Street Designs

7/30/2019 Street Designs

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Te location and shape o curb lines exerts a stronginuence on pedestrian comort and usability o streets aspublic spaces. Tis chapter describes pedestrian-orientedguidelines or curb lines, crosswalks and other streetdesign eatures to enhance pedestrian saety and comortand enable generous, usable public spaces

G U I D E :

STREET DESIGNS

C H A P T E R

5.0STREET DESIGNS5.1 Crosswalks and Pedestrian Signals

5.2 Corner Curb Radii

5.3 Curb Extensions (Bulb-Outs)

5.4 Medians and Islands

5.5 Transit-Supportive Streetscape Design

5.6 Parking Lane Treatments

5.7 Traffic Calming and Roundabouts

5.8 Pedestrian-Priority Designs


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Marked crosswalks

are an essential parto the pedestrianrealm that enablesae, convenientpedestrian travelacross roadways.

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Crosswalk Markings

Marked crosswalks are an essential tool or helping pedes-trians move saely, conveniently and predictably acrossroadways. When treated with decorative paving material,crosswalks also provide a unique streetscape design treat-ment to emphasize pedestrians presence and primacy.

Marked crosswalks alert drivers to expect crossing pedestri-ans and to direct pedestrians to desirable crossing locations marking crosswalks at every intersection is not necessaryor desirable. Although many motorists are unaware otheir precise legal obligations at crosswalks, the CaliorniaVehicle Code requires drivers to yield to pedestrians in anycrosswalk, whether marked or unmarked.

Streetscape design should emphasize crosswalks as a un-

damental part o the pedestrian realm, not as an intrusioninto the roadway reserved or vehicles only.

Placement

Crosswalks are present by law at all approximately rightangle intersections, whether marked or unmarked, unlessthe pedestrian crossing is specically prohibited. At mid-block locations, crosswalks only exist where marked. Atthese non-intersection locations, it is the crosswalk mark-ings that legally establish the crosswalk. Most importantly,the decision to mark a crosswalk should not be considered

Crosswalks and Pedestrian Signals

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in isolation, but rather in conjunction with other measuresto increase motorists awareness o pedestrians. Withoutadditional measures, marked crosswalks alone are unlikelyto increase pedestrian saety and may decrease saety, par-ticularly on multi-lane streets. Follow SFMA crosswalkguidelines in determining when to stripe new crosswalks.

Controlled Intersections

Intersections can be controlled by trac signals or SOPsigns. Per existing City policy, marked crosswalks shouldbe provided on all intersection legs controlled by tracsignals, unless the pedestrian crossing is specically prohib-ited. Crosswalks may be considered at all SOP-controlledintersections. SFMA has developed detailed guidelineson when to stripe crosswalks at controlled intersections.Factors to be considered include: high pedestrian volumes,vehicle volumes, school zone location, substantial volume

o elderly or disabled use, or other saety reasons.

Uncontrolled Intersections

Intersections without trac signals or SOP signs are con-sidered uncontrolled intersections. Te decision to marka crosswalk at an uncontrolled location should be guidedby an engineering study. Factors considered in the studyinclude vehicular volumes and speeds, roadway width andconguration, stopping sight distance, distance to the nextcontrolled crossing, night time visibility, grade, and pedes-trian volumes.

See the SFMA crosswalk guidelines or direction on when

to stripe crosswalks at uncontrolled intersections.

High-Visibility Crosswalks

Because o the low approach angle at which pavementmarkings are viewed by drivers, the use o longitudinalstripes in addition to or in place o the standard trans-verse markings can signicantly increase the visibility oa crosswalk to oncoming trac. While research has notshown a direct link between increased crosswalk visibilityand increased pedestrian saety, high-visibility crosswalkshave been shown to increase motorist yielding and chan-nelization o pedestrians, leading the Federal HighwayAdministration (FHWA) to conclude that high-visibility

pedestrian crosswalks have a positive efect on pedestrianand driver behavior.

San Francisco has chosen to utilize continental crosswalksor high-visibility crosswalk locations. Maintenance andinstallation o high-visibility continental crosswalks costsmore than standard crosswalks. Despite their added costand the lack o hard evidence pointing to their saetybenets, many cities see continental crosswalks as a cost-efective way to improve the walking environment and tosend a message that pedestrians are present. For this reasonthey are oten employed even at controlled locations thatare neither near schools nor at mid-block locations yet stilldeserve extra attention.

In San Francisco, continental crosswalks have typicallybeen employed only at school crossings and mid-blocklocations. Te SFMA plans to expand the use o conti-nental crosswalks to some uncontrolled intersections.

Mid-Block CrosswalksIn areas with short block lengths, closely-spaced intersec-tions ensure that pedestrians can easily nd crosswalkswithout having to go out o their way, but many areas havelong blocks with widely-spaced intersections and ewercrossing opportunities. Mid-block crosswalks may providea convenient crossing or pedestrians when other crossingopportunities are distant, or where a destination createshigh crossing demand.

See the SFMA crosswalk guidelines or direction onwhen to stripe mid-block crosswalks. Site-specic analysisand environmental clearance would be required or any

proposed mid-block crossing to identiy whether it wouldresult in or contribute to unacceptable levels o service ordelay to transit vehicles.

Design

Crosswalks should be at least as wide as the sidewalk, butmay be wider in locations with high pedestrian demandor narrow sidewalks. Crosswalks should be no less than10 eet in width. Crosswalks must be outtted with curbramps and tactile warning strips per ederal accessibilityguidelines. Te Caliornia Manual on Uniorm racControl Devices (MUCD) contains standards andguidance on crosswalk warning signs and supplementary

markings.

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Drivers view of crosswalk markings.Source: ITE Professional Development Complete Streets

Typical crosswalk markings.Left to right: Standard, Continental, Ladder, Staggered Continental


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Standard Crosswalks

Te standard treatment or marked crosswalks at inter-section locations consists o two 12 inch-wide white

retro-reective thermoplastic stripes that delineate the sideso the pedestrian walking area. Te stripes should be per-pendicular (or transverse) to the direction o vehicle traveland parallel to the direction o pedestrian travel. Schoolcrosswalks must be yellow per state code; in San Francisco,school crossings should be given a yellow, continentalcrosswalk treatment.

High-Visibility Crosswalks

High-visibility crosswalks should be marked using thecontinental pattern o crosswalk striping, which consistso a series o wide stripes parallel to the curb or the lengtho the crossing. (Tese are distinguished rom laddercrosswalks, which retain the transverse side stripes o thestandard crosswalk in addition to the wide rungs o theladder, or zebra crosswalks, which have diagonal stripes.See diagram on previous page.)

suppleMentary pedestrian Crossing

treatMents

Pedestrian Warning SignsPedestrian warning signs are used to alert road users tothe potential presence o pedestrians. Teir use shouldollow MUCD guidance and be limited to locationswhere pedestrians may make unexpected entries into theroadway or where drivers sight distance is restricted. InSan Francisco, placement o pedestrian warning signs hashistorically not ollowed this guidance, leading to an over-prolieration o the signs and a consequent dilution o theirefectiveness. Te City should review the placement oits existing pedestrian warning signs and remove them atunwarranted locations, potentially increasing their impactwhere they are most needed.

Advance Stop and Yield Lines

Stop lines (or limit lines) are solid white lines 12 to 24inches wide, extending across all approach lanes to indicatewhere vehicles must stop in compliance with a stop signor signal. Advance stop lines reduce vehicle encroachmentinto the crosswalk and improve drivers view o pedestrians.

On multilane roads, advance stop & yield lines can be anefective tool or preventing multiple threat vehicle andpedestrian collisions. SFMA has developed guidelines orthe installation o advanced stop lines consistent with the

national guidance ound in section 3B.16 o the MUCD,which allows or their use rom 4 to 50 eet in advance ocrosswalks, depending upon location-specic variables suchas vehicle speeds, trac control, street width, on-streetparking, potential or visual conusion, nearby land useswith vulnerable populations, and demand or queuingspace.

Yield lines are another option that can be used to reducethe possibility o multiple threat collisions at uncontrolledcrosswalks on multi-lane roadways. Tey consist o a singlerow o white triangles placed across each approach to indi-cate the point at which vehicles must yield, and may beplaced a minimum o 4 eet in advance o uncontrolled

marked crosswalk locations.

In order to provide high-visibility crosswalks while mini-mizing increases to maintenance costs, the SFMA plansto implement a pilot installation o a staggered conti-nental crosswalk, with the longitudinal stripes positionedto avoid vehicle wheel paths as much as possible, reduc-ing wear. Tis strategy has been employed successully inWashington, Oregon, and Colorado or many years.

Mid-Block Crosswalks

Mid-block crossings should:

be enhanced through the use o signage, striping, sig-nalization, or other special treatments such as ashingbeacons, special paving materials, or raised crossings;

be constructed in combination with mid-block curbextensions (see Curb Extensions, Section 5.3); and

include pedestrian lighting oriented toward thecrossing.

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5.1 CRoSSwalkS aND pEDESTRIaN SIGNalS

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The staggered continental crosswalk increases crosswalk

visibility but positions stripes to avoid vehicle wheels,

reducing maintenance burdensMid-block crossings

improve pedestrian

convenience, especially

on long blocks.


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Flashing Lights and Beacons

In-roadway ashing lights are intended to call extra atten-tion to pedestrians in crosswalks where signage or other

design treatments are deemed insucient. Te asherscan be activated passively with inra-red or microwavedetectors, or actively by pedestrian push-buttons. In SanFrancisco and elsewhere, in-roadway ashing lights havenot perormed well due to ongoing maintenance issues.In San Francisco, little or no efect on injury collisions hasbeen discernible (or lack o collisions), but measurableincreases in motorists yielding to pedestrians have beenound.

Section 4L.02 o the MUCD provides a list o actors toconsider (including vehicle and pedestrian volume thresh-olds) when evaluating the need or in-pavement warninglights at crosswalks, as well as standards or their installa-

tion and operation.

I reliability can be improved, in-pavement ashing cross-walks should be considered at high-conict uncontrolledcrossing locations with posted speeds under 35 mph andsignicant pedestrian volumes that require extra visibility.

Flashing beacons can be used to control trac at intersec-tions where trac or physical conditions do not justiya ull signal but crash rates indicate the possibility o aspecial need, or to provide supplementary warning o amidblock or uncontrolled school crosswalk. Tey shouldbe considered or use at high-conict uncontrolled crossinglocations with signicant pedestrian volumes where visibil-ity is compromised by grades, curves, or other conditions.

Chapter 4K o the MUCD provides guidance or the useo ashing beacons.

Parking Restrictions at Crosswalks

Red parking zones on approaches to crosswalks improvesight distance between pedestrians and approachingmotorists and are recommended in the MUCD or

both controlled and uncontrolled intersections. In SanFrancisco, a minimum 10 oot red zone should be paintedon all crosswalk approach legs. Longer red zones shouldbe used at locations with a greater need or improved vis-ibility due to unique sight distance, geometric, or otherconditions.

In San Francisco, due to l imited on-street parking supplyand high demand, the practice has been to allow parkingup to intersections unless there are location-specicgrounds or parking removal. Te new 10 oot minimumguideline will be implemented on a case-by-case basis asresources allow. Priority should be given to intersectionswith saety issues, existing project locations, and loca-tions where staf is conducting saety reviews. SFMAsCrosswalk guidelines should be consulted or urther guid-ance regarding red zones.

Special Intersection Paving

Special intersection paving treatments can break thevisual monotony o asphalt streets, highlight crossings asan extension o the pedestrian realm, and announce keycivic or commercial locations. Special intersection pavingtreatments include integrated colors, textures, and scoringpatterns. Tey may be instituted within crosswalk mark-ings or across an entire intersection.

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Pedestrian

warning sign

Advance yield lines (top) alert drivers to an impending

crosswalk; advance stop lines (bottom) require vehicles to

stop in advance of a crossing


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Special decorative paving, including colored and/or t ex-tured concrete, asphalt or pavers, or any similar treatmentdoes not dene a crosswalk and should not be seen as asaety measure. Standard transverse or longitudinal high

visibility crosswalk markings are still required.

Special intersection paving treatments are more costlyto build and maintain than standard treatments. Wherecapital and maintenance budgets all ow, they may be con-sidered on:

streets important to the city pattern;

commercial streets;

at entries to residential areas where residential streetsintersect with higher volume streets;

at key civic locations, such as civic buildings or entriesto open spaces; and

at mid-block crosswalks.

Paving treatments should:

use integrated color, texture, and pattern. Potentialmaterials include but are not limited to colored andstamped asphalt, poured concrete, and stone or con-crete pavers;

provide a surace that does not cause discomort dueto excessive vibration to those u sing wheelchairs orother assistive mobility devices;

use stable, durable, and slip resistant materials perDPW Directors Order 176,112;

include edging treatments to visually contrast with theprimary material and with the asphalt roadway; and

include crosswalk striping (parallel white lines) on theouter edge o the crossing.

See also Section 6.4: Paving.

Raised Crosswalks and Intersections

Raised crosswalks bring the level o the roadway to thato the sidewalk, orcing vehicles to slow beore passing

over the crosswalk and providing a l evel pedestrian patho travel rom curb to curb. Raised crosswalks can belocated at intersections or mid block. At intersection loca-tions, the raised area can be extended to include the entireintersection.

Raised crosswalks should be considered:

as a standard treatment at alleys and shared publicways;

where low-volume streets intersect with high-volumestreets, such as at alley entrances, neighborhood resi-dential streets, and local access lanes o multi-way

boulevards;where a street changes its unction or street type. Forexample, a commercial throughway may become aneighborhood commercial or a residential street as theland uses along it change; and

at key civic locations.

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Raised crosswalks make pedestrian crossing

easier and safer for pedestrians by more

overtly continuing the sidewalk across an

intersection, not only making crossings more

visible to drivers, but physically requiring

them to slow.

Special crosswalk treatments may include a raised

crosswalk, colored paving treatment, and trees in theparking lane

Raised crossing at Octavia and Hayes Streets


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Raised crosswalks should not be used on designated transitroutes or where there are steep grades or sharp curves.

Raised crosswalks should:

be ush with the sidewalk in height, and at least thewidth o the crossing or intersection;

be long enough in the direction o travel to allow bothront and rear wheels o a passenger vehicle to be ontop o the table at the same t ime - typically 10 eet.Specic lengths should be determined by using theIE/FHWA document rac Calming: State o thePractice;

be instituted in combination with special paving treat-ments as discussed above, or use the same material asthat o adjacent sidewalks;

provide detectable warnings where pedestrians willcross into the vehicle area;

be designed such that the vertical transition does notcause unnecessary jarring or discomort to vehicle pas-sengers with spinal cord injuries when driven over atthe appropriate speed; and

consider resulting drainage patternsdepending ongrade, this may necessitate additional catch basins,trench drains, or other measures;

Pedestrian refuge islands

Crosswalks may also include pedestrian reuge islandsto break up the crossing and slow cars. See Section 5.4:Medians and Islands.

pedestrian signals

Pedestrian signal indications should be used at all tracsignals. Te international pedestrian symbol signal should

be used rather than WALK/DON WALK text.

Pedestrian Signal Timing

Pedestrian signals should allow sucient time or pedes-trians to cross the street, including seniors, children, andpeople with disabilities.

Historically, a standard walking speed o 4.0 eet persecond has been used to calculate the minimum pedes-trian clearance interval (the ashing red hand plus yellowand any all-red) or pedestrian signals in San Francisco. Inanticipation o upcoming changes to ederal standards, the

City has reduced the walking speed used to time the pedes-trian clearance interval to 3.5 eet per second. In nearly alllocations in the City, signals allow pedestrians walking asslow as 2.5 eet per second to cross the entire street i theystep of the curb at the beginning o the walk phase.

Walking speed is a unction o the age and physical abilityo the population. Te walking speed used to calculate the

In-roadway flashing

lights enhance

crosswalk visibility

Flashing beacon (at left)

pedestrian clearance interval should closely match thato pedestrians in San Francisco, including seniors, chil-dren, and people with disabilities. San Francisco is alsoexperimenting with video detection systems to give slower

pedestrians additional crossing time. As a next step, SanFrancisco should conduct studies to determine i slowerwalking speeds are appropriate and, i so, what thosespeeds should be.

Pedestrian scrambles: Exclusive pedestrian phases (i.e.pedestrian scrambles) may be used where turning vehiclesconict with very high pedestrian volumes and pedestriancrossing distances are short.

Pedestrian head-start signals: Leading pedestrian inter-vals, which give pedestrians a head start beore vehicles aregiven the green, may be considered at signalized intersec-

tions with a high incidence o pedestrian conicts andright-o-way violations.

Pedestrian-actuated signals: In San Francisco, signals onshort, xed time cycles should generally be used rather thanactuated signals (pedestrian push-buttons) to allow con-sistent crossing opportunities. Pedestrian actuation shouldonly be used when pedestrian crossings are intermittent, at

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locations with relatively long pedestrian clearance time thatcan result in excessive delay to transit vehicles, and to acti-vate audible pedestrian signals or to provide an extendedWALK interval. Since many pedestrians ail to notice

pushbutton devices, additional research on passive videoand inra-red detection should be conducted.

imed progression o trac signals should ensure that su-cient time is allocated per cycle or pedestrian crossings.

Pedestrian countdown signals

Pedestrian countdown signals are designed to enhance theefectiveness o pedestrian signals at clearing the crosswalkbeore a signal changes direction. Surveys show that mostpeople misinterpret the meaning o the ashing hand othe traditional pedestrian signal. Providing the pedestrian

countdown device helps pedestrians better interpret thepedestrian signals. Countdowns also enable pedestrians tostop on a median reuge, where provided, and wait or thenext phase i they nd the time let to be too short to nishcrossing. Pedestrian countdown signals have been shown tohave a 25% reduction in pedestrian injury collisions.

VehiCle turning MoVeMents at Crosswalks

Right Turn on Red

Te Caliornia Vehicle Code allows drivers to turn right onred ater coming to a complete stop, unless prohibited bya sign. Right turn on red (ROR) prohibitions can be animportant tool or increasing pedestrian saety at certainintersections. Under some circumstances, prohibitingROR can reduce conicts and collisions, and it detersmotorists rom blocking the perpendicular crosswalk whilethey inch orward to turn. On the other hand, prohibitingROR may mean increased vehicle delay, including delayto transit. ROR prohibition can also lead to more con-icts during right turns on green, since turning motoristsmust now wait to turn while pedestrians are crossing withthe green light.

Te MUCD and the Institute o ransportationEngineers suggest considering the prohibition o RORunder the ollowing circumstances:

inadequate sight distance to vehicles approaching romthe let (or right, i applicable);

geometrics or operational characteristics o the inter-section that might result in unexpected conicts;

an exclusive pedestrian phase;

an unacceptable number o pedestrian conicts withright-turn-on-red maneuvers;

Pedestrian countdownsignal and accessible

pedestrian signal

Pedestrian scrambles allow a dedicated signal

phase for pedestrians to cross in any direction

at an intersection

Pedestrian countdown signals should be provided at all sig-nalized intersections.

Accessible pedestrian signalsAccessible pedestrian signals (APS) provide inormation innon-visual ormat such as audible tones, verbal messages,and/or vibrating suraces. Te MUCD addresses specicpushbutton design and placement or APS and containsstandards on audible tones, verbal messages and vibro-tactile devices. San Franciscos observations have shownthat APS benets all pedestrians by providing audible andvibro-tactile cues.

APS should be provided at all new signalized intersec-tions. Existing signals should be retrotted over time, usingthe SFMAs APS Prioritization ool, developed using

the drat version o the National Cooperative HighwayResearch Program (NCHRP) APS Prioritization ool, inconsultation with the Mayors Oce on Disability andindividuals and advocacy groups representing the visuallyimpaired community.

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heavy volume o pedestrian crossings;

request rom pedestrians with disabilities using theintersection;

school crossings;

railroad crossings; and

trac signals with three or more phases.

Beyond the conditions listed above, the City also considershigh speeds on cross streets and a veried collision historycaused by ROR maneuvers. As o 2007, signs were postedon one or more approaches o 14% o all signalized inter-sections citywide (169 out o 1,166).

San Franciscos practice o considering ROR prohibi-

tion at intersections on a case-by-case basis should becontinued, subject to the gu idelines listed above. RORprohibitions may be considered at intersections that:

have ewer than 300 cars making the right turn perhour; and

do not have curb-running transit with near-side transitstops.

At intersections that do not meet all o these criteria,ROR prohibitions may still be appropriate pursuant toadditional study and environmental review.

Multiple turn lanes

Compared to single turn lanes, multiple turn lanes decreasepedestrian comort and increase potential conicts betweenturning vehicles and pedestrians crossing concurrently withthe vehicular turning movement. Saety may be compro-mised i one turning vehicle obscures the drivers view opedestrians in the crosswalk rom a second, trailing vehiclein an adjacent turn lane. Multiple turn lanes may also com-promise bicycle saety.

Te presence or absence o multiple turn lanes is not byitsel a predictor o an intersections propensity to gener-ate pedestrian collisions. It is important to consider howremoving a multiple turn lane and requiring the same

number o vehicles to turn rom one lane will afect pedes-trian and vehicular saety. However, pedestrian perceptiono saety and conict reduction is also an important con-sideration in intersection design.

Multiple turn lanes should be avoided wherever possible.No new multiple turn l anes with conicting vehicle/pedes-trian movements should be built in San Francisco. Existingmultiple turn lanes should be pro-actively eliminated ormitigated.

Feasibility o multiple turn lane removal is contingentupon vehicle level o service, queuing, transit operations,

and upstream trac saety considerations. Even i consid-eration o these criteria do not point to removal o multipleturn lanes, it may still be advisable to make lane assign-ment changes i there is a documented history o relevantcollisions involving pedestrians, and other attempted miti-gations have proven inefective.

I removal is not possible, the City should consider poten-tial mitigations or multiple turn lane conditions ound tobe problematic. Strategies to mitigate problematic multipleturn lane conditions include the ollowing:

separate pedestrian and turning movements;

leading pedestrian intervals;

permissive-protected signal phasing (pedestrian cross-ing phase ends beore vehicle phase);

limited hours o multiple turn lanes;

parking restrictions; and

signs and enorcement.

Crosswalk Closures

San Francisco has a number o closed crosswalks, creat-ing discontinuous pedestrian paths o travel and making

walking inconvenient. A primary motivation or closingcrosswalks is to saeguard pedestrians in the ace o veryhigh trac volumes or speeds and auto-oriented design,but many times pedestrians ignore crosswalk closuresrather than crossing three times to reach a destination thatcould be reached by one illegal crossing, creating additionalsaety issues.

New crosswalk closures should not be instituted.

Existing closed crosswalks should be evaluated or opening.Tis may necessitate additional saety measures such aspedestrian actuation and signal timing changes. Reopening

o crosswalk closures will require site-specic analysis andenvironmental review. At the time the study is undertaken,the efects o removal o crosswalk closure would be evalu-ated or its impact on the physical environment.

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Intersection leg closed to pedestrian crossing


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Curb raMps

Curb ramps provide pedestrian access between the side-walk and roadway or people using wheelchairs, strollers,

walkers, crutches, handcarts, bicycles, and pedestrians whohave trouble stepping up and down high curbs.

Curb ramps must be installed at all intersections and mid-block locations where pedestrian crossings exist per ADAguidelines. Curb ramps are required at mid-block locationsto access on-street accessible parking spaces, where pro-vided, and at all new passenger loading zones. New curbramps should be prioritized per the Citys ADA transitionplan or sidewalks and curb ramps.

Guidelines

Curb ramps must comply with DPW standard plans. ADArequired slopes and dimensions are detailed in DPW CurbRamp Standard Plans CR-1 through CR-6 and summa-rized in the gure below.

Per standard plans, curb ramps should be installed parallelto the direct path o travel across an intersection. At our-way intersections, two curb ramps should be installed ateach corner.

At raised crossings or intersections or other ush transi-tions between the sidewalk and the roadway, curb rampsare not necessary, but detectable warning strips must beprovided. A 3 oot deep detectable warning surace isrequired where the ramp, landing, or blended transitionconnects to a crosswalk.

On new streets, storm drainage inlets should be placed onthe uphill side o curb ramps to prevent standing water atcurb ramp landings.

Small planting areas can be installed at corners on eitherside o curb ramps as shown in the diagram below.

Curb ramps and crosswalks should remain clear oobstacles. Existing conicting elements should be movedas opportunities and budgets allow. No new pole, utilityor other impediment should be placed in the curb rampreturn areas.

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Cross-slope

2%M

ax.

48 inch

Minimum

48inch

Minimum

5%M

ax.

within24inches

ofcurbramp

Down

8.3

%M

ax.

(1:12slope)

10% Max.10% Max.

Accessible curb ramps

Accessible curb ramps should be provided

at all corners, one per crosswalk end


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Te length oa corner radius

can have asignicant efect

on the overall

operation andsaety o an

intersection.

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Te shape o a corner curb radius (the radius dened bytwo sidewalks on perpendicular streets that come togetherat a corner) has a signicant efect on the overall operationand saety o an intersection. Smaller turning radii increase

pedestrian saety by shortening crossing distances, increas-ing pedestrian visibility, and decreasing vehicle turningspeed.

Te shape and dimensions o curb radii vary based onstreet type and transportation context

definitions

Design vehicle:selected vehicle type used in determiningappropriate turn radius at an intersection

Design or [a vehicle turn]: to allow or a particular vehicletype to complete a turn ully within its designated travellane or lanes

Accommodate [a vehicle turn]: to allow or a particularvehicle type to complete a turn with latitude to use adja-cent or opposing lanes on the origin or destination streets

Curb radius: the actual radius proscribed by the curb lineat an intersection

Efective radius: Te radius available or the design vehicleto make the vehicle turn, accounting or the presence oparking, bike lanes, medians, or other eatures

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EFFECTIVE RADIUS: Where a curbside parking and/or bicycle

lane is present, the effective radius of the turn is increased.

guidelines

Curb radii should be designed to maximize pedestrianspace and shorten pedestrian crossing distance to the great-est extent easible; the smallest possible curb radius should

be used while allowing vehicle movements as describedbelow.

Te efective turning radius, not the curb return radius,should always be used to determine the ability o vehiclesto negotiate a turn.

Tese guidelines provide a general overview o the bulb-outdesign process. However, curb radius design is sensitive toa wide range o variables; these guidelines cannot replaceproessional judgment and technical analysis. Each projectshould consider the particular characteristics o the site,and adjust the design as necessary.

Design vehicles

Determining a design vehicle should consider and balancethe needs o the various users o a street, rom pedestriansand bicyclists to emergency vehicles and large trucks, con-sidering the volume and requency o these various users.Te designer should distinguish between designing orand accommodating the needs o large vehicles (see de-nitions above).

For example, on designated transit or reight routes withrequent large turning vehicles, streets should be designedor these vehicles. Where large vehicles are occasionalusers o a street, there are low trac volumes, or othercharacteristics such as high pedestrian volumes necessitatetaking greater measures or pedestrian saety and comort,designers may consider accommodating these vehicles.

General conditions

General conditions apply to all streets where conditions arepresent as described below.

Emergency vehicles: All streets greater than 150 in lengthshould accommodate emergency vehicle (WB-40) turnswithin the ull right-o-way o the intersection. Becauseemergency vehicles have sirens and ashing lights andother vehicles must pull over, they can typically use the ullright-o-way without encountering opposing vehicles. Onbusier streets, the ability o emergency vehicles to swingwide may be limited by queued trac which may not be

able to pull over.

ransit routes: ransit routes include transit service routesas well as routes transit vehicles use to start their run andreturn to the yard. At intersections where buses makedesignated turns, streets should be designed or a B-40bus. On some Muni community routes, Muni may use aB-30 check with SFMA. On other corners along Muniroutes, where buses may have to make occasional detours,turns should accommodate a Muni vehicle using the entireroadway, similar to an emergency vehicle.

To accommodate a vehicle turn

To design for a vehicle turn (left)

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Other transit considerations include:

o determine whether a particular intersection is usedby transit vehicles to start their run or return to the

yard, check with SFMA.

On trolley bus routes, overhead wire locations deter-mine the turning envelope or the bus. No curb radiusshould be constructed that orces the bus to deviatemore than nine eet on center rom the middle othe overhead wires. On Muni LRV routes, the curbradius should be constructed such that no part o thesidewalk is closer than two eet rom the dynamicenvelope o a turning LRV. Tese routes must alsoaccommodate historic streetcars.

On streets where other transit providers are present,the curb radius should be designed or their transitvehicles as well.

Consideration should also be given to private transitoperators in areas where large tourist buses and vansare likely to conduct business on a regular, ongoingbasis.

Freight routes: Freight routes are streets that are designatedas Routes with Signicant ruck rac on Map 15 inthe ransportation Element o the General Plan. Freightroutes should be designed or WB-50 trucks. Larger WB-

60 trucks may also be present on City streets, particularlyon designated state highways and in industrial areas. Tesemay need to be accommodated in certain instances, thoughthey are not practical in most o San Francsico.

Standard street types

Standard street types describe appropriate design vehiclesto use per street types, based on Better Streets Plan streettypes.

Local streets: Local streets are typically narrower streetswith low trac volumes and speeds, and limited need orlarge vehicles.

Pedestrian-activity streets: Pedestrian-activity streets typi-cally have high volumes o pedestrians, moderate trac

CaTEGoRY loCaTIoN DESIGN VEhIClE poTENTIallY allowablE EXCEpTIoNS

TRANSITROUTES

corners with turning buses on Muni rapid orlocal routes or routes rapid or local buses useto start run or return to yard

B-40 P: turn partially from adjacent lane

corners with turning buses on Muni commu-nity routes or routes community buses use tostart run or return to yard

B-40; some routeshave B-30 buses,check with SFMTA

P: turn partially from adjacent lane

corners with turning buses on routes servedby Golden Gate Transit, AC Transit, SamTrans,Vallejo Transit, University of California transitservices, PresidiGo

check with transitprovider

P: turn partially from adjacent lane

corners with potential occasional turning busesdue to detours

B-40 P: turn partially from adjacent lane; turn fullyfrom adjacent lane, turn from opposite lane,turn into opposite lane

EMERGENCYVEHICLES

a ll i ntersec ti ons a t s tr ee ts > 150 i n length WB-40 P: turn par ti al ly f rom adjacen t lane, turn f ul lyfrom adjacent lane, turn from opposite lane,turn into opposite lane

DESIGNATEDFREIGHTROUTES

GP transportation element Map 15 designatedRoutes with significant truck traffic

WB-50 P: turn partially from adjacent lane

P = permitted

Small curb radii are more pedestrian

friendly because they decrease crossing

distances and slow vehicles at turns.

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3

2

1volumes, and requent need or loading access. Teyunction as the central public space o San Francisconeighborhoods.

Troughways: Troughways typically have wide roadways,high trac volumes and speeds, and more large vehicles.Tey may have signicant pedestrian volumes and/or con-cerns about pedestrian saety or wide crossing distances.

Industrial streets: Similar to reight routes, industrialstreets are used or loading, shipping and deliveries. Teyare typically located in industrial areas with lower levels opedestrian and car trac.

Alternative strategies for intersections with frequentlarge vehicle turns

Beore increasing curb radius dimensions to accommodatenecessary design vehicles, consider the alternative measuresdescribed here:

Compound radius: A compound radius changes the curbradius over the length o the turn, such that it has a smallerradius at the crosswalks, and a larger radius in the centerwhere vehicles are turning. Compound radii efectivelyshorten crossing distances and make pedestrians visiblewhile accommodating larger vehicles to turn; becausethey allow more sweeping turns, they do not slow turningvehicles.

Compound radii may be considered where there are highpedestrian volumes, or a desire to make pedestrians visible,but a need or requent large turning vehicles such as right-turning buses.

At-grade paving treatments: o accommodate occasionaltrucks in very low trac areas, consider a corner design inwhich the area between the large and the small curb returnsis at street level, and is textured to discourage high-speedturns but allow low-speed use by larger vehicles. Tis treat-ment has limited application, such as industrial streets.

Advance stop lines: Advance stop lines on the destinationstreet can increase the space available or large vehicles tomake a turn by enabling them to swing into opposing laneson the destination street while opposing trac is stopped.

Painted median: Where there is sucient lane width onthe destination street, a painted median can enable a largevehicle to complete a turn without turning into opposingtrac.

Restricted access: Where there is a desire to keep curb radiismall, restrictions on large vehicles making the turn maybe considered. Tis should be considered in light o theoverall street network.

Two strategies to

extend effective

turn radius.

1,2: At-grade

paving treatment

3:Paintedmedian to extend

turn radius

CaTEGoRY bSp STREET TYpES DESIGN VEhIClE aCCoMMoDaTIoN VEhIClE*

LOCAL a lley, sha red pub li c way, nei ghborhood resi dent ia l,local lanes of boulevard

Passenger car SU-30

PEDESTRIAN-ACTIVITY

neighborhood commercial, downtown commercial,downtown residential

SU-30 WB-40

THROUGHWAY commercial throughway, residential throughway, urbanmixed-use, parkway, through lanes of boulevard

SU-30 WB-40

INDUSTRIAL industrial WB-40 WB-50

VARIES park edge, ceremonial Varies Varies

* Accommodations include: turning partially or entirely from adjacent lanes, turning from opposing lanes, or turning into opposing lanes

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Curb extensions (also called bulb-outs) extend the sidewalkinto the parking lane to narrow the roadway and provideadditional pedestrian space at key locations; they can beused at corners and at mid-block locations.

Curb extensions enhance pedestrian saety by increasingpedestrian visibility, shortening crossing distances, slowingturning vehicles, and visually narrowing the roadway.Generally, these benets are greater the urther the bulb-out extends into the roadway and the tighter the turnradius created by the bulb-out, but should be balancedagainst roadway characteristics and the needs o large vehi-cles to navigate turns.

Curb extensions can oten be lengthened to create publicspaces, landscaped areas, or transit waiting areas. Tey canalso be employed as neckdowns or chokers, trac calming

techniques that reduce vehicle travel lanes.

Curb extensions can have the ollowing benets:

Increased pedestrian visibility at intersections throughimproved sight lines.

Decreased pedestrian exposure to vehicles by shorten-ing the crossing distance.

Reduced vehicle turn speeds by physically and visuallynarrowing the roadway.

Increased pedestrian waiting space.

Additional space or street urnishings, plantings andother amenities.

Reduced illegal parking at corners crosswalks and busstops.

Facilitated ability to provide two curb ramps per

corner.

Curb Extensions (Bulb-Outs)

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Although curb extensions have many benets, they maynot be appropriate in all circumstances. Use o curb exten-sions should consider the ollowing:

Tey may be more expensive to construct than other

measures.

Tey can reduce exibility o the roadway in construc-tion routing.

Tey can reduce uture exibility in making changesto the location o bus zones, roadway lane layout, orcrosswalks.

Bulb-outs should also be considered as one among manystrategies to enhance pedestrian saety and streetscape char-acter; in some cases, median reuges, raised crossings, otherimprovements, or a combination o strategies may be more

appropriate.

plaCeMent

Curb extensions should be considered on all street types.Specic priority areas or curb extensions include:

new streets;

streets with high pedestrian volumes and/or hightrac volumes and speeds;

wide streets with long crossing times;

streets with a history o pedestrian saety concerns;

locations where neighborhood streets intersect withbusier throughways; and

transit priority streets where shortening crossing cycleswould improve transit ow.

Lower priority areas or curb extensions include streetswith lower pedestrian and trac volumes and lowerspeeds, such as neighborhood residential streets and alleys.However, they may be considered on these street types aswell.

Curb extensions should not be used on streets without aparking lane, or that have a peak period tow-away parkinglane.

Curb extensions should be placed at transit stops perSection 5.5. Where curb extensions are provided at t ransitstops, they should be a ull-length transit bulb, and not astandard corner bulb, as it can be dicult or a bus to exitor re-enter trac around a corner bulb-out.

guidelines

Bulb-outs should be designed to maximize pedestrian spaceand minimize crossing distances as much as easible, whileallowing vehicle movements as described in Section 5.2.

Width and lengthBulb-out width should be maximized based on space oradjacent vehicle and bicycle travel lanes (see Figure 1). Tebulb-out should extend to the ull width o the parkinglane or leave:

10 eet or the nearest auto travel lane;

11 to 12 eet or the nearest travel lane i it is a transitlane;

12 eet or the nearest travel lane i it is a designatedreight route or industrial street; and

5 eet or the ull width o any adjacent bicycle lanes.

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Where bike lanes are present, curb extensions

should be set back so that the gutter pan does not

extend into the bike lane

Curb extensions can provide

usable neighborhood space

for community gathering and

socializing.

Typical bulb-out

dimensions

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Street Sweeping at Curb Extensions

Currently in San Francisco, interior radii at curb extensions

are designed with wide, curving radii so that street cleaningmachines can access the entire street. While these are prefer-

able from a maintenance standpoint, they result in inefficientuse of space, with less space available for pedestrian use andlandscaping, greater parking loss, and a less sharply defined

curb extension. Neighborhoods with bulb-outs that dont meetstreet sweeping requirements, such as Duboce Triangle, havesome of the most desirable streets in the city.

The Better Streets Plan recommends as an alternative the

use of sharper turn radii, such that curb extensions return tothe prevailing curb line to make efficient use of space. Givencurrent maintenance practices, the alternative strategies sug-gested in the text should only be used on streets withoutmechanical street cleaning, on areas with a low maintenance

burden (for example on North-South residential streets withless windy conditions), where maintenance funding or agree-ments are in place (for example, where CBDs or adjacent

merchants or property owners agree to pay for hand streetsweeping of corners), or in special cases where the benefit ofdoing so will outweigh the additional maintenance costs.

These recommendations require further discussion and

study.Meanwhile, the City should explore maintenance strat-

egies to achieve effective street cleaning at curb extensionswith sharp radii, such as expanding the use of maintenanceagreements.

Beore reducing the width o the proposed bulb-out,consider modications to lane striping across the entireroadway to provide or the above-listed clearances. Sincebulb-outs are oten expensive to construct, they should be

suciently wide to maximize their benet. Bulb-outs lessthan 4 eet in width may not be a cost-efective solution ascompared to other potential interventions.

Curb extensions should not encroach on cyclists space.Where bike lanes use a painted inside edge, the bike laneshould be painted continuously as the bike lane passes thecurb extension, and the bulb-out should be set back so thatthe gutter does not extend into the bike lane. On lower-speed and volume streets where bikes can travel in mixedow with vehicles, wider curb extensions may be appropri-ate, but care should be taken not to orce cyclists to mergeunexpectedly with aster moving cars at the end o theblock. I bulb-outs extend beyond the limit o parked cars,additional eforts should be made to ensure their visibility.

Bulb-outs should continue at least to the inside edge othe crosswalk, and ideally extend 5 eet beyond the prop-erty line beore beginning to return to the curb to provideadditional width or pedestrians, landscaping, or otherstreetscape eatures. Existing driveways may cross throughbulb-outs.

Radii

Curb extensions should ollow corner curb radius guid-ance in Section 5.2. Where turn radii make addingbulb-outs at each corner prohibitive, strive or two bulbsper intersection, kitty-corner to each other, in order to

improve pedestrian conditions or all our crossings o anintersection.

Curb extensions should return to the prevailing curb line assharply as possible to maximize useable space and minimizeparking loss, per the oll owing guidelines:

Standard return: Standard bulb-outs should be designedwith an inner/outer curb radius o 20 and 10, sometimesreduced to 15 and 10, to enable street sweeping machin-ery to sweep the entire curbline.

Non-standard return: Sharper curb returns increase pedes-trian space and minimize parking loss while better deninga curb extension. However, they are more dicult andcostly to maintain. Where maintenance unding or agree-ments are in place to account or this, designs may considerthe non-standard treatments described below:

90 degree return: Curb extensions may return to theprevailing curb line at a 90 degree angle. Tis con-guration may be used with parallel or perpendicularparking.

45 degree return: Curb extensions may return to theprevailing curb line at an angle. Tis may be used witheither parallel parking (45 degree return) or angledparking (at angle o parking lane).

Temporary Bulb-Outs

Temporary bulb-outs may be used in some instanceswhere permanent bulb-outs are cost-prohibitive. These

can be created by delineating the edge of a curb exten-sion with bollards, striping, and other elements to protectthe extended sidewalk corner without bringing the curbextension up to the sidewalk level. This should be con-sidered a temporary treatment until funding and time

allow construction of a standard curb extension.

Standard

Alternative

(angled return -may be parallel or

angled parking)

Alternative (90

degree return

- may be parallel

or perpendicular

parking)

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Where necessary, driveways can cross curb extensions.

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Corner bulb-outs and sidewalk wid-enings are among the most effectivetools to enhance pedestrian safety andquality. They are essential compo-

nents of a truly successful pedestrianenvironment.

However, they are very expensive toconstruct, particularly when compared

to other potential strategies, which oftenprohibits their inclusion in pedestrianprojects with limited budgets. The highcost of building bulb-outs and wideningscomes from various factors, including:

demolition and reconstruction of

curbs;re-grading of the roadway;

curb ramp construction;

re-alignment of utilities lines andpoles;

more costly re-paving;

catch basin relocation; and

fire hydrant relocation.

Some strategies may be considered toreduce costs:

Allowing utilities to remain under1.sidewalk extensions. Per DraftSFPUC policy, sidewalks may beconstructed over existing sewer or

water lines.

Use of trench drains (channels2.covered with metal grating) toeliminate the need to relocate

catch basins or re-grade streetsfor drainage. Trench drains requireadditional maintenance to cleanout channels, particularly on high-use and commercial streets. See

Section 6.2.

Allowing fire hydrants to remain3.in place. Fire hydrant relocationcan be prohibitively expensive

($50,000-$100,000) whenconstructing sidewalk bulb-outsor widenings, often resulting in adecision to not construct a par-

ticular curb extension. CurrentFire Department standards requirehydrants to be between 24 and 27

inches from the curb line. Whencurb lines are moved, hydrantsthat are present must be shifted aswell. Allowing hydrants to remain

in place would result in signifi-cant cost savings for constructingbulb-outs and widenings. Thebulb-outs would also keep the

area clear of illegally parked cars,which improves access to thefire hydrants. Instead of movinghydrants, in-street reflectors,painted curbs, and other technolo-

gies may be used to make existinghydrants easy to locate. F udiscussins it te Fire Dertment ud

e necessry t imement tis recmmen-dtin. Te City sud see sutin ttddresses te need t esiy nd quicycte ydrnts ie ening te cst-effective cnstructin f cur extensinsit significnt edestrin sfety enefits.

Making Sidewalk Widenings and Bulb-Outs

More Cost-Effective

Trench drains may be used to

allow pre-existing catch basinlocations to be maintained

and decrease the potential

cost of curb extension

construction. See Section 6.2

for appropriate use and design

of trench drains.

Curb extensions shorten crossings and can act as a choker,

narrowing traffic lanes at intersections to calm traffic, improvingpedestrian safety at crossings

Where turning radii limit bulb-out dimensions, consider

two bulb-outs at opposite corners, thereby shorteningall crosswalk lengths

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Shape

Bulb-outs should strive or a rectilinear shape to keep adirect path o travel and to regularize crossings and curbramps. Te adjacent gures show alternative bulb-out

shapes with the same turn radius. Te gure at let pro-vides greater overall space or pedestrians waiting to crossthe street, which may be useul at impacted locations. Tegure at right provides more clear directionality and directcurb ramps, as well as a tighter corner. Both alternatives areacceptable; the resulting design should be balanced withthe overall goals o the project.

Other design features

Bollards, planters, or other xed objects may be placed atthe back o curb where necessary to protect pedestrians andprevent vehicles rom driving onto the sidewalk.

Curb extensions should be designed to hold the 100-yearstorm within curb width. Stormwater eatures can help toofset reduced capacity rom curb extensions. Individualanalysis should be conducted or each project.

Curb extensions should either relocate the corner catchbasin to the outer edge o the extension, or provide acovered channel (trench drain) to convey stormwater tothe existing catch basin (see side bar, previous page). Techannel must be covered with an ADA-compliant cover.

extended bulb-outs

Longer curb extensions may be considered to create spaceor seating, landscaping, stormwater eatures, and otheramenities, particularly in areas lacking in open space.Extended bulb-outs should use special paving or an edgingtreatment to distinguish the space as a plaza space separaterom the through travel area.

Street urnishings and other above-grade objects shouldbe located on curb extensions outside o crossing areasto increase space or pedestrian through travel on thesidewalk.

Mid-block curb

extensions

Mid-block bulb-outs can provide space for landscaping, cafe seating,

or pedestrian furnishings.

Mid-bloCk bulb-outs

Mid-block bulb-outs may be considered on all street typesto provide additional sidewalk space or landscaping,seating, stormwater treatment, and amenities, and improvesaety at mid-block crossings by shortening crossing dis-tances and enhancing pedestrian visibility. Mid-blockbulb-outs should ollow these guidelines:

Tey should include bollards, landscaping, or otherbufers between pedestrians and passing vehicles,designed to not impede a drivers view o pedestrians.

Tey should use special paving or an edging treatmentto distinguish the space as a plaza space separate romthe through travel area.

Street urnishings and other above-grade objectsshould be located on curb extensions where spaceallows to increase space or pedestrian through travel

on the sidewalk.

Mid-block curb extensions should be used at des-ignated mid-block crossings. Mid-block crosswalksshould be provided per Section 5.1.

Te City should explore the use o curb extensions inront o re hydrants so that the hydrant is not blocked byillegally parked vehicles. Tis would require a change tocurrent City standards regarding location o re hydrantsrelative to the curb. See sidebar.

R1

R1

R2R2

R1 = Actual curb radius

R2 = Effective turn radius

Option 1:A shorter crossing andlarger overall bulb-out

Option 2: Greater directionality andsharper curb radius

Bulb-out shape alternatives

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Medians andislands can calm

trac and providesae pedestrian

reuge, whileincorporating

space or amenities,landscaping

and stormwatermanagement

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A median is the portion o the roadway separating oppos-ing directions o the roadway, or local lanes rom throughtravel lanes. Medians may be depressed, raised, or ushwith the road surace. Medians are generally linear and

continuous through a block. An island is a dened as anarea between trac lanes used or control o trac move-ments. Within an intersection, a median is considered anisland.1

Raised medians and islands provide space to locate pedes-trian saety eatures and trac control devices, amenities,landscaping and stormwater management. Tey canprovide trac calming and aesthetic benet, but the addi-tion o medians alone may also cause an increase in vehiclespeeds by reducing riction between opposing directions.

1 AASHO Green Book

Te unctions and benets o medians include:

separate opposing trac;

provide a recovery area or out-o-control vehicles;

provide an emergency stopping area;

provide space or speed changes and storage or let-and u-turns;

minimize headlight glare;

restrict through travel on streets with two-way letturn lanes or where cross streets intersect with moresignicant throughways;

Medians and Islands

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Stormwater Managementin Medians

Landscaped medians reduce impervious space inthe roadway, allowing stormwater infiltration or

retention in the exposed soil. Medians can also bedesigned to retain, cleanse, and infiltrate storm-water runoff from the roadway, Where stormwatermanagement is intended in the median, the streetshould be graded to drain toward the median. For

more information on stormwater management, seeSection 6.2.

provide space or a pedestrian reuge on wide streetswhere those on oot cannot cross the entire street inone phase;

reduce excessive pavement areas, and provide opengreen space;

provide space or transit stops;

separate through trac rom local trac on ulti-wayboulevards; and

create space or a distinctive design treatment.

Where no median is present, raised islands can be usedas trac calming eatures to briey narrow the traveledway, either in mid-block locations, or to create gateways atentrances to residential streets. Islands may also be ound atcorners.

guidelines

At crossings, the end o medians should be ush withthe edge o the crosswalk and should not be signicantlyrounded. A thumbnail, or raised island on the intersectionside o the crosswalk, should be provided in medians thatunction as pedestrian reuge islands.

Medians may be combined with parking lane planters, chi-canes, bulb-outs, or other trac calming measures where itis desirable to urther moderate trac speed.

Medians and islands more than 3 eet wide, includingcurbs, should be landscaped and used or stormwater man-agement. When street trees are desired, a median shouldbe a minimum o 5 eet wide, including curbs, to providesucient space or healthy root growth per Sections 6.1and 6.2.

As budgets allow, medians should be built to the maximumwidth possible, rather than providing a striped area outsidethe median. Landscaped medians should be congured sothat maintenance personnel do not have to work in traclanes, by providing a minimum 2 oot walkable edge orstriped area adjacent to the median.

Design and landscaping o medians should empha-size continuity on throughways and ceremonial streets.Landscaping, lighting and street urnishings should main-tain a similar look and eel even as the corridor varies inland use, scale and intensity. On neighborhood streets, theymay have a more exible, organic design.

Islands should not interere with driveway access,unless that is the purpose o the installation (i.e. accessmanagement).

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Medians provide

space for trees and

planting, visually

break down the scale

of the right-of-way,

and create space for

pedestrian refuges.

Median islands can

designate entrances

to residential streets

Landscaped medians provide visual

coninuity to a corridor

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Choosing Median Refuge Islands vs

Curb Extensions

Pedestrian refuge islands and curb extensions both

improve comfort and safety for crossing pedestrians.Curb extensions minimize the distance needed to crosswide streets and facilitate crossing in one stage, whilepedestrian refuge islands offer a comfortable restingplace between crossing stages. Pedestrian refuge islands

are typically significantly cheaper to construct thanbulb-outs.

Under the following conditions, median refuge islandsmay be preferable to curb extensions, or it may be pos-

sible to use median refuge islands in addition to curbextensions:

two-way left-turn lanes;

excessively wide travel lanes or turn lanes;

4 lanes or more where it is may be difficult to crossin one stage;

a ceremonial purpose, where medians provide animportant design function; and

an existing median.

pedestrian refuge islands

Pedestrian reuge islands are protected areas where peoplemay saely pause or wait while crossing a street. Pedestrian

reuge islands are particularly helpul as resting areas orseniors, persons with disabilities, children, and others whomay be less able to cross the street in one stage. At signal-ized intersections, they allow slow moving pedestrians tocross in two phases. At unsignalized locations, they sim-pliy the act o nding a gap in trac to cross since vehiclesrom only one direction must be reckoned with at a time.

Raised pedestrian reuge islands can be provided in paintedcenter medians, side access lane medians, transit boardingislands (Section 5.5), and corner islands.

Placement

Pedestrian reuge islands should be considered under theollowing conditions:

streets with high pedestrian activity;

where crossing distances are long (60 eet or greater);

near and within neighborhood retail areas, civic andinstitutional uses, schools and senior acilities;

locations with many transers between transit lines;and

unsignalized intersections with large numbers opedestrians.

less than 6 6 to 16 more than 16

no detectablewarnings

2 detectable warn-ings at refuge

3 detectable warn-ings at curb ramps

at-gradethrough refuge

at-gradethrough refuge

raised medianat refuge

curb ramps(typ. 6 at 1:12grade)

timed to cross insingle phase

min. 2 clearwaiting area

4 clear waiting area

Median design at various widths

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Dimensions

On streets with medians less than 6 eet wide, signalsshould be timed so that pedestrians can cross in one signalphase and detectable warning strips are not required.

On medians between 6 and 16 eet wide, the pathway andwaiting area should be at street grade, with a row o 2 ootwide detectable warning strips on each end, leaving a 2oot wide clear zone in the center.1

On medians 16 eet wide or greater, pedestrian reugeislands should be raised to provide more visibility orwaiting pedestrians. Raised islands should include tworamps (typically 6 eet wide) with 3 oot wide detectablewarning strips on each end and a minimum 4 oot widewaiting area.2 See graphic.

Safety and Design ElementsIn order to protect waiting pedestrians, the ollowing ele-ments should be used in pedestrian reuge islands:

Raised thumbnails should be provided on the inter-section side o reuge islands, ideally outside o thecrosswalk edge.

1 Source: Access Board, Drat Public right-o-way Accessibility Guidelines (R305.4.2)

2 Source: AASHO ped guide

o accommodate turning radii or large vehicles, thethumbnail may need to be within the crosswalk, orhave a mountable outside edge.

A bollard, landscaped eature, or sign should beprovided on the thumbnail, unless it is a mountablethumbnail. Tese eatures should be 2 to 4 eet tall.

aller elements such as light xtures or sign poles maybe appropriate i they are thin enough to not obscuredrivers view o pedestrians.

Pedestrian reuge islands should use diferent paving(concrete or other) in order to distinguish them romthe roadway. See Section 5.4: Paving.

On wider medians, a seatwall or other amenities maybe provided

Offset crossings should minimize inconvenience to pedestrians. The photo on

the right would benefit from a feature to redirect people with visual impairments

to the direction of the crosswalk.

Offset or Corral Crosswalks

Offset crosswalks are treatments in which the crosswalk issplit by a median and is offset on either side of the median.This design forces pedestrians to turn in the median and face

oncoming traffic before turning again to cross the second halfof the roadway, which may improve safety, especially wherethere is no signal control at mid-block and T-intersectionlocations.

While offset crossings provide safety benefits, they may incon-venience or delay pedestrians. Wherever feasible, pedestriansshould be given sufficient time to cross the entire roadway inone phase. However, two-phase crossings may occasionally

be unavoidable, and in some cases may benefit transit.

Unless offset crosswalks provide tactile cues for visually impairedpedestrians to re-orient themselves before crossing the second

half of the roadway, pedestrians navigating with a cane may bemisdirected. Offset crosswalks should be built so that each sideof the median pass through features a curb running parallel to thecrosswalk, forming a Z.

In order to discourage shortcutting and encourage pedestrians tofollow the intended path, some staggered crosswalks include arailing to contain pedestrians and direct them along the desiredroute, called a corral-crossing. Corral crossings should be avoided.Care should be taken to design a pleasant walking environment

that does not make pedestrians feel like barnyard animals. A lowseatwall or landscaping may provide an attractive alternative wherea physical barrier higher than a curb is necessary.

Corner islands

Where the pavement area within an intersection becomesexcessively large as a result o eforts to accommodate turning

movements o large vehicles or due to streets coming togetherat unusual angles, adding corner islands can help controltrac and break up the crossing or pedestrians.

Adding corner islands creates a slip lane, which separatesright turning vehicles rom through trac. Slip lanes can bestop- or signal-controlled, but are oten yield-controlled.Slip lanes and the very large corner radii that come withthem can pose a hazard to pedestrians or a number oreasons:

Drivers tend to concentrate on merging with oncom-

ing trac and may not see pedestrians entering thecrosswalk.

In high-trac areas, inadequate gaps in uncontrolledright-turning trac may exist, making crossing a slipturn lane dicult or pedestrians.

Te non-standard corner geometry introduced by sliplanes is dicult or people with visual impairments tonegotiate.

Source (right image): http://www.contextsensitivesolutions.org/content/case_studies/mid-block-crosswalks-school-zone-olympia-wa/#

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Smaller radiusresults in need forvehicles to slow toenter traffic,as wellas improvedvisibility of pedes-trians and on-coming traffic.

Removing the sliplane results inshorter crossingfor pedestrians,safer conditions atthe intersection,and space for land-scaping,seating,orother useableamenities.

Larger radius resultsin faster turns andless visibility ofpedestrians waitingto cross.

Slip lanes and corner islands should be avoided andremoved to create additional pedestrian space whereverpossible.

Where the large turning radius provided by a slip laneproves unnecessary, the slip lane should be removed andthe corner added to the sidewalk area. Tis reclaimed spacecan be made into an attractive pedestrian plaza with ur-nishings and plantings.

At intersections with very high right turning volumes orwhich must accommodate very large vehicles, slip lanesmay be unavoidable. Where it is not possible to avoid orremove slip lanes, their design should be mitigated, per theollowing guidelines:

Raised islands should include a pedestrian reuge

Uncontrolled slip turn lanes, especially those that turn

into a dedicated exit lane (ree right turn slip lanes),are discouraged where pedestrians are present

For maximum pedestrian benet, slip lanes should bedesigned with a maximum 30-35 oot turning radius;however, they should ollow the guidance in Section5.2.

Slip lanes should incorporate additional pedestriansaety measures. Signalizing the right-turn movementcreates gaps in vehicle trac or pedestrians and maybe the saest alternative. Crosswalk treatments, such aswarning signage, special paving in the slip lane, or araised crosswalk connecting the sidewalk with a reugeisland, may also improve conditions or pedestrians.Slip turn design may employ a compound radiusto slows vehicles and improve drivers visibility. SeeSection 5.2 or discussion o compound curb radii.

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1. Center median

2. Corner island

3. Side median with pedestrian refuges

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ransit supportivestreetscape design

includes sae,comortable transit

waiting areas,convenient routes

to transit, anddesign to enhance

pedestrian andtransit circulation.

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ransit stops enhance the experience o waiting or andboarding transit vehicles. Successul transit stops are wellconnected to the local network o sidewalks and pedestrianroutes, and provide convenient connections to residences,

work places, and other destinations.

Streetscape elements and pedestrian acilities should bedesigned to support t ransit operations. Streetscape designsthat benet pedestrians are oten helpul to transit as well.

transit stops

Placement

Sidewalk transit stops should be located in a curb exten-sion wherever possible, per guidelines below. ransit stopsshould be located in median islands where transit uses

center lanes.

At signalized intersections, transit stops should typicallybe located at the ar side o intersections to acilitate busoperations, transit signal priority, and pedestrian move-ment. Tis also enables the crossing to be located behind

the bus, which is preerable or pedestrian saety. At stopsigns, transit stops should typically be located near side.See SFMAs stop location guidelines or more details.

ransit stops should be located in places that are activeand visible to maximize personal security o waiting transitusers.

ransit stops should not be located at driveways whereverpossible; new driveways should be discouraged at transitstops (and generally along major transit routes).

Transit-Supportive Streetscape Design

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Transit stops should include sidewalk treatment, better

circulation, a clear flag sign, pedestrian lighting, trees, and

amenities to create a safe and pleasant waiting experience.

Layout

Good layout o a transit stop ofers transit patrons visualcues on where to wait, clearly denes the transit stop andcalls it out as a special place in the sidewalk environment,

allows ease o access between the sidewalk, the transit stop,and the transit vehicle, and does not block the path otravel on the adjacent sidewalk.

ransit stops should abide by the ollowing layoutguidelines:

Streetscape elements should be consolidated tocreate clear waiting space and minimize obstructionsbetween the adjacent sidewalk, waiting areas, andboarding areas.

Streetscape elements should be evenly spaced through-out the transit stop or ease o access. Tey should

be aligned or ease o detection by people with visualimpairments.

ransit stops may be distinguished rom the adjacentsidewalk through the use o special paving treatments,curb extensions, or a row o trees or planters, wherespace allows. Use o a diferent species o tree than theprevailing block pattern can help to diferentiate thetransit stop. Tese treatments are most appropriate onthe Muni Rapid Network or at major transer points.

ransit stops should be integrated with adjoiningactivity centers wherever possible to activate and createa sae space.

ransit stops must include the ollowing accessibilityeatures:

A clear 5 oot by 8 oot loading area perpendicular tothe curb, with a maximum 2% cross-slope, to allow a

transit vehicle to extend its ramp to load people withmobility impairments. Te clear loading area shouldbe at the ront o the boarding zone and accessiblerom the transit shelter (where present) and adjacentsidewalk. I a zone is designed or more than one bus,a wheelchair loading zone should be provided or eachvehicle.

A 30 inch by 48 inch clear oor wheelchair spacewithin the transit shelter (where present). Tis spacemust be accessible rom the sidewalk and the loadingarea. In some cases, this may necessitate removing oneo the panels at the rear o the transit shelter.

Where boarding platorms are not level with the side-

walk, an accessible ramp must be provided rom thesidewalk to the platorm.

Transit-Specific Streetscape Elements

ransit-specic streetscape elements should be locatedwithin transit stops as ollows:

Flag signs should be placed near the ront o the stop, toindicate where passengers should wait to board the vehicle.At ar side or mid-block stops with bus zones, the ag signshould be placed approximately 25 to 35 eet behind theront o the stop to allow or the bus to pull out o the stop

and re-enter trac. At near side zones, or where there isa transit bulb-out or boarding island, this setback is notnecessary.

ransit shelters should be located toward the ront o thestop to indicate where customers should wait to board thevehicle. Te shelter should be placed approximately 25eet behind the ront o the stop to allow or an accessibleboarding area (5 eet by 8 eet) and or the bus to pull outo the stop (approximately 20 eet). Where there is a transitbulb-out or boarding island, the rst 20 eet o setback isnot necessary.

Munis

approved

transit shelter

design

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The Transit Effectiveness Project(TEP)

The Transit Effectiveness Project (TEP) is a comprehen-sive effort to review Muni and recommend ways to create

a faster, more reliable and more efficient public transitsystem for San Francisco. Launched in May 2006, theTEP gathered significant ridership data, studied bestpractices from other transit systems, and conductedextensive public outreach. Informed by these efforts, theTEP developed a set of preliminary proposals designed

to improve reliability, reduce travel delay, and updateroutes to better meet current and projected travel pat-terns throughout the City. The SFMTA Board of Directorsendorsed the TEP recommendations in October 2008.

The Draft TEP recommendations describe a Muni serviceframework, based on ridership and frequency of routes.The recommendations focus on providing resourceswhere they are most needed. This includes new routes

and route extensions, more service on busy routes and

elimination or consolidation of certain routes or routesegments with low ridership. The framework categorizesMuni routes into Rapid, Local, and Communitylines, and Special Services. These terms are referenced

in this document.

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Generalized transit stop layout

Special paving (distinct scoring,alternative paving material,edge

treatment)

Street lighting

Flag sign

5X 8loading area

Muni shelter (size varies)- Real-time info

- Route Map

- Push-to-talk button

- Seating

Trash can

Ticket vendingmachine

Street trees - may bedistinct species (per

Section 6.1)

Seating (bollards,benches,etc.)

Bicycle racks

#,%!20%$%342)!.4(2/5'(7

!9

(Width varies)

Per BSP

sidewalk width

guidelines

(section 4.2)

,ENGTHVARIES

FORBUS

TO

PULLOUT

OFSTOP

4min.(or other

accessible

routeto shelter

provided)

ransit shelters should be provided where existing side-walk space allows or where a curb extension can be addedto provide sucient space, and demand warrants. Teyshould not be provided where sidewalk width is insu-cient to accommodate a shelter and at least the minimumrequired clear path o travel around the shelter (per Section4.2) or the ability to carry expected pedestrian volumes.

Shelters should be located in the urnishings zone whereverpossible. Tey should be located to provide at least 4 eeto clear space between the edge o the curb and the rontedge o the shelter, or another accessible path to the sheltershould be provided (or example, by removing one o theback panels o the transit shelter). Alternately, shelterscan be placed in the rontage zone so long as they dontblock building entrances, but should leave the minimumrequired clear sidewalk width per Section 4.2.

ransit shelters must use the approved Muni transit shelterdesign, including real-time transit inormation, routemaps, and a push-to-talk button. Exceptions may be con-sidered or LR or BR lines to give these lines a distinctcharacter.

ransit shelter widths vary, rom 3 eet to 7 eet in widthand 8 eet 6 inches to 16 eet 6 inches in l ength. ransitshelters should be selected to t the sidewalk contextonnarrower sidewalks, narrower shelters should be used toallow pedestrians to pass reely behind. Larger sheltersshould be used on LR, BR, or Rapid Network lines, orat major transer points where passenger demand is high.

When modiying sidewalks at existing or new transit stops,evaluate adding electrical systems to provide power orshelter amenities such as lighting and real-time inormation

icket vending machines (VMs), where provided, shouldbe located near to transit shelters within the transit stop. Attransit stops where a proo-o-payment (PoP) zone is used,ticket vending machines should be placed outside the paidzone, not next to the transit shelter (see sidebar).

Other Streetscape Elements

ransit stops and their surrounding area deserve a higherthan average level o streetscape amenities to serve waitingpassengers. Streetscape amenities should use the ollowingguidelines:

Urban Forest: rees and planters may be used to distin-guish the transit stop rom the adjacent sidewalk area orto continue the prevailing pattern o tree planting along ablock, but should not interere with transit operations or

pedestrian travel. See Section 6.1 or the correct placemento trees and landscaping at transit stops.

Tis may oten mean that, where space allows, street treesin a transit stop would not be along the same alignmentas trees on the rest o the block. Tis can help call out thetransit stop as a special location on the sidewalk; in thesecases, selecting tree species distinct rom the prevailing treespecies on the street can enhance this efect. Tis treatmentis most appropriate on LR, BR, or other Rapid Networklines, or at major transer points.

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Tree planting in bus zones. See also Section 6.1.

Far Side Bus Stop

Near Side Bus Stop

FrontDoorZone

Planting Allowed

Bus Zone

8min.

35

4min.

5min.

25min.

FrontDoorZone

Planting Allowed

Bus Zone

8min.

10min. 20

4min.

5min.

Far Side Bus Stop

Near Side Bus Stop

FrontDoorZone

Planting Allowed

Bus Zone

8min.

35

4min.

5min.

25min.

FrontDoorZone

Planting Allowed

Bus Zone

8min.

10min. 20

4min.

5min.



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Muni Rapid Network station (typical) Muni Local Network station (typical)

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Street trees (distinctspecies), located perSection 6.1

Site furnishings(bike racks,benches, trashcans, etc.)

Distinct pavingtreatment (scoring,material, or edgetreatment)

Transit amenities(shelter, TVMs,flag sign)

B

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Site furnishings(bike racks, trashcans, etc.)

Transit amenities(shelter, flag sign)

5.5 TRaNSIT-SUppoRTIVE STREETSCapE DESIGN


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Stormwater: Stormwater acilities may be located withintransit areas; however they should not impede the ability toaccess the transit shelter (where present), or boarding areas.Stormwater acilities appropriate to transit stops includepermeable paving in the sidewalk area, building-adjacentplanters, or covered channels. See Section 6.2.

Lighting: Lighting should be located to illuminate thetransit stop area, particularly the ront o the stop and thetransit shelter (where present). Lighting may be integral tothe transit shelter, or may be provided by standard pedes-trian or roadway lighting, where sucient. See Section 6.3.

Paving: Special paving may be provided to distinguish thetransit stop area rom the adjacent sidewalk. Special pavingmay include a unique scoring pattern, a contrasting pavingmaterial, or a paving edge treatment delineating the edgeo the transit stop. Special paving may be expensive, and

is most appropriate at major stops on LR, BR, or otherRapid Network lines or at other major transer points. SeeSection 6.4.

Site urnishings: Other site urnishings should be locatedwithin transit stops as ollows. Individual site urnishingsshould ollow the design guidelines in Section 6.5.

Seating should be located within the transit shelter(where present). Additional seating, either ormal(benches, seats with armrests) or inormal (bollards,low seat walls, leaning bars), may be placed outsideo the shelter, provided it allows permeability to androm the transit shelter and boarding area.

rash cans should be pl aced adjacent to the transitshelter (where present).

Bike racks, where provided, should be placed nearthe back o the transit stop (urther rom the shelter- where present), or be placed outside o but adjacentto the transit stop. Bike-sharing pods, where provided,should be placed outside o but adjacent to the transitstop.

Waynding inormation may be located within transitstop areas, particularly in downtown, commercial, ortouristed areas.

design by type of transit route

Service amenities and design should be consistent acrossservice categories (Rapid, Local, Community) to increasethe legibility o the Muni system. ransit stops on LR,BR, or other Rapid Network corridors and at majortranser points should include a greater level o eaturesand amenities than other locations. LR, BR, and otherspecial lines should be designed to have a distinct identityand be branded to emphasize their special nature. Specialtreatments or transit stops along these lines may includespecial signage, unique transit shelters, VMs, specialpaving or landscape treatments, premium materials, andhigher numbers o amenities at each stop.

At major transer stops, stop design should aci

Documents

Street Designs