Chapter 17.35
DESIGN STANDARDS
Sections:
17.35.010 Principles of acceptability.
17.35.020 Subdivision general standards.
17.35.060 Grading of building sites.
17.35.080 Large building sites.
17.35.090 Land for public purposes.
17.35.100 Special district/flood hazard area.
17.35.010 Principles of acceptability.
A land division, whether by a subdivision, creation of a street, or a partitioning, shall conform to the comprehensive plan and its implementing ordinances and shall conform to the design standards established by this title. [Ord. 469 § 7.010, 1980].
17.35.020 Subdivision general standards.
(1) A subdivision shall conform to the following standards:
(a) Each proposed lot must be buildable in conformance with the requirements of this title and all other applicable regulations.
(b) Each lot shall abut upon a public street other than an alley for a width of at least 25 feet.
(c) If any lot abuts a street right-of-way that does not conform to the design specifications of this title, the owner may be required to dedicate up to one-half of the total right-of-way required by this title.
(d) Lot Width-to-Depth Ratios. To provide for proper site design and prevent the creation of irregularly shaped parcels, the depth of any lot or parcel shall not exceed three times its width (or four times its width in rural areas) unless there is a topographical or environmental constraint or an existing manmade feature such as a railroad line.
(2) Further subdivision of the property shall be prohibited unless the applicant submits a plat or development plan in accordance with the requirements of this title. [Ord. 469 § 7.015, 1980].
17.35.030 Streets.
(1) General. The location, width and grade of streets shall be considered in their relation to existing and planned streets, to topographical conditions, and to the proposed use of land to be served by the streets. The street system shall be laid out in accordance with the future street plan and functional classification maps to assure adequate traffic circulation that is convenient and safe. Intersection angles, tangents and curves shall be appropriate for the traffic to be carried, considering the terrain. Street determinations shall be made in accordance with the street standards provided in the future street plan and functional classification maps. The criteria contained in the following subsections shall be coordinated with adopted street standards as outlined in the this title and will consider both solar access to building sites and the need for utility location. Additional setbacks may be required as set forth in MCMC 18.145.020. Where appropriate location of streets within and/or adjacent to a development is not shown in the comprehensive plan (future street plan and functional classification maps), the arrangement of streets shall either:
(a) Provide for the continuation of appropriate projection of existing principal streets in surrounding areas; or
(b) Conform to a plan for the neighborhood approved or adopted by the planning commission to meet a particular situation where topographical or other conditions make continuance or conformance to existing streets impractical.
(2) Minimum Right-of-Way and Roadway Width. Unless otherwise indicated in the comprehensive plan, the street right-of-way and roadway widths shall not be less than the minimum width in feet shown in the following table, except:
(a) Where conditions, particularly topography or the size and shape of the tract, make it impractical to otherwise provide buildable sites, narrower right-of-way may be accepted, ordinarily not less than 50 feet. If necessary, slope easements may be required.
(b) Where it is determined that two-level streets best serve lots in the residential hillside district (R-H), the right-of-way shall be of sufficient width to provide, on each level, space for one sidewalk and a minimum width of 20 feet for pavement, curbs and drainage facilities. Between the two street levels and out to the right-of-way lines there shall be space for all cut and fill slopes.
(c) Paths and Bicycle Ways. To provide appropriate circulation, an accessway for pedestrians and bicycles shall be required to connect to all cul-de-sacs. Accessways are also required to allow passage between unusually long or oddly shaped blocks.
(3) Reverse Frontage Lots.
(a) Lots that front on more than one street shall be required to locate motor vehicle accesses on the street with the lower functional classification. Direct access to arterials or major collector streets shall not be permitted for reverse frontage lots or parcels.
(b) When a residential subdivision is proposed which abuts an arterial, it shall be designed so the lots abutting the arterial will only take access from a frontage road or interior local road. A planting screen easement or buffer yard at least 10 feet wide, across which there shall be no rights of access, may be required along the line of lots abutting such traffic arterial. Such area shall be considered the rear portion of the lot or parcel. The planting screen easement or buffer yard shall not be located within the public right-of-way.
(4) Flag Lot Standards.
(a) Flag lots shall not be permitted when the result would be to increase the number of properties requiring direct and individual access connections to the state highway system or other arterials unless the property would otherwise be landlocked.
(b) Flag lots may be permitted for residential development when necessary to achieve planning objectives, such as reducing direct access to roadways, providing internal platted lots with access to a residential street, or preserving natural or historic resources, under the following conditions:
(i) Flag lot driveways shall be separated by a minimum of 120 feet (twice the minimum lot width). Adjacent, or side-by-side, flag lot driveways shall not be permitted.
(ii) The flag lot driveway shall have a minimum width of 12 feet and maximum width of 20 feet.
(iii) In no instance shall flag lots constitute more than 10 percent of the total number of building sites in a recorded or unrecorded plat, or three lots or more, whichever is greater.
(iv) The lot area occupied by the flag driveway shall not be counted as part of the required minimum lot area of that zoning district.
(v) No more than one flag lot shall be permitted per private right-of-way or access easement.
|
Type of Street |
Right-of-Way Width |
Roadway Width |
|---|---|---|
|
Arterial |
|
|
|
– Within CBD (downtown) |
64 feet |
46 feet |
|
– Non-CBD |
80 feet |
48 feet |
|
Collector |
|
|
|
– Major Collector |
60 – 80 feet |
36 – 46 feet |
|
– Minor Collector |
60 feet |
36 – 40 feet |
|
Local Street |
|
|
|
– Major (Necessary) Local |
60 feet |
36 feet |
|
– Local Street (minor street less than 2,400 feet in length which cannot be extended) |
50 feet |
28 feet |
|
Radius for turnaround at end of cul-de-sacs |
50 feet |
40 feet |
|
Alleys |
20 feet |
20 feet |
(5) Reserve Strips. Reserve strips or plugs controlling access to streets will not be approved unless necessary for the protection of the public welfare or of substantial property rights, and in these cases they may be required. The control and disposal of the land comprising such strips shall be placed with the jurisdiction of the city under conditions approved by the city council.
(6) Street Alignment. As far as is practical, streets other than minor streets shall be in alignment with existing streets by continuations of the centerlines thereof. Staggered street alignment resulting in T intersections shall, wherever practical, leave a minimum distance of 200 feet between the centerlines of streets having approximately the same direction and, in no case, shall be less than 100 feet.
(7) Future Extensions of Streets. Where necessary to give access to or permit a satisfactory future division of adjoining land, a public street will be extended to the boundary of the development and the resulting dead-end street may be approved without a turnaround. A reserve strip or street plug may be required to preserve the objective of the street extension. A turnaround will be required if the dead-end street is more than 100 feet from an intersection. The street shall be located to align with any future streets identified in the future street plan and functional classification maps.
(8) Bicycle Routes. As identified in the bicycle plan map, bicycle lanes within streets, separate bicycle paths, or bike route signage shall be required when developing new, or reconstructing existing, streets. These new bicycle facilities will provide connections to improve the overall bicycle network for the community. Bicycle lanes shall be four to six feet wide and located on both sides of the street, where practical. Refer to MCMC Table 17.50.030 for affected street types.
(9) Sidewalks. Sidewalk improvements shall be installed to serve each building site as is required for a subdivision unless alternative pedestrian routes are available and such facilities are not called for in the pedestrian plan map. Required sidewalk widths shall vary between five and eight feet, depending on the roadway’s functional classification. Refer to MCMC Table 17.50.030 for affected street types.
(10) Shared Access. Subdivisions with frontage on an arterial or major collector shall be designed to indirectly access the roadway via a secondary lower classification road. If access via a secondary road is infeasible, the partition or other land division shall utilize a single shared access onto the arterial or major collector.
(11) Connectivity. The street system of proposed subdivisions shall be designed to connect with existing, proposed, and planned streets outside of the subdivision as identified in the future street plan and functional classification maps.
(a) Wherever a proposed development abuts unplatted land or a future development phase of the same development, street stubs shall be provided to provide access to abutting properties or to logically extend the street system into the surrounding area. All street stubs more than 100 feet from an intersection shall be provided with a temporary turnaround, unless specifically exempted by the city engineer, and the restoration and extension of the street shall be the responsibility of any future developer of the abutting land.
(b) Collector and local residential streets shall connect with surrounding streets to permit the convenient movement of traffic between residential neighborhoods or facilitate emergency access and evacuation. Connections shall be designed to avoid or minimize through traffic on local streets.
(12) Cul-de-sacs and Accessways.
(a) Cul-de-sacs or permanent dead-end streets may be used as part of a development plan; however, through streets are encouraged except where topographical, environmental, or existing adjacent land use constraints make connecting streets infeasible. Where cul-de-sacs are planned, accessways shall be provided connecting the ends of cul-de-sacs to each other, to other streets, or to neighborhood activity centers.
(b) A cul-de-sac shall be as short as possible and shall have a maximum length of 400 feet and serve building sites for not more than 18 dwelling units. A cul-de-sac shall terminate with a circular turnaround.
(c) For subdivision developments creating blocks of 1,000 feet or more, accessways for pedestrians and bicyclists shall be 10 feet wide and located within a 20-foot-wide right-of-way or easement. If the streets within the subdivision are lighted, the accessways shall also be lighted. Stairs or switchback paths may be used where grades are steep.
(13) Intersection Angles. Streets shall be laid out to intersect at angles as near to right angles as practical except where topography requires a lesser angle, but in no case shall the acute angle be less than 80 degrees unless there is a special intersection design. An arterial or collector street intersecting with another street shall have at least 100 feet of tangent adjacent to the intersection unless topography requires a lesser distance. Other streets, except alleys, shall have at least 50 feet of tangent adjacent to the intersection unless topography requires a lesser distance. Intersections which contain an acute angle of less than 80 degrees or which include an arterial street shall have a minimum corner radius sufficient to allow for a roadway radius of 20 feet and maintain a uniform width between the roadway and the right-of-way line. Ordinarily, the intersection of more than two streets at any one point will not be approved.
(14) Existing Streets. Whenever existing streets adjacent to or within a tract are of inadequate width, additional right-of-way shall be provided at the time of the land division.
(15) Street Names. Except for extensions of existing streets, no street name shall be used which will duplicate or be confused with the name of an existing street. Street names and numbers shall conform to the established pattern in the city and shall be subject to the approval of the city administrator or the city administrator’s designee on behalf of the city council.
(16) Grades and Curves. Grades shall not exceed six percent on arterials, 10 percent on collector streets or 12 percent on other streets. Centerline radii of curves shall not be less than 300 feet on major arterials, 200 feet on secondary arterials or 100 feet on other streets, and shall be to an even 10 feet. Where existing conditions, particularly the topography, make it otherwise impractical to provide buildable sites, the city council may accept steeper grades and sharper curves. In flat areas, allowance shall be made for finished street grades having a minimum slope, preferably, of at least 0.5 percent.
(17) Streets Adjacent to Railroad Right-of-Way. Wherever the proposed land division contains or is adjacent to a railroad right-of-way, provision may be required for a street approximately parallel to and on each side of such right-of-way at a distance suitable for the appropriate use of the land between the streets and the railroad. The distance shall be determined with due consideration at cross streets of the minimum distance required for approach grades to a future grade separation and to provide sufficient depth to allow screen planting along the railroad right-of-way.
(18) Alleys. Alleys shall be provided in commercial and industrial districts, unless other permanent provisions for access to off-street parking and loading facilities are approved by the planning commission. The corners of alley intersections shall have a radius of not less than 12 feet. [Ord. 469 § 7.020, 1980].
17.35.040 Blocks.
(1) General. The length, width and shape of blocks shall take into account the need for adequate building site size and street width and shall recognize the limitations of the topography.
(2) Size. No block shall be more than 1,000 feet in length between corner lines unless it is adjacent to an arterial street or unless the topography or the location of adjoining streets justifies an exception. The recommended minimum length of blocks along an arterial street is 1,800 feet. A block shall have sufficient width to provide for two tiers of building sites unless topography or the location of adjoining streets justifies an exception.
(3) Easements.
(a) Utility Lines. Easements for sewers, water mains, electric lines or other public utilities shall be dedicated wherever necessary. The easements shall be at least 12 feet wide, except for utility pole tieback easements, which may be reduced to six feet in width.
(b) Water Courses. If a tract is traversed by a water course such as a drainage way, channel or stream, there shall be provided a stormwater easement or drainage right-of-way conforming substantially with the lines of the water course, and such further width as will be adequate for the purpose. Streets or parkways parallel to the major water courses may be required.
(c) Paths and Bicycle Ways. When desirable for public convenience, a pedestrian or bicycle way may be required to connect to a cul-de-sac or to pass through an unusually long or oddly shaped block or otherwise provide appropriate circulation. [Ord. 469 § 7.030, 1980].
17.35.050 Building sites.
(1) Size and Shape. The size, width, shape and orientation of building sites shall be appropriate for the location of the land division and for the type of development and use contemplated, and shall be consistent with the residential lot size provisions of MCMC Title 18 with the following exception:
Where property is zoned and planned for business or industrial use, other widths and areas may be permitted at the discretion of the planning commission. Depth and width of properties reserved or laid out for commercial and industrial purposes shall be adequate to provide for the off-street parking and parking facilities required by the type of use and development contemplated.
(2) Access. Except as set forth in MCMC 17.40.020, each lot and parcel shall abut upon a street other than an alley for a width of at least 25 feet.
(3) Through Lots and Parcels. Through lots and parcels shall be avoided except along streets that have been designated as limited access or restricted access streets, or where they are essential to provide separation of residential development from major traffic arteries or adjacent nonresidential activities or to overcome specific disadvantages of topography and orientation. If through lots or parcels are created, the rear setback area shall be increased to equal the required front setback area. Access to through lots or parcels shall be via the street frontage on the front side of the lot or parcel; there shall be no right of access to a street via the rear frontage. In approving the creation of through lots or parcels, the planning commission may impose additional conditions or restrictions as may be found necessary to preserve or protect the character of the area.
(4) Lot and Parcel Side Lines. The lines of lots and parcels, as far as is practicable, shall run at right angles to the street upon which they face, except that on curved streets they shall be radial to the curve. [Ord. 469 § 7.040, 1980].
17.35.060 Grading of building sites.
Grading of building sites shall conform to the following standards unless physical conditions demonstrate the propriety of other standards:
(1) Cut slopes shall not exceed two feet horizontally to one foot vertically.
(2) Fill slopes shall not exceed two feet horizontally to one foot vertically.
(3) The character of soil for fill and the characteristics of lots and parcels made usable by fill shall be suitable for the purpose intended. [Ord. 469 § 7.041, 1980].
17.35.070 Building lines.
If special building setback lines are to be established in a subdivision, they shall be shown on the subdivision plat, or, if temporary in nature, they shall be included in the deed restrictions. [Ord. 469 § 7.050, 1980].
17.35.080 Large building sites.
In dividing tracts into large lots or parcels which, at some future time, are likely to be redivided, the planning commission may require that the blocks be of such size and shape so as to be suitable for redivision into building sites. They may contain such site restrictions as will provide for extension and opening of streets at intervals planned to permit a subsequent redivision of any tract into lots or parcels of smaller size. [Ord. 469 § 7.060, 1980].
17.35.090 Land for public purposes.
If the city has an interest in acquiring a portion of a proposed subdivision for a public purpose or if the city has been advised of such interest by a school district or other public agency and there is reasonable assurance that steps will be taken to acquire the land, then the planning commission may:
(1) Require that those portions of the subdivision be reserved for public acquisition for a period not to exceed one year, at a cost not to exceed the value of the land prior to subdivision; or
(2) The planning commission may require a parcel of land of not more than six percent of the gross area of the subdivision to be set aside and dedicated to the public by the subdivider for purposes to serve the area containing the subdivision. [Ord. 469 § 7.070, 1980].
17.35.100 Special district/flood hazard area.
All land division in the floodplain shall conform to the requirements of the special district/flood hazard area regulations contained in MCMC Title 18 and shall provide for:
(1) A minimum residential building site of 6,000 square feet, exclusive of floodway.
(2) Protection for streambank vegetation.
(3) Open space dedication in accordance with the greenway proposal. [Ord. 469 § 7.080, 1980].