council. Address designations for all buildable lots created shall be provided by the Zoning Administrator and shown on the final plat and shall be subject to approval by the Council.
  1. 1.
    All newly platted streets shall be named in a manner conforming to the prevailing street naming system.
  2. 2.
    Proper names of individuals shall not be considered acceptable as street names, except upon approval of the Council. The Council may commemorate or honor an individual who has made a significant contribution of high recognition to the community, State or nation by requiring that name to be shown on the plat.
  3. 3.
    The last name of all streets in the City shall be determined as follows:
    a.
    North and south streets shall end with Street or Court
    b.
    East and west streets shall end as Drive, Avenue, Place, Circle, or Lane
    c.
    Major arterial or collector streets that run in any direction will be named as Boulevard, Way, or Road.
  4. 4.
    Streets which are looped, with their two (2) accesses from the same street and whose predominant street alignment is perpendicular to the street from which its access is obtained, shall have a minimum of two separate street name identifications; if a significant segment of such looped street has an alignment generally parallel to the street from which access is obtained, a third street name within the loop may be permitted.
  5. 5.
    A looped street may have only one (1) name if its predominant alignment is parallel to the street from which access is obtained, and provided the segments of the loop street not parallel to the street from which access is obtained are not significant in length and have few lot frontages.
  6. 6.
    Addresses for buildable lots shall be reviewed by City staff and approved by the Commission and Council as part of their review of the final plat. Addresses shall be designated based upon a grid system with intervals of eight (8) blocks of approximately 660 feet per block in the north-south alignment, and 14 blocks of approximately 380 feet per block in the east-west alignment.
2. B.
  As a general policy for numeric addressing of lots, addresses shall be sequenced in increments of four (4) per lot for north-south streets and increments of eight (8) per lot for east-west streets. Variations from this number sequencing may be required for subdivisions with large lots. Addresses on the north and east sides of a street shall be odd numbers, and addresses on the south and west sides of a street shall be even numbers.

Effective on: 5/1/2023

196.05 NON-MOTORIZED CONNECTIONS

Mid-Block Pedestrian Crossings

A.
A mid-block pedestrian crossing shall be installed when a new street extends more than 990 feet without an intersection. This shall also apply when an existing street is extended.
B.
Mid-block pedestrian crossings shall:
1. 1.
  Be located approximately equidistant from either intersection in the pair;
2. 2.
  Be located along property boundaries wherever possible;
3. 3.
  Be located at least 10 feet from the nearest driveway curb-cut, measured edge to edge;
4. 4.
  At a minimum, the crossing shall be marked with signage per the Manual on Uniform Traffic Control Devices (MUTCD). Crossings may be improved with a treatment determined by average daily traffic, road speed, and roadway width as referred to in the Federal Highway Administration (FHWA) Guide for Improving Safety at Uncontrolled Pedestrian Crossings. The following uncontrolled pedestrian crossings shall be prohibited:
  1. a.
    Raised pedestrian crossings
5. 5.
  Connect at both ends to either:
  1. a.
    A public sidewalk or similar pedestrian feature; or
  2. b.
    Another public off-street pedestrian pathway;
6. 6.
  Not conflict with utility structures, manhole covers, and storm sewer grates.
C.
The City Council may waive any of the mid-block crossing requirements if one (1) or more of the following circumstances have been demonstrated to their satisfaction:
1. 1.
  The average daily trips on the roadway to be crossed is less than 1,000 vehicles per day; or
2. 2.
  Pedestrian safety concerns exist from diminished sight lines or other physical constraints; or
3. 3.
  The crossing would encroach on a significant natural feature (e.g., stream channel, wetland, steep slope); or
4. 4.
  The crossing would not serve to connect to a trail, sidewalk, or destination.

Bicycle and Pedestrian Connections

A.
Provisions shall be made in all new developments to encourage the use of bicycle and pedestrian travel through the integration of bicycle and pedestrian paths, trails, and/or bicycle lanes that connect to parks, open spaces, schools, public transit, and shopping areas. Within new subdivisions, bicycle and pedestrian paths, trails, and/or bicycle lanes shall also connect to collector and minor arterial streets.
B.
Easements and/or rights-of-way shall be provided for bicycle/pedestrian paths/trails between and within developments as necessary to provide pedestrian and bicycle linkages between developments, unless waived by the City Council based upon the applicant demonstrating that to do so would be infeasible based on topography or constraints posed by the site layout of pre-existing development.

Trail Linkages

A.
All development, either at the time of platting or during site plan approval, shall be required to demonstrate that the design of the proposed development includes open space and trail linkages pursuant to the City’s Comprehensive Plan and Parks and Trails Master Plan.
B.
In residential areas, blocks longer than 990 feet shall be provided with 10-foot wide trails extending between residential lots in locations deemed necessary to allow for residents to safely connect to neighboring streets or neighborhoods. Suitable easements, setbacks, paving, landscaping, or fencing may be required.

Figure 196.1 Mid-block Trail Linkages

1. C.
  Trails shall be constructed at the time of development in accordance with City Policy.

Effective on: 5/1/2023

Johnston City Zoning Code

CHAPTER 196

SUBDIVISION DESIGN STANDARDS

196.01 GENERAL DESIGN AND DEVELOPMENT STANDARDS

Suitability.

A.
No land shall be developed which is held unsuitable for such use due to steep slopes, flooding, inadequate drainage, adverse soil or rock formation, unfavorable topography or any of the feature likely to be harmful to the health, safety, or welfare of the community.
B.
When slopes over 14% are proposed to be disturbed, a slope stability analysis shall be submitted to demonstrate that the area may be disturbed without risk of ongoing erosion and detailing if any protective measures shall be incorporated to reduce the risk of erosion during disturbance or post-disturbance.
C.
Areas deemed unsuitable for development shall be protected through the use of unbuildable outlots or conservation easements.

A.
The lots created would be an appropriate division of land and shall not hinder the future upgrade of public services to a level as envisioned in the Comprehensive Plan.
B.
Any on-site wastewater treatment system must be approved by Polk County or the Iowa Department of Natural Resources.
C.
The existing street system has the capacity and is in satisfactory condition to support the increased development.
D.
The proposed subdivision is an infill project within an existing neighborhood.
E.
The subdivision shall create no more than four (4) lots accessing a shared driveway.
F.
The property owner seeking to develop the subdivision shall acknowledge through a petition and waiver (voluntary assessment) that they will be in full support of any future capital improvement project in that neighborhood. The project will be one that is financed all or partially by special assessment and built to the City’s subdivision regulations and standard specifications. In addition, the City Council may interpret the vote for that property and/or subsequent lots as votes in support of the project.

Subdivisions immediately adjacent to Camp Dodge. Any property immediately adjacent to Camp Dodge or which is within a Camp Dodge Noise Zone shall at the time of subdivision:

A.
Include a statement in the deed that notes the property’s proximity to Camp Dodge and that there may be impacts from adjoining Camp Dodge activities.
B.
Provide a landscape buffer at least 50 feet wide along any shared property line with Camp Dodge. The buffer shall contain plant materials as described for a 50-foot wide buffer in Section 182.04.

Effective on: 5/1/2023

196.02 BLOCKS & LOTS

Blocks

A.
Blocks shall not be greater than 1,320 feet in length, except if necessary due to unusual topographic conditions, water frontage, or other circumstances.
B.
Blocks for commercial and industrial areas may vary from the elements of design contained in this Section if the nature of the use requires other treatment. In such cases, off-street parking for employees and customers shall be provided along with safe and convenient limited access to the street system. Space for off-street loading shall also be provided with similar access. Extension of roads, railroad access right-of-way and utilities shall be provided as necessary.
C.
Blocks shall be wide enough to allow for two (2) tiers of lots, except lots adjoining a lake, stream, railroad, or arterial, or where one (1) tier of lots is necessary because of topographic conditions.

Lots

A.
The minimum dimensions for lots shall be in accordance with the bulk regulations of the Zoning Ordinance for the district within which the subdivision is located; provided, corner lots shall be of such width as to permit the maintenance of all yard requirements as required by the Zoning Ordinance.
B.
Street Frontage Required.
1. 1.
  No lot shall be created for residential purposes and no building permit shall be issued for a residential structure unless:
  1. a.
    The lot abuts for at least 40 feet on a public street; or
  2. b.
    An exclusive unobstructed private easement of access or private right-of-way of a least 25 feet wide to a public street is provided up to and including the lot being created.
  3. c.
    The subdivision of land into lots not meeting the provisions of 1.a and 1.b above may be permitted if the Council determines the lot cannot be included as part of adjoining vacant land to create a subdivision in compliance with this Ordinance.
2. 2.
  If a shared driveway will provide access for two (2) to four (4) single-family dwellings, the shared driveway easement shall be at least 50 feet wide from the public street up to and including the lot being created. A lot served by a shared driveway shall not be created until the Council can make a determination that:
  1. a.
    The shared driveway easement is a reasonable and necessary means of access in lieu of a public street;
  2. b.
    A shared maintenance agreement has been established between the property owners served by the shared driveway; and
  3. c.
    The shared driveway improvements are adequate for their intended use and comply with fire code requirements.
3. 3.
  Private streets. For any subdivision that does not meet the provisions of B.1 or B.2 above, a private street shall be created to serve those lots. The private street shall be located on a separate outlot or parcel and encumbered within an easement. A homeowners association shall be established to maintain ownership of the private street parcel.
C.
All side lot lines shall be substantially at right angles or radial to street centerlines, unless the Council agrees that a variation to this requirement will provide for a better street and lot arrangement. Double frontage lots shall be avoided except where essential to provide separation of residential development from major arterial streets or to overcome specific disadvantages of topography.
D.
The minimum required lot width for corner lots shall be increased by a minimum of 10 feet to allow for the additional required corner yard setback. For example, if the minimum lot width is 60 feet, the minimum width of a corner lot shall not be less than 70 feet.
E.
All lots at street intersections shall have a radius of not less than 15 feet at the street corner. A greater radius shall be required for intersections involving one (1) or more major streets. A cutoff or chord may be substituted for the circular arc.

Effective on: 5/1/2023

196.03 EASEMENTS

Easements for utilities, trails, sidewalks, and stormwater management

A.
Easements for public and private utilities, open space, trails, sidewalks, conservation, and stormwater management shall be provided as determined necessary based upon the subdivision design and as required in the Comprehensive Plan, Parks and Trails Master Plan, or Watershed Assessment and Stormwater Management Plan.
B.
Easement Widths
1. 1.
  Easements for private utilities only shall be a minimum of 10 feet wide.
2. 2.
  Easements for sidewalks only shall be a minimum of 10 feet wide.
3. 3.
  Easements for trails only shall be a minimum of 20 feet wide.
4. 4.
  Easements for dedicated public utilities shall be a minimum of 10 feet wide on either side of the centerline of the utility.
5. 5.
  Combined private utility and sidewalk easements shall be a minimum of 15 feet wide, while combined private utility and trail easements shall be a minimum of 20 feet wide.
6. 6.
  Public utility easements (PUE) shall be a minimum of 10 feet on the rear or side lot line except where impractical due to physical constraint.
7. 7.
  Drainage easements may vary in width depending upon drainage requirements as specified in the site’s stormwater management plan.
C.
The applicant shall provide and dedicate to the City an easement along each side of any stream or major surface watercourse in sufficient width to meet the requirements of CHAPTER 183 Stream Buffer Protection. Easements identified on the preliminary and final plats shall be by separate written document approved by the City Attorney and Zoning Administrator and filed in conjunction with the final plat.
D.
Proper coordination shall be established between the subdivider, Department of Community Development, and the utility companies for the establishment of utility easements.

Effective on: 5/1/2023

196.04 STREET DESIGN

General

A.
Relationship to Adjoining Street System. The arrangement of streets in new subdivisions shall make provision for the continuation or proper intersection of existing streets in adjoining subdivisions. Proposed streets shall be extended to the boundary lines of the tract to be subdivided, unless prevented by topography, or unless, in the opinion of the City Engineer, such extension is not necessary or desirable for the coordination of the layout of the subdivision with the most advantageous future development of adjacent tracts. The width of such streets in new subdivisions shall not be less than the minimum street widths established herein. The street arrangement shall cause no hardship to owners of adjoining property and its ability to be platted consistent with this chapter.
B.
Half-Streets. The platting of half-streets shall be discouraged. Whenever there exists a dedicated or platted half-street or alley adjacent to the tract to be subdivided, the other half of the street or alley shall be platted.
C.
Minimum Curvature of Streets. The minimum radius of curvature for streets shall be established according to the most current version of SUDAS as adopted by the City.
D.
Maximum Grade. The maximum grade for any street shall be established according to the most current version of SUDAS as adopted by the City as well as the most current versions of ADA and PROWAG.
E.
Street lights and city utilities, including but not limited to hydrants and watermains, shall be located on the north and east side of all public roads unless otherwise approved by the City Council.
F.
Fire hydrants shall be spaced at a maximum of 450 feet in residential areas; 300 feet in multi-family, commercial, and industrial areas, and not greater than 250 feet from major structures.

Street Right-of-Way and Pavement Dimensions

A.
The design standards for street right-of-way and pavement dimensions listed in Table 196.1 shall be considered minimum standards for the design of subdivisions in the City and shall be based upon the street’s functional classifications.
B.
Right of way and pavement width dimensions for major collector and arterial streets may be increased or decreased after consideration of traffic safety and performance by the City Engineer.

Table 196.1 Summary of Street Classification System
Street Designation	Volume¹	Right-of-Way Width	Pavement Width²
Local loop	Less than 250 average daily trips (ADT) or serving fewer than 24 dwelling units	60 feet	26 feet
Cul-de-sac	Less than 250 ADT or serving fewer than 24 dwelling units	90 feet diameter	80 feet diameter
Local	Less than 1,500 ADT Or serving 25 or more dwelling units	60 feet	29 feet
Minor collector - residential	Less than 2,500 ADT	70 feet	31 feet
Minor collector - commercial	Less than 2,500 ADT	80 feet	34 feet
Major collector	Less than 5,000 ADT	80 feet	40 feet
Minor Arterial3	Greater than 5,000 ADT	100 feet	64 feet (5-lane) 2-26 feet (4-lane divided)
Major Arterial3	Greater than 12,000 ADT	120 feet	Determined by traffic impact study
1. Traffic generation will be based upon actual traffic counts or upon trip generation surveys of the Institute of Traffic Engineers. 2. Pavement width is measured from back of curb to back of curb. 3. Arterial street rights-of-way with greater widths than listed above shall be required to maintain an adequate area between the street pavement and the right-of-way boundary to accommodate desired corridor area of a minimum of 15 feet for utilities and public sidewalks, unless a greater width is required by other ordinances or standards of the City.

Table 196.1 Summary of Street Classification System
Street Designation	Volume¹	Right-of-Way Width	Pavement Width²
Local loop	Less than 250 average daily trips (ADT) or serving fewer than 24 dwelling units	60 feet	26 feet
Cul-de-sac	Less than 250 ADT or serving fewer than 24 dwelling units	90 feet diameter	80 feet diameter
Local	Less than 1,500 ADT Or serving 25 or more dwelling units	60 feet	29 feet
Minor collector - residential	Less than 2,500 ADT	70 feet	31 feet
Minor collector - commercial	Less than 2,500 ADT	80 feet	34 feet
Major collector	Less than 5,000 ADT	80 feet	40 feet
Minor Arterial3	Greater than 5,000 ADT	100 feet	64 feet (5-lane) 2-26 feet (4-lane divided)
Major Arterial3	Greater than 12,000 ADT	120 feet	Determined by traffic impact study
1. Traffic generation will be based upon actual traffic counts or upon trip generation surveys of the Institute of Traffic Engineers. 2. Pavement width is measured from back of curb to back of curb. 3. Arterial street rights-of-way with greater widths than listed above shall be required to maintain an adequate area between the street pavement and the right-of-way boundary to accommodate desired corridor area of a minimum of 15 feet for utilities and public sidewalks, unless a greater width is required by other ordinances or standards of the City.

3.
Residential Streets
1. A.
  Residential streets shall be laid out so that use by through-traffic will be discouraged. Traffic-calming techniques such as diverters, neck-downs, street gardens, and curvilinear alignments to reduce speeds and cut-through traffic are encouraged.
2. B.
  To the maximum extent practicable, streets shall be arranged to follow the natural contours of the site.
3. C.
  Should topography or other constraints require the use of streets that extend more than 660 feet without being punctuated by cross streets, an oblong median, traffic-calming device, or similar feature shall be used to slow traffic and break-up the “runway” appearance. Location, dimensions, and design of such features shall be coordinated with required mid-block pedestrian connections to maximize pedestrian safety.
4.
Cul-de-Sacs
1. A.
  Cul-de-sac streets are discouraged when through streets are practical.
2. B.
  Cul-de-sac streets are limited for health and safety purposes to provide adequate fire protection and suitable ingress/egress for emergency vehicles and for occupants.
3. C.
  Cul-de-sacs shall be limited to land uses which generate less than 250 average daily trips which rely entirely upon the roadway for ingress/egress to their property. For the purposes of this section, a single-unit residence would generate 10 ADT.
4. D.
  Cul-de-sacs serving 250 ADT or more or extending 1,000 feet or more in length may be permitted by the Council if the following two (2) provisions have been demonstrated to the Council’s satisfaction:
  1. 1.
    The terminated roadway cannot be extended further due to:
    a.
    The presence of (but not limited to) unique or excessive slopes or drainage ways which would require substantial cuts and fills, the extension of which may cause adverse visual and environmental effects, blockage of natural drainage ways, disturbance of natural areas, or other adverse environmental impacts; or
    b.
    Unique configurations of land ownership or existence of public land ownership where the extension of the roadway is not consistent with the purpose of the open space.
  2. 2.
    One (1) or more of the following innovative design measures that suitably mitigate the intent to maintain fire protection and emergency vehicle ingress/egress and satisfy all other City standards and specifications shall be incorporated:
    a.
    Median divided boulevards
    b.
    Additional roadway width beyond required minimums
    c.
    Parking restrictions
    d.
    Alternate vehicular access designed to accommodate the size and weight of rescue equipment
    e.
    Required fire suppression systems
5.
Temporary Dead-End Streets
1. A.
  All temporary dead-end streets serving four (4) or more lots or exceeding 150 feet in length shall terminate in a temporary turn-around by fire code standards and shall be constructed of temporary concrete or alternate approved by the Jurisdictional Representative.
2. B.
  The normal development of subdivisions may result in only one (1) means of ingress/egress for a period of time until a later phase of development occurs or until an abutting property extends the roadway. Temporary dead-end streets that serve land uses that generate more than 500 ADT shall provide an alternative access or make other necessary accommodations for safe ingress and egress to the satisfaction of the Council.
6.
Street Names and Lot Addresses
1. A.
  Names of new streets within a subdivision shall be shown on the preliminary plat and shall be subject to review by City staff and approval by the Council. Address designations for all buildable lots created shall be provided by the Zoning Administrator and shown on the final plat and shall be subject to approval by the Council.
  1. 1.
    All newly platted streets shall be named in a manner conforming to the prevailing street naming system.
  2. 2.
    Proper names of individuals shall not be considered acceptable as street names, except upon approval of the Council. The Council may commemorate or honor an individual who has made a significant contribution of high recognition to the community, State or nation by requiring that name to be shown on the plat.
  3. 3.
    The last name of all streets in the City shall be determined as follows:
    a.
    North and south streets shall end with Street or Court
    b.
    East and west streets shall end as Drive, Avenue, Place, Circle, or Lane
    c.
    Major arterial or collector streets that run in any direction will be named as Boulevard, Way, or Road.
  4. 4.
    Streets which are looped, with their two (2) accesses from the same street and whose predominant street alignment is perpendicular to the street from which its access is obtained, shall have a minimum of two separate street name identifications; if a significant segment of such looped street has an alignment generally parallel to the street from which access is obtained, a third street name within the loop may be permitted.
  5. 5.
    A looped street may have only one (1) name if its predominant alignment is parallel to the street from which access is obtained, and provided the segments of the loop street not parallel to the street from which access is obtained are not significant in length and have few lot frontages.
  6. 6.
    Addresses for buildable lots shall be reviewed by City staff and approved by the Commission and Council as part of their review of the final plat. Addresses shall be designated based upon a grid system with intervals of eight (8) blocks of approximately 660 feet per block in the north-south alignment, and 14 blocks of approximately 380 feet per block in the east-west alignment.
2. B.
  As a general policy for numeric addressing of lots, addresses shall be sequenced in increments of four (4) per lot for north-south streets and increments of eight (8) per lot for east-west streets. Variations from this number sequencing may be required for subdivisions with large lots. Addresses on the north and east sides of a street shall be odd numbers, and addresses on the south and west sides of a street shall be even numbers.

Effective on: 5/1/2023

196.05 NON-MOTORIZED CONNECTIONS

Mid-Block Pedestrian Crossings

A.
A mid-block pedestrian crossing shall be installed when a new street extends more than 990 feet without an intersection. This shall also apply when an existing street is extended.
B.
Mid-block pedestrian crossings shall:
1. 1.
  Be located approximately equidistant from either intersection in the pair;
2. 2.
  Be located along property boundaries wherever possible;
3. 3.
  Be located at least 10 feet from the nearest driveway curb-cut, measured edge to edge;
4. 4.
  At a minimum, the crossing shall be marked with signage per the Manual on Uniform Traffic Control Devices (MUTCD). Crossings may be improved with a treatment determined by average daily traffic, road speed, and roadway width as referred to in the Federal Highway Administration (FHWA) Guide for Improving Safety at Uncontrolled Pedestrian Crossings. The following uncontrolled pedestrian crossings shall be prohibited:
  1. a.
    Raised pedestrian crossings
5. 5.
  Connect at both ends to either:
  1. a.
    A public sidewalk or similar pedestrian feature; or
  2. b.
    Another public off-street pedestrian pathway;
6. 6.
  Not conflict with utility structures, manhole covers, and storm sewer grates.
C.
The City Council may waive any of the mid-block crossing requirements if one (1) or more of the following circumstances have been demonstrated to their satisfaction:
1. 1.
  The average daily trips on the roadway to be crossed is less than 1,000 vehicles per day; or
2. 2.
  Pedestrian safety concerns exist from diminished sight lines or other physical constraints; or
3. 3.
  The crossing would encroach on a significant natural feature (e.g., stream channel, wetland, steep slope); or
4. 4.
  The crossing would not serve to connect to a trail, sidewalk, or destination.

Bicycle and Pedestrian Connections

A.
Provisions shall be made in all new developments to encourage the use of bicycle and pedestrian travel through the integration of bicycle and pedestrian paths, trails, and/or bicycle lanes that connect to parks, open spaces, schools, public transit, and shopping areas. Within new subdivisions, bicycle and pedestrian paths, trails, and/or bicycle lanes shall also connect to collector and minor arterial streets.
B.
Easements and/or rights-of-way shall be provided for bicycle/pedestrian paths/trails between and within developments as necessary to provide pedestrian and bicycle linkages between developments, unless waived by the City Council based upon the applicant demonstrating that to do so would be infeasible based on topography or constraints posed by the site layout of pre-existing development.

Trail Linkages

A.
All development, either at the time of platting or during site plan approval, shall be required to demonstrate that the design of the proposed development includes open space and trail linkages pursuant to the City’s Comprehensive Plan and Parks and Trails Master Plan.
B.
In residential areas, blocks longer than 990 feet shall be provided with 10-foot wide trails extending between residential lots in locations deemed necessary to allow for residents to safely connect to neighboring streets or neighborhoods. Suitable easements, setbacks, paving, landscaping, or fencing may be required.

Figure 196.1 Mid-block Trail Linkages

1. C.
  Trails shall be constructed at the time of development in accordance with City Policy.

Effective on: 5/1/2023