In the Spring of 2010, a graduate class at San José StateUniversity in Urban and Regional Planning teamed upwith theSanta Clara Valley Transportation Authority (VTA) to studyparking at transit‐oriented development (TOD) residentialprojects in the southern portion of the San FranciscoBayArea.By observing the parking utilization rates at 12 housingdevelopments near VTA light rail and Caltrain stations, thiscollaborative research effort produced valuable, local evidencethat the parking supply at projects of this type exceeds actualdemand. And in corroborating recent researchwhich demon‐stratedthatotherTODresidentialpropertiesintheBayAreaarealso “over‐parked” (Cervero 2009), the study provides usefulevidence to help inform decision makers that less parking canand ought to be required for housing projects that are locatednearrailtransitservice.

This article presents a summary of the objective,methodology,key findings, and policy implications of this collaborativeresearchproject. A full descriptionof theprojectmethodology,local background, survey data, research findings, and policyimplications is presented in the Technical Report datedNovember2010,availableonline(seebelowforwebaddress).

PROJECT OBJECTIVE AND METHODOLOGY

Theintentofthisresearchproject istocorroboratethefindingsofotherresearchonthetopicandprovideevidencethatreducedparking requirementsmaybe feasible inSantaClaraCounty. Ifthe surveys demonstrate lower actual parking utilization thancurrentparkingsupply, itwould indicate that local jurisdictionswith land‐use control surrounding rail transit stations couldreduce their parking requirement standards. This reduction inparking requirements could have the effect of reducing TODconstruction costs and reducing the footprint of TOD develop‐mentprojectstomakelandavailableforotherandbetteruses.

An initial literature review was conducted to collate existingresearchrelatedtoparkingutilizationanddemand. Theresultsfromtheliteraturereviewwereusedtodeterminebestpracticesin estimating parking demand, identify local parking require‐mentsinthestudyarea,anddevelopaparkingsurveyworkplan.Parking literature often refers to a critical threshold being

Problem:TODresidentialprojectsinSantaClaraCountyarebelievedtobe“over‐parked.”Localdatademonstratingthiseffectpreviouslydidnotexist.Purpose:ThecollaborativeresearchprojectbetweenSJSUandVTAwasintendedtodeterminewhetherornotactualparkingutilizationissignifi‐cantlylowerthanparkingsupply.ThisinturnwouldprovidelocalevidencethatparkingrequirementsforTODresidentialprojectscouldbereduced.Methods:Parkingutilizationsurveyswereconductedat12TODresidentialpropertiesthroughoutSantaClaraCountyduringpeakparkingperiods.Resultsandconclusions:All12sitesexhibitanover‐supplyofparkingfacilities,onaverageby26percent.Whileonaverage1.7parkingspacesperdwellingunitwereprovided,only1.3wereneeded.Takeawayforpractice:LocalparkingrequirementscanbereducedatTODresidentialpropertieswithoutfearofcausingspillovereffectsonneighboringproperties.

NewResearchIndicatesthatTransit‐OrientedDevelopmentResidentialPropertiesInSantaClaraCountyare“Over‐Parked”

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reached around 85 percent utilization—above thispoint,parkingsupplyisperceivedtobefullbyusers,and spillover or illegal parkingmay occur. From amethodologicalperspective, if theobservedparkingutilizationratesatTODresidentialpropertiesintheCountywere found to be significantly lowerthan 85 percent, then the parkingdemand at these sites could beestimated from the observedrates without additional sur‐veys. However, if the ob‐servedutilization rateswerefound to be significantlyhigherthan85percent,thenmore extensive surveyswould be needed to estimatethe total parking demand be‐cause parking overflow is likely.In either case, the use of parkingutilization surveys would answer thekey research question of whether TOD residentialprojects in Santa Clara County are “over‐parked,”because they would determine whether the usageratesareaboveorbelow85percent.Therefore, theResearch Team proceeded with on‐the‐groundparking surveys, collecting a range of parking‐relateddatafrom12TODresidentialpropertiesthatmet the selection criteria listed inBox1. Thedatacollectedby theResearchTeamwere analyzed in avarietyofways, and thekey findings arepresentedinthisarticle.

KEY RESEARCH FINDINGS

All12TODresidentialpropertiesoffermoreparkingthan residents need and actually use. Each of thesurvey sites has significant unused parking, by aslittle as 17 percent and as much as 39 percent;overall, out of the total parking spaces (9,751supplied)about26percentofthemwerenotutilized(2,496 unused) at the time of the on‐the‐groundsurveys. Table1showsthatonaverageonlyabout1.3 spaces1 are needed per dwelling unit in a TODresidential site in Santa Clara County, while theaverage parking supply ratewas 1.7 for the survey

sites(calculatedfrom9,751totalsuppliedspacesfor5,801totaldwellingunits).Thefactthattheparkingsupplyrateisfoundhigherthantheparkingdemandrate for all 12 sites (22 percent higher on average)indicates that more parking is provided than is

actuallyneeded.

Since parking requirements forresidential developments are setby local zoning requirements,local parking requirementshave clearly contributed tothe large amount of parkingsupplied at the residentialdevelopment sites surveyed.The 2,496 unused parkingspaces in 12 residential siteslead the Research Team to

conclude that parking facilities atTODresidentialprojects inSantaClara

County may be underutilized. This findingsuggests that local parking code requirements forTOD residential properties in Santa Clara County,and other similar locations, could be reducedby asmuchas26percent.

Basedon theobservedpeakparkingutilization, theparking demand rates for the 12 TOD survey sitesarenearthebottomoftherangeofrequiredparkingsupply levels for municipalities across Santa ClaraCounty (see Figure 1), which in some cases mayexceed 2.5 parking spaces per dwelling unit undercurrent local zoning requirements. This researchproject shows that parking demand at residenceswithinone‐halfmileofarailstationislessthanwhatcurrent zoning codes require. As such,manySantaClara County municipalities could reduce theirresidential parking requirements significantlywith‐outtheriskof“underparking”aTODresidentialsite.

UnutilizedParkingSpaces

UtilizedParkingSpaces

1.ThisresultforSantaClaraCountyTODsitesiscomparabletotheaverageparkingdemandrateof1.2spaceperdwellingunitforotherSanFranciscoBayAreaTODsitesstudiedbyRobertCerveroin2009(seeTable2.1intheTechnicalReport).

BOX 1 TOD Residential Project Survey Criteria

• Within½mileofarailtransitstation• Minimumresidentialoccupancyof85percent• Overoneyearold• Freeparking• Restricted/designatedparking• Opensurfaceparkingorpodiumgarage• Atleast80unitsor100parkingspaces

3

POLICY IMPLICATIONS

Reduce Costs of Unused Parking

Sinceunusedparkingsupplyconsumesland,money,and other resources in its construction andmaintenance,reductioninparkingrequirementsforTOD residential projects could benefit both localmunicipalities and developers alike. Constructingparking facilities increasescosts fordevelopersandproves inefficient for themunicipalitywhena largeproportion of a development site is unused. Thereare potential cost savings that could be garnered ifparking requirements are reduced to levelssuggested by the utilization data presented in thisstudy.Thesavingsindevelopmentcostscouldthenbeused tosupportotherenhancements toprojects,which may be desired by the local agency and thecommunity.

Simplify Local Parking Requirements

ManymunicipalitiesinSantaClaraCountyhavetheirown unique way of granting reduced parking

requirementsforresidencesneartransitstations. Inthemajority of cases, theprocess requires case‐by‐case decision making (such as conditional usepermits) or a previously completed planning effort(such as a Specific Plan). In several jurisdictions,reductionscanonlybegrantedthroughissuanceofavarianceor in conjunctionwith the sitedeveloper’sparticipation in and promotion of transportationdemandmanagement(TDM)programs.

Providing reduced parking requirements for TODresidentialsitesdirectly intothezoningcodewouldsave municipalities the staff time and resourcesrequired for additional permitting efforts.Additionally, this formofregulationwould likelybeseenasbeneficialinthedevelopmentcommunity,asitwouldallowforagreatermeasureofpredictabilityand simplicity in determining the costs associatedwith developing a residential site. Such a benefitmay even result in an increased number of TODresidential projects in municipalities that simplifytheparkingrequirementsinsuchamanner.

1.27

1.49 1.54

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0.6

0.8

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1.2

1.4

1.6

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2.2

2.4

2.6

2.8

3.0

ParkingUtilzationRate

RangeofLocal

ParkingRequirem

nts

FIGURE 1 Parking Utilization Rates for Surveyed Sites Compared to Local Zoning Requirements

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Future Transit Expansion

Several new transit projects are planned for SantaClara County in the coming years, notably severalBus Rapid Transit (BRT) lines and the BARTextension to San José. The new transit lines willprovide better transit service to many areasthroughout SantaClaraCounty, including importantdestinationssuchascentralbusinessdistricts,henceprovidingresidents theoptiontoaccess theseareaswithout driving. As more areas in Santa ClaraCountyareconnectedbyfrequent,convenienttransitservice,therewillbenewopportunitiesforresidentsto take advantage of the accessibility andconveniencethatTODresidentialprojectsoffer,andmore developments should be able to reduce theirparkingsupply.

This research has shown that TOD residential sites,whichmeet the criteria inBox 1 and are near railstationsinSantaClaraCounty,areover‐parked.This

reasoning could befurther expanded tosuggest that TODresidential projects nearnewBRTtransitstationscouldalsohavesimilarlyreduced parking de‐mand. If the quality ofBRTservice intermsofconvenienceandcomfort iscomparable to rail service, then there is thepotential to reduce parking requirements for TODresidentialsitesnearBRTstationsaswell.

Better Land Use and Urban Form

Municipalities could expect positive impacts fromdecreasing parking ratios for TOD residentialprojects. Land would be more efficiently used bymaking it available for additional housing orenhanced community amenities. Decreasingparkingratios from2.2 to1.1—whileholdingother

Site City Housing Parking Parking

Utilization Ratio

Parking Demand

Rate

Parking Supply

Rate Over Supply

(%)

Total

Units Occupied

Units Total

Spaces Utilized Spaces

Unused Spaces

(Utilized Spaces / Total Spaces)

(Utilized Spaces / Occupied Units)

(Total Spaces / Total Units)

(Supply - Demand) / Supply

1. Avalon at Creekside MV 294 288 438 365 73 0.83 1.27 1.49 15

2. Domicilio SC 306 294 568 439 129 0.77 1.49 1.86 19

4. Mansion Grove SC 924 832 1,654 1,282 372 0.78 1.54 1.79 14

5. North Park SJ 2,760 2,622 4,605 3,409 1,196 0.74 1.30 1.67 22

6. Kensington Place SU 186 182 317 262 55 0.83 1.44 1.70 16

11. City Heights* SJ 93 93 122 99 23 0.81 1.06 1.31 19

13. Paseo Plaza SJ 210 200 373 271 102 0.73 1.36 1.78 24

14. Paseo Villas SJ 104 100 240 148 92 0.62 1.48 2.31 36

16. Skyline at Tamien SJ 115 113 186 132 54 0.71 1.17 1.62 28

18. Ohlone Chynoweth Commons

SJ 176 174 338 241 97 0.71 1.38 1.92 28

20. Almaden Lake Village

SJ 250 242 387 287 100 0.74 1.19 1.55 23

21. Monte Vista SJ 383 383 523 320 203 0.61 0.84 1.37 39

Total 5,801 5,522 9,751 7,255 2,496 Average 483 460 813 605 208 0.74 1.31 1.68 22

Std. Dev. 751 709 1,258 936 324 0.07 Notes MV = Mountain View | SC = Santa Clara | SJ = San José | SU = Sunnyvale * Site 11 has an occupancy rate of 75% (it was the only survey site with an occupancy rate less than 90%). The total number of housing units and parking spaces were adjusted for Site 11 to reflect an occupancy rate of 100%.

TABLE 1 Parking Survey Data

Tamien

Palo Alto

Santa Clara

San Antonio

Mountain View

California Ave

Race

Gish

Bascom

Cottle

Tasman

Diridon

Curtner

Almaden

Whisman

Campbell

Fruitdale

Fair Oaks

Great Mall

River Oaks

Santa ClaraSaint James

Japantown-Ayer

Ohlone-Chynoweth

Paseo de San Antonio

Milpitas

Saratoga

Palo Alto

Cupertino

Los Altos

Los Gatos

Sunnyvale

Menlo Park

Santa Clara

Los Altos Hills

Diridon

Santa Clara

Saint James

Japantown-Ayer

Paseo de San Antonio

Whisman

Mountain View

17

85

101

101

880680

280

87

237

87

237

85

0 0.5 10.25 Miles

Downtown San Jose

Downtown Mountain View

N

0 21 Miles4

VTA LTR stopVTA priority siteCaltrain stopCaltrain priority siteLight RailCaltrainHighwayCounty lineUrbanized areaStudy areaSurvey site nearby

FIGURE 2 Study Area

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factors constant—increases the potential forbuildingmoreunitsby20 to33percent (Arrington& Cervero 2008). Reducing parking ratios shouldresult in lower construction costs, greater housingproduction, higher transit ridership, and improvedoverallphysicalformandperformanceofresidentialdevelopments(Arrington&Cervero2008,48‐51).

Another implication of lowered parking ratiosrelates to urban form. By reducing the amount ofparking (especially surface parking) required at asite, the overall physical form on residentialproperties can be improved to make them moreinviting and pedestrian friendly, and thus more“livable.” Putting lots of surface parking betweenhousing units and the adjacent roads and walkingpathstypicallycreatesbarrierstowalkability.

AREAS OF FURTHER RESEARCH

Mixed‐use developments and TOD projects presentan excellent opportunity for shared‐parkingsituations, which could increase the efficiency ofparking facilities that serve these types of develop‐ments. Dependingon the timeofday, sharedpark‐ing between residents and commercial businesspatronsenables theuseof spaces thatmightother‐wise be unused. If a mixed‐use development islocatedwithinone‐halfmileofatransitstation,thenoverallparkingcouldbereducedandsharedacrossall land uses. By integrating commercial and resi‐dential parking, the overall parking supply will bemore efficiently used. Future research on sharedparking in TOD projects in Santa Clara would beusefulinplanningandpermittingTODprojects.

BOX 2 Parking Utilization Ratios for Survey Sites

Asnotedearlierinthisarticle,parkingliteratureoftenreferstoacriticalthresholdaround85percentutilization,abovewhichpointparkingsupplyisperceivedtobefullbyusersandspilloverorillegalparkingmayoccur.Thisfigureshowsthattheparkingutilizationratesforallsurveysiteswerebelowthiscriticalthresholdof85percent.Therefore,theobservedparkingutilizationcanbeconsideredtorepresentthetotalparkingdemandforthesurveyedsites.

83% 77% 78%74%

83% 81%71%

62%

71% 71%74%

61%

0%

25%

50%

75%

100%

ParkingUtilization

85%CriticalUtilizationThreshold

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POLICY IMPLICATIONS SUMMARY

• LoweredconstructioncostsassociatedwithreducedrequiredparkingcouldincentivizemoreTODresidentialprojectsandsupportotherenhancementstoprojectsdesiredbythelocalagencyandthecommunity.Thecostofconstructingparkingfacilitiesoftenexceeds$30,000perspaceinagarageandabout$5,000perspaceforsurfacelots.Furthersavingscouldbeachievedbyavoidingthecostofmaintainingparkingspacesthatarenotfullyutilized.

• Simplifyinglocalparkingrequirementswouldsavemunicipalitiesstafftimeandresources.Andbyprovidinggreaterpredictability,developersmightpursueTODresidentialprojectsincitiesthatsimplifyparkingrequirements.

• AsmoreareasinSantaClaraCountyareconnectedbyfrequent,convenienttransitservice,therewillbenewopportunitiesforresidentstotakeadvantageoftheaccessibilityandconveniencethatTODresidentialprojectsoffer,andmoredevelopmentsshouldbeabletoreducetheirparkingsupply.TODresidentialprojectsnearnewBRTtransitstationscouldalsohavesimilarlyreducedparkingdemand.

• Byreducingtheamountofparking(especiallysurfaceparking)requiredatasite,theoverallphysicalformonresidentialpropertiescanbeimprovedtomakethemmoreinvitingandpedestrianfriendly,andthusmore“livable.”

TOD residential properties with reduced parkingratios should result in higher transit ridership.Municipalities could then offer an incentive toprivate developers in the form of reduced traffic‐related impact fees. The rationale would be thatsince theseTODresidentialprojectsgenerate fewervehicletrips,theirassociatedfair‐sharecontributiontoroadwaytrafficimpactscouldbelowered.Futureresearch studies could be conducted to verify thatpeople in Santa Clara Countywho choose to live inTODresidentialpropertiesdrivelessoftenandhavefewer cars, thereby reducing their demand forparking.

TheResearchTeamdevelopedaresearchworkplanfor estimating parking demand using stated‐preference user surveys. For reference in futureresearch, a methodology for conducting a usersurveyisincludedinAppendixCofthefinalresearchreportforpartieswhomaywishtoestimatethetotalresidentialparkingdemandatTODsites,particularlyfor those TOD residential projects that exhibit veryhighparkingutilization.

FURTHER READING

Arrington,G.B.andRobertCervero.2008.EffectsofTODonHousing,Parking,andTravel.Washington,D.C.:TransportationResearchBoard.

Cervero,Robert,ArlieAdkins,andCathleenSullivan.2009.AreTODsitesOver­Parked?UCTCResearchPaperNo.882.Berkeley,CA:UniversityofCaliforniaTransportationCenter.

Lee,Richard,RobertRees,andMackenzieWatten.2010.SmartGrowthParkingRequirementsReview.ITEJournal80,no.12:36‐40.

Litman,Todd.2006.ParkingManagementBestPractices.Washington,D.C.:AmericanPlanningAssociation.

Smith,Mary.2005.SharedParking,2nded.Washington,D.C.:UrbanLandInstituteandtheInternationalCouncilofShoppingCenters.

Willson,Richard.2005.ParkingPolicyforTransit‐OrientedDevelopment:LessonsforCities,TransitAgencies,andDevelopers.JournalofPublicTransportation8,no.5:79‐94.

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Abouttheprimaryauthors:

EduardoC.Serafin,PE,AICP(eduardo.serafin@sjsu.edu)servesastheTechnicalProgramManageroftheTechnologyTransferProgramoftheInstituteofTransportationStudiesattheUniversityofCalifornia,Berkeley.Heleadsthetechnicalmanagementofongoingtrainingandprofessionaldevelopmentprograms,aswellastechnicalassistanceservicesforlocalagencies.HeiskeyinthedevelopmentoffuturetrainingprogramstoaddressthedynamicneedsoftheCaliforniaprofessionalcommunityintransportationengineeringandplanning.Mr.SerafinisalsoanadjunctlecturerfortransportationplanningcoursesintheUrbanandRegionalPlanningprogramatSJSU.

JustinM.Meek,MUP(justin.meek@gmail.com)isarecentgraduateofSJSUandiscurrentlyprovidingcontractplanningservicesfortheCityofPacificGrove.HealsoactsasResearchAssistantfortheMinetaTransportationInstitute,servesastheAdministrativeDirectorontheAmericanPlanningAssociationCalifornia‐NorthernSectionboard,andsitsonthePolicyCommitteeforAPA’sHealthyCommunitiesInterestGroup.

Aboutthecollaboratingauthors:

RobertW.Swierk,AICP(robert.swierk@vta.org)isaSeniorTransportationPlanneratVTA.Hehasmorethan10yearsofexperienceintheplanningfield,includingtransitserviceplanning,stationareaplan‐ning,andTransit‐OrientedDevelopment.BeforejoiningVTA,Mr.SwierkworkedasatransportationplannerintheprivatesectorintheTorontoandBostonareas.HeholdsMastersdegreesinCityPlanningandTransportationEngineeringfromUC‐Berkeley,andaBSinGeological&EnvironmentalSciencesfromStanfordUniversity.

YingC.Smith,AICP(ying.smith@vta.org)hascloseto15yearsofexperienceintransportationplanning.InhercurrentpositionasaTransportationPlanningManagerforVTA,Ms.Smithleadsateamofprofes‐sionalplannerstocompleteprogressivetransportationplanninginitiatives,suchaslanduseandtransporta‐tionplanningintegration,guidelinesformultimodaldesigns,andbicycle/pedestrianprograms.Ms.Smithalsohasextensiveexperienceintransitplanning,regionaltransportationplanning,cityplanningandprivateconsulting,andisagraduateofthemaster’splanningprogramatUniversityofNebraska–Lincoln.

Abouttheresearchsponsors:

At San José StateUniversity (SJSU), theDepartment ofUrban and Regional Planning offers graduate studyleadingtothedegreeofMasterofUrbanPlanning.Thisprogram, accredited by the Planning AccreditationBoard,isdesignedtoprepareskilledprofessionalswhoare well grounded in the theories, methods, andtechniques of planning in local, regional, and stategovernmentforthepurposeofimprovingthequalityofurbanregions.Inaddition,itprovidesstudentswithanopportunity fordevelopinga significantbackground inaparticularareaofspecialization,whichincludes:

• CommunityDesignandDevelopment• EnvironmentalPlanning• TransportationandLandUsePlanning• ApplicationsofTechnologyinPlanning

Aspecialmissionofthedepartmentistopromoteplan‐ning education opportunities for a diverse studentpopulation, including working students who prefer toattendtheprogramonapart‐timebasis.

Thedepartmentengages facultyandstudents inpublicserviceprojectsdesignedtoassistlocalcommunitiesinaddressing topical planning issues,while complement‐ing the academic curriculum with real‐world profes‐sionalexperiences.

TheVTAbeganasaCountydepartmentcreatedbytheSanta Clara County Board of Supervisors on June 6,1972 to oversee the region’s transportation system.Until1995,VTA'sprimaryresponsibilitywasthedevel‐opment,operationandmaintenanceofthecounty’sbusandlightrailsystem.VTAseparatedfromtheCountyofSanta Clara and merged with the region’s CongestionManagementAgencyinJanuary1995,thusundertakinganotherresponsibility:managingthecounty'sblueprinttoreducecongestionandimproveairquality.

Workingunder thedirectionofa12‐memberBoardofDirectors, VTA has a $363 million annual operatingbudget(FY'08). VTA's low‐floorbus fleetservesa326square mile urbanized area. The 42.2 mile light railsystemisoperatedwithafleetof100low‐floorlightrailvehicles.

As the multimodal transportation agency for SantaClara County, VTA has a strong interest in seeingtransit‐supportive landuseand transportationpoliciesimplementedbylocalagenciesinthecounty.