Chapter 4 - Design Principles and Standards
SECTION 4.0 - DESIGN CRITERIA
In addition to the criteria for plat approval determination provided in Chapter 2, Section 2.0, the Plan Commission shall further determine if the plat conforms to the principles and standards of this ordinance, which shall be deemed to be minimal.
In the subdividing of land, due regard shall be shown for all natural features, such as tree growth, watercourse, or similar conditions, which if preserved, will add to the aesthetics and value of the development. Consideration shall be given to the prevention of air and stream pollution and to the elimination of any other blighting characteristics. The layout of the subdivision shall be of such a nature as to protect the health, safety, and general welfare of the City and it residents.
SECTION 4.1 - PRINCIPLES OF STREET DESIGN
The subdivider shall be guided by the following principles in laying out the street system within the subdivision:
All parcels shall have adequate and safe vehicular and pedestrian access and street systems shall be designed to minimize through traffic movement. However, connections into and from adjacent Areas may be required by the Plan Commission where it will not substantially increase through traffic. The design shall provide reasonable direct access to the primary circulation system and not conflict with the efficiency of bordering arterial routes.
To function effectively and safely, the circulation system within a subdivision shall be designed with the least number of interruptions possible, and further, to discourage excessive speeds and minimize pedestrian-vehicular points of conflict. The streets shall be related to topography and shall minimize space devoted to streets and intersections.
All dedicated rights-of-way shall conform to the following minimum widths:
- Arterial Streets . . . . . . . . . . . . . 120 feet
- Major Collector Streets . . . . . . . 100 feet
- Minor Collector Streets . . . . . . . . 70 feet
- Local Residential Streets . . . . . . . 60 feet
- Cul-De-Sacs . . . . . . . . . . . . . . . . 60 feet*
- Crosswalks . . . . . . . . . . . . . . . . . . 10 feet
- Utility Easements . . . . . . . . . . . . . 20 feet
The following criteria in street design shall be observed in laying out streets in a new subdivision:
Street jogs with centerline offsets of less than 125 feet shall not be permitted.
All streets shall intersect at 90 degrees whenever possible for a minimum distance of 100 feet; however, in no instance shall they intersect at less than 80 degrees onto arterial or collector streets or less than 50 degrees onto local streets.
To insure adequate sight distance, when the street centerlines deflect more than 10 degrees, connections shall be made by horizontal curves. The minimum centerline radius for local residential streets shall be 200 feet and for all other residential streets, 400 feet.
A tangent, of at least 100 feet, shall be introduced between reversed curves on local and collector streets.
The maximum vertical grade for arterial streets shall not exceed 7.5 percent; for collector streets, 10 percent; and for local streets, 12 percent; provided, however, that within 200 feet of a street or railway intersection, the maximum grade permitted shall be 50 percent of the maximum grade specification.
The maximum length for cul-de-sac streets shall be 500 feet measured along the centerline from the intersection at origin through the center of the circle to the end of the right-of-way. Each cul-de-sac shall have a terminus of nearly circular shape with a minimum right-of-way diameter of 120 feet, unless an equally safe and convenient form of space as approved by the Plan Commission.
Only one street, or point of vehicle access shall be permitted from a subdivision onto a major collector street or an arterial street or road. Two or more streets, or points of vehicle access onto a minor collector street may be permitted by the Plan Commission only if they are definitely needed to improve the safety and traffic circulation in the area.
No street names may be used which will duplicate or be confused with names of existing streets. Streets which are logical extensions or continuations of existing streets shall bear the names of such existing streets.
Right-of-way for proposed streets shall be extended to the boundary lines of the proposed subdivision so that a connection can be made to adjacent properties unless such extension is not feasible because of topography or other physical conditions, or unless, in the opinion of the Plan Commission, such extension is not necessary or desirable for the advantageous development of adjacent tracts. No subdivisions shall be designed so as to create or perpetuate the land-locking of adjacent undeveloped land.
Temporary dead-ended streets shall be permitted only when a street is proposed and should logically be extended, but is not yet constructed. An adequate easement for a turn-around shall be provided for all temporary dead-ended streets which extend 200 feet or more in length. Such easement shall be automatically vacated to abutting property owners when the street is extended.
In subdivisions that adjoin or include existing streets that do not conform to the minimum right-of-way dimensions as established by this ordinance, the subdivider shall dedicate additional width along either one or both sides of such streets so as to bring them up to standards, provided the area to be used for widening is owned or under the control of the subdivider.
No driveway shall be located within 70 feet of the intersection of two street lines.
SECTION 4.2 - BLOCK STANDARDS
Block length and width shall be such as to accommodate and provide for convenient access, circulation control, and safety of traffic. Blocks that are unreasonable large or small will not be approved. Maximum block length shall be 1200 feet. The Plan Commission may require pedestrian crosswalks at a point useful to facilitate pedestrian circulation to a school, park, recreation area, or significant neighborhood destination.
Residential Blocks shall normally be of sufficient depth to accommodate two tiers of lots, except where lots border a freeway, arterial street or flood plain and are designed as through lots.
Blocks must fit easily into the overall plan of the subdivision and evidence consideration of lot planning, traffic flow, and public areas.
SECTION 4.3 - LOT STANDARDS
Lot arrangement shall be such that there will be no foreseeable difficulties for reasons of topography or other conditions in securing building permits to build on all lots on compliance with the Zoning Ordinance. Provisions shall be made for driveway access to all lots from an approved street at a proper distance from intersecting streets.
Lot dimensions shall comply with the minimum requirements of the Zoning Ordinance. Lot size, width, depth, shape, grade, location and orientation shall be in proper relation to street and block design and to existing and proposed topographical conditions.
Through lots shall be avoided where necessary to provide separation of residential development from traffic arterials or to overcome specific disadvantages of topography and orientation.
A subdivider shall be required to furnish and install fences wherever the Plan Commission determines a hazardous condition may exist. The type of fencing material and height shall be noted on the final plat.
A no-access screened buffer strip of ten feet shall be provided along lot lines adjoining an adverse influence or an arterial street or highway, if required by the Plan Commission. This requirement shall be noted on the final plat.
Corner lots shall be sufficiently larger than interior lots to allow proper setback from both streets. Side lines of lots shall be approximately at right angles to the street lines.
Lots shall be laid out so as to provide positive drainage away from all buildings. Individual lot drainage shall be coordinated with the general storm drainage pattern for the area and drainage shall be designed so as to avoid concentration of storm water drainage from one lot to adjacent lots. Where possible, drainage should be contained on each lot or parcel.
SECTION 4.4 - EASEMENTS
Adequate Areas of suitable size and location shall be allocated for utility easements. As a general principle, such easements shall be a minimum of 30 feet in width, and shall provide reasonable continuity from block to block. They shall be located at rear lot lines whenever possible and along side and front lines only when deemed necessary.
Where subdivision is traversed by a watercourse, drainage way, channel or stream, adequate Areas for storm water or drainage easements shall be allocated for the purpose of widening, deepening, sloping, improving or protecting said watercourses in accordance with the requirements of the County Drainage Board.
Whenever practicable, the subdivider shall be encouraged to design for the placement of utility lines underground, following the required standards and specifications established by each utility company. The location of each underground utility system shall be shown by appropriate easement lines on the proposed plat.
SECTION 4.5 - COMMERCIAL AND INDUSTRIAL SUBDIVISIONS
Commercial and industrial subdivisions face unique problems of lot design not encountered in residential subdivisions. For this reason, the emphasis of the Plan Commission consideration shall be upon street layout and block arrangement. The procedural requirements shall be basically as outlined in this ordinance, with the exception being the subdivider need show only tow lots along with the street and block layout.
As lots are sized to the specifications of the prospective purchaser, the owner shall submit an amendment to the previously approved recorded subdivision plat for Plan Commission consideration. Regular procedural requirements for a final subdivision plat shall then apply.
Streets that have been built to the specifications of previously approved plans on the recorded plat shall not have to be rebuilt because of the adoption of new criteria by the City. This shall also apply to storm drainage facilities within said subdivision unless run-off characteristics have been changed by the newly proposed improvements or by unauthorized existing improvements.
A non-residential subdivision shall also be subject to all requirements set forth in the Zoning Ordinance. Site plan approval and non-residential subdivision plat approval may proceed simultaneously at the discretion of the Plan Commission.
In addition to the principles and standards in these regulations, which are appropriate to the planning of all subdivisions, the applicant shall demonstrate to the satisfaction of the Commission that the street, parcel, and block pattern proposed is specifically adapted to the uses anticipated and takes into account other uses in the vicinity.
Proposed industrial parcels shall be suitable in area and dimensions to the types of industrial development anticipated. Street right-of-way and pavement shall be adequate to accommodate the type and volume of traffic anticipated to be generated thereupon.
Special requirements may be imposed by the Plan Commission with respect to street, curb, gutter, sidewalk design and construction as well as installation of public utilities, including water, sewer and storm water drainage.
Every effort shall be made to protect adjacent residential Areas from potential nuisance from a proposed commercial or industrial subdivision, including the provision of extra depth in parcels backing up on existing or potential residential development and provisions for permanently landscaped buffer strips when necessary.
Streets carrying non-residential traffic, especially truck traffic, shall not be extended to the boundaries of adjacent existing or potential residential areas.
SECTION 4.6 - RESERVE STRIPS
The creation of reserve strips shall not be permitted adjacent to a proposed street in such a manner as to deny access from adjacent property to said street.