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Home My WebLink AboutRevision 11.pdfREVISION DIRECTIONS AUBURN DESIGN STANDARDS EFFECTIVE DATE 09/03/2014 Revision No. 11 Chapter 10.08 New, reprinted pages included with this revision are listed by page number in the right- hand column below. The left-hand column lists obsolete material, which should be removed from the book. Follow the instruction columns in sequence: remove and insert pages as necessary. When completed, insert these directions in a convenient place near the front of the Design Standards Manual. For future reference, the person making these changes may also date and initial this page. Remove these pages Insert these pages Chapter 10, Pages 10-37 to 10-58 Chapter 10, Pages 10-37 to 10-61 12/21/2009 ........................................... Design Standards ....................................... Page 10-37 REF. H\DEVELOPMENT\Design Standards\Chapter 10 (01-10) 10.07.3.3.2 Medium Soils These soils are relatively firm when wet and may contain some amounts of silt. These soils would be classified as SP, SM, or SC as per Unified Soils Classification System. The CBR value would range from 6 to 10. 10.07.3.3.3 Good Soils These soils retain a substantial amount of their load-bearing capacity when wet. These soils would be classified as GM, GC, SW, or SM as per the Unified Soils Classification System. The CBR value for these materials may range from 10 to 20. 10.07.3.3.4 Excellent Soils These soils are basically unaffected by moisture or frost. These soils would be classified as GW, GP, GM, GC, SW, or SM as per the Unified Soils Classification System. The CBR value for these materials would be greater than 20. 10.07.3.3.5 Unified Soils Classification Symbols GW: Well graded or gravel-sand mixtures with little or no fines. GP: Poorly graded gravels or gravel-sand mixtures with little or no fines. GM: Silty gravels or gravel-sand mixtures. GC: Clayey gravels or gravel-sand-clay mixtures. SW: Well graded sands or gravelly sands with little or no fines. SP: Poorly graded sands or gravelly sand mixtures with little or no fines. SM: Silty sands or sand silt mixture. SC: Clayey sands or sand-clay mixtures. ML: Inorganic silts and very fine sands, rock flour, silty or clayey fine sands or clayey silty that are slightly plastic. CL: Inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays, lean clays. OL: Organic silts and organic silt clays of low plasticity. MH: Inorganic silts, micaceous or diatomaceous fine sand or silty soils, elastic silts. CH: Inorganic clays of high plasticity, fat clays. OH: Organic clays of medium to high plasticity and organic silts. 10.07.3.4 Report Submittal The applicant must submit a roadway analysis report to the City of Auburn, including a narrative of the site conditions, the pavement sections, and applicable background information for review and approval. The report must detail data on how the design was achieved including information on the subgrade soils. (Note: The soils classification in Section 10.07.3.3 is not a substitute for tests to support soil capacity.) 09/03/2014 ........................................... Design Standards ....................................... Page 10-38 REF. H\DEVELOPMENT\Design Standards\Chapter 10 (01-10) 10.07.4 Materials Specifications The following material requirements are referenced from the City of Auburn’s Engineering Construction Standards Manual and WSDOT Standard Specifications and are subject to change. For the most current definitions, please reference the Construction Standards Manual. 10.07.4.1 Gravel Base Gravel base shall be bank run gravel, defined as naturally occurring material having characteristics such that when compacted in place on the roadway, it will provide a course having greater supporting value than the subgrade on which it is placed. It shall be from a pit approved by the City Engineer and shall be specified in Division 9- 03.10 of the WSDOT Standard Specifications. 10.07.4.2 Crushed Rock Crushed rock use in City street construction will fall under the following two classifications: A. Crushed Surfacing Top Course (CSTC) B. Crushed Surfacing Base Course (CSBC) CSTC and CSBC shall be in accordance with Section 9-03.9(3) of the WSDOT Standard Specifications. 10.07.4.3 Asphalt Concrete Pavement Asphalt use in City street construction will typically fall under the following two classifications: A. HMA Class “E” B. HMA Class “B” Asphalt Concrete Pavement shall be in accordance with WSDOT Standard Specifications and the City’s Engineering Construction Standards Manual. 10.08 Landscaping 10.08.1 General Landscaping Requirements An area devoted to landscaping is included within the right-of-way of all street classifications. This landscape strip is an integral part of the roadway cross-section. It serves several important functions, including improving pedestrian safety by providing a buffer between traffic and the sidewalk; providing the perception of a narrower travel corridor, thereby slowing traffic; improving air quality; and improving the aesthetic appearance of the street. Located between the sidewalk and the street, landscape strips are frequently used by pedestrians, hence they should not contain shrubs for these can create a tripping hazard. Shrubs with a mature height not greater than 3 feet are however often appropriate in medians, entry features and other landscaped areas in the public right of way not traversed by pedestrians. The applicant shall design and install the landscape strip in accordance with these design standards. The proposed design shall be reviewed and approved by the City. 09/03/2014 ........................................... Design Standards ....................................... Page 10-39 REF. H\DEVELOPMENT\Design Standards\Chapter 10 (01-10) Landscape strips are required for local residential streets and residential collector streets. The minimum width required for landscape strips is five feet (5’). Landscape strips shall be located between the back of the curb and the sidewalk. The applicant shall provide for and plant street trees within the landscape strip in accordance with these design standards. Street trees are required for principal arterials, minor arterials, non-residential collectors, and local non-residential streets. Street trees shall be placed within the sidewalk in tree pits with tree grates and spaced in accordance with the standards identified in Section 10.08.5.1. 10.08.2 Landscape Strip Components Landscape strips contain several components. These include soil, the plants themselves, structural items such as root barriers and tree grates, and may include street furnishings such as luminaries, traffic signs, bus stops or shelters, benches, and mail boxes. 10.08.3 Landscape Strip Dimensions The roadway sections designate either five-foot (5’) or five and half-foot (5½’) wide landscape strips. 10.08.4 Plant Layers In order to balance a safe walking environment and improved aesthetics and air quality, a multilayer planting approach is recommended in the landscape strip. For instance, grass or an approved ground cover should be used at the ground level. Properly spaced trees form the upper or canopy level. Within this general framework are many choices, outlined in the Plant Selection section below. In summary, the landscape strip will contain the following layers: 1. Ground Cover(s) or Grass—Required 2. Trees—Required 10.08.5 Trees 10.08.5.1 Placement and Spacing Trees shall be placed so that they do not obstruct the view of any street intersection, driveway, or visibility of any traffic control device or sign. Sight distance triangles shall be used to analyze visibility at street intersections. Trees shall be centered in the landscape strip. When a landscape strip is not required, trees shall be placed in tree wells with tree grates within the sidewalk per City of Auburn Standard Detail TRAFFIC-64. Nearby features such as street lighting, inground utilities, buildings or overhead wires will also affect where trees should be located. Minimum size for street trees shall be a two inch (2”) caliper, measured two feet (2’) above the root ball. Minimum spacing for street trees should be 1 1/2 times the mature diameter of the tree canopy as identified in Table 10-5A. 09/03/2014 ........................................... Design Standards ....................................... Page 10-40 REF. H\DEVELOPMENT\Design Standards\Chapter 10 (01-10) Planting Next to a Building: Where a building is placed close to the sidewalk, the mature size of a tree should be considered when selecting species. Trees with a pyramidal, columnar, or oval shaped canopy are preferable; a tree with a round head is generally unsuitable in this situation. Overhead Wires: When trees must be planted directly under or when the mature canopy is within twelve feet (12’) of overhead utility lines, species with a mature maximum height of twenty-five feet (25’) must be selected. Street Lighting: Trees need to be located at least half their mature canopy width or twenty feet (20’) from light standards, whichever is greater. Planting locations should be coordinated with locations of lighting standards. Street Signage: Trees shall be planted to avoid blocking the view of street signage. Underground Utilities: Trees shall be planted so as to avoid impacts on underground utilities. Clearance: Trees shall be pruned as they grow to provide at least seven feet (7’) vertical clearance above sidewalks and fourteen feet (14’) of vertical clearance above roadway surfaces. 10.08.5.2 Tree Canopy Shape Tree canopy shapes are an important factor in the selection of street trees. The setting will often dictate which canopy shapes are most appropriate. This in turn will aid in the selection of the most suitable species. The guidance offered below includes information about which tree canopy shapes work best under different conditions. Table 10-5A offers information about tree species and their canopy shapes. 10.08.5.2.1 V-Shaped Trees V-shaped (sometimes also called “vase shaped”) trees have canopies that are narrow toward the bottom and broad at the top. The American Elm is a classic street tree with this shape. V-shaped trees may have arching branches that form a canopy over both street and sidewalk. They generally do not cause problems with overhead power lines or traffic. 10.08.5.2.2 Pyramidal Trees Pyramidal or cone-shaped trees are typically broad at the base of the canopy and are somewhat pointed at the top. Planted close together, pyramidal trees can screen unwanted views or create vistas. Lower branches sometimes droop with age and may have to be limbed up in later years to provide the needed clearance. 10.08.5.2.3 Round Trees These are generally wide spreading trees that need more space than other shapes. 10.08.5.2.4 Oval Trees Oval trees are taller than they are wide and cause less interference with traffic. 10.08.5.2.5 Columnar Trees Columnar trees are useful in locations where there is little available room between the street and buildings, awnings, or other features. Branches of columnar trees 09/03/2014 ........................................... Design Standards ....................................... Page 10-41 REF. H\DEVELOPMENT\Design Standards\Chapter 10 (01-10) tend to grow up rather than out. Many branch lower than other types of trees without causing problems with traffic or pedestrians. 10.08.5.3 Root Direction Devices All street trees planted within a five foot (5’) wide landscape strip shall use a root direction device to deflect tree roots downward into the soil. Any tree planted on public property within 10 feet or less of a sidewalk or curb shall be planted with a root directional device. These devices are used to eliminate damage to sidewalks as the tree roots extend beyond the original planting pit. The root barrier should be placed along two sides of the tree, parallel to the sidewalk and to the curb line. Under specific circumstances, wider strips that contain utilities may also need root barriers to reduce conflicts. Plan submissions should indicate the location of root barriers and provide a specification sheet on the product to be used. 10.08.5.4 Tree Planting Wells and Grates In highly urbanized settings such as downtown, it may be necessary to install street trees into an existing street and sidewalk setting. Where high levels of pedestrian traffic is expected, it may be necessary to place trees into a paved area rather than a landscape strip. In these situations planting wells and grates may be necessary. The desirable size for a tree planting well is thirty-six square feet (36 sq.ft.) or greater. A minimum of twenty-five square feet (25 sq.ft.) should be provided. Where trees are within a heavily traveled pedestrian area, their roots can be easily damaged. In these areas tree grates or other means such as pavers in sand will be required to protect the health of the tree. Where tree wells or grates are necessary, provide planting details, specifications, and product sheets for proposed tree-planting wells and tree grates. See Standard Details TRAFFIC-14. 10.08.6 Plant Selection There are innumerable plant choices for each layer of the landscape strip. Selection is based on:  Size of the landscape strip  Canopy shape of trees  Size and type of leaves  Root shape  Site environmental conditions, such as the amount of sunlight available or moisture in the soil; and  Aesthetic qualities desired. Needled evergreens shall NOT be used in landscape strips, unless the strips are very wide. 10.08.7 Plant Selection Table Table 10-5A provides several acceptable species of trees. Many other trees are appropriate and alternative selections may be proposed if desired. Alternative plant choices must be evaluated and approved by the City. 09/03/2014 ........................................... Design Standards ....................................... Page 10-42 REF. H\DEVELOPMENT\Design Standards\Chapter 10 (01-10) Column Headings: A short description of several of the column headings follows: Height and Canopy Width (in feet): Trees vary considerably in height and mature width and these dimensions are identified per species to ensure that the right tree is being planted in the right location. Landscape Strips/Wells and Grates and Median: This section identifies which species are appropriate to be planted in these locations Sun: Sun Needs full sun Sun/Shade Takes sun to part shade; needs at least ½ day of sun Shade Shade to part shade. Protect from full sun, especially in afternoon H20 Req. (Requirement): Low Drought tolerant after 1st year Mod Moderate water need. May need supplemental watering during dry season. High Requires irrigation Canopy Shape: “V” V-shaped Trees (sometimes also called “vase shaped trees”) Pyramid Pyramidal trees or cone shaped trees Round Round trees Oval Oval trees Col. Columnar trees See Table 10-5A with Tree Matrix. 09/03/2014 ........................................... Design Standards ....................................... Page 10-43 REF. H\DEVELOPMENT\Design Standards\Chapter 10 (01-10) TABLE 10-5A (TREES FOR THE PUBLIC RIGHT-OF-WAY ENVIRONMENT) Botanical Name Common Name Mature Height (ft.) Mature Canopy Width (ft.) Min. Landscape Strip Width Planting OK? Leaf Size Canopy Shape H20 Req Sun Remarks 5'- 6' >10' Wells & Grates Median Acer campestre Queen Elizabeth Maple 'Evelyn' 35 30 x x x 2"-4" Oval Mod Sun/ part. sun Hardy tree Acer freemanii Autumn Blaze Maple 50 40 x x 4"-8" Oval Mod Sun Fast Growing Acer ginnala Amur Maple 'Flame' 20 20 x x x 1.5"- 3" Round Mod Sun/ part. sun Good power line tree. Acer grandidentatum Rocky Mt Glow Maple 'Schmidt' 25+ 15 x x x x 4"-8" Round Mod Sun/ part. sun Requires pruning for clearance Acer Nigrum Green Column Maple 'Green Column' 50 20 x x x x 4"-8" Col Mod Sun/ part. sun Acer platanoides Norway Maple 'Emerald queen' 50 40 x x 4"-8" Oval Mod Sun/ part. sun Popular variety Acer platanoides Norway Maple 'Columnar' 40 15 x x x x 4"-8" Col Mod Sun/ part. sun Good street tree Acer rubrum Bowhall Maple 'Bowhall' 40 15 x x x x 2"-4" Upright/ round Mod Sun/ part. sun tolerant of wet soil Acer rubrum Scarlet Sentinel Maple 'Scarsen' 40 20 x x x x 2"-4" Col Mod Sun/ part. sun tolerant of wet soil Acer rubrum Karpick Maple 'Karpick' 35-40 20 x x x x 2"-4" Col Mod Sun/ part. sun Acer saccharum Sugar Maple 'Green Mountain' 45 35 x x 3"-6" Oval Mod Sun/ shade/ part. sun Acer truncatum x A. platanoides Pacific Sunset Maple 'Warrens Red' 30 25 x x x x 4"-8" Round Mod Sun Good fall colors Amelanchier x grandiflora Serviceberry 'Princess Diana' 20 15 x x x 2"-4" Upright/ round Mod Sun/ part. sun Small tree, red in fall Amelanchier x grandiflora Serviceberry 'Autumn brilliance' 20 15 x x x 2"-4" Upright/ round Mod Sun/ part. sun Resistanc e to ice breakage Carpinus betulus Pyramidal European Hornbeam 'Fastigiata' 35 25 x x x x 2"-4" Col Low Sun/ part. sun Very urban tolerant, good street tree 09/03/2014 ........................................... Design Standards ....................................... Page 10-44 REF. H\DEVELOPMENT\Design Standards\Chapter 10 (01-10) TABLE 10-5A (TREES FOR THE PUBLIC RIGHT-OF-WAY ENVIRONMENT) continued Botanical Name Common Name Mature Height (ft.) Mature Canopy Width (ft.) Min. Landscape Strip Width Planting OK? Leaf Size Canopy Shape H20 Req Sun Remarks 5'-6' >10' Wells & Grates Median Carpinus betulus Frans Fontain Hornbeam 35 15 x x x x 2-4 " Col Mod Sun Cercidiphyllum Japonicum "Rotfuchs" Red Fox Katsura 30 16 x x x x 4" Oval Mod Sun Fagus sylvatica Green Beech 50 40 x x 5" Oval Mod Sun/ part. sun Does not like wet soil Fagus sylvatica Dawyck Purple Beech 'Dawyck Purple' 40 12 x x x x 2"-4" Col Mod Sun/ part. sun Purple leaves Fagus sylvatica Red Obelisk 35 12 x x x x 2 - 4 " Col Mod Sun Fraxinus americana Ash 'Autumn Applause' 40 25 x x x x 2"-4" Oval Low Sun/ part. sun Deep red fall colors Fraxinus oxycarpa Raywood Ash 'Raywood' 45 30 x x x x 2"-4" Oval Low Sun Fraxinus pennsylvanica Leprechaun Ash 'Johnson' 18 16 x x x x 2"-4" Round Mod Sun Good power line tree. Fraxinus pennsylvanica Ash 'Urbanite' 50 40 x x 2"-4" Pyramid Low Sun Fraxinus pennsylvanica Patmore Ash 'Patmore' 45 35 x x x x 2"-4" Oval Low Sun Very good tree Ginko biloba Ginko 'Autumn Gold' (Male Trees Only) 45 35 x x x x 2"-4" Oval Mod Sun/ part. sun Use males only Ginko biloba Ginko 'Princeton Sentry' (Male Trees Only) 40 15 x x x x 2"-4" Col Mod Sun/ part. sun Use males only Liriodendron tulipefera Tulip Tree 60 30 x x 4"-6" Oval Mod Sun Extremely large tree Lirioendron tulipifera Tulip tree 'Arnold' 60 30 x x x 4"-8" Oval Mod Sun Grows extremely large Malus "Marilee" 24 10 x x x x 2"-4" Cone Mod Sun No fruit. Good power line tree. Nothofagus antartica Southern Beech 50 35 x x 2"-4" Round Mod Sun Plantus x acerifolia Planetree 'Yarwood' 50 40 x 6"-7" Round Mod Sun Bark defoliates Prunus Mt. St. Helens Plum 'Frankthrees' 20 20 x x x x 2"-3" Round Mod Sun Hardy tree. Good power line tree. 09/03/2014 ........................................... Design Standards ....................................... Page 10-45 REF. H\DEVELOPMENT\Design Standards\Chapter 10 (01-10) TABLE 10-5A (TREES FOR THE PUBLIC RIGHT-OF-WAY ENVIRONMENT) continued Botanical Name Common Name Mature Height (ft.) Mature Canopy Width (ft.) Min. Landscape Strip Width Planting OK? Leaf Size Canopy Shape H20 Req Sun Remarks 5'- 6' >10' Wells & Grates Median Prunus Snow Goose Cherry 'Snowgoose' 20 20 x x x 2"-4" Upright spreading Mod Sun Disease resistant. Good power line tree. Prunus cerasifera Flowering Plum 'Krauter Vesuvius' 30 15 x x x x 2"-4" Round Mod Sun Prunus sargentii Cherry 'Columnarus' 35 15 x x x x 4"-8" Col Mod Sun Fast grower. Prunus serrulata Flowering Cherry 'Amanogowa' 20 6 x x x x 2"-4" Vase Mod Sun/ part. sun Short lived. Good power line tree. Prunus x hillieri Cherry 'Spire' 30 10 x x x x 2"-4" Col Mod Sun/ part. sun Good fall colors. Prunus x yedoensis Flowering Cherry 'Akebono' 25 25 x x x 2"-4" Round/ vase Mod Sun Best pick for region. Good power line tree. Pyrus calleryana Pear 'Capital' 35 12 x x x 2"-4" Col Mod Sun Susceptible to fire blight. Pyrus calleryana Pear 'Aristocrat' 40 28 x x x x 2"-4" Pyramid Mod Sun Susceptible to fire blight Pyrus calleryana Pear 'Redspire' 35 25 x x x x 2"-4" Pyramid Mod Sun Susceptible to fire blight Pyrus calleryana Pear 'Autumn Blaze' 30 25 x x x 2"-4" Round Mod Sun Susceptible to fire blight Quercus Crimson Spire Oak 'Crimschmidt' 45 15 x x x x 4"-8" Round Mod Sun Quercus robur Skyrocket Oak 'Fastigiata' 45 15 x x x 4"-8" Oval Mod Sun Good street tree Styrax japonica Japanese Snowbell 25 25 x 2"-4" Round Mod Sun/ part. sun Slow growing. Good power line tree. Tilia americana Linden 'Redmond' 35 20 x x x x 4"-8" Pyramid Mod Sun/ part. sun tolerant to wet soil Tilia cordata Linden 'DeGroot' 30 20 x x x x 2"-4" Pyramid Mod Sun/ part. sun Tilia cordata Chancelor Linden 'Chancole' 35 20 x x x x 2"-4" Pyramid Mod Sun/ part. sun Good street tree Tilia cordata Linden 'Greenspire' 40 30 x x x x 2"-4" Pyramid Mod Sun/ part. sun Tolerant to difficult conditions Zelkova serrata Zelkova 'Village Green' 40 38 x x 1"-3" Vase Mod Sun Good tree 09/03/2014 ........................................... Design Standards ....................................... Page 10-46 REF. H\DEVELOPMENT\Design Standards\Chapter 10 (01-10) Table 10-5B provides several acceptable species of ground covers and, shrubs less than 3 feet high. Many other types of plants may be appropriate and alternative selections may be proposed if desired. Alternative plant choices must be evaluated and approved by the City. See Table 10-5B. TABLE 10-5B (GROUND COVER/LOW SHRUBS) Botanical Name Common Name Mature Height (ft.) Minimum Planting Area Width (ft.) Sun Obvious Flowers Remarks Arctostaphylos Una-Ursi Kinnikinnick Bearberry 0.5’ to 1’ 5 to 6' Full sun to partial shade Yes Useful on slopes, poor or dry soils. Slow to establish; must be weeded early. Ceanothus Gloriosus California Wild Lilac 1.5’ 6' to 8' Full sun Yes Cotoneaster Dammeri Bearberry Cotoneaster < 2’ 5 to 6 ' Yes Fast growing Euonymus Fortunei Coloratus Purple Leaf Winter Creeper 1.5’ 6' to 8' Full sun to light shade Yes Hypericum Calycinum St. John's Wort 1’ to 1.5’ 2' Full sun to partial shade Yes Juniperus Horizontalis Blue Chip Juniper/Hughes Juniper 1’ 6' to 8' Full sun No Microbiota Decussata Siberian Carpet Cypress 1.5’ 7' to 8' Full sun to light shade No Rubus Calycinoides Evergreen Bramble 1’ 6' Full sun Yes Vinca Minor Periwinkle 0.5’ 1.5' Full sun to partial shade Yes 09/03/2014 ........................................... Design Standards ....................................... Page 10-47 REF. H\DEVELOPMENT\Design Standards\Chapter 10 (01-10) 10.08.8 Planting Methods and Maintenance Good horticultural practice should be employed in the preparation of the soil and planting pits. This will include: 1. Conserving topsoil and replacing it on the site. 2. Performing soil tests. 3. Providing corrective soil preparation as necessary. 10.08.9 Establishment Period The developer will be responsible for maintaining the trees and plants in the public landscape strip, medians and entry features in a healthy condition for one (1) year after acceptance of the project. Because landscape strips do not usually include irrigation, maintenance will include providing water during dry periods. Weeds, diseases, and insect pests must also be controlled. 10.08.10 Deviations from the Landscape Strip Standards Site conditions may occasionally make adhering to the landscape strip standards difficult. Deviations from the standards may be requested. The following paragraphs list circumstances that may be appropriate conditions for requesting a departure from the design standards: Grass or Ground Cover: Where it is extremely difficult to maintain grass in a landscape strip, heav y stone aggregate such as a washed river rock may be an acceptable substitute. Lightweight rock such as lava rock is not acceptable. Paving over the landscape strip is not acceptable. 10.09 Mailboxes See Standard Details TRAFFIC-16 thru TRAFFIC-19 Locating and installing mailboxes in connection with the construction or reconstruction of a City street shall follow AASHTO and Post Office guidelines. 10.09.1 Mailbox Locations Mailboxes shall be located a minimum of two feet (2’) back from the face of curb on streets which have a curb. For streets without a curb, setbacks shall be determined using ASSHTO standards. When locating mailboxes, access, sight distance, and landscaping requirements shall be taken into account. Final locations shall be detailed on the civil plans and approved by the serving Post Office and the City. When mailboxes are located in the sidewalk, individually or in clusters, sidewalks shall be widened to provide a minimum five feet (5’) of clearance around the mailboxes. Widening of the sidewalk may require the dedication of additional right-of way. 10.09.2 Mailbox Installation The owners or residents served by mailboxes will install and thereafter maintain their own individual, clustered, or separated mailboxes as instructed by the U.S. Postal Service. Mailbox installation shall follow City of Auburn Standard Details TRAFFIC-16, TRAFFIC- 17, TRAFFIC-18, and TRAFFIC-19. 12/21/2009 ........................................... Design Standards ....................................... Page 10-48 REF. H\DEVELOPMENT\Design Standards\Chapter 10 (01-10) 10.10 Illumination 10.10.1 General The City desires to have safe and uniform lighting standards for streets to allow safe comfortable use by all users. The City has approved standard lighting infrastructure for reliability and ease of parts inventory and maintenance. Roadway lighting is required along all City owned streets except classified Rural Collectors and Rural Residential. Street lighting design shall be in conformance with the design criteria in the most recent edition of the IES Lighting Handbook (Illuminating Engineering Society of North America) and applicable WSDOT and City of Auburn Construction Standards. 10.10.2 Design The City of Auburn prefers staggered lighting on all Principal and Minor Arterials. Single sided lighting may be acceptable if approved by the City. Local Residential streets will have a choice between a standard light and an ornamental alternative. Table 10-6 has been included as a general guideline for determining illumination sizing and location requirements. Project specific lighting calculations shall be provided to insure minimum illumination levels will be met. Light level calculations shall be done ignoring any existing substandard luminares (PSE lights on wood poles, etc.). All poles and bracket arms shall be designed for the street lighting luminaire with a minimum weight of fifty pounds (50 lb.) and to withstand pressures caused by wind loads of ninety miles per hour (90 mph) with a gust factor of 1.3. Special consideration shall be given for light levels at crosswalks, curves, conflict points and street ends and shall be designed to meet the minimum light level of 0.2 foot candle. Roadway lighting levels also are impacted by the type of pavement surfacing and special consideration shall be given for surfaces like concrete roadways. When pedestrian lighting is used the street light design shall be done independent from the influence of the pedestrian lighting. Pedestrian light spacing shall not exceed five times the mounting height. When pedestrian lighting is installed, sidewalk lighting shall be designed for two foot (2’) candles. All illumination plans shall include a lighting schedule. Each luminaire shall be numbered such that the circuit number, the mounting height, davit length and wattage are clearly indicated. For Boulevard streets, streets with median islands, double arm street lights in the median may be allowed meeting all applicable design criteria of these standards. In addition, access accommodations allowing for light maintenance vehicles to park outside the travel way must be incorporated into the median island design. The locations of street lights shall take into consideration any obstacles which may screen or impede lighting levels such as street trees and awnings. Street trees shall be located a minimum of twenty feet (20’) from all streetlights. 10.10.3 Table 10-6 Lighting Schedule The following Light Spacing is based on the roadway classifications for a typical straight roadway section with a staggered lighting configuration. Wider road sections, curves, intersections, cul-de-sacs and single sided lighting configurations must use a calculated design meeting the criteria on Table 10-6 with the exception of the Spacing criteria. 12/21/2009 ........................................... Design Standards ....................................... Page 10-49 REF. H\DEVELOPMENT\Design Standards\Chapter 10 (01-10) TABLE 10-6 Street Classification Street Width (feet) Lamp Wattage Average Maintained Light Level (foot- candle) Required Uniformity Ratio Minimum Light Level (foot- candle) Luminaire Mounting Height (feet) Light Pattern Davit Arm Length (feet) Spacing (feet) Principal Arterial 61 400 1.4 3 To 1 0.2 35 40 M-C III 12 190 Minor Arterial 50/61 250 0.9 3 To 1 0.2 35 M-C III 10 190 Non- Residential Collector 44 250 0.9 3 To 1 0.2 35 M-C III 6 200 Residential Collector 34 150 0.6 3 To 1 0.2 30 M-C III 6 175 Local Non- Residential 34 150 0.6 3 To 1 0.2 35 M-C III 6 160 Rural Collector* Local Residential 28 100 0.4 6 To 1 0.1 30 M-C III 8 185 Local Residential Ornamental Alternative 28 100 0.4 6 To 1 0.1 12 M-C III N/A 140 *Illuminate Signalized Intersections only. For downtown pedestrian lighting requirements, contact the City of Auburn. 12/21/2009 ........................................... Design Standards .......................................... Page 10-50 REF. H\DEVELOPMENT\Design Standards\Chapter 10 (01-10) 10.10.4 Light Standard Foundations See Standard Detail TRAFFIC-49, TRAFFIC-61 & TRAFFIC-63 All light poles shall be placed on a foundation. Foundations for light standards shall conform to Standard Detail TRAFFIC-49, or TRAFFIC-61 and TRAFFIC-63 for the Downtown light standards. Light pole foundations adjacent to sidewalks shall include a four inch (4”) concrete pad and conform to Standard Detail TRAFFIC-48. 10.10.5 Service Cabinet See Standard Detail TRAFFIC-51 All new luminaires shall be connected on an electrical circuit that is connected to a power source through a service cabinet. Service cabinets shall conform to Standard Detail TRAFFIC-51 and shall be metered with a photocell installed for luminaire control. The service cabinet shall be within fifty feet (50’) of the Puget Sound Energy (PSE) point of service connection. Service cabinets should be installed behind the sidewalk when possible at locations that do not impede maintenance access. The cabinet should be located in the center of the system so there are a near equal number of lights being served on separate circuits from each side of the cabinet. The number of luminaires per service will be based upon the type of luminaire and the capacity of the service. Testing may be required to determine if additional luminaires may be added to an existing service. 10.10.6 Service Cabinet Foundations See Standard Detail TRAFFIC-51 The Service Cabinet foundation shall conform to Standard Detail TRAFFIC-51. 10.10.7 Conduit Street light conduit shall be Schedule 40 PVC-ASTM D1785. All conduits for street crossings shall be Schedule 80 PVC-ASTM D1785. All conduits installed under sidewalk and driveway areas shall be Schedule 40 PVC-ASTM D1785. Conduit type shall not change within a run. Conduits installed under paved roadway, not crossing the roadway, shall be Schedule 80 PVC-ASTM D1785. Conduits shall have a minimum of twenty-four inches (24”) of cover. The City requires that street light conduit be extended through a property’s frontage for future expansion of the lighting system. 10.10.8 Junction Boxes See Standard Detail TRAFFIC-50 A. Street Junction boxes shall conform to Standard Detail TRAFFIC-50. Junction boxes shall be of the type specified on the plans and shall conform to the requirements of WSDOT Standard J-40.10-01. All junction boxes shall be locking. B. Type 1 junction boxes shall be located adjacent to the sidewalk within the landscaping strip, if provided, or adjacent to the back of sidewalk if a landscape strip does not exist, or within the shoulder of a non-curbed roadway. 10.10.9 Light Standards A. STANDARD LUMINARE See Standard Detail TRAFFIC-49 Lighting standards shall be tapered aluminum, davit-style units, with five feet nine inch (5’9”) radius per Section 9-29.6(1)A (Lighting Standards and Davit Arms, of the City of Auburn Engineering Construction Standards), and shall 12/21/2009 ........................................... Design Standards .......................................... Page 10-51 REF. H\DEVELOPMENT\Design Standards\Chapter 10 (01-10) be installed in conformance with City of Auburn Standard Detail TRAFFIC-48 and TRAFFIC-49. B. DOWNTOWN STREET LIGHTING LUMINARE See Standard Detail TRAFFIC-63 Light standards located within the Downtown Urban Center as depicted on the Comprehensive Zoning Map shall be a 40 foot Concrete Ameron MBR. C. DOWNTOWN PEDESTRIAN LUMINARE See Standard Detail TRAFFIC-61 & 61a Pedestrian light standards located within the Downtown Urban Center as depicted on the Comprehensive Zoning Map shall be 18 ft concrete Ameron VBR. D. LOCAL RESIDENTIAL ORNAMENTAL ALTERNATIVE LUMINARE See Standard Detail TRAFFIC-62 The Local Residential Ornamental Alternative light standard shall conform to Standard Detail TRAFFIC-62 and shall be Holophane Wadsworth series fluted shaft with seventeen-inch (17”) diameter base (W12F4/17CA/BK or DG) and may be used in residential plats in place of the standard luminare. E. ANCHOR BASES Anchor bases per Section 9-29.6(2) (Anchor Bases, of the City of Auburn Engineering Construction Standards) shall conform to the Standard Detail TRAFFIC-49, TRAFFIC-61, TRAFFIC-62, or TRAFFIC-63. 10.10.10 Light Standard Handholes See Standard Detail TRAFFIC-49 Light Standards handholes shall be four inches by six inches (4”x 6”) nominal non-flush type in accordance with Standard Detail TRAFFIC-49. 10.10.11 Photoelectric Controls Photocells installed on the service cabinet shall be “SST” Series model “SST-IES” or approved equal in conformance with Section 9-29.11(2) (Photoelectric Controls) of the City of Auburn Engineering Construction Standards. A bypass switch shall be required inside the service cabinet, clearly marked PE Bypass. One photocell will be required per service cabinet. 12/21/2009 ........................................... Design Standards .......................................... Page 10-52 REF. H\DEVELOPMENT\Design Standards\Chapter 10 (01-10) 10.10.12 Luminaires A. Luminaires shall meet the general requirements of Section 9-29 (Illumination, Signals, Electrical) of the City of Auburn Engineering Construction Standards with the following modifications: 1. Clear burning high-pressure sodium light sources of the ratings shown in the lighting schedule shall be used. 2. Street and Pedestrian Luminaires shall operate on 240 Volt AC and all luminares shall be full cuttoff. B. All luminaires and circuits shall conform to Table 10-7 below: TABLE 10-7 Wattage Max. LuminairesPer Circuit 100 14 150 12 250 8 400 7 C. All luminaires shall be provided with markers for positive identification of light source and wattage per Section 9-29.10 (Luminaires) of the City of Auburn Engineering Construction Standards. A maximum of five percent (5%) voltage drop across each circuit will be permitted. Voltage drop calculations will be required for all non-standard illumination systems. 10.11 Survey Monuments Standard Details TRAFFIC-20 thru TRAFFIC-22 Survey monuments shall be placed or replaced in accordance with good practice in land surveying. Monuments are required along the centerline of improvement of all new or reconstructed streets. Monuments shall be placed at intersections, P.C. (points of curvature), and P.T. (points of tangency). All existing survey monuments that are disturbed, lost, or destroyed during construction shall be replaced by a registered land surveyor registered in the State of Washington at the expense of the responsible builder or developer. 10.12 Guardrail Evaluation of embankments for guardrail installations shall be in accordance with Chapter 710 of the WSDOT Design Manual. Guardrail installations shall conform to WSDOT/APWA Plan C-1, Beam Guardrail Type 1. End anchors shall conform to WSDOT/APWA Plan C-6, Beam Guardrail Anchor Type 1. 12/21/2009 ........................................... Design Standards .......................................... Page 10-53 REF. H\DEVELOPMENT\Design Standards\Chapter 10 (01-10) 10.13 Bollards Standard Detail TRAFFIC-06 When necessary to deny vehicle access to an easement, tract, or trail (except for maintenance or emergency vehicles) the point of access shall be closed by a line of bollards. These shall include one or more fixed bollards on each side of the traveled way and removable, locking bollards across the traveled way. Spacing shall provide one bollard on centerline of the trail and other bollards at a maximum spacing of three feet (3’) to preclude vehicular access. Bollard design shall be in conformance with Standard Detail TRAFFIC-06. Fire access roads shall not be blocked in this manner without the concurrence of the Fire Marshal. Bollards shall be ten feet (10’) from the paved edge of roadway. 10.14 Transit Stops This section provides the minimum design standards to be used in the design of bus transit facilities in the City of Auburn. Bus facilities shall be designed, located and installed in cooperation with appropriate operating transit agency. When determined appropriate by the City Engineer, or if comments are made by a transit service agency, an applicant for new or expanded development is encouraged to consult with King County METRO, or Pierce Transit to determine the practicality of how the site can be served by transit oriented improvements such as bus pullouts, bus stops, or other appurtenances. 10.14.1 Bus Pullout Requirements Bus pullout lanes may be required where bus queuing or staging is required by the transit agencies operations and at the discretion of the City Engineer. The following are guidelines that would indicate pullouts would be appropriate: A. Traffic and passenger boarding and debarking conditions warrant. B. Traffic flow would be greatly hindered due to in lane stopping. C. The posted speed limit is in excess of thirty miles per hour (30 mph). 10.14.2 Locations for Bus Pullouts Bus pullout locations shall meet the following requirements: A. Placement of bus pullouts shall be on the far side of signalized intersections and non-signalized intersections immediately following the intersection. Distance between pullouts should not be less than one thousand feet (1000’). B. If far side pullouts are not possible, nearside pullouts will be evaluated. Mid-block pullouts are discouraged. If a situation arises where a mid-block bus pullout is the only option, pullouts should be constructed on both sides of a two-way street in a complementary pair. C. Maintaining adequate separation between access points, intersections, and bus pullouts can increase the safety and efficiency of both the roadway and the transit service. 12/21/2009 ........................................... Design Standards .......................................... Page 10-54 REF. H\DEVELOPMENT\Design Standards\Chapter 10 (01-10) D. When locating a bus pullout consideration shall be given to existing access points and where passengers have safe and direct access to sidewalks, crosswalks, ramps, or other pedestrian facilities. Consideration shall also be given to trip attractors, and activity centers. E. Bus pullouts must meet sight distance requirements. See Section 10.03. 10.14.3 Design of Bus Pullouts Bus Pullouts shall be designed in accordance with the applicable operating transit agency’s guidelines. Designs must follow applicable guidelines for facilities used by the physically challenged (Americans with Disabilities Act). The King County Metro Transit Planning Office or Pierce County Transit should be contacted for specific design questions. 10.14.4 Bus Stop Requirements Bus stops are located, designed and installed as part of a cooperative effort between the City and the operating transit agency. Bus stops are managed as part of a right of way use permit granted by the City to the operating transit agency. In general bus stop location and design decisions should follow the facility design guidelines of the operating transit agency. The King County Metro Transit Planning Office or Pierce County Transit should be contacted for specific design questions. 10.14.5 Locations for Bus Stops In general bus stop location and design decisions should follow the facility design guidelines of the operating transit agency. The following are guidelines that indicate where bus stops are appropriate: A. Projected or existing passenger boarding and debarking demand warrant a stop. B. Traffic characteristics and street design make the location safe to stop a transit vehicle. C. The location meets the facility guidelines and fleet specifications of the operating transit agency. D. The stop is required to be accessible to the physically challenged (Americans with Disabilities Act). 10.14.6 Bus Stops Features In general bus stop location and design decisions should follow the facility design guidelines of the operating transit agency. The following are some guidelines that would indicate what type of treatment would be appropriate by type of bus stop. A. Shelters should be installed at bus stops with an existing or estimated 25 or more boardings per day. B. Benches should be installed at bus stops with an existing or estimated 15 or more boardings per day. C. Trash receptacles should be installed and maintained by the operating transit agency at all bus shelters. A sign should be placed indicating that the shelter stop is maintained by the operating transit agency and giving specific contact information to report problems with the stop including a phone number. D. At all bus stops experiencing 15 or more boardings per day trash receptacles may be placed by the City or adopt a spot group and should be maintained by the City or the adopt a stop group. 12/21/2009 ........................................... Design Standards .......................................... Page 10-55 REF. H\DEVELOPMENT\Design Standards\Chapter 10 (01-10) E. Information schedules and schedule holders shall be placed at all inbound stops (stops where buses are headed toward a major Central Business District), at all transfer points and at heavily used outbound stops. F. Additional bus stop lighting should be provided at locations where lighting levels are determined to be less than 3 foot candles. G. The stop should be accessible to the physically challenged (meeting the requirements of the Americans with Disabilities Act). 10.15 Traffic Control Devices Traffic Control devices are all signs, signals, markings and other devices used to regulate, warn, or guide traffic. All traffic control devices shall meet the requirements of FHWA’s latest adopted version of the Manual on Uniform Traffic Control Devices (MUTCD) and the standards herein. 10.15.1 Median Islands Median Islands are raised barriers constructed between opposing lanes of travel. Median Islands are generally restricted to classified roadways and may be required in order to: 1. Control access along a corridor, or 2. Provide a traffic calming element. 10.15.1.1 Median Island Design Median Islands shall be designed using the same geometric criteria as the street on which they will be constructed. Medians shall also meet the following requirements: A. Median Ends: Median ends shall be flared at intersections and at breaks to allow for transitioning traffic, ease of street sweeping and shall include signage in accordance with MUTCD requirements. B. Width: Median islands shall be a minimum curb to curb width of eight feet (8’) when landscaped and a minimum of four feet (4’) in width when paved. C. Shy Distance: One foot (1’) minimum shy distance shall be maintained from face of median curbs to edge of travel lanes. D. Landscaping/Paving: Landscaping in medians shall conform to the requirements of Section 10.08. Median paving shall be stamped asphalt with colors and patterns approved by the City. E. Irrigation: Landscaped medians shall include irrigation systems. F. Illumination: Street lights on streets with median islands eight feet (8’) in width and greater shall be located in the medians using dual arm posts and shall meet the minimum light level requirements of Section 10.10. G. Maintenance Access: Median islands eight feet (8’) in width and greater shall provide a paved maintenance staging area fifty feet (50’) in length with mountable curbs. Median islands smaller than eight feet (8’) in width shall include one fifty foot (50’) break in the median per block. 12/21/2009 ........................................... Design Standards .......................................... Page 10-56 REF. H\DEVELOPMENT\Design Standards\Chapter 10 (01-10) 10.15.2 Traffic “C” Curbs Traffic “C” Curbs are barrier curbs used for the restriction of turning movements and to aid in the channelizing of traffic, Traffic “C” curbs may be required in order to control access along a corridor within the restricted zones of any functional intersection boundary as defined in Section 10.04. 10.15.2.1 Traffic “C” Curb Design Traffic “C” Curb layout shall be designed using the geometric criteria for channelization. An approved list of barrier curb products can be obtained from the Public Works Department. Use of any Traffic “C” Curb products not on the approved list must be approved by the City Engineer and meet the following requirements: A. Shall be a National Cooperative Highway Research Program (NCHRP 350) approved product. B. Shall be constructed of all-weather, shatter and crumble resistant materials. C. Shall not restrict the flow of street surface drainage. D. Shall include MUTCD compliant reflective markings and vertical channelizing devices. 10.15.3 “Pork Chop” Islands “Pork Chop” Islands are barrier islands used to restrict turning movements at driveways. They may be required at any driveway where left turns are restricted and Median Islands or Traffic “C” Curb installation is not feasible. When required, Pork Chops shall be accompanied by appropriate turn restriction signing and pavement markings. 10.15.4 Signing All signing shall be per the “Manual on Uniform Traffic Control Devices” (MUTCD) and City of Auburn Engineering Construction Standards. Developments shall be responsible for providing and installing all traffic control signs, including but not limited to street name signs, regulatory signs, warning signs, barricades, and bicycle/pedestrian signs as required. 10.15.5 Pavement Markings See Standard Detail TRAFFIC-35 Pavement markings, raised markers, or striping shall be used to delineate channelization, lane endings, crosswalks, and longitudinal lines to regulate, warn or guide traffic. The City shall approve all channelization plans and crosswalk locations. 10.15.5.1 Crosswalks See Standard Details TRAFFIC-36 thru TRAFFIC-38 & TRAFFIC-58 Crosswalks shall be installed at all intersections controlled by traffic signals and other areas approved by the City. Crosswalks shall be a piano key design consisting of white thermoplastic material. The position of the crossbars should be spaced in such a way as to allow the majority of wheel traffic to pass in the unpainted space. 10.15.5.2 Left-turn Channelization See Standard Detail TRAFFIC-40 & 42 Left-turn channelization shall include a minimum of one hundred fifty feet (150’) of full- width lane to include storage and a reverse curve ninety feet (90’) in length for posted speed up to forty-five miles per hour (45 mph). The reverse curve may be included in the taper distance. The standard width of a left-turn lane will be eleven feet (11’). Left-turn arrows per Standard Detail TRAFFIC-35 shall be installed twenty-five feet 12/21/2009 ........................................... Design Standards .......................................... Page 10-57 REF. H\DEVELOPMENT\Design Standards\Chapter 10 (01-10) (25’) behind the stop bar. Additional storage may be required for long vehicles or anticipated left-turn queues longer than the minimum storage. If storage length exceeds one hundred fifty feet (150’), auxiliary turn arrows will be installed at one hundred foot (100’) intervals. Deviation requests from the minimum left turn lane storage requirements will need a traffic study submittal and approval by the City Engineer. 10.15.5.3 Left-turn Lane at End of Two-way Left-turn Lane See Standard Detail TRAFFIC 39 Left-turn lane at the end of two-way left-turn lanes shall conform to Standard Detail TRAFFIC-39. 10.15.5.4 Lane Division See Standard Detail TRAFFIC-43 All pavement markings used to separate or channelize traffic shall conform to Standard Detail TRAFFIC-43. 10.15.5.5 Painted Islands Painted islands will be allowed on a case-by-case basis with approval from the City Engineer. Pavement markings for painted islands shall meet the MUTCD requirements. 10.15.5.6 Two-way Left-turn Lanes See Standard Detail TRAFFIC-40 & -41 The installation of two-way left-turn lanes on City streets will be determined by the City based on street classifications and left turn requirements. The minimum width of a two-way left-turn lane shall be eleven feet (11’). The delineation lines shall be SBY (Single Broken Yellow) and a SSY (Single Solid Yellow) along the opposing lanes per the MUTCD. Two-way traffic arrows shall be spaced every one hundred fifty feet (150’) along this lane. The designer should pay special attention to the beginning and endings of this type of lane and use clearly defined tapers or islands to maintain traffic safety. 10.15.6 Construction Area Temporary Traffic Control The contractor shall be responsible to provide and maintain all signs, barriers, warning lights, striping, and flag control required for maintaining public safety in construction areas. Traffic control shall be maintained at all times when construction is in progress on all streets, and access points in the construction area. Construction activities will not be allowed in the public right of way without an approved traffic control plan. 10.16 Roadway Barricades Standard Detail TRAFFIC-05 Temporary and permanent barricades shall conform to the standards described in Section 6C-8 of the Manual on Uniform Traffic Control Devices (MUTCD) and Standard Detail TRAFFIC-05. A. Type I or Type II barricades may be used when traffic is maintained through an area being constructed/reconstructed. B. Type III barricades may be used when streets are closed to traffic. Type III barricades may extend completely across the street (as a fence). Where provision must be made for access of equipment and authorized vehicles, the Type III barricades may be provided with movable sections that can be closed when work is not in progress, or with indirect openings that will discourage public entry. Where job 12/21/2009 ........................................... Design Standards .......................................... Page 10-58 REF. H\DEVELOPMENT\Design Standards\Chapter 10 (01-10) site access is provided through the Type III barricades, the developer or contractor shall assure proper closure at the end of each working day. C. In the general case, Type III barricades shall be installed to close arterials or other through streets hazardous to traffic. They shall also be used to close off lanes where tapers are not sufficiently delineated. D. Type III barricades shall be used at the end of a local access street terminating abruptly without cul-de-sac bulb or on temporarily stubbed off streets. Each such barricade shall be used together with an end-of-road marker. 10.17 Traffic Impact Analysis The City of Auburn has established guidelines for Traffic Impact Analysis that are herein adopted by reference. These guidelines are used to identify capacity and safety concerns, to assist in the evaluation of site design as it relates to traffic engineering issues, and to identify appropriate solutions and mitigation. To adequately assess a development’s traffic impact, the City Engineer may require a Traffic Impact Analysis. The requirement for a Traffic Impact Analysis will be based on the size of the development proposed, existing street and intersection conditions, traffic volumes, accident history, safety considerations, community concerns, and other pertinent factors relating to traffic impacts attributable to the development. 10.17.1 When Traffic Impact Analyses are Required The following is a list of some specific conditions that may dictate the requirement for preparing a Traffic Impact Analysis.  The development generates more than 30 PM peak hour trips on a corridor.  The development may potentially affect the implementation of the street system as outlined in the Comprehensive Transportation Plan and Six Year Transportation Improvement Program (TIP), or of any other documented transportation project.  The development proposes a rezone of the subject property.  The original Traffic Impact Analysis for a future development is outdated due to changes in traffic volumes in the vicinity of the proposed project or approved pipeline projects or a change in the proposed land use’s trip generation and/or distribution.  The development could potentially affect safety or requires an analysis to assist in designing appropriate access. 12/21/2009 ........................................... Design Standards .......................................... Page 10-59 REF. H\DEVELOPMENT\Design Standards\Chapter 10 (01-10) 10.17.2 Elements of a Traffic Impact Analysis Each development traffic review is different and, as such, each traffic study should be cooperatively designed to address the city’s specific concerns. Traffic impact analyses are therefore required to be scoped by and with the City Engineer. They may include all or some of the following elements:  Corridor Level of Service analyses,  Intersection Level of Service analyses,  Access point level of service analyses,  Critical gap analyses,  Horizontal and vertical sight distance analyses,  Roundabout analyses,  Traffic signal warrant analyses,  Stop control warrant analyses,  Turn lane warrant analyses,  Access management design,  Other analyses and information as required by the City Engineer. 10.17.3 Special Uses Special event land uses which do not exhibit typical trip generation characteristics may require unique analysis, including but not limited to weekend and off-peak scenarios, and AM versus PM time frames. Examples of such uses would be concert stadiums, racetracks or uses which exhibit substantial traffic peaking associated with special events that are scheduled on a periodic basis. The traffic analysis for such uses may include a traffic management plan to control traffic impacts associated with the special events. 10.17.4 Mitigation Identification In order to protect the public from potentially adverse impacts of the proposal, to fulfill an identified need for public services within the impacted area related to the development, or both, the Traffic Impact Analysis shall identify methods of mitigating on-site and off-site deficiencies for present and proposed phases of the development. The analysis shall make recommendations for improvements necessary for safe and efficient traffic flow and bicycle, pedestrian, and transit movement and access proportional to the identified impacts. Build-out Year, Long-Range Forecast Year, and project phasing impacts shall be considered. All or some of the following items are to be included in the mitigation identification:  Methods for mitigating on-site impacts and mitigation recommendations,  Methods for mitigating off-site impacts and mitigation recommendations,  Discussion of whether on-site and off-site improvements are justified, reasonably related to, and proportional to the impacts of the proposed development,  Any requirements or mitigation measures associated with the Area Circulation Plan. 12/21/2009 ........................................... Design Standards .......................................... Page 10-60 REF. H\DEVELOPMENT\Design Standards\Chapter 10 (01-10) 10.17.5 Recommendations The Traffic Impact Analysis report shall clearly state the mitigation measures recommended by the analysis and shall summarize how the recommended mitigations are proportional to the identified impacts. The recommended street and highway mitigation measures shall be explained in sufficient detail in the analysis to allow them to be understood and evaluated. The recommendation shall also include the following:  Clear statements of the applicant’s recommended mitigation measures.  Scaled drawings depicting recommended mitigation improvements and their relationship to existing and proposed conditions if drawings are needed. 10.17.6 Area Circulation Plan Area Circulation Plans are plans which support the development of a multi-modal transportation network with safe, efficient and pleasant routes for pedestrians, bicyclists, transit users, and motor vehicle occupants. The plan recognizes the link between land use and transportation planning and promotes land use and development patterns that encourage walking, bicycling, and transit use. The goal of an Area Circulation Plan is to "provide a transportation system that will facilitate the safe and efficient movement of people and goods throughout the community while supporting the designated Land Uses in the Comprehensive Plan.” This goal applies to all aspects of circulation including: vehicular, mass transit, bicycle, and pedestrian. In order for the City of Auburn to successfully meet the vision set forth in the Comprehensive Plan, the Area Circulation Plan will need to address a variety of transportation modes to facilitate the convenient and efficient movement of people in and near new development. Area Circulation Plans are required for all new development of general commercial and industrial property. They also may be required for land uses which do not exhibit typical trip generation characteristics that require unique analysis, including but not limited to weekend and off-peak scenarios, and AM versus PM time frames. The Area Circulation Plan shall include sufficient information to adequately assess the functionality of the proposed development and its impact on surrounding properties and circulation systems, including but not limited to:  Mapping details, such as site boundaries and dimensions, site acreage, vicinity map, north arrow, scale, title block, etc.;  Access to the site and interior site circulation;  Proposed lot layout;  Other items which may impact adjacent property, such as general parking arrangement, delivery truck/dock locations, medians or traffic control devices, median breaks, and other information as deemed necessary by the City Engineer and Planning Director. Any development or subdivision of the property shall generally be consistent with the Area Circulation Plan as approved or amended. No plat, building permit, or certificate of occupancy shall be issued for the property unless all construction and development generally conforms to the Area Circulation Plan. 12/21/09 ...................................................................................................................................................... ..................... Design Standards ............................................................................................................................................... Page 10-61 REF. H\DEVELOPMENT\Design Standards\Chapter 10 (01-10) 10.18 Table 10-1 Summary Matrix of Minimum Street Design Requirements CLASSIFICATION SECTION PRINCIPAL ARTERIAL MINOR ARTERIAL RESIDENTIAL COLLECTOR NON-RESIDENTIAL COLLECTOR RURAL COLLECTOR LOCAL RESIDENTIAL LOCAL NON-RESIDENTIAL RURAL RESIDENTIAL Roadway Section Standard Detail No. TRAFFIC-27 TRAFFIC-28 TRAFFIC-29 TRAFFIC-30 TRAFFIC-31 TRAFFIC-32 TRAFFIC-33 TRAFFIC-34 Average Daily Traffic (ADT) 10.01 Over 15,000 10,000 – 15,000 2,500 – 10,000 2,500 – 5,000 1,000 – 5,000 Up to 1,200 Up to 1,200 Up to 1,000 RIGHT-OF-WAY Width (ft) 10.02.9 876 71/826 556 65 60 50 55 50 Intersection Radii- Min. (ft) 10.02.9 39.5 29.5 19.5 24.5 17 9 24.5 7 TRAVELWAY Roadway Width (ft) 10.02.9 616 50/616 346 44 28 28 34 24 Curb/Gutter 10.02.9.4 Y Y Y Y N Y Y N Number Of Lanes 10.01 5 4/5* 2/3* 3 2 2 2 2 Inside Through Lane Width (ft) 10.02.9.1 11 11 N/A N/A N/A 10 N/A N/A Curb Lane Width (ft) 10.02.9.1 14 14 11.5 16 14 10 17 12 Center Turn Lane Width (ft) 10.02.9.2 11 11 11 12 N/A N/A N/A N/A Bikeway Class/Width (ft) 5 10.06 Cl. 1 / 10 Cl. 1 / 10 Cl. 2 / 6 N/A Cl. 3 N/A N/A N/A Intersection Curb Radii (ft)1 10.02.9.6 50 40 30 35 30 20 35 20 Parking Allowed 10.02.9.5 N N N N N Y, one-side N Y/ two-sides4 ROADSIDE Shoulder Width (ft) 10.02.9.4 N/A N/A N/A N/A 8 N/A N/A 3 Sidewalk Width (ft) 10.05.1 10 10 5 10 0 5 10 0 Street Trees with Grates 10.08 Y Y N/A Y N/A N/A Y N/A Landscape Strip Width (ft) 10.08.1 5 w/ Cl. 1 trail5 5 w/ Cl. 1 trail 5 5 N/A N/A 5.5 N/A N/A Illumination 10.10 Y Y Y Y Only at Intersections Y Y Only at Intersections INTERSECTION Min/Max Horizontal Approach Angle 10.04.1.2 90° ± 5° 90° ± 5° 90° ± 5° 90° ± 5° 90° ± 5° 90° ± 5° 90° ± 5° 90° ± 5° Minimum Landing Approach Length (ft) 10.04.1.5 30 30 20 20 20 20 20 20 Maximum Landing Approach Grade (%) 10.04.1.5 3 3 5 5 5 5 5 5 GEOMETRIC DESIGN CRITERIA Posted Speed (mph) 2 10.02.7 45 40 35 35 30 30 30 40 35 30 25 30 25 Design Speed (mph) 2 10.02.7 55 50 45 45 40 35 35 45 40 35 30 35 30 Min. Horizontal Curve Radius (ft)2, 8 (For Standard Cross Section) 10.02.1 9720 8150 4930 1121 821 544 544 1125 821 544 333 510 333 Min. Tangent Between Reverse Curves (ft) 2 10.02.2 150 150 150 150 150 100 150 100 Maximum Rate of Superelevation, e (%) 10.02.3 8 8 0 0 8 0 0 0 Max. Vertical Grade (%)2, 3,7 10.02.4 6 6 8 8 8 8 8 8 Cross Slope (%) 10.02.6 3 3 3 3 3 2 2 2 DRAINAGE Closed System 6.00 Y Y Y Y Only at Driveways Y Y Only at Driveways Open System 6.00 Y Y * Minor Arterials may be designed as either a four (4) lane road (two lanes in either direction) or a five (5) lane road (two lanes in either direction and a center turn lane) based on the Comprehensive Plan designation. Residential Collectors may be designed as either a two (2) (one lane in either direction) or three (3) (one lane in either direction and a center turn lane) lane road based on the configuration of access points to the collector system. 1 At intersections with two different street classifications, use the highest classification for curb radii. 2 Table values are for standard cross sections with a relatively level grade and are for reference only. For accurate design values reference the AASHTO Manual “A Policy on Geometric Design of Highways & Streets.” 3 Vertical curves will be required when the algebraic grade difference is more than 1%. 4 Parking shall be located where space is available, outside of the required three-foot (3’) shoulder. 5 The construction of separated bikeways shall be required in conjunction with street projects when designated by the Comprehensive Plan. 6 Required pavement and right-of-way widths may be greater then that shown to accommodate medians and/or bike lanes as required to meet Comprehensive Plan designations or to address traffic calming. See Section 10.06. 7 Vertical grades may be increased to 10% for non-arterial streets upon approval of the City Engineer. 8 Minimum radii are for streets designed using the recommended cross slopes listed above. Minimum street radii for Arterials and rural Collectors may be reduced by superelevating the street section per the requirements above.