Intent. The intent of this article is to provide design standards and specifications for all subdivisions created pursuant to this chapter.

Conflicting regulations. Whenever any provision of this article imposes more stringent requirements or limitations than required by the provisions of any other ordinance or portion of this chapter, then the provisions of this article shall govern. Whenever the provisions of any or other ordinance or portion of this chapter impose more stringent requirements than imposed by this article, then the provisions of such ordinance or portion of this chapter shall govern.

Scope. The requirements of this article apply to all subdivisions of land throughout the city and portions of the county, which are subject to review and approval pursuant to this chapter.

Relation to adjoining street system. The arrangement of streets in new subdivisions shall make provision for the continuation of the principal existing streets in adjoining areas (or their proper projection where adjoining land is not subdivided) insofar as they may be deemed necessary by the board for public requirements. The width of such streets in new subdivisions shall be not less than the minimum widths established in this article. The street and alley arrangement shall be such as not to cause a hardship to owners of adjoining property when they plat their own land and seek to provide for convenient access to it. Off-set streets should be avoided. The angle of intersection between streets should not vary by more than ten degrees from a right angle. Streets obviously in alignment with existing streets shall bear the names of the existing streets. All proposed street names shall be checked against duplication of other street names.

Street and alley width.

1. 1.
   As a minimum requirement for streets, avenues and sidewalks, the plat shall dedicate a width of at least 50 feet, at least five feet thereof on each side for sidewalks, and at least 40 feet intervening between sidewalks; provided, that in the event that the city commission, upon recommendation by the city planning board, finds that traffic conditions and transportation requirements so demand, a greater width may be required; and except that, dead-end streets not exceeding 1,000 feet in length and termination in a turnaround with a minimum radius of 50 feet may have a minimum width of 40 feet.
2. 2.
   When streets parallel and adjoin unsubdivided property, a half street, at least 25 feet in width, may be dedicated, and whenever subdivision property adjoins a half street, the remainder of the street shall be dedicated.
3. 3.
   Alleys are not recommended in single-family and two-family residential districts; and when provided a minimum width of 20 feet shall be required. Alleys are required in the rear of all business lots and shall be at least 20 feet wide. A five-foot cut-off shall be made at all acute angle intersections.

Easements. Easements of at least five feet in width shall be provided on each side of all rear lot lines and along side lot lines, where necessary, for poles, wires, conduits, storm and sanitary sewers, gas, water or other mains. Easements of greater width may be required along or across lots where necessary for the extension of main sewers or other utilities or where both water and sewer lines are located in the same easement.

Blocks.

1. 1.
   No block shall be longer than 1,200 feet. Where blocks are over 1,000 feet in length, a crosswalk at least ten feet in width may be required near the center of the block.
2. 2.
   In platting residential lots containing less than 15,000 square feet, the depth of the block should not exceed 300 feet.
3. 3.
   Where a tract of land is of such size or location as to prevent a lot arrangement directly related to normal street design, there may be established one or more courts, dead-end streets or other arrangements; provided that, proper access shall be given to all lots from a dedicated street or court. A dead-end street shall terminate in an open space (preferably circular) having a minimum radius of 50 feet. A dead-end street shall not exceed 1,000 feet in length.

Lots.

1. 1.
   The lot arrangement and design shall be such that all lots will provide satisfactory and desirable building sites, properly related to topography and the character of surrounding development.
2. 2.
   All side lines of lots shall be at right angles to straight street lines and radial to curved street lines, except where a variation to this rule will provide a better street and lot layout. Lots with double frontage shall be avoided.
3. 3.
   No lot shall have an area or width less than that required by any zoning ordinance. In an unzoned area, no lot shall have an average width of less than 60 feet, nor shall it contain less than 7,500 square feet.
4. 4.
   Where corner lots back upon lots facing the side street, the corner lots shall have extra width sufficient to permit the establishment of front building lines on both the front and side of the lots adjoining the streets.

Building lines. Where the subdivided area is not under zoning control, the subdivider shall establish building lines in accordance with the needs of each development, but in no case shall such building lines be less than 30 feet from the right-of-way of the street or highway upon which the lot fronts. Restrictions requiring buildings to be set back to such building lines shall be shown on the plat. Except where zoning regulations apply, restrictions shall also be made and shown on or referred to on that plat requiring all residential buildings to be set at least six feet off each side lot line and not less than 30 feet from rear lot lines.

Character of development. The subdivider shall confer with the board regarding the type and character of development that will be permitted in the subdivision and may agree to place certain minimum restrictions upon the property to prevent the construction of substandard buildings, control the type of structures or the use of the lots which, unless so controlled, would clearly depreciate the character and value of the proposed subdivision and of adjoining property. Deed restrictions or covenants running with the land may be included to provide for the creation of a property owner's association or board of trustees for the proper protection and maintenance of the development in the future; provided that, such deed restriction or covenants shall not contain reversionary clauses wherein any lot shall return to the subdivider because of a violation thereof of the terms of the restrictions or covenants. Where the subdivision contains sewers, sewage treatment plants, water supply systems, park area, street trees or other physical facilities necessary or desirable for the welfare of the area and which are of common use or benefit and which the city or county does not desire to maintain, provision shall be made by trust agreement as part of the deed restrictions, acceptable to the city or county for the proper and continuous maintenance and supervision of such facilities by the lot owners in the subdivision.

Parks, schools sites, etc. In subdividing property, consideration shall be given to suitable sites for schools, parks, playgrounds and other common area for public use so as to conform to any recommendations of the currently effective city plan. Any provision for schools, parks and playgrounds should be indicated on the preliminary plan in order that it may be determined when and in what manner such areas will be provided or acquired by the appropriate public agency.

Easements along streams or canals. Whenever any stream or important surface drainage course is located in an area which is being subdivided, the subdivider shall provide or dedicate an adequate easement along each side of the stream for the purpose of widening, deepening, sloping, improving or protecting the stream or for drainage, parkway or recreational use.

Minimum radius for property lines of corner lots. The property lines of all corner lots at the intersecting street lines of all subdivisions of property hereafter submitted shall have a minimum radius as follows:

1. 1.
   Residential areas, 15 feet.
2. 2.
   Business and commercial areas, ten feet.
3. 3.
   Streets intersecting main arterial boulevards:

   1. a.
      In residential areas, 20 feet.
   2. b.
      In business and commercial areas, ten feet.

Other design standards. Subsection 94-44(e) should be referred to for other design standards associated with minimum subdivision improvements.

Generally. All street paving shall be of the flexible type, with limerock or local shellrock base and asphaltic concrete wearing courses. All streets shall be bordered on all edges by concrete vertical curbs or headers. Street construction shall conform to the current standards, as established by the city public department, and materials and methods of construction shall comply with the latest edition of the state department of transportation standards specifications for road and bridge construction, unless otherwise specified in this section.

Subgrade. The subgrade shall be free of muck, silt or other unsuitable materials, and shall have naturally, or shall be stabilized to, a minimum bearing value of 40 psi to a depth of ten inches, as determined by the state bearing test. The top ten inches of the subgrade shall be compacted to a density of not less than 100 percent of the maximum density as determined by A.A.S.H.O. Method T-180.

Base. All paving base courses shall consist of a minimum compacted thickness of six inches of limerock, or, as an alternate, a minimum compacted thickness of eight inches of local shellrock, constructed on the previously prepared subgrade, as defined in this section. The base courses shall be compacted to a density of not less than 100 percent of the maximum density, as determined by A.A.S.H.O. Method T-180.

Prime and tack coats. All base courses shall be given a prime coat. A tack coat shall be applied at the option of the city engineer.

Wearing courses. A wearing course of hot plant mix asphaltic concrete shall be constructed on the base course. Types and thickness of wearing courses for different classes of streets shall conform to the following as a minimum:

1. 1.
   Major streets. One-and-one-half-inch thickness of state department of transportation type I asphaltic concrete.
2. 2.
   Collector streets. One-and-one-half-inch thickness of state department of transportation type II asphaltic concrete.
3. 3.
   Minor or local streets and alleys. One inch thickness of state department of transportation type II asphaltic concrete.

Curbs and sidewalks. All curbs and sidewalks shall be constructed in accordance with current standards established by the city engineer.

City engineer supervision. All construction plans and all plant, equipment, materials, mixes and methods shall be subject to review and approval by the city engineer. Where unsatisfactory results are being obtained, he may direct any changes deemed necessary and may stop the work when these directions are not followed until such time as they are complied with or until satisfactory results, complying with these specifications, are obtained.

Crown and drainage. Excessive crown heights shall be avoided. In general, crowns shall not exceed 1½ inches for each ten feet of width of paving. Gutters shall be sloped to drain with minimum slopes limited to 0.15 percent. Valley gutters shall not be continued across a roadway unless approved by the city engineer, but inlets and a siphon sewer shall be installed. An adequate storm drainage system shall be provided.

Conformance to street cross section plan. All of the requirements of this section shall be in accordance with a standard street cross section plan and standard details, prepared by the city engineer, and on file in the city records.