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Design Standards – Geometric Design

A. Horizontal Curves

1. Minimum curve radii with and withoutsuperelevation are shown in the Roadway Designsection for the various classifications of streets.These radii are derived from the CaliforniaDepartment of Transportation (CalTrans)Highway Design Manual comfortable speed onhorizontal curves chart.

2. Superelevation

a. Local streets and two-lane residentialcollectors should not be superelevated atcurves.

b. Superelevation is allowed on all other streets ifrequired to maintain the design speed alongcurves.

c. When superelevation is required, the minimumamount permitted is plus 2 percent. Themaximum superelevation permitted, regardlessof circumstances, is 4 percent for designspeeds of 30 mph (50 km/h) and lower, 6percent for urban classifications with designspeeds between 35 mph (60 km/h) and 45mph (70 km/h), and 10 percent for ruralclassifications and for design speeds of 50mph (80 km/h) and higher.

d. Superelevation must be designed to showlength, transition, and crown runoff. Designmust follow CalTrans standards as provided inits Highway Design Manual, Chapter 200.

e. Superelevation shall extend uniformly from theflow line of the gutter on the high side of thestreet to the lip of the gutter on the low side ofthe street, keeping the standard slope of thegutter on the low side unchanged. This shall

also include the slope of median gutters, if any,as shown in Regional Standard Drawing G-6.

f. All streets not superelevated shall be crownedat 2 percent.

3. Sight distance on horizontal curves shall bedetermined from CalTrans Highway DesignManual Figure 201.6, “Stopping Sight Distanceon Horizontal Curves.”

4. Compound curves are prohibited.

5. Reversing Curves

a.Reversing curves are permitted; but, for allstreets other than local streets, they must beseparated by a tangent length adequate toprovide safety of travel.

b.For non-superelevated reversing curves, thetangent length provided shall be compatiblewith probable driving speed, type of vehicleuse, and individual curve radius and length.

c.Superelevated reversing curves shall beseparated by tangents sufficient to contain allof the superelevation runoff required.

6. Knuckles. Knuckles may be approved on anexception basis for residential cul-de-sacs with200 ADT or under, intersecting at right anglesplus or minus 5 degrees. Knuckles should not beused in lieu of providing a 100-foot (30 m)minimum curve radius required on residential cul-de-sacs.

7. Sharp horizontal curves must not begin nearthe top of pronounced crest vertical curves ornear the low point of pronounced sag verticalcurves.

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B. Vertical Curves

1. Vertical curves shall be designed to the currentCalTrans Highway Design Manual StoppingSight Distance based on design speed.

2. For local streets, the minimum acceptablevertical curve is ten feet (3 m) of curve foreach one percent difference in grade.

3. Vertical curves leading into intersections shallbe designed such that the grade immediatelyapproaching a cross gutter is no greater than 4percent.

4. Sight distance on vertical curves shall bedetermined from CalTrans Highway DesignManual figures 201.2 and 201.4, “Passing andStopping Sight Distance on Crest VerticalCurves,” and from CalTrans Figure 201.5,“Stopping Sight Distance on Sag VerticalCurves.”

C. Intersections

1. Streets are to intersect at 90-degree angles oras close thereto as practicable.

2. Two streets intersecting opposite sides of athird street are to have the same points ofintersection or else their centerlines are to beseparated by a minimum of 120 feet (40 m) forlocal streets and a minimum of 200 feet (60 m)for all other streets on the third street.

3. Median breaks for intersections along majorstreets with other streets of collector or higherclassification shall be no closer than one-fourthof a mile (400 m).

4. Full access intersections of local streets withmajor streets should be kept to a minimum,and such intersections shall be at least 500feet (150 m) apart, measured between

centerlines, and shall be farther apart whereturn pockets dictate longer spacing. The needfor left-turn storage may require a greaterdistance. Pedestrian access to transit andadjacent commercial uses should beconsidered in major street intersectionspacing.

5. Local streets should not intersect primaryarterials.

6. Maximum grade across intersections alonglocal and two-lane sub-collector and two-lanecollector streets shall not exceed 8 percentand along four-lane streets and greater shallnot exceed 5 percent.

7. Curb return radius should accommodate theexpected amount and type of traffic and allowfor safe turning speeds at intersections. Curbreturn radius shall be installed in accordancewith Table D-1.

Table D-1 Curb Return Radius a

a. Curb return radius for all other intersectionsnot covered in Table D-1 shall be 30 feet(9.0m).

8. Sight distance at intersections must considerthe following factors: grades, curvature, andsuperelevation.

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a. The minimum corner sight distance at anintersection of a street (public or private) ormultiple dwelling residential/ commercial/industrial driveway with a collector orhigher classification street shall be inconformance with AASHTO Standards.

b. Adequate sight distances at intersectionsand along horizontal curves must beobtained. A sight distance easement thatrequires fences, monuments, signs,landscaping, walls, and slopes or any otherobstruction at and beyond the right-of-wayline to be eliminated, kept low, or set backis only acceptable when relocation of theintersection or redesign of the curve doesnot permit adequate sight distance.

9. The City Engineer may prohibit parking atcritical locations.

10. The City Engineer may control access alongmajor streets at critical locations.

D. Transitions

1. No pavement widening transition is required toincrease the number of travel lanes beyondthat needed for drainage flow.

2. When reducing the number of through travellanes, the paved section shall undergo atransition as follows:for V > 40 mph, L = W x V;for V 40 mph, L = W x V 2/60;where:V = design speed, in miles per hour;W = width of roadway transition, in feet;andL = transition length, in feet.

E. Cul-de-Sacs

1. Objectivesa. Cul-de-sacs can be used to minimize

encroachments into steep topography orother sensitive environmental features.However, when utilizing cul-de-sacs, careshould be taken to design aninterconnected street pattern within aresidential neighborhood in order toprovide, to the maximum extent feasible,direct pedestrian/bicycle routes to localdestinations.

b. In an effort to encourage walking, bicycling,and transit as a viable means oftransportation within residentialneighborhoods, cul-de-sacs may beutilized within a subdivision so long as thedevelopment does not result in a circuitousstreet system that unnecessarily inhibitspedestrian circulation, discourages transitservice, or causes added traffic impacts toother residences within the neighborhood.

2. Connections/Accessa. When a cul-de-sac exceeds 150 feet (45

m) in length, and/or pedestrian or bicyclecirculation is being or will be significantlyimpacted and the traffic levels onneighboring streets are being or will bedegraded, additional design features,including but not limited to: 1) providing forpedestrian and bicycle connectionsthrough the cul-de-sac, or 2) theinterconnection of the turnaround of thecul-de-sac with an adjacent local street,should be considered in order to provideaccess to adjacent streets or to adjacentland uses such as open space, parks,trails, or commercial areas.

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b. The design of pedestrian and bicycle accessways should address the following toprovide for the safety of users:(1) Length should be kept to a minimum,

normally not in excess of 200 feet (60 m).(2) Adequate lighting should be provided.(3) Landscaping, fences, grade differences,

or other obstructions should not hindervisibility into the access way fromadjacent streets and properties.

(4) Surrounding land uses should bedesigned to provide surveillanceopportunities from those uses into theaccess way, such as with the placementof windows.

(5) Emergency vehicle access should beprovided in cases where externalsurveillance is inadequate.

3. Industrial and Commercial Areasa. Turnaround curb radius shall be 55 feet

(16.8m).

b. Such cul-de-sacs shall be limited to 500 feet(150 m) in length from property line of theintersecting street to end of the bulb unlessthere are clearly defined topographicconditions requiring greater lengths. In suchinstances, intermediate turnarounds orsecondary emergency vehicle only accessmay be required.

4. Residential Areasa. Cul-de-sacs serving more than four dwelling

units or over 150 feet (45 m) in length anddead-end alleys require a turn-around. Cul-de-sacs of 150 feet (45 m) or less shall bedeveloped such that access can beprovided without backing onto streetsintersecting the cul-de-sac.

b. Turnaround curb radius shall be 50 feet(15.0 m).

c. Turnaround curb radius may be reduced to35 feet (10.7 m) if cul-de-sac length is lessthan 150 feet (45m), measured to the endof the bulb.

d. Residential cul-de-sacs are limited to amaximum of 200 ADT unless there areclearly defined topographic constraints thatrequire greater volumes. Intermediateturnarounds shall have a 50-foot (15.0 m)radius. In all cases, intermediateturnarounds and/or special design may berequired to accommodate access byemergency vehicles and/or emergencyevacuations.

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-Street Element DesignDesign Standards

Design Standards – Street ElementDesign

A. Standard DrawingsMost design details, location requirements,pavement computations, and constructionmethods are included in San Diego Regional andCity of San Diego Standard Drawings

B. Street RequirementsCurb-to-curb width is that distance between thecurb lines of the respective curbs, as shown inSan Diego Regional Standard Drawings.

C. Drainage1. Street drainage is covered in detail in the City

of San Diego Drainage Design Manual.

2. In streets with raised medians, storm watermust be intercepted at the median in super-elevated sections to prevent flow at points oftransition to crowned sections.

3. In superelevated streets, storm water must beintercepted at side curbs to prevent flow fromside streets across the superelevated street.

4. Minimum grade is 0.6 percent unless drainageconditions cause a steeper minimum grade tobe required in accordance with City of SanDiego Drainage Design Manual.

D. Medians1. All center medians shall be raised, bounded by

6-inch B-2 concrete curbs and surfaced withstamped concrete, brick pavers, or otherdecorative paving as called for in the City ofSan Diego Standard Drawings.

2. Landscaped medians shall conform to City ofSan Diego Standard Drawing SDG-112.Maintenance for landscaped medians shall beprovided for through a maintenanceassessment district or by other agreement withthe City of San Diego.

E. Pavement1. Streets shall be paved with asphalt concrete

over cement-treated base, concrete, or full-depth asphalt concrete in accordance with Cityof San Diego Standard Drawing, SDG-113 orwith a com-parable structural section approvedby the City Engineer.

2. P.C.C. pavement is required for streets withgrades greater than 12 percent.

3. The same pavement section is required inshoulders as well as driving lanes, except forrural road classifications.

4. Concrete bus pads are required for bus stopsalong main transit corridors and shall consistof nine inches of Portland cement concrete.Refer to MTDB Design Guidelines for otherdimensions.

5. Raised pavement markers are required for allstreets of collector or greater classification.Installation and criteria must be according tothe latest edition of the State of CaliforniaTraffic Manual.

6. Stamped concrete or other types of decorativepaving will be permitted in the traveledroadway of a public and/or private streetprovided the following conditions are met:a. At signalized intersections to designate

pedestrian crosswalks (brick pavers, butnot stamped concrete, may be used);

b. The street grade is 8 percent or less;c. Maintenance is assured by either an

encroachment removal agreement or byinclusion in an assessment district.

Construction plans shall be prepared by aRegistered Civil Engineer and shall indicatethe location, color, type of material, andstamping pattern. Decorative paving may beallowed at other locations through thedeviation process (see Appendix VIII).

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7. Stamped concrete or other types of decorativepaving will not be permitted at non-signalizedintersections to designate pedestriancrosswalks or at locations where it mightappear to be a pedestrian crosswalk, in cross-gutters or gutters, or to be used to delineatepedestrian ramps. Stamped concrete or othertypes of decorative paving is permitted atlocations designated and marked aspedestrian crosswalks.

8. Engineers are cautioned that use of stampedconcrete in residential areas may causeadverse community reaction due to noisewhere the roadway is immediately adjacent todwelling units.

F. Rolled curbsRolled curbs are not permitted on publiclydedicated streets but may be used on privatestreets where the grade does not exceed 5percent.

G. Right-of-WayThat portion of the right-of-way beyond curbsshall slope upward away from the street at 2percent grade.

H. SidewalksWidths1. Minimum widths are set forth in the Parkway

configuration section for various streetclassifications.

2. The width of a contiguous sidewalk ismeasured from the back of the curb.

3. Sidewalk widths are intended to be clearwidths. Where fire hydrants, street furniture, orother above ground appurtenances reducesuch width, additional sidewalk shall beconstructed around the obstacles.

4. Where feasible, the location of transit stopsand shelters shall be determined and thesidewalk width shall be 10 feet (3.0 m) whereshelters are proposed. Other bus stop loca-

tions shall provide eight feet (2.4 m) ofsidewalk. The wider sidewalk widths for busshelters shall extend for 25 feet (8 m) parallelto the curb measured from the bus stop sign.This will provide adequate clearance toaccommodate bus lifts for disabled persons.Refer to MTDB design guidelines for furtherinformation.

5. Sidewalks less than 5 ft (1.5m) in continuouswidth shall provide passing space atreasonable intervals not to exceed 200ft (61 m).Passing space shall provide a 5ft by 10ft (1.5m by 3.0 m) minimum clear space and may beprovided at driveways, at building entrances,and at sidewalk intersections.

Locations1. Sidewalk areas within curb returns are to be

completely paved at all collector, major, andprimary arterial intersections, and at otherintersections where significant pedestrianvolumes are anticipated.

2. A variation or transition in sidewalk locationfrom that recommended above shall beconsidered to achieve consistency withexisting adjacent sidewalks.

3. Transitions shall be four-to-one.

Curb Ramps1. All sidewalk installations are to include curb

ramps at curbed intersections, T intersections,and alley aprons.

2. Installation of two curb ramps per corner isrequired for new intersections.

3. Existing intersections to be retrofitted for curbramps, one curb ramp per corner may beinstalled.

Innovative SidewalksInnovative sidewalks may be considered for areaenhancement and to avoid existing features suchas trees and may be approved on an individualbasis provided they are located within the streetright-of-way and maintenance of the area

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between the sidewalk and curb is provided byspecial assessment district or other agreementwith the City of San Diego. All other requirementsshown in Standard Drawings, such as 2 percentfall between property line and face of curb,should be complied with. Sidewalks and thepedestrian path shall be parallel to the curb to thegreatest extent practicable.

Construction1. Sidewalks shall be constructed in accordance

with San Diego Regional Standard Drawings.

2. Utility access panels within sidewalks must beslip resistant, flush mounted, and must notinclude holes greater than 1/4 inch.

3. Throughout the city, contractors stamp thework with their name and the date ofconstruction of the sidewalk. In addition to thecontractors’ stamp, the name of the street isoften imprinted in the curb. In many of thecity’s older neighborhoods, these streetnames may not be the current name of thestreet. However, these markers are anindicator of the age of a particularneighborhood and provide a sense ofcontinuity and history for the residents. Whenexisting sidewalks are being repaired orreplaced, care must be taken to retain in placethese stamps and imprints or to place themnear the new sidewalk work.

I. Landscape RequirementsStreet trees are urban amenities whose value isrecognized in many of the City’s land use policydocuments. These documents call for street treeplantings to achieve various goals including:establishing and preserving neighborhoodcharacter, encouraging commercial revitalization,and creating a comfortable pedestrian environ-ment. For requirements for street trees and otherlandscaping in the right-of-way, refer to thecitywide Landscape Regulations (San DiegoMunicipal Code section 142, chapter 14, Article 2,Division 4) and the associated LandscapeTechnical Manual.

The citywide Landscape Regulations addressesrequirements such as the quantity, distribution,size, selection, and approval of plant material,including street trees. The Landscape TechnicalManual establishes standards, guidelines, andcriteria for all landscaping in the public right- of-way, such as: locational criteria (distance of treesfrom the face of curb for certain streetclassifications and speeds, and from trafficsignals, signs, and underground utilities), plantselection, maintenance, median landscaping,irrigation, and electrical services.

For all street trees and landscape plantings inroadway islands, watering and maintenance willbe assured through an agreement with the City,such as a street tree permit, encroachmentremoval and maintenance agreement, ormaintenance assessment district.

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J. Driveways1. Access to private property from public and

private streets shall be by standard concretedriveways. Curb returns will be permitted whenthe driveway is signalized. Driveway widths onstreets with collector or higher classificationshall be consistent with the Land DevelopmentCode. Driveways shall be designed such thataccess can be provided without backing ontostreets that are collector or higher.

2. No driveway access is normally permitted to aprimary arterial. Should a lot have frontageonly on a primary arterial, driveway accesslimited only to right turns in and out will bepermitted at locations and under conditionsspecified by the City Engineer and may requirean additional lane.

3. Median breaks for driveway access to majorstreets will not normally be permitted unless allthe following conditions exist:a. The property to be served is a major traffic

generator and has a continuous frontage of1,200 feet (360 m) or more along the majorstreet and is situated between streets thatintersect the major street from the sideoccupied by the property.

b. The median opening is not less than 600feet (180 m) from an intersection with amajor or collector street.

c. The median opening is not less than 400feet (120 m) from an intersection with alocal street. The need for left-turn storagemay require a greater distance.

d. The median opening is not less than 600feet (180 m) from any other existing orproposed mid-block median opening.

e. All costs, i.e., base material, surfacing,traffic safety street lighting, traffic signals,reconstruction or utility relocation requiredby a mid-block opening will be borne by therequesting party.

K. Guardrail and Safety Devices1. All guardrail installations must be done in

conformance with the latest edition of State ofCalifornia Traffic Manual and Regional/City ofSan Diego Standard Drawings.

2. Guardrail may be required at certain locationsfor safety purposes in accordance withguidelines in the State of California TrafficManual.

3. Reflectors and other safety structures may berequired when necessary for public safety.

4. Where fire hydrants are required, guardrailshall be installed in a manner so as to notinterfere with the operation of such hydrants.

L. Street Name SignsMetal street name signs on metal posts arerequired at each intersection, at any point ofstreet name change, and at midpoint in blocksover 2,000 feet (600 m) in length, in conformancewith City of San Diego Standard Drawings.

M. Traffic Control and SignalizationWhere two or more streets intersect, some formof traffic control is usually needed to define theright-of-way of the vehicles entering theintersection. This control can take the form ofyield signs, stop signs on the minor street, all-way stop control, or traffic signals. Stop signs andall-way stop controls are installed according toCity Council Policy 200-8. Traffic signals areinstalled according to City Council Policy 200-6.These Council Policies prescribe warrants basedon City, state of California, and federal standards.The warrants take into consideration vehicularand pedestrian volumes, accident history, trafficsafety, the transportation system, and otherrelevant factors.

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When traffic signals are synchronized andoperating in a coordinated system, they canfacilitate the flow of vehicular traffic along a streetcorridor and within a network of streets.Coordinated traffic signals can reduce delay andtravel times of vehicles, minimize the number ofstops and starts and improve air quality byreducing vehicular emissions caused by the startsand stops. For efficient coordination, intersectionscontrolled by traffic signals should be spacedapproximately one-fourth mile (400 m) to one-halfmile (800 m) apart.

N. Street Furniture1. Street Furniture and above-ground

appurtenances placed in the public right-of-wayshall conform to the requirements set forth inthe San Diego Municipal Code and applicablecouncil policies.

2. Street Furniture and above-groundappurtenances shall be located in a fashion thatpreserves the safety, integrity, and layout of thepedestrian passageway and assures that theright of the public to use the public sidewalk isnot unreasonably restricted.

3. Bicycle racks, where placed in the public right-of-way, should be sited in a well-lit area asclose to building entrances and regular foottraffic as possible without unreasonablyrestricting pedestrian passageway. The rackmust support the bicycle frame (not the wheel)at two points of contact and permit the use of aU-shaped lock to secure the frame and onewheel. The rack must be positioned to provide 2feet by 6 feet (0.6m by 1.8m) of space perbicycle.

Design Standards- Planned ResidentialDevelopments

A. GeneralThese standards shall apply only to areas thathave an approved Planned ResidentialDevelopment Permit.

B. Private Streets1. Private streets may be utilized where there is a

homeowners association established thatwould maintain the street system.

2. The entrance to private streets shall advise thepublic of the nondedicated status of the streetsystem and shall have an entrance design thatvisibly reinforces the private access. As aminimum, absent other design features, thisdesign shall consist of signage designating thestreet as private. Such entrances must beprovided with adequate visitor parking andturnaround facilities.

3. Private streets shall be designed andconstructed to the same structural, geometric,lighting, and drainage standards as dedicatedstreets. Private streets with parking on bothsides of the street shall have a minimum curb-to-curb width of 34ft (10.2 m).

4. General utility easements will be required overprivate streets. Width of easement should beconsistent with street right-of-way.

C. Driveways1. Driveways, where permitted in lieu of either

dedicated or private streets, must be designedto allow direct access to all developed areas ofthe project.

2. Driveways serving as fire lanes shall bedesigned with a semi truck turning radius of 50feet (15.2 m).

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3. Minimum driveway width shall be consistentwith the Land Development Code, with a 26-foot (7.9 m) width within 20 feet (6.0 m) of afire hydrant.

D. WalkwaysA system of improved all-weather walkways mustbe provided connecting each dwelling unit tostreet sidewalks within and adjacent to thedevelopment and to major points of pedestrianattraction within the development.

E. Parking on Private Streets and Driveways1. Parking shall meet the minimum requirements

established by the applicable zone ascontained in the Land Development Code.

2. An unobstructed minimum distance of 25 feet(7.5 m) from the circulation driveway curb tothe structure or carport area and not less than20 feet (6.0 m) from the back of sidewalk shallbe provided.

3. Parking bays, both parallel and perpendicular,may be utilized on low-volume residentialstreets. Such facilities, normaly, would beincluded within the right-of-way or privatestreet easement and would be maintained aspart of the street. Where a sidewalk is locatedon the same side of the roadway as theparking bay, a continuous walkway must bemaintained either by restricting parking withinfive feet of the extended curb line or byproviding an improved walkway around theparking bay. All parking bays shallaccommodate full-size vehicles.

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Appendix

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APPENDIX I - Street Classification

A. Functional ClassificationThe width, street configuration, alignment, anddesign speed of a street is related to its functionalclassification. For the purpose of theseguidelines, the following functional classificationsshall apply.

1. Alley: A roadway, usually unnamed, whichprimarily provides secondary vehicular accessto the rear and side entrances of abuttingproperty. It should be a minimum of 20 ft (6m)and a maximum of 24 ft (7.2m) in width.

2. Private Street: A street that provides,primarily, direct access to abutting property. Itcarries low vehicular movement, low-to-heavypedestrian movement, and low-to-moderatebicycle movement. It has the same overallstandards, design and construction as a publicstreet with the exception that the responsibilityfor maintenance is private.

3. Pedestrianway/Bikeway: A facility thatprovides, primarily, for pedestrian and bicyclecirculation between two closely spaced (250feet (75 m) or less) streets. It has a walkway/riding surface and landscaping, and mayinclude pedestrian-scale lighting and anunderground utility corridor.

4. Bike Path: A facility that provides exclusivelyfor bicycle circulation along major corridors. Ithas an all-weather riding surface.

5. Transitway: A street that provides, primarily,for moderate-to-heavy transit movement andmoderate-to-heavy pedestrian movement in apedestrian/transit mall setting, with commercialretail, food service, and entertainment uses. Ithas a narrow transit roadway, wide sidewalks,street trees, traffic safety street lighting, andlandscaping. It may include planter boxes,

pedestrian-scale lighting, and other pedestrianamenities, and an underground utility corridor.

6. Local Street: A street that provides, primarily,direct access to abutting property. It carries lowvehicular movement, low-to-heavy pedestrianmovement, and low-to-moderate bicyclemovement. It has on-street parking, streettrees, traffic safety street lighting, andsidewalks. It may include landscaping,pedestrian-scale lighting, and undergroundutilities.

7. Collector Street: A street that primarilyprovides movement between local/collectorstreets and streets of higher classifi- cationand, secondarily, provides access to abuttingproperty. It carries low-to-moderate vehicularmovement, low-to-heavy pedestrian movement,moderate-to-heavy bicycle movement, and low-to-moderate transit movement. It has on-streetparking, street trees, traffic safety streetlighting, and sidewalks. It may also includelandscaping, pedestrian-scale lighting, andunderground utilities.

8. Major Street: A street that primarily provides anetwork connecting vehicles and transit toother major streets and primary arterials, and tothe freeway system and secondarily providingaccess to abutting commercial and industrialproperty. It carries moderate-to-heavy vehicularmovement, low-to-high pedestrian and bicyclemovements, and moderate-to-high transitmovement. It has a raised center median,street trees, traffic safety street lighting, andsidewalks, and may include landscaping,pedestrian-scale lighting, underground utilities,on-street parking, and/or bike lanes.

9. Primary Arterial: A street that primarilyprovides a network connecting vehicles andtransit to other primary arterials and to thefreeway system. It carries heavy vehicular

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movement while providing low pedestrianmovement and moderate bicycle and transitmovements. It has a raised center median,bicycle lanes, street trees, traffic safety streetlighting, sidewalks, and no access fromabutting property. It may include undergroundutilities.

10. Rural Local Road: A road in agricultural,natural open space, and large lot (greater than2.5 acres) residential areas that primarilyprovides direct access to abutting property. Itcarries low vehicular movement, lowpedestrian movement, and low bicyclemovement. It may include traffic safety streetlighting and underground utilities. It typicallydoes not have sidewalks or landscaping.

11. Rural Collector Road: A road in agricultural,natural open space, and large lot (greater than2.5 acres) residential areas that primarilyprovides movement between local andcollector roads and roads or streets of higherclassification and secondarily provides accessto abutting property. It carries low-to-moderatevehicular movement, low pedestrianmovement, low-to-moderate bicyclemovement, and low transit movement. It mayinclude traffic safety street lighting andunderground utilities. It typically does not havesidewalks or landscaping.

B. BoulevardsThe progress Guide and General Plan andvarious community plans designate certainstreets as being of great importance to acommunity and recommend special treatment torecognize this. The Bay-Park Link and Broadwayin Centre City are two such examples. Therecommendations may call for the street to bedesigned as a boulevard. A boulevard is definedas “a street or promenade planted with trees.”

The Boulevard Book 1 describes three boulevardtypes:

1. A street with a wide central landscapedmedian flanked on either side by roadwaysand sidewalks. The central median may be apedestrian promenade or planted with grass.

2. A street with a wide central roadway andbroad, tree-lined sidewalks along each side.

3. A multi-way boulevard is designed to separatethrough traffic from local traffic and, often, toprovide special pedestrian ways on tree-linedmalls. It is characterized by a central roadwayof at least four lanes for generally fast andnon-local traffic. On either side of this roadwayare tree-lined medians that separate it fromparallel, one-way side access roads for slow-moving traffic.

Each street designated as a boulevard willrequire a unique and specialized designtreatment; therefore, no standards are providedin the Street Design Manual. Boulevarddesigners are referred to the design and policyguidelines found in The Boulevard Book citedabove.

1 Allan B. Jacobs, et al., MIT Press, 2000

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Source: Allan B. Jacobs, et al, The Boulevard Book, MIT Press, 2000.

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APPENDIX II–Land Use

A. Open SpaceLand protected for outdoor recreation andeducation, for scenic and visual enjoyment, andfor controlling urban form and design.Environmentally sensitive lands are alsopreserved in open space.

Open Space-Park Public parks and facilities, once they arededicated as park land, and providing for varioustypes of recreational needs of the community.

Open Space-ConservationLand preserved for the purpose of protectingnatural and cultural resources andenvironmentally sensitive lands.

Open Space-FloodplainLand within floodplains where development iscontrolled to protect the public health, safety, andgeneral welfare, and land areas identified by theflood insurance rate maps on file with the City ofSan Diego Floodplain Administrator.

B. AgricultureAreas that are rural in character and aredesignated for agricultural uses or are notdesignated for long-term agricultural use but areawaiting development at urban intensities.Includes all types of agricultural uses and someminor agricultural sales.

C. ResidentialLarge Lot Single Dwelling ResidentialSingle dwelling units on large lots with someaccessory agricultural uses. Applies to areas thatare rural in character. Lots are greater than 2.5acres. Densities are 0.4 dwelling units per acre orless.

Single Dwelling ResidentialSingle dwelling units on individual lots that have avariety of lot sizes and residential product types.Lot sizes range from 3,000 square feet to 2.5acres. Densities range from 0.4 dwelling units peracre to 8.7 dwelling units per acre.

Low Density Multiple Dwelling ResidentialTwo dwelling units per lot, with lot sizes rangingfrom 4,000 square feet to over 6,000 square feetand densities up to 21.8 dwelling units per acre.Includes townhouse developments with densitiesup to 19.8 dwelling units per acre.

Medium to Very High Density MultipleDwellingMore than two dwelling units per lot with densitiesranging up to 217.8 dwelling units per acre.

D. CommercialIncludes a wide range of uses for theemployment, shopping, services, recreational,and lodging needs of the residents and visitors tothe City of San Diego. Also includes mixed usedevelopment.

Neighborhood CommercialSmaller scale, lower density developments thatare consistent with the character of thesurrounding residential areas. May include mixeduse (commercial/ /residential). Primarily locatedalong local and selected collector streets.

Pedestrian-Oriented Commercial RetailDeveloped in a pedestrian-oriented pattern. Afunctional, convenient, and pleasant environmenthas been created for people arriving on foot,bicycle, and transit. Also accessible by theautomobile.

Community CommercialDevelopments with community-servingcommercial services, retail uses of moderate

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intensity and small-to-medium scale. Includesshopping centers and auto-oriented stripcommercial areas. Primarily located alongcollector streets, major streets, and publictransportation lines.

Regional CommercialHas the broadest mix of retail, wholesale,commercial service, and business/professionaloffice uses. Includes large scale, high intensitydevelopments. Primarily located along arterials,major streets, and major public transportationlines.

Commercial OfficeIncludes employment uses together with limitedcomplementary retail and medium-to-high densityresidential development.

Visitor CommercialProvides for the lodging, dining, and recreationalneeds of both tourists and the local population.

Urban VillageAn Urban Village is a compact pattern of land useincluding housing, public parks and plazas,offices, stores, and major transit stops on theexisting and planned transit system, wherepedestrian and bicycle activity is desired. UrbanVillages are characterized by interconnectedstreets, building entries along the street, andarchitectural features and outdoor activities thatencourage pedestrian and bicycle activity andtransit accessibility. Urban Villages have theirhighest intensity of development focused neartransit, and a mix of land uses convenient toresidents and employees.

E. IndustrialIncludes a wide range of industrial/manufacturingactivities.

Industrial ParkIncludes high quality science and business parkdevelopment in a campus-like environmentcharacterized by comprehensive site design andsubstantial landscaping.

Small Lot IndustrialSmall-scale industrial activities within urbanizedareas.

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APPENDIX III–References

A. Federal Government and Other NationalSourcesAmericans With Disabilities Act AccessibilityGuidelines, (ADAAG), Department of Justice;Title II, “State and Local Government Programsand Services,” and Title III, “PublicAccommodations and Commercial Facilities.”

A Policy on Geometric Design of Highways andStreets, American Association of State Highwayand Transportation Officials (AASHTO)

Manual on Uniform Traffic Control Devices,(MUTCD), Federal Highway Administration.

B. State Government and Other RegionalSourcesHighway Design Manual, California Departmentof Transportation (Caltrans).

Standard Plans, California Department ofTransportation.

Standard Specifications, California Department ofTransportation.

Title 24, Office of the State Architect, AccessCompliance Section.

Traffic Manual, California Department ofTransportation.

C. Local SourcesCentre City Streetscape Manual, Centre CityDevelopment Corporation (CCDC), latest version.

Designing for Transit, A Manual for IntegratingPublic Transportation and Land Development inthe San Diego Metropolitan Area, MetropolitanTransit Development Board (MTDB), latestversion.

Drainage Design Manual, City of San Diego,Engineering & Capital Projects Department,Transportation & Drainage Design Division.

Landscape Technical Manual, City of San Diego,Planning Department, Landscape PlanningSection; Document No. RR-274506, approved byCity Council on October 3, 1989.

Standard Special Provisions Street Lighting &Traffic Signal Systems of the City of San Diego,City of San Diego, Engineering & Capital ProjectsDepartment, latest version.

Transportation & Drainage Design Division;Document No. 769814, filed on October 21, 1993in the Office of the City Clerk.

Standard Drawings of City of San Diego, includesall San Diego Area Regional Standard Drawings;latest version.

Standard Specifications for Public WorksConstruction, latest version, with City of SanDiego Supplement Amendments and RegionalSupplement Amendments, Document No.769818, filed on February 2, 1995 in the Office ofthe City Clerk.

Transit-Oriented Development DesignGuidelines, prepared by Calthorpe Associates forthe City of San Diego; approved by the CityCouncil on August 4, 1992.

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APPENDIX IV–Midblock Pedestrian Crosswalk

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APPENDIX V–Summary of TrafficCalming Measures

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APPENDIX VI–Best ManagementPractices Available To Address StormRunoff Water Quality Associated withStreet Design

The 1972 Federal Clean Water Act establishedthe National Pollutant Elimination System(NPDES) permit program to regulate thedischarge of pollutants to waters of the UnitedStates. Governmental agencies in San DiegoCounty collect and discharge storm water andurban runoff containing pollutants through theirstorm water conveyance systems. Theseagencies, including the City of San Diego,implement programs to reduce pollutants underNPDES permit requirements commonly known asthe Municipal Storm Water Permit for San DiegoCopermittees. The City of San Diego iscommitted to protecting and improving waterquality of the rivers, bays, and ocean in theregion, and achieving Municipal Permitcompliance. To comply with the Municipal Permit,the City will “enforce the use of storm water BestManagement Practices (BMPs) to prevent orreduce discharges of pollutants to the municipalstorm drain system.”

The intent of this appendix is to providedevelopers, project engineers, and planners withsite design concepts or BMPs that couldpotentially be incorporated into the design ofstreets to address adverse impacts to waterquality associated with storm water runoff. It isimportant to note that other City regulations,including, but not limited to, the Storm WaterStandards (scheduled to become effectiveDecember 2, 2002), will dictate the mandatorysite design, source control and treatment controlrequirements related to development projects ofall types, including streets.

The feasibility of using a BMP listed in thisappendix should be evaluated by project

engineers on a project-by-project basis. CertainBMPs discussed in the appendix may not beappropriate for a street classification due toconstraints associated with site conditions.

A. Effect of Storm Water Runoff From Streetson Water Quality

Storm water runoff from streets contains a varietyof pollutants collected and concentrated fromimpervious surfaces (1) . Streets and othertransportation structures typically can comprisebetween 60 and 70% of an urban city’s totalimpervious area and, streets are almost alwaysdirectly connected to an underground stormwater system(1). Pollutants collect on impervioussurfaces and are conveyed into the storm drainsystem in higher concentrations following a rainevent. Discharge of concentrated pollutants fromimpervious surfaces to the storm drain systemafter a significant rain event is referred to as the“first flush”.

Urban runoff from a developed site includingstreets has the potential to contribute pollutants,including oil and grease, suspended solids,metals, gasoline, pesticides, and pathogens tothe storm water conveyance system andreceiving waters(2). Primary sources of oil andgrease in storm runoff are petroleumhydrocarbon products, motor products fromleaking vehicles, esters, oils, fats, waxes, andhigh molecular-weight fatty acids(2). Introductionof these pollutants to the water bodies are verypossible in association with typical developmentprojects due to the wide uses and applications ofsome of these products in municipal, residential,commercial, industrial, and construction areas(2).Elevated oil and grease content from, in part,automobile sources can decrease the aestheticvalue of the water body, as well as the waterquality(2) .

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B. Site Design Best Management Practices forRoadways

A BMP incorporated into a street design isprimarily intended to minimize the amount ofimpervious surface. A goal of project site designshould involve constructing streets, sidewalksand parking lot aisles to the minimum widthsnecessary, provided that public safety and awalkable environment for pedestrians are notcompromised.

The design of private roadway drainage shouldconsider using at least one of the following (forfurther guidance, see Start at the Source [1999]).(Note: the City may impose the following andother requirements to private roadway designsthrough the Storm Water Standards [scheduledto be implemented on December 2, 2002].Consult the Development Services Departmentfor more information.

• Rural swale system: street sheet flows tovegetated swale or gravel shoulder, curbs atstreet corners, culverts under driveways andstreet crossings;

• Urban curb/swale system: street slopes tocurb, periodic swale inlets drain to vegetatedswale/biofilter;

• Dual drainage system: First flush captured instreet catch basins and discharged toadjacent vegetated swale or gravel shoulder,high flows connect directly to storm waterconveyance system.

• Other methods that are comparable andequally effective within the project.

Private roadways for storm water requirementpurposes are defined as low traffic private roads.However, use of these type of site design BMPscould be applied to public road classifications.Descriptions of these systems are discussedbelow.

1. Descriptions of Best Management Practices forUrban Curb/Swale System Roadways

For streets where a rigid pavement edge isrequired, curb and gutter systems can bedesigned to empty into drainage swales. Runofftravels along the gutter, but instead of beingemptied into a catch basin, multiple openings inthe curb direct runoff into surface swales orinfiltration/detention basins(1). The urban curb/swale system design would be appropriate forLocal Street, Collector Street, Major Street,Primary Arterial, Expressway and Freewayclassifications that require use of curb and gutter.

a. Urban Curb/Swale Inlet Design

Typical, curb and gutter systems collect runoffinto an underground pipe system. A swale inletcollects runoff into a surface infiltration system. Adiagram and section of a typical urban curb/swalesystem are shown in Figures 1 and 2. The swaleinlet includes features such as cobbles todissipate flow velocities and minimize erosionfrom initial first flush of runoff. Swales removedissolved pollutants, suspended solids (includingheavy metals, nutrients), oil and grease byinfiltration using the following features: 1) runoffthrough the swale topography that collects waterin a forebay/ settlement basin prior to discharge;and 2) infiltration of runoff into groundwaterthrough vegetative surface layer or Biofilter. (1)

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Figure 1Urban Curb/Swale System-Diagram(1)

b. Surface Vegetated Swale/Bio Filter Design

Vegetated swales used in the urban curb/swaledesign are vegetated earthen channels thatconvey and infiltrate water and removepollutants. A grass swale is planted with turfgrass; a vegetated swale is planted with bunchgrasses shrubs or trees. (1) A photograph as wellas sections of typical vegetated swale are shownin Figures 3 and 4.

Figure 3Vegetative Swale Design Section(1)

Appendix

Figure 2Urban Curb/Swale Inlet Design Section(1)

Figure 4Vegetative Swale – Southbound Interstate 5 nearLa Costa Avenue Offramp

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2. Descriptions of Best Management Practices forRural Swale System Roadway Classifications

Rural swale systems are a combination of streetdesign elements that allow for surface drainagewhile simultaneously protecting the roadwayedge, organizing parking and allowing fordriveway access. (1) A section of a typical ruralswale system is illustrated in Figure 5. As shownin Figure 5, curb and gutter is not required. Thestreet is crowned to direct runoff to shoulderswhere it is collected into a vegetated swale orgravel shoulder. The rural swale system would beappropriate for Private Street, Rural Local Roadand Rural Collector Road classifications.

Figure 5Rural Swale System Diagram(1)

3. Description of Best Management Practices forDual Drainage Systems

Dual drainage systems provide a pair of catchbasins at each inlet point. The first is sized todirect the water quality volume into a landscapedinfiltration area, and the second collects theoverflow of larger storms and directs it to thestorm drain system. A section of a typical dualdrainage system is shown in Figure 6. (1) TheDual Drainage system design would beappropriate for Local Street, Collector Street,Major Street, Primary Arterial, Expressway andFreeway classifications that require use of curband gutter.

As shown in Figure 6, in a dual drainage systemtwo catch basins are located adjacent to eachother. The first uphill catch basin involves adesign outlet pipe to accommodate the waterquality volume and direct to adjacent grass orvegetated swale. When first catch basin is full,water will flow past first basin inlet and entersecond catch basin. (1)

Appendix

Figure 6Dual Drainage System Diagram(1)

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4. Description of Best Management Practices forConcave Medians

Conventional medians are normally designed asa convex surface to shed water onto adjacentpavement and into a curb and gutter system.Concave medians reverse this relationship bydesigning the median to receive runoff. (1) Adiagram and section of a typical concave medianis shown in Figure 7.

The infiltration portion of the landscape mediancan be designed as a landscaped swale or turf-lined biofilter to treat first-flush runoff. Catchbasin and underground storm drain systems maybe required for high flows depending on theavailable area for infiltration and the duration thatwater is retained in the swale. (1)

Figure 7Concave Median Diagram and Section (1)

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5. Description of Best Management Practices forCul-de-sacs

Typical cul-de-sacs are paved across their entirediameter. This large impervious area adds toenvironmental degradation by increasing runoff.Adding a landscaped area in the center of thecul-de-sac (See Figure 8) can reduce imperviousland coverage by 30-40%, depending onconfiguration, while maintaining the requiredturning radius. (1)

Figure 8Cul-de-sac Best Management Practices (1)

Appendix

References

1. Start at the Source, Bay Area StormwaterManagement Agencies Association, 1999.

2. Reference Guide for Stormwater BestManagement Practices, City of Los AngelesStormwater Management Division, July 2000,www.lacity.org/SAN/wpd/index.htm.

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APPENDIX VII – Transit Streets

The Strategic Element of the City of San DiegoProgress Guide and General Plan and the TransitFirst initiative of the Metropolitan TransitDevelopment Board recommend majorimprovements to the region’s transit system.These improvements include a system of rubbertire trolleys operated on separate rights-of-waywithin road alignments.

The first phase includes several “showcase” pilotprojects; and, each of them will require a specialand unique design solution. This design manualsets forth basic design guidelines for the designof transit streets.

Reference: Designing for Transit, A Manual forIntegrating Public Transportation and LandDevelopment in the San Diego Metropolitan Area.MTDB, July 1993.

The following includes few examples of how toaccommodate exclusive transit lanes within thepublic right-of-way.

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Transit Lanes – Four Lane Urban Collector

Transit Lanes – Four Lane Urban Major

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Transit Lanes – Four Lane Major

Transit Lanes – Six Lane Urban Major

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Transit Lanes – Six Lane Primary Arterial

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APPENDIX VIII–Deviation From Standards Form

Appendix

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