CHAPTER  800.  Design Standards.

 

801.  Street Design. Subdividers shall locate streets within the subdivision so that the streets will connect with existing streets.  Streets shall be located and designed so that the adjoining land shall not be diminished in value.  If the adjoining land is zoned for residential use, streets shall be located so that the adjacent land may be most efficiently sub‑divided.  Half streets on the boundary of a subdivision are discouraged.

 

802. Angle of Minor Streets. Minor streets shall approach the major or collector streets at an angle of at least 80 degrees for a distance of at least 100 ft.  Street grades at intersections shall be no greater than 4% for at least 50 ft.

 

803. Transportation Section of General Plan. Major and collector streets shall conform to the width designated of the major street plan wherever a subdivision is in an area for which a major street plan has been adopted.  For territory where such street plan has not been completed at the time the subdivision preliminary plan is submitted to the Planning Commission, major or collector streets shall be provided as required by the Planning Commission; with minimum right‑of‑way widths of 100 feet from major roads and 66 to 80 feet for collector streets.

 

804. Street Design Criteria.  In order to comply with the requirements the North Logan City Code within chapters 12.C. Land-Use – Zoning, 12.D. Land-Use – Subdivisions, and Title 11. Street and Public Ways, the following design criteria shall be used to establish street widths and types.  All street designs shall conform to the City’s standard drawings, the transportation section of the General Plan, the expected traffic upon complete build out or a 20-year traffic forecast and the Cache Metropolitan Planning Organization’s (CMPO) long range plan if applicable.

 

  1. Street rights-of-way:  All street rights-of-way shall be determined in accordance with the criteria outlined below.

·        Minor residential streets are those streets serving up to and including 25 residences. They serve an ADT of 250 or less.  They shall have a minimum 50-foot right-of-way.

·        Major residential streets are those streets serving 26 – 75 residences.  They serve an ADT of 750 or less.  They shall have a minimum 60-foot right-of-way.

·        Collector streets are those streets required to service areas that have over 75 residences, have an ADT between 750 and 4000, and/or as designated in the transportation section of the City’s General Plan.  They shall have a minimum

66-foot right-of-way.

·        Arterial streets require an 80 or 100-foot right-of-way in accordance with the City’s transportation General Plan and/or traffic analysis, or as otherwise specified by the responsible jurisdiction.

 

  1. Street types:  There are two street types for residential and collector streets outlined in the City’s transportation section of the General Plan. They are conventional cross-sections and low impact road cross-sections.   Applicants shall select a street type that will address the potential needs of the area in which the street is to be located and will produce the best use of the street in accordance with the City’s General Plan.

 

Applicants shall select the street types by:

 

A.        Preparing a report that addresses all of the design criteria and considerations listed in paragraph 3 below and the City’s General Plan. 

B.         Submitting the report to the City for review and approval of the street types that have been selected.

 

The report shall have a conclusion and the recommended street types based on the information gathered from the report.  The City Council shall give final approval of all street types.  They may require the applicant to employ a qualified transportation engineer to determine the design considerations and criteria when it is felt that the needs of the area cannot otherwise be adequately defined.

 

  1. Design Considerations:  Streets shall be designed taking into account the surrounding areas and the City’s transportation section of the General Plan.  Design considerations and criteria shall be evaluated using sound engineering practices and shall be used to select the street types.  The following design considerations shall be used to evaluate a street:

 

    • How does this street fit with the General Plan and the surrounding area?
    • What is the historic use of the property? 
    • What are the uses surrounding the property?
    • What are the soil types and how do they perform?
    • What is the existing grade like? 

·        How does the street and related stormwater runoff function in relation to planned open spaces?

    • Are there existing features to be built around? 
    • What is the groundwater elevation and does it change throughout the year?
    • What is the runoff potential? 
    • Is a canal, floodplain, or drainage corridor nearby?
    • What is the flood management plan for this area?
    • Are curbs with gutters needed for flood control management in the area?
    • What is the level of pollutants this street will collect?
    • Can roadside swales facilitate the amount of pollutants being distributed? 
    • What are the treatment needs for the pollutants?
    • What is the estimated traffic volume for the street now? 
    • What is the 20-year estimated volume for the street?
    • What is the estimated traffic volume at build-out?
    • What are the potential services to be built along the street? 
    • Will there be any schools, churches, parks, or commercial uses?
    • What are the parking needs for the roadway now and in the future?
    • What are the types and amounts of pedestrian use expected now and in the future? 
    • What is the commuter use now and in the future? 
    • Are there services that are or may interrupt commuting?
    • Define the origin/destination points of the street.  
    • Define the vehicle types that will use the street.
    • What are the traffic volumes and what lane widths are needed? 
    • What amounts of lane restrictions are acceptable? 
    • What is the frequency that lanes may be restricted?
    • Are turning, merging, acceleration and/or deceleration lanes needed?
    • What access control measures are needed? 
    • Is the street part of the CMPO transportation plan? 
    • How should the street be designed to comply with the current standards of the City and/or CMPO?

(Res. 01-14)

 

805.  Unique and Limiting Site Conditions

 

When a newly proposed street is found by the design considerations and criteria to have very unique or prohibitive site conditions, exceptions may be made to the standard cross-sections.  Such changes shall be limited to those necessary to protect the integrity of the street and the areas surrounding it.  All such changes shall require final approval of the City Council. 

 

Modifications in cross-sections for existing streets may be allowed when necessary, with the approval of the City Engineer, under conditions where current streets were built to previous City standards and the current street cross-sections, if built, will be detrimental to the surrounding area.  Changes may include but are not limited to sidewalks, planting or swale areas, and asphalt widths.  (Res. 01-14)

 

806.  Alleys.  Alleys shall have a minimum width of 20 feet. Alleys may be required in the rear of business lots, but will not be accepted in residential blocks except under unusual conditions where such alleys are considered necessary by the Planning Commission.

 

 807. Cul‑de‑Sacs. Cul-de-sacs must be terminated by a turn‑around having a right‑of‑way of not less than 110 feet in diameter/55 feet radius. The maximum length of the cul‑de‑sac shall not exceed 600 feet. The length of a cul-de-sac shall be measured from the center of the radius of the cul-de-sac to the center of the right-of way on the street perpendicular to the street of the cul-de-sac.  The final grade within the turnaround shall not exceed 3% grade.  If surface water drainage flows into the turnaround due to the grade of the street, necessary catch basins and drainage easements shall be provided.  Where a street is designed to remain only temporarily as a dead‑end street, an adequate temporary turning area shall be provided at the dead end thereof to remain and be available for public use so long as the dead end exists.   The size and type of curb, gutter, sidewalk, and planting strip within the turnaround area of a cul-de-sac shall match the road cross section leading into the turnaround.         (Ord. 97-11 & 98-03)

 

 808.  Natural Drainage and Other Easements.  The Planning Commission shall, require that easements for drainage through a sub‑ division and adjoining property be provided by the subdivider, and easements of not less than 16 feet in width for water, sewers, drainage, power lines and other utilities shall be provided in the subdivision.  Easements shall be equally split along side and rear lot lines where necessary.

 

 809. Service Roads.  Service roads paralleling major street shall be required unless the Planning Commission approves double frontage lots which may back onto major highways or collector streets as designated on the major street plan.  Where lots back onto a major highway or collector street, a buffer planting strip of trees or shrubs shall be provided at a width of ten feet or wider, but in no case less than ten feet.

 

 810.  Protection Strips Prohibited.  Protection strips are prohibited. Plats shall not be approved where a proposed sub‑ division plat or any proposed or actual street to the subdivision cuts off access to the proposed or actual street by adjacent property owners.

 

 811.  Blocks.

 


(1)        Length and Walkways.  Blocks shall not be longer than 1600 feet.  Dedicated walkways six feet wide may be required in the middle of blocks.  Where a walkways is required, the subdivider shall surface the full width of the walkway with concrete or asphalt and install a chain link fence at least four feet high on each side the full length of the walkway.  The chain link fence shall be owned and maintained by the property owner on whose property the fence is located.

 

(2)        Width. Blocks shall be at least two building lots wide.

 

(3)        Irregular Shapes.  Irregular shaped blocks, indented by cul‑de‑sacs, or containing interior spaces, are prohibited, but may be allowed where the topography necessitates such shapes.

 

 812.  Lots.

 


(1)        Minimum Requirements.  All lots shown on the subdivision plan shall conform to the minimum requirements of the Zoning Ordinance for the zone in which the subdivision is located, and to the minimum requirements of the engineer and the Board of Health for sewage disposal.  The minimum width for any residential building lot shall be as required by the Zoning Ordinance.

(2)        Lots Fronting Cul‑de‑sac   Lots fronting on Cul‑de‑sac locations shall meet 80% of the required frontage at the building set back line.

(3)        Abuttals.  All lots shall abut a dedicated street, a public street or a street which has become public by right of use.  Street pavement shall be at least 26 feet wide.  In the event a lot abuts a public right‑of‑way created by use, the subdividers shall improve the right‑of‑way to the standards required by this ordinance.

(4)        Corner Lots. Corner lots shall have extra width sufficient for maintenance of required building lines on both streets.

(5)        Side Lines. Side lines of lots shall be at right angles or radial to the street line.

(6)        Lot Remnants. All remnants of lots less than minimum size left over after subdividing a larger tract shall be added to adjacent lots rather than allowed to remain lot remnants. 

(7)        Property Ownership. Where the land in a subdivision includes two or more parcels in separate ownership and the lot arrangement is such that a property ownership line divides one or more lots, the land in each lot so divided shall be held in either single or joint ownership before approval of the final plan and such ownership shall be recorded in the office of the County Recorder.

(8)        Lot Corners. All corners of each lot shall be located by #5 (5/8") x 36" (re‑bar) monuments placed in the ground.

 

 813. Curves. Where street lines within a block deflect from each other at any one point there shall be connecting curves. The radius of the curve for the street center line shall be not less than 350 feet for arterial streets, 250 feet for collector streets, and 100 feet for local streets.

 

814.  Grades. Minimum street grades of 0.3% are required.  The maximum grade for roads in all zones shall be 8% provided, however, the City Engineer may grant variances to 10% for short distances up to 300 feet within a continuous lineal length of 2,000 feet when conditions warrant that traffic safety and economy of road maintenance can be secured. 

 

            When such standards cannot reasonably be achieved, applicants may submit a grade design layout for their proposed streets to the City Council for special approval.  The City Council shall conduct a thorough review of all possibilities to have streets comply.  When no alternatives exist, they may allow steeper grades on the conditions that it can be shown the safety of life and property is not at risk, and that all intersecting roads meet the grade provisions for intersections elsewhere in the City’s standards.  (Res. 01-14)

 

 815. Egress and Ingress.  A minimum of two points of ingress and egress shall be provided in all subdivisions to allow an escape route in case of fire or other catastrophe or hazard. 

 

(1) Exceptions may be approved by the City Council if it can be shown that in a reasonable time subsequent phases of the subdivision, other planned roads or access points will provide the required minimum two points of ingress and egress.

(2)  Cul-de-sacs meeting city standards, by definition provide only one point of ingress and egress to a subdivision or a portion of a subdivision.   Due to the fact that they are limited in length, cul-de-sacs are not considered to be a violation of this section and may be allowed as an exception.

 

816. Driveways.  Driveways crossing swale areas within the City right-of-way may be constructed of impervious materials for a maximum width of 15 feet for any one access.  Two accesses are the maximum allowed per lot or parcel and when two accesses are used, the curb cuts must be at least 40 feet apart and the combined total of all curb cuts shall not exceed 25 feet.

 

Driveways may cross through swale areas following the swale contour or bridge the swale provided the culvert or area under the bridge is kept clear by the landowner.  Culvert sizes shall be a minimum of eight inches in diameter.

 

Conventional street driveways shall have a maximum curb cut of 20 feet for any one access.  Two accesses are the maximum allowed per lot or parcel and when two accesses are used, the curb cuts must be at least ten feet apart and the combined total of all curb cuts shall not exceed 30 feet.

(Res. 01-14)

 

 

817.     Swale Landscaping.

The swale system in a low impact roadway is an infiltration and conveyance system for storm water.  The swale is an integral element in the street’s drainage plan, and as such the developer must submit a design to the City Engineer for approval . Including a vegetation/re-vegetation plan. 

 

Swale designs shall include but are not limited to providing the methods and planting materials that will be used to ensure the integrity of the swale is maintained in a manner that will prevent erosion of soils and infiltration of silt and other materials along the swale area and into storm retention systems, streets, and other properties.   The developer is responsible to maintain the swales for a warranty period of two years.  This can be accomplished by landscaping the swale areas using the best management practices specified in Section 600.  When drought resistant plant materials are desired, refer to section 600 for plant list.   

 

Adjacent Pproperty owners are responsible to maintain swales along the frontage and side yards of their properties after the street warranty period ends.  This can be most easily accomplished by maintaining the previously established vegetation and/or further landscaping the swale areas using the best management practices identified in Section 600.  Property owners may landscape the swales with any materials that comply with the uses and restrictions listed in section 818.

 

(Res. 01-14)

 

818.  Swales uses and restrictions.

The following list comprises the uses and restrictions allowed for swale areas.

 

q       Any non-pervious material such as concrete, asphalt, etc. is not allowed in the swale area under any circumstance except where driveways are permitted. 

 

q       Back-slopes:  Trees and shrubs may be located only on the back slope of the swale away from the roadway edge.  This location accommodates motorist safety and should not obstruct views of oncoming traffic.  No trees or shrubs shall be planted within ten feet of any driveway approach.  Trees shall be of a type that does not have large root system that may affect the sidewalk or road structure.  Trees and shrubs shall be a type that does not exceed a growing height of approximately 20 feet.  The total branch area of a tree shall not exceed a width of five feet in diameter unless they are of a type that branches out at a height exceeding seven feet above the sidewalk elevation.

 

q       Fore-slopes:  Only short grasses are allowed on the fore-slope. This accommodates motorist safety and will create the least impact to snow removal, and emergency vehicle response.  No sprinklers are allowed to be installed in the fore-slope.  Objects that can be constructed in the fore-slope are limited to mailboxes and City signage.  The U.S. Postmaster requirements for the mailbox is that it be at a height of 42” to 48” measured from the curb and that the front of the box be approximately 18” from the edge of the curb. 

 

q       Swales shall not convey irrigation flows under any circumstance without the written approval of the City Engineer.

 

q       Parking or vehicle storage is not an allowable use for swale areas.

 

(Res. 01-14)

 

819.   Construction Access, Limits of Disturbance. Where swale areas are constructed, landscaped and vegetated construction activities including access are prohibited in the swale area except that access may be across the swale at the location of the future driveway. The City Engineer may require a temporary construction barrier to designate the area of the swale and/or limits for construction access or activities.  (Res. 01-14)

 

820.  Disturbance, Rehabilitation. Swale areas are to be protected from any use or activity that may adversely impact the swale integrity, plant materials and stabilization of the soil during the two-year warranty period. The City Engineer may require potential problem areas to be fenced by a temporary construction barrier during and/or after the warranty period.

 

The City Engineer may allow disturbance of the swale areas for construction and service of utilities. Contractors, developers, landowners, disturbing swale areas will be required to rebuild them to the previous condition. Topsoil and the plant materials removed will need to be replaced or repaired to the previous conditions.

(Res. 01-14)

 

821.  Intersection Corner Radius.  Residential intersection radii shall be a minimum of 20’ measured from the curb.  Collector intersection radii shall be a minimum of 30’ measured from the curb.  Arterial intersection radii shall be a minimum of 45’ measured from the curb. (Res. 01-14)

 

822.   Standard Drawings.  The designs and standards specified on the following pages are hereby adopted by the City of North Logan and shall apply to all projects and work performed within the city. (Res. 01-14)

 

823.  Standard Drawing List      

 

50’ streets                                (50’ ROW CONV & LIR cross sections)

60’ streets                                (60’ ROW CONV & LIR cross sections)

66’ streets                                (66’ ROW CONV & LIR cross sections)

Intersection                               (Sidewalk/curb/ramp intersection detail)

LIR sdwk-cg                            (LIR Sidewalk with curb and gutter details)

Driveway Details                      (CONV & LIR driveway details)

Wtr Vlv Mnhl                           (Water Valve Manhole and Check station)

Meter Station                           (3” and 4” Meter Station detail)

80-100’street   (80’, 100’ row street cross sections)

roadedge          (Maricopa edge – bituminous)

driveway          (Concrete driveways details)

ramp                (Access ramp for handicapped)

sdwk-int10       (Sidewalk intersection detail)

sdwk-int25       (Sidewalk intersection detail)

sdwk-cg           (sidewalk with curb and gutter details)

curb6               (Concrete curb and gutter)

gutter-inout       (Inlet and outlet gutter transition details)

x-drain             (Typical “X” drain section, plan, and details)

cmp-con           (Watertight connection band for c.m.p. pipe)

culv-end           (Metal culvert end sections)

sewer               (Typical sewer service connection)

sew-ejector      (Sewage ejector pump details)

manhole            (Sewer manhole detail)

smh-cutout       (Asphalt cutout and installation of sewer manhole)

pipebury           (Backfill over pipe)

meter                (Typical water meter detail and service connection)

thrust                (Thrust block detail)

firehyd              (Fire hydrant installation details [5 ¼”])

junct-box          (Junction box details)

con-barrier       (Pre-cast concrete barrier)

monument         (City street monument detail)

sign-a               (Object markers)

sign-b               (Object markers)

sign-c               (Street sign / intersection markers)

sign-culv           (Culvert markers)

fence                (Chain link and wood fence details)

fence-int           (Fences at intersections)

(Res. 01-14)