MichiganDepartmentofTransportation
EVALUATIONOFR1-6GATEWAYTREATMENTALTERNATIVESFORPEDESTRIANCROSSINGSFinalReport
Preparedby:WesternMichiganUniversityT.Y.LinInternationalFebruary2016
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings
1. Report No. RC-1638
2. Government Accession No. N/A
3. MDOT Project Manager Carissa McQuiston 5. Report Date
4. Title and Subtitle Comparison of Alternative Pedestrian Crossing Treatments 6. Performing Organization
Code N/A
7. Author(s) Ron Van Houten, Jonathan Hochmuth
8. Performing Org. Report No. N/A 10. Work Unit No. (TRAIS) N/A 11. Contract No. 2013-0069
9. Performing Organization Name and Address Western Michigan University 1903 West Michigan Avenue Kalamazoo, Michigan 49008
11(a). Authorization No. Z2 13. Type of Report & Period Covered Final Report 10/01/13 to 2/28/2016
12. Sponsoring Agency Name and Address Michigan Department of Transportation Research Administration 8885 Ricks Rd. P.O. Box 30049 Lansing MI 48909
14. Sponsoring Agency Code N/A
15. Supplementary Notes 16. Abstract. A series of studies evaluated the Gateway configuration of R1-6 in-street signs. A Gateway configuration consists of an R1-6 sign on the centerline, an R1-6 signs on both edges of the roadway, and R1-6 signs on the lane lines if it is a multilane road. The Gateway treatment was markedly more effective than the use of signs only on the centerline or on lane lines. The results showed: 1. That yielding was related to the narrowness of the gaps between signs; that a Gateway configuration consisting of R1-6 signs was markedly more effective than a Gateway made up of blank signs of the same size and background color. Research also demonstrated that mounting edge signs on the curb face was nearly as effective of placing signs in the gutter pan, and that the use of a robust delineator in place of the R1-6 signs on the lane lines was almost as effective as the use of the R1-6 signs on lane lines. This study also examined the efficacy of the Gateway on different types of crosswalk applications, the long-term persistence of effects and sign survival. 17. Key Words In-street sign, R1-6 Sign, Gateway Treatment of R1-6 Sign, Gateway
18. Distribution Statement No restrictions. This document is available to the public through the Michigan Department of Transportation.
19. Security Classification - report Unclassified
20. Security Classification - page Unclassified
21. No. of Pages 98
22. Price N/A
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings
TABLEOFCONTENTSExecutiveSummary 1Introduction 4Chapter1–ConfigurationsInfluencingtheEfficacyoftheGatewayTreatment 11
Chapter2-EvaluationofVariationsthatImprovetheSurvivaloftheGatewayTreatment 26Chapter3-EvaluationoftheGatewayTreatmentinVariousCrosswalkApplications 35
Chapter4-PotentialRoadwayCharacteristicsInfluencingtheefficacyoftheGatewayTreatment 48Chapter5–EvaluationoftheLongTermEfficacyandSurvivaloftheGatewayTreatment 51
Chapter6-CostsforInstallationandMaintenanceoftheGatewayTreatment 53Chapter7Conclusions 54
Bibliography 57Appendix–StatisticalDataAnalysis 59
LISTOFTABLESTableA-1Numberofin-streetsignsitesreportedby11poolfundstates 9
TableA-2Numberofin-streetsignsitesreportedin24cities 10Table1-1Percentageofdriversyieldingtopedestrians 18
Table1-2Meanpercentageofdriversyieldingtopedestriansduringbaseline,theblanksigngatewayandtheR1-6signgatewayconfigurations 22
Table1-3Meanpercentageofdriversyieldingtopedestriansduringbaseline,thefullgateway,R1-6signsonlyattheedgeoftheroadway,andR1-6signsonlyonthelanelines 23
Table2-1Percentofdriversyieldingtopedestriansduringthebaseline,gutterpanplacementandcurbtopplacementconditions 29
Table2-2Percentofdriversyieldingtopedestriansateachcrosswalkduringthebaseline,thegatewaywithallR1-6signs,andthegatewaywithdelineatorcondition 33
Table3-1Percentofdriversyieldingtopedestriansduringeachconditionatthetwotrailcrossings 44
Table3-2PercentofdriversyieldingatthemidblockcrosswalkinAlleganwhentheRRFBwasactivatedandnotactivated,duringbaselineandafterthegatewaywasinstalled 46
Table4-1SelectroadwaycharacteristicsforMDOTproject120239(ResearchonComparisonofAlternativePedestrianCrossingTreatments)andMDOTproject114527(EvaluatingPedestrian
SafetyImprovement)andyieldingresults 49Table5-1Percentofdriversyieldingtopedestriansduringbaseline,initialtemporaryinstallation,
andafterpermanentinstallationateachofthetreatmentsites 51Table6-1Costsforinstallationandmaintenanceofthegatewaytreatment 53
Table6-2Removalandreinstallationtimesforgatewaytreatment 53
LISTOFFIGURESFigure1-1Diagramfortypicalsignplacementforgatewaytreatment 12
Figure1-2R1-6Signmountedonacurbtypebaseaffixedtotheroadway 16Figure1-3AblanksignthesamesizeastheR1-6signmountedtoaremovablebase 16
Figure1-4Arobustdelineatorattachedtoabasecementedintothepavement 17
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings
Figure1-5DriveryieldingattheMarshallTrafficCircleNWcrosswalkleg 19Figure1-6In-streetsignshowingagatewaywithallR1-6signs 20
Figure1-7In-streetsignshowingagatewaywithallblanksigns 20Figure1-8Percentageofdriversyieldingtopedestriansduringeachconditionatthetwocrosswalks
onRoseStreetatAcademy 21Figure1-9Percentageofdriversyieldingtopedestriansduringeachconditionatthetwocrosswalks
onRoseStreetatKVCC 22Figure1-10Driverspeedapproachingthecrosswalkatthedilemmazone(blueline)andatthe
crosswalk(redline)duringbaselineandgatewayconditiononRoseStreet 24Figure2-1GatewayconfigurationwiththeedgesignonthecurbatacrosswalkonHuronStreet 27
Figure2-2Percentofdriversyieldingduringeachconditionoftheexperiment 29Figure2-3Percentofdriversyieldingduringeachconditionoftheexperiment 30
Figure2-4Percentofdriversyieldingduringeachconditionoftheexperiment 30Figure2-5Percentofdriversyieldingduringeachconditionoftheexperiment 31
Figure2-6Gatewaytreatmentwithdelineatorsplacedonwhitelanelines 32Figure2-7PercentageofdriversyieldingtopedestriansatRoseandAcademyduringbaseline,the
R1-6gatewayconditions,andthegatewaywithdelineatorcondition 33Figure2-8PercentageofdriversyieldingtopedestriansatRoseandKVCClocationduringbaseline,
R1-6gateway,andgatewaywithdelineatorconditions 33Figure2-9PercentageofdriversyieldingtopedestriansatWestnedgeandRaneyduringbaseline,
theR1-6gatewayconditions,andthegatewaywithdelineatorcondition 34Figure3-1Left:widegateway.Right:narrowgateway 35
Figure3-2DriveryieldingattwocrosswalksatatrafficcircleinMarshall,Michigan 36Figure3-3Gatewayconfigurationatoneoftheroundaboutlocations 37
Figure3-4Percentageofdriversyieldingduringthebaselineandgatewaytreatmentsatthetworoundaboutlocations 37
Figure3-5Ratioofdriversyieldingtopedestriansuponenteringandexitingtheroundaboutduringthebaselinecondition 38
Figure3-6PhotographofthesidewalkapproachingthenorthentrancetoInterstateI-94atWestnedgeAvenue 39
Figure3-7Left:wideconfigurationofthegateway.Right:narrowconfigurationwithdelineator 39Figure3-8PercentageofdriversyieldingtopedestriansatnorthandsouthentrancerampstoI-94
duringeachconditionoftheexperiment 41Figure3-9WidegatewayconfigurationonOaklandStreet 42
Figure3-10WidegatewayconfigurationonatthetrailcrossingonGardenLane 43Figure3-11Percentofdriversyieldingtopedestriansduringeachconditionatthetwotrail
crossingsduringeachtreatmentcondition 44Figure3-12RRFBlocationinAllegan,Michigan 45
Figure3-13DiagramofintersectionofMainStreetandBennettStreet,ThreeRivers,Michigan 46Figure3-14Percentofdriversyieldingatthelegofanintersectionwithgatewaytreatmentand
otherlegofintersectionthatwasnottreated 47Figure4-1StudyAreaMap 50
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings
LISTOFACRONYMSAverageDailyTraffic ADT
Baseline BLFederalHighwayAdministration FHWA
InstituteofTransportationEngineers ITEManualonUniformTrafficControlDevices MUTCD
MichiganDepartmentofTransportation MDOTMilesperHour mph
MinnesotaDepartmentofTransportation MNDOTNationalCooperativeHighwayResearchProgram NCHRP
NationalHighwayTrafficSafetyAdministration NHTSAPedestrianHybridBeacon PHB
RectangularRapidFlashingBeacon RRFBWesternMichiganUniversity WMU
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 1
EXECUTIVESUMMARYTheGatewayconfigurationofR1-6,instreetsigns,hasbeendocumentedtoproduceamarkedincreaseindriveryieldingtopedestriansovertheuseofasinglesign.FigureashowsaGatewayconfigurationwith a signon the centerline, a signs at the edge of the road, and signson the
whitelanelinesthatdivideslanes.In2013,theMichiganDepartmentofTransportation(MDOT)initiated a multi-year study with Western Michigan University (WMU) in order to evaluatefactorsrelatedtotheefficacyofagatewaytreatmentusingR1-6signs(gatewaytreatment);the
longtermeffectsofpermanentinstallations;configurationsthatcontributetotheeffectivenessofthetreatment;andthelong-termsurvivalofthetreatment.
Figurea.ApictureofaGatewayconfigurationofR1-6signs.
Aseriesofstudieswerecompletedinordertodeterminetheeffectivenessofthein-streetsigngatewaytreatment,determinewheretheyshouldbeused,anddeterminethecostbenefitsofusingthein-streetsigngatewaytreatmentincludingoperation,maintenanceandreplacement
costsandcomparativeanalysiswiththeRRFBandHybridBeacon.Inordertoaddresstheseobjectives,theWMUteamconductedanumberofactivities;eachiscapturedasanindividualchapterofthisreport.Althougheachoftheseinterventionswereonlycomparedatarelatively
smallnumberofsites,eachconditionwasintroducedmultipletimesateachsiteproducingmultiplereplicationsofeachcondition,theobviouslargechangesindriverbehavior,andtheconsistencyofresultsatthesesitessuggestthatthesefindingarerobust.Thisconclusionis
supportedbythestatisticalanalysisreportedintheappendixtothisreport.Alloftheconfigurationstestedincreaseddriveryieldingbehavior.
One hypothesis examined was that the narrowness of the gap between the signs would beinversely related to treatment effect size. This hypothesiswas confirmedwith narrower gaps
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 2
leading to larger increases in driver yielding right-of-way to pedestrians. Another hypothesis
tested was that the sign message itself had little influence on driver yielding behavior. Thishypothesiswasfoundtobeincorrect;agatewayconfigurationconsistingofallblanksignswassignificantly lesseffectivethantheGatewayconfigurationwiththemessagepresent(standard
R1-6signs).Aconfigurationanalysisalsoshowedthatthepositionofthesignisacriticalfactorinfluencing
driveryieldingbehavior.Notallpositionsusedinisolationresultedinthesamedegreeofdriveryielding right-of-way to pedestrians. Signs placed on the white lane line alone exertedmorecontrol over driver yielding behavior than signs placed at the edge of the roadway positions
alone at all sites and both types of placements produced less yielding than the full Gatewaytreatment. However, the partial effects produced by all of the partial gateway configurationsshowsthatifasignishitduringaseasonandnotreplaceduntilthefollowingyearwhenallthe
signsarereinstalledafterwinter,theremainingsignswouldstillbeofbenefittopedestriansfortheremainderoftheseason.
SpeeddatacollectedatonesiteshowedtheGatewaytreatmentisassociatedwithlargespeedreductions evenwhen pedestrianswere not present at the crosswalk and that drivers beganslowingatthedilemmazone.Thesedatasuggeststhatthespeedreductionislikelygradual.This
is an important finding because reduced speed gives drivermore time to respond to avoid acrash.Thisfindingrequiresfurtherreplication.
Although these studies and previous conducted research (2) demonstrate that the gatewaytreatmentproducedchanges indriveryieldingbehaviorat crosswalksonmultilane roads thatrivalstreatmentsthatareoneandtwoordersofmagnitudemoreexpensivetoinstall,itisalso
importanttoshowthatthistreatmentwillnotrequireexcessivemaintenanceefforts. Inareasrequiringsnowremoval,thesignswouldneedtoberemovedduringthewintermonths.Mostofthesignstestedcanberemovedandreinstalledquicklyaftertheinitialinstallation.Although
in-street signs are designed to rebound after being struck, sign survival withmultiple strikeswouldbeexpectedtobeanissue.
Two configurations were tested that should greatly increase sign survival only producedmoderatedecrementsintheefficacyoftheGatewaytreatment.Thefirstconfigurationtested
involved installingsignsontopof thecurb facerather than in thegutterpan (requiredFHWApermissiontoexperiment).Placingsignsontopofthecurbwasonlyassociatedwithonlyasmallreductionintheeffectivenessofthetreatment.Signsontopofthecurbfacearelesslikelytobe
struck thansignsplaced in thegutterpananddonotpresentaproblemfor sweepersnordotheyintroducepotentialdrainageissues.
The most vulnerable element of the sign configuration is the signs placed on white linesseparating lanes carrying traffic in the same direction. The substitution of a robust flexibleyellowgreendelineatordevicefortheR1-6signwouldbeexpectedto increasethesurvivalof
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 3
signs placed on thewhite lane lines. A delineatorwas selected thatwas tested by the Texas
TransportationInstituteandfoundtosurvive100strikesat60mph.Thistypeofadeviceshouldhaveanevenlongerlifespanonurbanroadswithspeedlimitsof35mphorless.DatareportedinChapter2showsthattheuseofarobustdelineatoronlyproducedamodestreductioninthe
effectivenessoftheGatewaytreatment.Ifthereisamedianorrefugeislandtheuseofcurbtopplacement and use of a delineator at the lane line covers all installations with devices thatshouldprovideatroublefreeinstallationformanyyears.
MostoftheapplicationstudiedinanearlierMDOTstudyexaminedtheefficacyoftheGatewaytreatmentatcrosswalksonarterialorcollectorroadsandatuncontrolledcrosswalkslocatedat
the intersectionwith a stop controlledminor road. Amap of locations used for this study isprovidedinChapter4.ThisresearchalsoevaluatedtheGatewaytreatmentinavarietyofnewcrosswalk applications, including traffic circles, roundabouts; interstate entrance ramps, and
trails crossings. The results of these studies showed: theGateway treatmentwasmoderatelyeffectiveatthetrafficcircleandtworoundaboutlocations,particularlyatcrosswalksexitingtheroundabout.Theapplicationat interstateentrancerampsonlyproducedmarginal increases in
yieldingbehavior.TheGatewayisthereforenotrecommendedforthistypeofapplication.TheGatewaywashighlyeffectiveatoneofthetwotrailcrossingsbutonlymoderatelyeffectiveatthe second crossing that had a higher operating speed. Another study replicated an earlier
findingthattheGatewaytreatmentcanincreaseyieldingatanRRFBsitetoveryhighlevels.Thefinal study in this series found that treating only one crosswalk leg at an intersectionwith aminorroadcouldimproveyieldingattheuntreatedcrosswalkleg.
Permanent installation of these sites provided preliminary evidence of the long-termpersistenceofincreaseddriveryieldingright-of-waytopedestriansatGatewaylocationsandthe
long-term survival of the Gateway treatment. Results only demonstrated that the signsmaintained their effectiveness in Ann Arbor over two months and at the sites in thesouthwesternsideofthestateforthree-monthsbecausethesesignsneededtoberemovedfor
winter. Because the signs were only installed for two months in Ann Arbor and only threemonths at the sites in southwest Michigan, supplemental data will be required in order toprovide clear evidence that the effects persist over time. Preliminary data on sign survival
indicate that Gateway signsmounted in the roadway on installable curb basesmay bemorerobust than signs installed flush with the roadway and that the robust flexible delineator
installedona lane linecansustainmanyhitsbutmaynotsurviveforanentireseasonatsiteswithhigherspeedsandhighADT.
ThefinalchapterprovidedinformationonmaterialsandapproximatesinstallationcostsforeachoftheelementsoftheGatewaytreatment. Thesedatashowthat it isarelatively inexpensivetreatment. Most items can be removed easily in winter and reinstalled easily in the spring.
Estimated removal and reinstallation costswere also provided. The final chapter provides anoverviewoftheconclusionsreachedbytheresearchteamaspartofeachtaskofthemulti-yearstudyandcostdataforvariousGatewaypedestriancrossingconfigurations.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 4
INTRODUCTIONIn2013, theMichiganDepartmentofTransportation (MDOT) initiatedamulti-year studywithWesternMichiganUniversity(WMU)inorderto:1.Evaluatefactorsrelatedtotheefficacyofa
gatewaytreatmentusingR1-6signs(gatewaytreatment),2.Determinethelong-termeffectsofpermanent installations,and3.Examineconfigurations that contribute to theeffectivenessofthetreatment.
As MDOT would like to increase its focus on reducing the number of pedestrian crashes inMichigan as part of the Toward Zero Deaths statewide safety campaign, the WMU/T.Y. Lin
International team (hereafter referred to as the “WMU team”) proposed the followingobjectives:
1. Determinetheeffectivenessofdrivercompliancewithgatewaytreatmentincomparisontotherectangularrapidflashbeacon(RRFB)andthepedestrianhybridbeacon(PHB).
2. Determinewhereandwhenthegatewaytreatmentshouldbeusedandthemosteffective,configurationsoftheR1-6signs.
3. Determinethecostbenefitsofusingthegatewaytreatmentincludingoperation,maintenanceandreplacementcostswiththeRRFBandPHB.
Inordertoaddresstheseobjectives,theWMUteamconductedanumberofactivities;eachiscaptured as an individual chapter of this report. The following provides an outline of the
individualchaptersandtherebytheactionstakenaspartofthismulti-yearstudy:Chapter1–ConfigurationsInfluencingtheEfficacyoftheGatewayTreatment.
Chapter2–EvaluationofConfigurationsthatImprovetheGatewayTreatmentSurvival.Chapter3–EvaluationoftheGatewayTreatmentConfigurationinVariousApplications.Chapter4–PotentialRoadwayFactorsInfluencingtheEfficacyoftheGatewayTreatment.
Chapter5–LongTermEfficacyandSurvivaloftheGatewayTreatment.Chapter6–CostsAssociatedwithInstallationandMaintenanceoftheGatewayTreatment.Chapter7–Conclusions.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 5
LITERATUREREVIEWTraditionalApplicationsoftheIn-StreetSignAlthoughpedestriancrashesaccountforonly1percentofreportedmotorvehiclecrashesinthe
UnitedStates,theyaccountfor14percentoffatalcrashes(1).Zegeeretal.(2)comparedcrashesat1,000markedand1,000matchedunmarkedcrosswalksin30U.S.cities.Thestudyfoundnosignificantdifferenceincrashesbetweenmarkedandunmarkedcrosswalksatsites
withonelaneineachdirection,buthighercrashratesatmarkedcrosswalksonmultilaneroadswithanuncontrolledapproachwhentheroadhadaverageannualdailytraffic(AADT)above12,000withoutaraisedmedian,andabove15,000witharaisedmedian.Theyalsoobserveda
higherincidenceofmultiplethreatcrashesatthesesites.Thesedatashowtheneedforlowcostcountermeasurestoincreaseyieldingtopedestriansatcrosswalksonmultilaneroadswithmoderatetohighlevelsofaveragedailytraffic(ADT).Currenttreatmentsincludethe
rectangularrapidflashingbeacon(RRFB),whichcostsaround$20,000perinstallationandthepedestrianhybridbeacon(PHB)thatcosts$100,000perinstallation.Boththesetreatmentsshouldbeusedwithadvanceyieldorstopmarkingstoencouragedriverstoyieldfurtherfrom
thecrosswalk.Whenthesetreatmentsareusedtogether,theRRFBorPHBincreasesyieldingwhiletheadvancestopandyieldmarkingsprimaryinfluencesafetybyreducingtheprobabilityofamultiplethreatcrash.Itshouldbenotedthatthecostsassociatedwiththeinstallationof
theRRFBandPHBtreatmentslimittheirdeployment.Onewaytoimprovethesafetyatpedestriancrossingsistheuseofthein-streetsign.Thissignis
installedintheroadwayandremindsdriversthatitisthelawtoyieldtopedestrianswithincrosswalks.Oneadvantageofthisdeviceisitrequiresnoactionfromthepedestriantoactivatethedeviceanditisthereforeactiveforeverycrossing.Manystudieshavedocumentedthat
placing“YieldtoPedestrianSigns”intheroadwaycanincreasethepercentageofmotoristsyieldingtopedestrians(3,4)Huang,Zegeer,andNassi(3)evaluatedtheeffectsofin-street“STATELAW:YIELDTOPEDESTRIANSINYOURHALFOFROAD1”signsplacedinthemiddleofthe
crosswalkondriveryieldingbehaviorat7locations.Yieldingincreasedfrom70%beforethesignswereinstalledto81%afterthesignswereinstalled.Thein-streetsignproducedlargereffectsthananoverheadcrosswalksignorapedestrianregulatorysigninthisstudy.The
authorsalsonotedthattherewerereportsthatsomemotoristsranoverthein-streetsignsintentionally.Althoughin-streetsignsaredesignedtorecoverwhenstruckbyvehicles,repeatedstrikes,orhigh-speedstrikescanpermanentlydamagethesesigns.
In-streetsignswerealsoevaluated(4)inastudyjointlyfundedbytheTransitCooperativeResearchProgramandtheNationalCooperativeHighwayResearchProgramthatcompared
severaltreatmentstoimprovemotoristyieldingtopedestriansatunsignalizedintersections.Theresearchteamcollecteddataonmotoristyieldingbehaviorat42crosswalksindifferent
1 It should be noted that Michigan does not have a state law on yielding to pedestrians incrosswalks, instead local ordinances or local adoption of the Uniform Traffic Code need toaddressROWinMichigan(otherthanatsignalizedintersections).
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 6
regionsoftheUnitedStates.Theresultsindicatedthatin-streetsignswereassociatedwith
yieldingratesof87%ontwolaneroads.In-streetsignsweresuperiortoyellowoverheadflashingbeacons,pedestriancrossingflags,andin-roadwaywarninglights.Onlyaredsignalorredbeacondevicesproducedhigheryieldingbehaviorthanin-streetsigns.Theresultsofthe
studyshowedin-streetsignstobehighlycosteffectiveinincreasingyieldingbehavioratcrosswalksthattraverseroadswithonelaneineachdirection.Dataalsoshowedthatin-streetpedestriansignsperformedequallywellonroadswith25and30mphspeedlimits.Theywere
notevaluatedonroadswithhigherspeedlimits.Theauthorsalsoconcludedthatthesesignswerenoteffectiveonmulti-laneroadsandonlyrecommendedtreatmentswitharedindicationatthesesites.
Onestudyexaminedtheeffectofplacingthesesignsonthecenterlineatthecrosswalkline,20feetinadvanceofthecrosswalkline,and40feetinadvanceofthecrosswalklineatthree
crosswalksondriveryieldingbehaviorontwo-laneroads(5).Atoneofthethreelocationsplacingthesignatthecrosswalklineorinstallingthreesignswassignificantlymoreeffectivethaninstallingthesignat20or40ftinadvanceofthecrosswalk.Atanothersiteinstallingthe
signatthecrosswalklineorinstallingallthreesignswassignificantlymoreeffectivethaninstallingthesign40ftinadvanceofthecrosswalk.Overallitappearedthatinstallingthesignsatthecrosswalklinewasaseffectiveormoreeffectivethaninstallingthesigninadvanceofthe
crosswalkorinstallingthesignsatallthreedistancesfromthecrosswalk.Atoneofthethreesites,pedestrianswereoftentrappedinthemiddleoftheroadduringthebaselinecondition;thein-streetsignwashighlyeffectiveinreducingthenumberoftrappedpedestriansregardless
ofwhereitwasplaced.Itshouldbeexpectedthatlargeincreasesinyieldingshouldbeassociatedwithreductionsinthepercentageofpedestrianstrappedinthemiddleoftheroadwaywhereverthisproblemexits.Thesedatasuggestthatthein-streetsignsaremostlikely
effectivebecausetheplacementinthestreetisparticularlysalienttodrivers.Anotherstudy(6)replicatedtheVanHouten,et.al.(5)studybycomparingplacingsignsatthe
crosswalkline,withplacingthem30ft,60ft,90ftand120ftinadvanceofthecrosswalklineon8two-laneroads.Theyfoundthatthein-streetsignplacedatthecrosswalkwasmoreeffectivethansignsplacedinadvanceofthecrosswalk.Theyalsoexaminedwhethertheinstallationsof
anin-streetsigninfluencedvehiclespeedandfoundthein-streetsignssignificantlylowervehiclespeedsatthecrosswalkinbothdirectionsat7ofthe8sites,andinonedirectionatthe
remainingsite.Theseresultsarepromising,howeverallsiteshadverylowpostedspeedlimits(25mphat5sitesand20mphatthe3remainingsites).Kannel,Souleyrette,&Tenges(7)alsoreportedasmallreductioninspeedatasingleconventionalin-streetsignlocationpostedat30
mph.EvaluationofaGatewayInstallationonMultilaneRoads
Onelimitationofthein-streetsignisitsfailuretoproducehighlevelsofyieldingonmultilaneroads.Shurbutt,VanHouten,Turner,andHuitema(8)documentedhowtheefficacyofanotherpedestriancrosswalkcountermeasure,theRRFB,couldbeincreasedbyintroducingathird
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 7
deviceonthemedianislandproducingatypeof“gateway”visualeffectforapproachingdrivers.
BennettandVanHouten(9)usedagatewayconfigurationofthein-streetsign(theuseofasignonthelanelineandtworoadwayedgesigns-threesignsforeachtwolaneapproachtothecrosswalk)producedamarkedimprovementinyieldingatmultilaneuncontrolledcrosswalks
thatwascomparabletothoseproducedbyanRRFBorPHB(10,11).Onereasonthegatewayin-streetsignconfigurationwassoeffectivemayhavebeentheperceivednarrowingoftheroadwayproducedbyaddingsignsonbothsidesoftheroadoutsidethelaneseventhoughthe
widthofthetravelwayitselfwasnotactuallynarrowed.Itisalsolikelythatthreesignsweremorevisiblethanonesign,particularlyifvehiclesaheadofamotoristapproachingthecrossingblockedthemotorist’sviewofthelocationofthesinglesign.
Itisalsopossiblethatthegatewayeffectacquiredcapturesdriverattentionindependentofaperceivednarrowingeffect.Thisrationaleissupportedbyresearchshowingthegateway
configurationoftheRRFBalsoproducedamarkedeffecteventhoughbeaconswerenotintheplacedintheroadway.In-streetsignsmayalsoprovidebetterdelineationoftheedgeoftheroadwaywhentheyarepresent.Specifically,theboundariesoftheroadareextendedvertically
viathesigns.Adrivermayignoretheboundariesoftheroadwhiledriving.However,whenthevisualboundariesaremademoresalient,itmaycausedriverstoslowdown.Thiseffectmayoccurbecauseitreducesthenarrowingofperspectivethatoccurswhensomeoneisdriving
makingitmorelikelythedriverwillattendtoapedestrianstartingtocrossattheedgeoftheroad.
BecausethedatareportedbyBennettandVanHouten(9)werecollectedovermonths,theyalsocapturedtheeffectivenessoftheinterventionovertime.However,itisnotknownwhethertheseresultswillbesustainedoverlongerperiodsoftime.Researchisneededtoaddressthis
questionaswellasdataonhowthein-streetsignperformsatnight.InstallationoftheIn-StreetSignatRRFBandPHBSites
DatacollectedbyDr.VanHoutenforMDOT(12)alsorevealedthattheRRFBandPHBproducedpooreryieldingresultsinMichiganthandatacollectedinalarge-scaleFHWAevaluation.DatacollectedinareviewconductedbyDr.VanHoutenalsoshowedthatthisproblemwasnot
uniquetoMichigansiteswithsimilarresultsreportedinKansasandPortland,Oregon(13,14).Itislikelythepoorerresultsareafunctionofthesmallernumberofunitsinstalledinsometest
communitiesandtherelativelylowerlevelofoutreacheffortsatsitesthatwerenotpartoftheFHWAresearchproject.DatafromtheMichigansitesseemtoconfirmthisfinding.DatacollectedbyintheMDOTstudyalsosuggestthattheuseofthein-streetsignatnewRRFBand
PHBsitesmaybearelativelylowcostalternativetolarge-scaleoutreachefforts.BennettandVanHouten(9)foundthatasinglein-streetsignatRRFBandPHBsitesinMichiganproducedhigherlevelsofyieldingthanRRFBorPHBtreatmentsusedalone.
Itisimportantthatadditionalstudiesexaminetheinteractionofthein-streetsignwiththeRRFBandPHBinordertodeterminewhyitiseffect.Onequestionthatneedstobeaddressedis
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 8
whetherdriverslearntorespondtobettertotheRRFBandPHBinstallationswithoutthein-
streetsignafterithasbeenpairedforaperiodofmonthswiththein-streetsign.
TheRoleofAdvanceStoporYieldSignandMarkingsWheneverdriversyieldrightofwaytopedestriansonmultilaneroadwaysandstopsclosetothecrosswalkline,theycanscreentheviewofpedestriansfromvehiclesapproachinginadjacent
lanes,increasingtheprobabilityofmultiplethreatcrash.Aseriesofexperiments(15,16,17,18,19)hasdemonstratedthatthecombinationofadvanceyield/stopmarkingsalongwith“Yield/StopHereforPedestrian”signsinadvanceofthecrosswalkreduceddriver/pedestrian
evasiveconflictsby67%to87%andproducedalargeincreaseinthedistancemotoristsyieldedinadvanceofthecrosswalk.Thesedatastronglysupportalwaysusingadvancemarkingsatuncontrolledcrosswalksitesassociatedwithincreasedriskofmultiplethreatcrashes.These
sitesincludethosewithADTabove12,000withoutaraisedmedianand15,000witharaisedmedian.
QuestionstobeAddressedbyFurtherResearchTheresultsofthisresearchwillassistMDOTindetermininghowtomaximizepedestriansafetybenefitswithlimitedfinancialresources.Evaluatingtheimpactofthein-streetsigngateway
treatmentinavarietyofdifferentcrossingapplicationscouldhelpidentifypotentialapplicationsofthistreatmentoption.Itisalsoimportanttodeterminehowmuchthevisualnarrowingeffectofthegatewaytreatmentcontributestotheeffectandwhethersimilareffectscouldbe
obtainedbyusingdelineatorswithoutthein-streetsignmessage.Anotherissuethatrequiresstudyishowtoextendtheusefullifeofin-streetsigns.Onewaytoreducedamagetothesesignsistoplacethematroadwaylocationswheretheyarelesslikelytobehit.Therearea
numberofplacementstrategiesthatcouldextendthelifeofthesesigns,whichshouldbeevaluated.Additionalresearchshoulddeterminetheconditionswherethein-streetsigngatewaytreatmentcanbesubstitutedformoreexpensiveRRFBandPHBtreatments.
Newtrendsintrafficengineeringresearchhavefocusedondeterminingtheconditionsunderwhichatreatmentiseffective,andhowtooptimizethetreatment.Forexampleintworecently
fundedFederalHighwayAdministration(FHWA)studies,EllisandVanHouten(20)documentedhowmatchingcountermeasurestocrashtypesinMiamicouldreducepedestriancrashesinhigh
crashzonesby50%,andShurbutt,VanHouten,Turner,andHuitema(8)documentedhowtheefficacyoftheRRFBcouldbeincreasedbyfinetuninghowitisinstalledandhowitisoperated.ArecentlypublishedNationalHighwaySafetyAdministration(NHTSA)fundedstudy(21)has
alsodemonstratedhowthein-streetsigncouldbeusedaspartofanpedestrianright-of-wayenforcementprogramtoproduceacultureshiftinyieldingright-of-waytopedestriansonacitywidebasis.Ithasbeenlongknowthatresultsmayvaryfollowingtheimplementationofsignage
andtrafficcontroldevices.Inordertomaximizeresultspractitionersneedtobetterunderstandwhere,andhowtoimplementthesedevices.Itisalsoimportanttodeterminewhatvariablesinfluencingthelifespanorsurvivalofthesesignssincethisimpactsreplacementand
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 9
maintenancecosts.Researchonthein-streetsignshouldaddresstheseissuesaswellas
examinethelifespanofthesesignsusingdifferentstrategiestodevelopguidelinestobestinsureinstallationsarepracticalaswellascosteffective
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 10
SURVEYONUSEOFR1-6SIGNA survey was sent out on our behalf from FHWA to states participating in the pooled fundresearchprogram.Thesurveyaskedrespondentstoidentifythestate,anestimateofhowmany
in-street pedestrian crossing sign (R1-6, or R1-6a) have been installed in their state,whethertheywereaware ifanyonehadperformedacrashanalysisof theeffectivenessof thesesigns,andifacrashanalysishadbeenperformed,contactinformationtolearnmoreabouttheresults
of the study. We received feedback from the following 11 states: Florida, Iowa, Kansas,Minnesota, Missouri, Nebraska, New Hampshire, North Carolina, Oregon, Pennsylvania, andSouthCarolina.Noneofthestatepoolfundcoordinatorswereawareofanyresearchonthese
signs. With the exception of Pennsylvania, Minnesota, New Hampshire, and North Carolina,stateofficialsstatedtheyonlyreportedthenumberinstalledonstateroadsanddidnotattempttoestimatethenumberofsignsinstalledbycitiesandmunicipalities.Therefore,thislistshould
be considered to be a conservative estimate because inmost cases they only included thoseinstalledonstateroads. Pennsylvaniamentionedthattheypaidforall in-streetsignsinstalledby municipalities in the state since 2001, and therefore, the number they provided can be
viewed as accurate. New Hampshire mentioned that their number included in-street signspurchasedformunicipalitiesbutthattheyhadnoknowledgeofadditionalsignsmunicipalitiesmay have directly purchased and installed. Table A-1 shows the results of the pooled fund
survey.ThestateofPennsylvaniahadthelargestnumberinstreetsigns(7500).Itisnotknownwhetheranyofthesesignsareinstalledonmultilaneroads,andthereisnoindicationwhetheranyofthesesignsareinstalledinagatewayconfiguration.
TableA-1.Thenumberofin-streetsignsitesreportedby11poolfundstates.
State NumberofInstallations
Florida 24
Iowa 15
Kansas Afew
Minnesota 500
Missouri 0
Nebraska 5
NewHampshire 36
NorthCarolina 400
Oregon 0
Pennsylvania 7,500
SouthCarolina 0
Additionaldataonin-streetsigninstallationswerecollectedfromavarietyofcitiesaspartofaNCHRP study that is examining crash modification factors for various pedestrian safetycountermeasures. In-streetsignswerenotselectedasacountermeasurebecause thesesigns
were rarely reported be installed on roads with higher crash rates, such as crosswalks atmultilanelocations.Thenumberofin-streetsignsitesforeachcityisshowninTableA-2.Thesedatashowthattheuseofthistreatmentvariesconsiderablefromcitytocity.Atlantareported
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 11
having the most crosswalk sites with a total of 300, withWashington, D.C. reporting having
several 100 sites. The cityofArlington said theywill only replace in-street signs2or3 times.Atlantasaidtheyusedthemonalltypesofroads.ThecityofPittsburgsaidtheytaketheresignsdownatnightandthecityofCambridgesaidtheyremovethesignsduringthewintermonths.It
is clear thateach jurisdictionhasestablished theirownprocedures for theuseof thesesigns.Onlyonecity,Gainesville,FL,reportedusingagatewaytreatmentandtheyweresatisfiedwiththe performance of the gateway in-street sign installations on multilane roads. Gainesville
installed gateway in-street signs after learning of the data reported by MDOT. Subsequentinformation showed use of the gateway treatment in San Antonio, Texas and Palm Springs,California.
TableA-2.Thenumberofin-streetsignsitesreportedin24cities.
City State NumberofSites Notes
Phoenix AZ None
Scottsdale AZ 2 “YieldtoPedestrians”inDowntownArea
Tucson AZ 0
LaMesa CA 6
LosAngeles CA Many
SanFrancisco CA Afew Notsurehowmanyremain
SantaMonica CA Afew
Boulder CO 6-12 Text on in-road sign is “State Law - Yield toPedestrians”
Washington DC 100’s
Gainesville FL 6 Workwell,twogatewayinstallations
St.Petersburg FL None Nonein-road;mountedbehindcurbatstopbar
Atlanta GA 300 Alltypesofroads
Chicago IL 39 Installedin2011-2012,“StopforPedestrians”
Cambridge MA 12 Removedduringsnowmonths
Columbia MO ~25
Springfield MO 15-20
Charlotte NC 20-25 Mostwithrefugeisland
NewYork NY 0 They’redoingsignreduction;veryfewofthese
Portland OR Afew
Pittsburgh PA 20 Takethemdownatnight
Alexandria VA ~50
Arlington VA Some Don’treplaceafter2-3replacements
Kirkland WA 0
Milwaukee WI 40-50
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 12
CHAPTER 1 – CONFIGURATIONS INFLUENCING THE EFFICACY OF THEGATEWAYTREATMENT
INTRODUCTION
Pedestrian fatalities steadily decreased nationally from 5,801 pedestrian fatalities in 1991 to
their record low of 4,108 in 2009. Pedestrian fatalities began to rise in 2010 to 4,302 andcontinued to rise until 2012 when there were 4,818 pedestrian fatalities. 2013 saw a slightdecreaseof2%inpedestrianfatalitieswithatotalof4,735(22).
AttemptstoimprovepedestriansafetydatebacktoancientRome.The2,000-year-oldruinsofPompeiicontainedraisedstonesforpedestrianstousetocrossroads.Theseraisedcrosswalks
had gaps for the wheels of the cart to pass through. This design served as a form of trafficcalmingbecause thecartdriverneeded to slow inorder toalign thecartwheelswithgaps inraised crossways. Such a configuration couldbe thoughtof as a typeof gateway through the
crosswalk.Bennett,ManalandVanHouten(9)placed in-streetsignsoneachsideofamulti-laneroadat
uncontrolledcrosswalks,on the lane linesandon thecenter line.Thisnovel interventionwasreferred to as the gateway treatment. A diagram showing the placement of signs for thegateway treatment is shown in Figure 1-1. Additional configurations for varying roadway and
crosswalkcharacteristicsareprovidedintheUserGuide.
The 2009 version of the MUTCD (23) states that In-Street Pedestrian Crossing sign shall beplacedintheroadwayatthecrosswalklocationonthecenterline,onalaneline,oronamedianisland.Itdoesnotpermitplacementonasignpostatthesideoftheroadorontopofthecurb.
ThereforeFHWApermissiontoexperimentisrequiredtoplacethemontopofthecurbattheoutsideedgesoftheroadbutnotonthecurbofarefugeormedianisland.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 13
Figure1-1:DiagramofTypicalSignPlacementforGatewayTreatment
Thistreatmentusessixsignsforafour-laneroaddividedbyamedianorrefugeisland,andfivesigns for a crosswalk without a median or refuge island. The gateway treatment produced
markedincreasesinthepercentageofdriversyieldingatavarietyofcrosswalklocationsacrossMichigan.Yieldingratesincreasedfromabaselineaverageoflessthan25%to79%atonesiteand from23%to82%atanother site.Prior researchhaddemonstrated thata single in-street
sign installed on the centerline was effective on two lane roads with a travel lane in eachdirection but were relatively ineffective on streets with two or more travel lanes in eachdirection(4).
Thegatewaytreatmentalsoproducedhighyieldingresultswhenusedinconjunctionwithtwoprovenalternativeinterventions,therectangularrapidflashbeacon(RRFB),andthepedestrian
hybrid beacon (PHB)(9). The price of the gateway in-street sign treatment is relatively low at(approximately$200to$300persignandbase)andthusmaybemorecosteffectivethantheRRFB (estimated cost of $20,000) or the PHB (estimated cost of $100,000). However, little is
knownabouthowoftenthesignsmayneedtobereplaced.TheBennett,ManalandVanHoutenexperimentdidnottesttheeffectsofnarrowingtheroadusingthesigns,theeffectofthesignmessage,ortheeffectsofthesignsatdifferenttypesofpedestriancrosswalks.
The gateway treatment is both a traffic control device aswell as a geometric designelementbecause it involves the perceived narrowing of the roadway at the crosswalk. The gateway
treatmentcanbeviewedasa trafficcalmingdevicebyvisuallynarrowing the travelpathofadriver, and thereby inducing the driver to slow down when approaching the gap. Researchassistants all noticed an increase in driving scanning for pedestrians when the gateway was
IN-STREET PEDESTRIAN CROSSING SIGN EDGE ALIGNED WITH PARKING LANE
FLEXIBLE DELINEATOR
IN-STREET PEDESTRIAN CROSSING SIGN PLACED IN GUTTER PAN
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 14
present.Futureresearchshoulddirectlymeasuredriver-scanningbehavior.Thesignsmayalso
bemore visible to drivers because of their position on the sides and center of the roadway.Pedestriansareoftenpositionednearthe locationof thesidesigns inthegatewaytreatment.Theextentthatthesignfunctionsasatrafficcalmingdevicewascomparedwiththeeffectsof
thesignsasapromptfordriveryieldingbehaviorbymanipulatingavarietyofsignfeaturessuchasthepresenceorabsenceofthesignmessageandthenarrownessofthegap.
This chapter examines the effects of the gatewaywithdifferent configurations tounderstandhow they impact driver yielding to pedestrians in crosswalks. The configurations includevariationsingatewaywidthandsignmessage,andpartialgatewayconfigurations.Thegateway
effectonreducingvehiclespeedisdiscussed,aswell.
METHODOLOGY
DependentVariablesThenumberofmotoristswhodidanddidnotyieldtopedestriansincrosswalkswasmeasured.Driver yielding was measured in reference to an objective dilemma zone (a location beyond
which a driver can easily yield if a pedestrian enters the crosswalk). A formula used todeterminewhetheradrivercouldhavesafelystoppedatatrafficsignal,wasusedtodeterminewhetheradrivercouldhavestoppedforapedestrianstandingwithone foot in thecrosswalk
(24). This formula takes into account driver reaction time, safe deceleration rate, the postedspeed, and the grade of the road to calculate this interval for the yellow traffic light. Thisformulawasusedtodeterminethedistancetothedilemmazoneboundarybymultiplyingthe
time(y)bythepostedspeedlimitinfeetpersecond:
v y = t +
2a + 2Gg
wheret=theperceptionandreactiontimeinseconds(S);v=thespeedofapproachingvehiclesinfeetpersecond(thepostedspeedwasusedforapproachspeed);a=thedecelerationrate,recommendedat10 feet/S2;G=accelerationduetogravity (32 feet/S2);andg=thegradeof
theapproach.Toaidobserversinidentifyingthedilemmazone,thezonewasmarkedbyeitherasprinklerflag locatedadjacenttothecurborwithbrighttapethatextendedfromtheraisedconcreteofthecurbfaceintothegutterpan.
Motorists who had not passed the outer boundary of the dilemma zone when a pedestrianenteredthecrosswalkwerescoredasyieldingornotyieldingbecausetheyhadsufficienttime
andspacetostopsafelyforthepedestrian.Motoristswhoenteredthedilemmazonebeforethepedestrianplacedafootinthecrosswalkcouldbescoredasyielding,butcouldnotbescoredasfailing to yield because the motorist did not have adequate distance to yield based on the
calculated distance. However, the signal timing formula is relatively lenient; hence, many
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 15
vehiclesthatpassedthedilemmazonecouldyieldsafely,particularlythosetravelingbelowthe
speedlimit.ResearchDesign
A replication logic reversal designwasused in theseexperiments. In replication logic reversaldesign,atreatmentisintroduced,removed,andreintroducedtoisolatetheeffectivenessofthetreatment on driver behavior independent of other environmental factors. In all preliminary
studiesinChapters1through4temporarysignswereinstalledthatcouldbeeasilymovedandremoved by the research team. Evaluations in Chapter 5 evaluated more permanentinstallationsthatwouldonlyberemovedforwinter.
A trial, or staged crossing, beganwhen a researcher demonstrated an intention to cross thestreetbyplacingonefootwithinthecrosswalkwithhisorherheadturned inthedirectionof
theapproachingvehicle.Aresearchassistantrecordedtheresultsofthetrialonaclipboard.Eachsessionconsistedof20trials(pedestriancrossings).Thepercentageofdriverswhoyielded
the right-of-way to pedestrians was calculated for each session by dividing the number ofdriversthatyieldedtheright-of-waybythenumberofyieldingdriversandnon-yieldingdrivers.Datawerecollectedduringdaylighthoursbetween10:00a.m.and8:00p.m.Mondaythrough
SaturdayinMaythroughNovember.Datawerenotcollectedwhenitwasraining.Scoring
Drivers in the first two travel lanes nearest the pedestrianwere scored for yielding after thepedestrian had entered the crosswalk. This procedure was used because it conforms to theobligations of motorists specified in the Universal Vehicle Code and local ordinances in
Kalamazoo, and Ann Arbor regarding who has the right-of-way at what time. Drivers in thesecondhalfoftheroadwaywerescoredasaseparatetrial iftherewasapedestrianrefugeormedianislandseparatingthetravelway.Iftherewasnoisland,driversinthesecondhalfofthe
roadwerescoredwhenthepedestrianapproachedthecenterofthelasttravellaneadjacenttotheyellowcenterlineseparatingopposinglanesoftraffic.Motoristswerethenscoredusingthesametrialmethodasthecrossingforthefirsthalfoftheroadway.
DataCollectorTrainingProcedure
Researchersweretrainedtousetheoperationaldefinitionofyieldingbehavior.Theypracticedrecordingtogetheruntiltheyobtainedinter-observeragreement(seebelowforadescriptionofinter-observer agreement) of 90% or better for two consecutive sessions (a total of 40
observations). Researcherswere also trained on how to use awalkingwheel tomeasure thedistancetothedilemmazone,andhowtoinstalltheflagsorlaythetape.
DataCollectionSetupTheresearcherssetupthedilemmazonebeforebeginningtrials.Awalkingwheelwasusedtomeasurethedistancefromthenearestcrosswalklinetothedilemmazone.Duringthemarking
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 16
process,oneoftheresearchersservedasaspottertoensurethatthepersonusingthewalking
wheelwasclearoftraffic.Bothpersonsworeorangevestsduringthemarkingprocesstomakethemmorevisibletodrivers.Theresearchersthenmarkedthelocationwiththenecessaryflags,tape,orboth.
Inter-observerAgreementInter-observeragreementwascalculatedforatleast34%ofallobservationsinallexperiments,
and data were collected during each condition of each experiment in order to validate theobservationaldata.Eacheventthatwasscoredthesamebybothobserverswascountedasanagreement, and each event that was scored differently by each observer was scored as a
disagreement.Inter-observeragreementwascalculatedbydividingthenumberofagreementsduringeachsessionbythesumofagreementsplusdisagreementsforthatsession.Theresultofthiscalculationwasthenconvertedtoapercentage,asexpressedbytheformulabelow:
Agreements per session Inter-observer agreement (%) = (Agreements per session+ Disagreements per session)
During sessions in which agreement data were collected, the two observers stood several
metersapart at a locationwithanunobstructedviewof the crosswalk.Whenmore thanonepedestriancrossedataparticularcrosswalk,theprimaryobserveridentifiedthepedestrianforwhomyieldingbehaviorwastobescoredbydescribingadistinctivefeaturesuchaswhetherthe
person was a male or female or the color of his or her clothing. They then independentlyrecordedmotoristyieldingbehavioranddidnotdiscusswitheachotherhowtheyscoredanyofthetrials.Thisprocedurecontrolledforpotentialobserverbias.
Inter-observer agreement on the percentage of drivers yielding to pedestrians averaged 96%overallofthestudiescompletedinthisresearchwitharangeof88%to100%.
ApparatusThreetypesoftrafficcontroldevices(TCD)swereusedinthisstudy.ThefirstTCDdevicewasthe
R1-6in-streetsign.ThesecondTCDwasablanksignoftheexactsamesizeastheR1-6signandusing a similar diamond grade fluorescent yellow green background color. This was done todetermine whether the language and symbols on the sign influenced the yielding rate of
motorists. The third TCD was a robust flexible delineator that is designed to withstand 100impactsat60mph.ThisdevicewasthesamecolorasthebackgroundoftheR1-6sign. Itwasexamined in more vulnerable gateway treatment locations to address concerns about
survivabilityoftheintervention.
Figure1-2showsaR1-6signmountedonacurbdeviceaffixedtotheroadway.Figure1-3showsablank signmountedona removablebase,andFigure1-4 showsa flexibledelineator that isscrewedintoabasecementedintotheroadway.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 17
Figure1-2:R1-6Signmountedonacurbaffixedtotheroadway
Figure1-3:AblanksignthesamesizeastheR1-6Signmountedtoaremovablebase
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 18
Figure1-4:Aflexibledelineatorattachedtoabasecementedintothepavement
EVALUATIONOFTHEIMPORTANCEOFGATEWAYWIDTH
The first study in this seriesexamined theeffectsof gatewaywidthonyieldingbehavior. Thehypothesis was that the narrowing of the gateway was a factor associated with yielding
behavior.Thisstudyteststhishypothesis.Locations
ThecomparisonofgatewaywidthsmeasuredthelanewidthfromtheinsideedgeofoneR1-6signtotheinsideedgeofthecorrespondingR1-6signontheothersideofthetravellane.TheeffectofgatewaywidthwasmeasuredattwositesattheMarshalltrafficcircle,onecrosswalk
was on the NE side of the traffic circle and the other crosswalk was on the SW side of thecrosswalk. Itwasalsomeasuredattwotrailcrossings inPortageMi.OnetrailcrossingwasonOaklandStreetsouthofMilhamRoad,andsecondthetrailcrossingwasonGardenLanewestof
Kingston Dr. The freeway crosswalk siteswere at the two uncontrolled I-94 entrance rampsfromSouthWestnedgeAvenue.
ResearchDesignAreplicationlogicreversaldesignwasemployedinthisstudy.Followingmultipledailybaselinemeasures (sessions duringwhich no in-street sign treatmentwas present) the treatmentwas
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 19
introducedat onewidth formultipledays.Next, thewidthof the gatewaywas changed, and
observation data was collected again for multiple days. These changes were replicated byrepeatingmeasuresforeachofthegatewaywidthsseveraltimes.
Table1-1showsyieldingbehaviorforvariousgatewaywidths.Inspectionofthesedatarevealsthat in each case, narrower configurations lead to a higher driver yielding rates than widerconfigurations. The gap size (the difference between the wide and narrow width) varied
between2.4 feet to 9.4 feet across sites. Although thesedata show that gatewaywidth is afactor influencing yielding, it is clear that other variables also have an influence on driveryielding. This becomes apparent when one ranks sites by gateway treatment width, which
reveals that some narrow locations provide better yielding rates than other sites with evennarrowerconfigurations.Forexample,yieldingishigherattheMarshalltrafficcirclesitethanatthe Oakland trail crossing and I-94 entrance ramp even though the latter two sites are
considerablynarrowerthantheMarshalltrafficcircle.TheconsistencyofthesedatacanbeseenfrombyviewingdatacollectedovertimeattheMarshallNWleginFigure1-5.
Table1-1.Thepercentageofdriversyieldingtopedestrianswithawidevs.anarrowgateway.Thelastcolumnshowsthechangeinwidthbetweenthewideandnarrowgateway
WideConfiguration NarrowConfiguration Location Width Yielding Width Yielding GapWidth
Reduction Baseline Gateway Baseline Gateway MarshallTrafficCircleCrossingSEleg
44.8ft. 11% 15% 36.8ft. 11% 29% 8ft.
MarshallTrafficCircleCrossingNWleg
30.3ft. 13% 19% 22.3ft. 13% 48% 8ft.
OaklandSt.TrailCrossingSofMilham
17.5ft. 2.7% 10% 11.7ft. 2.7% 39% 5.8ft.
GardenLn.TrailCrossingE.ofS.Westnedge
19.5ft. 21% 67% 17.1ft. 21% 75% 2.4ft.
I-94RampE.BoundRampEntrance
20.0ft. 2% 17% 10.6ft. 2% 31% 9.4ft.
.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 20
Figure1-5.DriveryieldingattheMarshallTrafficCircleNWcrosswalkleg
EVALUATIONOFTHEIMPORTANCEOFTHESIGNMESSAGEIn order to determine whether the message on the signs in the roadway controlled driverbehavior, the gateway configuration with sign blanks with the reflective background but no
messagewerecomparedtothestandardR1-6signattwodifferentcrosswalklocations.ThefirstlocationwasatacrosswalkataT-intersectionthattraversedamulti-laneroadwithtwotravellanesineachdirectionandon-streetparking.Thesecondlocationwasatamidblockcrosswalk
withtwotravellanesineachdirection,apedestrianrefugeislandandnoparking.GatewayConfigurations
Two types of gateway configurations were used in this study. The first configuration was agatewaywithallR1-6 in-streetsigns.Thesecondtypeofconfigurationwasagatewaywithallblanksignsoftheexactsamesize,signsheetingbackgroundcolor(diamondgradefluorescent
yellow green), and shape as the R1-6 in-street sign to determine if themessage on the signinfluencedtheyieldingrateofmotorists.Figure1-6showsaphotogatewayconfigurationofthein-street sign with all R1-6 signs placed in the roadway. Figure 1-7 shows a gateway
configurationwithallblanksigns.Signplacementwasidenticalforthetwoconfigurations.
LocationsTwodifferentsitesinthecityofKalamazoo,Michiganwereusedinthisstudy.Thepostedspeedlimitatbothsiteswas35mph.ThefirstcrosswalkwasonRoseStreetattheT-intersectionwith
AcademyStreet.RoseStreethasfourlaneswithtwotravellanesineachdirectionandon-streetparking, the second sitewas amidblock crosswalk on Rose Street near the KalamazooValleyCommunity College Campus (KVCC) with two travel lanes in each direction and a pedestrian
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 21
refuge islandseparatingnorthandsouthbound traffic.TheAnnualDailyTraffic (ADT)onRose
Streetwas6,820.
Figure1-6:In-streetsignshowingagatewayatRoseSt.atAcademySt.withallR1-6Signs
Figure1-7:In-streetsignshowingagatewayatRoseSt.andAcademySt.withallblanksigns
ResearchDesignBecauseoftherobustchangesproducedbythistreatmentinthepreviousstudies,areplication
logic reversal design was employed in this study. Followingmultiple daily baselinemeasures(sessions during which no treatments were present) the treatments were evaluated in a
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 22
counterbalancedorder formultipledays.Datawere returned tobaseline andback to various
treatmentconditionsmultiple times toconfirmthe robustchanges indriverbehavior throughrepeateddirectreplications.
ResultsTheaveragepercentageofdriversyieldingright-of-waytopedestriansduringeachconditionatboth locations ispresented inTable1-2.AtRoseStreet. atAcademyStreet, yieldingbehavior
duringbaselineconditionaveraged6%.Duringthegatewaywithblanksconfiguration,yieldingaveraged32%.DuringthegatewaywithR1-6signsconfiguration,yieldingaveraged80%.AttheRose Street at KVCCmidblock location yielding during baseline also averaged 6%. During the
gatewaywithblanksconfiguration,yieldingaveraged36%.DuringthegatewaywithR1-6signsconfigurationyieldingaveraged78%.Figures1-8and1-9showstheaveragepercentofdriversyieldingduringeachsessionateachsite.Thesedatashowthatyieldingbehaviorwasrelatively
consistent at each site and that results did not varywhen the first treatmentwas either thegatewaywithblanksconfigurationorthegatewaywithR1-6signsconfiguration.Thestabilityofthe effect over multiple replications provides clear evidence that the differences in driver
yieldingbehaviorwerearesultofthetwodifferenttreatmentconditions.
RoseStreetatAcademyStreet RoseStreetMidblockatKVCC
Configuration MeanPercentYielding Configuration MeanPercentYielding
Baseline 6% Baseline 6%
BlankSigns 32% BlankSigns 36%
R1-6Signs 80% R1-6Signs 78%
Table1-2.Themeanpercentageofdriversyieldingtopedestriansduringbaseline,theblank
signgatewayandtheR1-6signgatewayconfigurations
Figure1-8.PercentofdriversyieldingtopedestriansatRoseSt.atAcademySt.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 23
Figure1-9.PercentofdriversyieldingtopedestriansduringeachconditionatRoseStreetatKVCC.
EVALUATIONOFPOSITIONOFSIGNS
This study compared the full Gateway configuration with R1-6 signs only on the white lines
separatingtravellanesinthesamedirectionandR1-6signsonlyattheedgeoftheroadwayattwosites.
LocationsTwodifferentsitesinthecityofKalamazoo,MIwereusedinthisstudy.Thepostedspeedlimitat both siteswas 35mph. The first crosswalkwas on Rose Street at the T intersectionwith
Academy Street. Rose Street has four lanes with two lanes in each direction and on-streetparking,thesecondsitewasatacrosswalkontheintersectionofSouthWestnedge,aone-wayroadwith two southbound lanes and on-street parking on both sides of the street, at the T-
intersectionwithRanneyStreet.TheADTonRoseStreetwas6,820andonSouthWestnedgeitwas14,709.
ResearchDesignBecauseoftherobustchangesproducedbythistreatment inthepreviousstudy,areplicationlogic reversal design was again employed in this study. Following multiple daily baseline
measures (sessionsduringwhichno treatmentswerepresent) the treatmentswereevaluatedformultiple days. Datawere returned to baseline and back to various treatment conditionsmultipletimestoconfirmtherobustchangesindriverbehaviorthroughdirectreplication.The
treatmentsevaluatedwere1.ThefullGatewaywithR1-6signsattheedgesoftheroadandonalllanelines;2.TheplacementofR1-6signsonlyontheedgesoftheroadway;3.TheplacementoftheR1-6signsonlyonthewhitelanelinesseparatingtravellanescarryingtrafficinthesame
direction.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 24
Results
The results of this experiment are presented in Table 1-3. At the Rose Street at Academylocationthebaselineyieldingwas6%,thefullGatewayproducedyieldingof80%,theedgesignsaloneconditionwasassociatedwith36%yieldingandthesignsonlyonthecenterlineproduced
52%yielding.At theSouthWestnedge siteyieldingwas0%duringbaseline,89%with the fullGateway,10%withtheedgesignsalone,and18%withsignsonlyonthewhitelanelines.
Table 1-3. Mean percentage of drivers yielding to pedestrians during baseline, the fullgateway,R1-6signsonlyattheedgesoftheroadway,andR1-6signsonlyonthewhitelanelines.
RoseSt.@AcademySt. Condition PercentYielding
Baseline 6%
GatewaywithallR1-6Signs 80%
CenterlineandEdgesignsonly 36%
R1-6SignsonlyonLaneLines 52%
S.WestnedgeAve.atRanneySt. Condition PercentYielding
Baseline 0%
GatewaywithallR1-6Signs 89%
R1-6SignsonEdgealone 10%
R1-6SignonLaneLinealone 18%
GATEWAYEFFECTONVEHICLESPEEDSpeed data were collected at one crosswalk in the presence and absence of the gatewaytreatmenttodeterminehowmuchdriversslowedwhentraversingthecrosswalk.
SettingThe participants were 2,000 motorists using two southbound traffic lanes approaching thecrosswalkonRoseStreetattheintersectionwithAcademyStreet.Driverswereexcludedifthey
changed lanes after their speed was read at the dilemma zone and if they parked at thesouthbound meters on Rose Street. It is important to note that drivers were excluded ifpedestrianswere attempting to enter orwithin the crosswalk and ifmotorists in northbound
traffic laneswere turningorattempting to turnwhileadriverwas in thedilemmazone.Thusthesedatashowtheeffectofthegatewayintheabsenceofpedestrians.
MethodThe dependent variablewas the vehicle’s speed at the dilemma zone,which begins 183 feetsouthofthecrosswalkandendsatthethresholdofthecrosswalk.Allspeedswerereadusing
laserradarlocatedinavehicleparkedsouthofthecrosswalk.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 25
Results
TheresultsarepresentedinFigure1-10.Thesedatashowdriverswereacceleratingduringthebaseline speedmeasures when the gateway was absent.When the gateway was introducedaveragespeeddecreasedfrom26.8mphto23.1mphatthedilemmazoneandfrom28.3mph
to18.1mphatthecrosswalk,a10mphdrop.AsingleR1-6signlocatedontheyellowlineatthecenteroftheroadwasassociatedwithaverysmallreductioninspeedsimilartothatreportedinresearchthatonlyusedonesign(7).
Figure1-10.Driver speedapproaching the crosswalkat thedilemmazone (blue line)andatthecrosswalk(redline)duringbaselineandgatewayconditiononRoseStreetatAcademy.
Discussion Thepurposeofthisseriesofstudieswastoevaluatevariablescontributingtotheimprovementproducedbythegatewaytreatmentondriveryieldingright-of-waytopedestriansatcrosswalks.
Althoughtheconfigurationswereonlycomparedatalimitednumberofsites,theconsistencyoftheresultsproducedforeachconfigurationintroducedmultipletimesateachsite,theobviouslargechangesindriverbehavior,andtheconsistencyofresultsbetweendifferentsitessuggest
thatthesefindingarerobust.Alloftheconfigurationstestedincreaseddriveryieldingbehavior.However, no configurationmatched the effectiveness of the complete gateway configurationwithallR1-6signs.
One hypothesis testedwaswhether the distance between the signs had an influence on theefficacyof thegatewayR1-6treatment.Theanalysisofgapwidthbetweensignsshowedthat
narrower configurations weremore effective at each site where this variable was examined.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 26
However,dataalsoshowedthatsignplacementhadaneffectonsignefficacy.Placingsignson
thewhite lane linepositionsaloneproducedbetterdriveryieldingbehavior than signsplacedonlyontheroadwayedgeatallsitesandthefullgatewayproducedthehighestlevelofdriveryieldingbehavior.
Another hypothesis tested was whether the content of the signs influenced driver yieldingbehavior. The blanks configurationwas significantly less effective than the configurationwith
thesignmessagepresent.Speed data suggest that the gateway treatment has a marked effect on vehicle speeds
approachingthecrosswalk,andthatdriversbeganslowingatthedilemmazonewhentheysawthe gateway ahead at the crosswalk. These data were collected because research assistantsfrequently observed drivers slowing as they approached the crosswalk. Not only was the
magnitudeof the reduction clearly visible, but it also reduced vehicle speedbelow the speedassociated with fatal crashes (25). Speed reductions can reduce both the probability of apedestriancrashbygivingdriversmoretimetoreact,andreducingthetunnelvisionassociated
withhighervehicle speeds.Reducedspeedcanalsodecrease the severityof injuries shouldacrashoccur.
InordertodeterminewhethertheGatewayincreasedthepercentageofhardbrakingdatawererecordedonhardbreakingattwositesinAnnArbor,MI:NixonRd.atBluettRd.,andS.DivisionSt. at E. Jefferson, St. At the Nixon Rd. crosswalks 758 vehicles that slowed at the crosswalk
wereobservedandnoinstancesofhardbrakingwereobserved.AttheS.Divisioncrosswalk912vehiclesthatslowedwereobservedandonlyoneinstanceofhardbrakingwasobserved.Thesedatawerecollectedseveralweeksafterthepermanentinstallations.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 27
CHAPTER2–EVALUATIONOFCONFIGURATIONSTHATIMPROVESURVIVALOFTHEGATEWAYTREATMENT
INTRODUCTION
Although the gateway R1-6 treatment in some applications has proven to be as effective atincreasingyieldingright-of-waytopedestriansasmoreexpensivetreatmentsliketheRRFBand
PHB, it ismoreeasilydamagedthantreatmentsmountedonamastarmoronthesideoftheroad.ThePHBhasbeenshowntoincreasethepercentageofdriversyieldingtopedestriansinMichigantobetweenfrom61%and95%andtheRRFBhasbeenshowntoincreaseyieldingin
Michigantobetween55%and89%(12).Thereareseveralwaystoreducethevulnerabilityofthegatewaytreatment.Onewaytoimprovesignsurvival istoinstallthesignsattheroadwayedgepositionofthegatewayoutofthetravelwayinthegutterpan.Gutterpaninstallationis
lesslikelytobehitbuthasseveralpotentialdrawbacks.First,itcouldpresentdrainageissuesatsomelocationswhendebrisaccumulatesaroundthesign.Second,gutterpanplacementcouldbeaproblemforstreetsweepers.Third,theremaynotbeagutterpanandtheentirelanemay
be needed for larger vehicles. Fourth, narrow bike lanesmay preclude gutter pan placementbecausethesignwouldbetooclosetoriders.
Onealternativetogutterpanplacementisplacementontopofthecurb.Thisplacementwouldbelessvulnerabletocollisionanddoesnothaveanyofthepotentialdrawbacksofgutterpansignplacementandcouldbeusedatedgesatthesideoftheroadandattheedgesofrefuge
islandsoramedianisland.Signsplacedontopofthecurbaspartofagatewaytreatmentlookvery similar to signsplaced in thegutterpan toapproachingdriversandmayproduce similareffects.However,curbtopplacementisonlypermittedonmedianandrefugeislandsbutnotat
theedgeoftheroad.Placementattherightedgeoftheroadcurrentlyrequirespermissiontoexperiment from the Federal Highway Administration (FHWA). Therefore, permission toexperimentwasobtainedfromFHWAforthisstudypriortoplacingR1-6signsontopofthecurb
attherightedgesoftheroad.
Anotherway to increase thesurvivalof in-street signsplaced inmorevulnerable locationsonwhile lines dividing lanes carrying traffic in the same direction is the use of a flexible robustdelineator at these gateway positions rather than a R1-6 sign. These delineators have been
documentedtotakelargenumberofhitsatspeedsgreatlyinexcessofthoseexpectedatmostcrosswalklocationsandhenceshouldbeexpectedtohavearelativelylonglife.Atsiteswithtwolanesineachdirectionandapedestrianrefugeislandseparatingopposingtraffic,edgesignson
bothsidesof thegatewaycouldbe installedoutof thetravelwayontopof thecurbonbothsidesoftheroad,ontopoftheedgeoftherefugeisland,andaflexibledelineatorpostcanbeinstalledonthewhitelinesdividingtravellanes.Onroadswithoutapedestrianrefugeisland,a
R1-6 signwould be required on the yellow centerline. Signs placed on a curb type basemayshowthebestsurvivalinthiscondition.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 28
The purpose of this series of studies is to compare the effects of gutter pan versus curb top
placement and R1-6 sign versus robust delineator placement on white lane lines on driveryieldingright-of-waytopedestrians.InExperiment1,gutterpanversuscurbtopplacementwascompared at four sites. In Experiment 2, the use of the R1-6 sign on thewhite lane linewas
comparedwiththeuseoftherobustdelineatoronthelaneline.
EVALUATIONOFGUTTERPANVERSUSCURBTOPPLACEMENT
InordertodeterminethedifferenceinyieldingbehaviorbetweenplacementofR1-6signsinthegutterpanandon topof curb, thegatewayconfigurationedgesignsplaced in thegutterpanweredirectlycomparedwiththeedgesignsplacedontopofthecurbatfourlocations.
GatewayConfigurationsTwo types of gateway configurations were used in this study. The first configuration was a
gateway with all R1-6 edge signs in the gutter pan. The second type of configuration was agatewaywithallR1-6signsontopofthecurbonthesideoftheroadorifpresentthesideofthemedianisland.Figure2-1showsagatewayconfigurationwiththeedgesignsonthecurb.
Figure2-1.GatewayconfigurationwiththeedgesignonthecurbatacrosswalkonEastHuron
Street.Locations
Fourdifferentcrosswalks,threeinthecityofAnnArbor,MIandoneinthecityofKalamazoo,Michiganwere studied in this experiment. The first crosswalkwasonEastHuronbetweenN.Thayer St. andN. Ingalls St. EastHuronat this locationhas two travel lanes in eachdirection
separatedbyapedestrianrefugeislandandaspeedlimitof30mph.ThesecondcrosswalkwasamidblocklocationonSouth7thStreetnorthofPioneerSchoolDriveandhadapostedspeedof35mph.Thisstreethastwolanesandabikelaneinonedirectionandonelaneandabikelane
intheseconddirectionwithamedian islandseparatingthetwodirectionsof travel.Thethird
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 29
crosswalkwasonNixonRd.atBluettRd.NixonRd.hastwolanesinonedirectionandonelane
intheotherdirectionandapostedspeedlimitof30mph.AtalloftheAnnArborcrosswalks,theR1-6asignwasusedwithastopsignsymbolinplaceoftheyieldsignsymbolbecauseAnnArborhad a stop rather than a yield ordinance. The fourth crosswalkwas on Rose Street at the T-
intersectionwith Academy Street in Kalamazoo. Rose Street has four laneswith two lanes ineachdirection,on-streetparking,aspeedlimitof35mphandanADTof6,820.
ExperimentalDesignAreplicationlogicreversaldesignwasemployedinthisstudy.Followingmultipledailybaselinemeasures(sessionsduringwhichnotreatmentswerepresent)theedgesignswerefirstinstalled
inthegutterpanandevaluated,thenplacedontopofthecurbandevaluated.Afterareturntothe baseline (no gateway) condition the signs were again introduced and evaluated in acounterbalancedorder formultipledays.Datawere returned tobaseline andback to various
treatmentconditionsmultipletimestoconfirmthechangesindriverbehaviorthroughrepeateddirectreplications.
ResultsTheaveragepercentageofdriversyieldingright-of-waytopedestriansduringeachconditionatboth locations ispresented inTable2-1.At themidblock locationonE.HuronStreet,yielding
behavior averaged 62% during the baseline condition, 97% during the gutter pan placementcondition, and 92%during the curb top placement condition. At themidblock location on 7thStreet,driveryieldingaveraged15%during thebaselinecondition,70%during thegutterpan
placementcondition,and54%during thecurb topplacementcondition.At theNixonRd.andBluett Rd. Site yielding averaged 40% during baseline, 93% during the gutter pan placementcondition,and86%duringthecurbtopcondition.AttheRoseSt.andAcademySt.site,yielding
averaged6%duringbaseline,82%duringthegutterpanplacementcondition,and72%duringthe curb top placement condition. Average performance across all four siteswas 31% duringbaseline, 86% during the gutter pan placement condition, and 76% during the curb top
placementcondition.Althoughyieldingwas10%lowerduringthecurbtopplacementcondition,it was still markedly higher than baseline. Figures 2-2, 2-3, 2-4, and 2-5 show the averagepercentofdriversyieldingduringeachsessionateachcrosswalk.Thesedatashowthatyielding
behaviorwas relatively consistent at each site and that results did not varywhen gutter panplacementwas the first treatment or curb top placement conditionwas introduced first. The
stabilityof theeffectovermultiplereplicationsprovidesclearevidencethat thedifferences indriveryieldingbehaviorwerearesultofthetwodifferenttreatmentconditions.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 30
Table 2-1. The percent of drivers yielding to pedestrians during the baseline, gutter panplacementandcurbtoplacementconditionsusingR1-6signsonatemporarybasis.
Location Baseline GutterPanPlacement CurbTopPlacement
E.HuronMidblock 62% 97% 92%
Midblock7thStreet 15% 70% 54%
NixonRd.atBluettRd 40% 93% 86%
RoseSt.atAcademySt. 6% 82% 72%
Mean 31% 86% 76%
Figure2-2.Percentofdriversyieldingduringeachconditionoftheexperiment
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 31
Figure2-3.Percentofdriversyieldingduringeachconditionoftheexperiment
Figure2-4.Percentofdriversyieldingduringeachconditionoftheexperiment
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 32
Figure2-5.Thepercentofdriversyieldingduringconditionoftheexperiment.
EVALUATIONOFROBUSTDELINEATORONTHEWHITELANELINE
Oneofthemostvulnerablepositionsinagatewaytreatmentisthewhitelanelineonmultilane
roads.Theuseofarobustdelineatoroffersseveraladvantages.First,itisnarrowerthanaR1-6sign.Second,itcansurvivesignificantlymorehitsathigherspeeds.Thedelineatorselectedfortestinginthisstudyhadbeentestedandfoundtowithstand100hitsatspeedsof60mph.The
purposeofthisstudyistodeterminehowmuchtheeffectivenessofthegatewaydeclineswhenayellowgreendelineatorissubstitutedfortheR1-6signsinthewhitelanelineposition.
GatewayConfigurationsTwo types of gateway configurations were used in this study. The first configuration was a
gatewaywith threeR1-6 signs ineachdirection (twoedge signsandoneon thecenterwhiteline).ThesecondtypeofconfigurationwasagatewaywithtwoedgeR1-6signsandadelineatoron thewhite lane line ineachdirection.Figure2-6 showsaphotoofagatewayconfiguration
withadelineatoronthewhitelanelines.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 33
Figure2-6.Gatewaytreatmentwithdelineatorsplacedonwhitelanelines
LocationsThreecrosswalk locationsinthecityofKalamazoo,Michiganwereusedinthisstudy.Allthree
crosswalkshadmultiple travel lanes in the samedirectionof travel. The first locationwasonRoseStreetattheT-intersectionwithAcademyStreet.RoseStreethasfourlaneswithtwolanesineachdirectionandon-streetparking,thesecondsitewasamidblockcrosswalkonRoseStreet
nearKVCCwithtwolanesineachdirectionandapedestrianrefugeislandseparatingnorthandsouthboundtraffic,andthethirdcrosswalkwasonaone-wayroadwithtwosouthboundlanesand on-street parking on both sides of the street on south Westnedge Avenue at the T-
intersectionwithRanneyStreet.TheADTonRoseStreetwas6,820andonSouthWestnedgeitwas14,709.
ExperimentalDesignAreplicationlogicreversaldesignwasemployedinthisstudy.Followingmultipledailybaselinemeasures, the treatmentswere evaluated in a counterbalancedorder formultiple days.Data
werereturnedtobaselineandbacktovarioustreatmentconditionsmultipletimestoconfirmthechangesindriverbehaviorthroughrepeateddirectreplications.
ResultsTheaveragepercentageofdriversyieldingright-of-waytopedestriansduringeachconditionis
showinTable2-2.Driveryieldingright-of-waytopedestriansaveraged5%acrossthethreesitesduringbaseline.ThecompletegatewaywithallR1-6signs increasedyieldingto82%whilethegatewaywiththedelineatorwasassociatedwith60%increaseinyielding.Figures2-7,2-8and
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 34
2-9 show that the individual level of yieldingwas very similar for each condition during each
replication.Table 2-2. The percentage of drivers yielding to pedestrians at each crosswalk during the
baseline,thegatewaywithallR1-6signs,andthegatewaywithdelineatorcondition.
Location BaselineGateway
withallR1-6SignsGateway
withDelineator
RoseStreetatAcademyStreet 7% 79% 60%
RoseStreetatKVCC 7% 77% 60%
SouthWestnedgeAvenueatRanneyStreet
0% 89% 59%
Mean 5% 82% 60%
Figure 2-7. The percentage of drivers yielding to pedestrians at Rose and Academy duringbaseline,theR1-6gatewayconditions,andthegatewaywithdelineatorcondition.
Figure2-8.ThepercentageofdriversyieldingtopedestriansatRoseatKVCClocationduringbaseline,theR1-6gatewayconditions,andthegatewaywithdelineatorcondition.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 35
Figure2-9.ThepercentageofdriversyieldingtopedestriansatWestnedgeandRaneyduringbaselinetheR1-6gatewayconditionsandthegatewaywithdelineatorcondition.Discussion The purpose of this series of studieswas to evaluatewhether gateway configurationswith apotentiallyhigherlikelihoodofsurvivalcouldyieldsimilarresultsasthoseproducedbythefull
R1-6gatewayconfiguration.Theresultsofthefirststudyshowedthecurbtopplacementoftheedgesignscould increasedriver’syieldingright-of-waytopedestriansto levelsalmostasgoodasthoseproducedbygutterpanplacement.Althoughsignsplacedinthegutterpanareashould
not be struck very often, they could present problems for drainage, street sweepers, and atlocations with narrow bicycle lanes. Placement on top of the curb would not share theselimitations. It is also the case that signs placed on top of the curb should also receive less
intentionalstrikesthensignsplacedinthegutterpan.Anotheradvantageofcurbtopplacementis that the sign bases could remain in place during the winter plowing season in northernclimates.However,itisnotclearwhetherthesignsthemselvescouldstanduptothesnowload
fromplowing.ThesecondstudyexaminedwhetherreplacingtheR1-6signsinstalledonthewhitelanelineon
multilaneroadswithaflexibledelineatorcouldproduceasimilarpercentageofdriversyieldingright-of-way topedestrians. The results of this study showed that a gatewaywithdelineatorsproduced much better yielding than baseline but 22% fewer drivers yielded right-of-way to
pedestriansduring thisconditionthanduring theR1-6signonwhite lane linescondition.Oneadvantage offered by the delineator is that they can withstand a large number of strikes.Anotheradvantageisthattheycanbeeasilyscrewedoutbeforethestartoftheplowingseason
innorthernclimates,andcanbereplacedinamatterofminutes.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 36
CHAPTER3–EVALUATIONOFTHEGATEWAYTREATMENTINVARIOUSCROSSWALKAPPLICATIONSThischapterevaluatestheuseofthegatewaytreatmentinavarietyofcrosswalkapplications,includingtrafficcircles,roundabouts,freewayentranceramps,andtrailcrossings.Theseapplicationsrevealedstrengthsandweaknessesofthegatewaytreatmentlocationandhelpeddeterminewheretheymaybemosteffectivelydeployed.Also,thechapterevaluatestheuseofagatewayinconjunctionwithaRRFB.Thefinalstudyinthischapterexamineswhetherplacingthegatewayatonecrosswalkatanintersectionwouldhaveaneffectofyieldingattheuntreatedleg.
TRAFFICCIRCLEINSTALLATIONSLocationsAgatewaywasinstalledattwocrosswalksatatrafficcircleinMarshall,Michigan.Bothgatewayswereinstalledbetweenthepaintedareaadjacenttothecenterislandofthetrafficcircleandthegutterpanontheoutsideofthecircle.Onecrosswalklocationhadawideconfigurationwithasinglelaneroadwaywidthof36.8feetbetweenthepaintedareaandtheoutercurb.Thesecondcrosswalklocationhadanarrowconfigurationwithasinglelaneroadwidthof22.3feetbetweenthepaintedareaandtheoutercurb.TheleftframeofFigure3-1showsthewideconfigurationcrosswalkandtherightframeshowsthenarrowconfigurationcrosswalk.ResultsThedata,asshowninFigure3-2,illustratesthatyieldingincreasedmoreatthesitewiththenarrowconfiguration.
Figure3-1.Left:widegateway.Right:narrowgateway.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 37
Figure3-2.DriveryieldingatthetwocrosswalksatatrafficcircleinMarshall,Michigan.DiscussionGatewaytreatmentsattrafficcirclesimproveddriveryielding.However,narrowingthegatewaygapresultedinahigheryieldingpercentage.DatareportedinChapter1alsocomparedwideandnarrowgatewayconfigurationsatbothofthesesitesandfoundbetteryieldingwiththenarrowerconfiguration.
ROUNDABOUTINSTALLATIONSLocationsThegatewayconfigurationwasexaminedattwosingle-laneroundaboutlocationsinBentonHarbor,Michigan.Eachroundabouthassplitterislandsateachentryandexitpointthatservedaspedestrianrefugeislands.Thereisalsoanislandinthemiddleofeachroundaboutwithlowgrowingfoliage.YieldingwasonlymeasuredatthefourcrosswalksonEastMainStreet.Thepostedspeedlimitwas35mphatbothroundabouts.Therewaslittlepedestriantrafficateachsite,butalargeamountofvehicletraffic.Figure3-3showsthegatewayconfigurationatonecrosswalklegoftheroundaboutattheEastMainStreet.Notethatallsignswereplacedinoradjacenttothegutterpan.Itshouldbenotedthattherewasalotoftrucktrafficatthissite.
ResearchDesignAmultiplebaselinedesignwasemployedinthisexperiment.Afterdatawerecollectedduringthebaselineconditionatbothsites,onesitereceivedthegatewayin-streetsigntreatmentwhilethesecondlocationremainedinthebaseline(untreated)condition.Afteraconvincingincreasewasnotedatthefirstsite,thegatewaytreatmentwasaddedatthesecondlocation.Someoftheyieldingdatawasseparatelycodedfordriverenteringandexitingthecrosswalk.
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EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 38
Figure3-3.Gatewayconfigurationatoneoftheroundaboutlocations.ResultsFigure3-4showsthepercentageofdriversyieldingright-of-waytopedestriansateachlocation.BaselinedriveryieldingbehaviorattheEastMainSt.atRiverviewDr.andEastMainSt.at5thSt.roundaboutsaveraged9%and19%respectively.TheintroductionofthegatewayattheEastMainStreetandRiverviewDr.siteincreasedyieldingto43%.TheintroductionofthegatewayattheEastSt.and5thsiteincreasedyieldingto45%.
Figure3-4.Thepercentageofdriversyieldingright-of-wayduringthebaselineandgatewaytreatmentsatthetworoundaboutlocations.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 39
DataforDriversEnteringandExitingRoundaboutsBecausethefrequencyofdriveryieldingright-of-waytopedestriansseemedhigherfordriversenteringtheroundaboutthanexitingtheroundabout,datacollectorswereinstructedtoseparatelymeasuretheyieldingbehaviorofdriversenteringandexitingtheroundabout.Figure3-5showstheratioofdriversyieldingright-of-waytopedestrianswhenenteringtheroundaboutcomparedtoyieldingwhenexitingtheroundabout.Driverswerealmosttwiceaslikelytoyieldright-of-waytoapedestrianwhenenteringascomparedtoexitingtheroundaboutatthesetwosites.
Figure3-5.Ratioofdriversyieldingtopedestriansuponenteringandexitingtheroundaboutduringthebaselinecondition.DiscussionDriverswerelesslikelytoyieldright-of-waytopedestriansincrosswalkswhenexitingtheroundaboutthanwhenenteringit.Althoughthetreatmentincreasedyieldingwhendriverswereenteringorexiting,thisrelationshipcontinuedtoholdwithdriversmuchlesslikelytoyieldwhenexitingthanentering.Althoughtheeffectsatroundaboutsweremodest,theywouldmakeiteasiertocross.BecauseotherdatashowthatthecombinationofthegatewaywithaRRFBleadstoveryhighlevelsofyielding,thistreatmentshouldbeconsideredatroundaboutswithanRRFBlocationwithrelativelypoordriveryieldingbehavior.
FREEWAYENTRANCERAMPINSTALLATIONSAnotherpossibleapplicationforthegatewaytreatmentisatfreewayentranceramplocations.Pedestrianscrossingentrancerampseitherapproachthecrosswalkfacingapproachingtrafficorwithapproachingtrafficattheirback.Crashriskshouldbehigherforpedestriansapproachingthecrosswalkwithtrafficapproachingfrombehind.
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EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 40
LocationsThegatewayconfigurationwasexaminedatthesouthandnorthentrancerampstoI-94onSouthWestnedgeAvenue.Bothrampshavealongdedicatedapproachlanetotherampentrance.Figure3-6showstheapproachtothenorthramp.TheleftframeofFigure3-7showsaphotographofthewidegatewayconfigurationatthenorthentrancerampandtherightframeshowsaphotographofthenarrowgatewayconfiguration.ThewideconfigurationconsistedoftwoR1-6signsinstalledinthegutterpan,whilethenarrowconfigurationaddedtwoflexibledelineatorpostsonthelanelines.
Figure3-6.PhotographofthesidewalkapproachingthenorthentrancetoInterstateI-94atWestnedgeAvenue.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 41
Figure3-7.Thephotoontheleftshowsthewideconfigurationofthegatewayandthephotoontherightshowsthenarrowconfigurationwithaddedflexibledelineatorpostsonthelanelines.ResearchDesignAmultiplebaselinedesignwasemployedinthisexperiment.Afterdatawerecollectedduringthebaselineconditionatbothsites,thenorthentrancerampreceivedthewidegatewayin-streetsigntreatmentwhilethesouthentranceramplocationremainedinthebaseline(untreated)condition.Afteraconvincingincreasewasnotedatthefirstsitethewidegatewaytreatmentwasaddedatthesecondlocation.Nextthenarrowgatewayconfigurationwasintroducedatthenorthramp.ResultsTheresultsofthisexperimentareshowninFigure3-8.Driveryieldingduringthebaselineconditionwasnegligibleatbothentranceramps(1%atthesouthrampand2%atthenorthramp).Duringthewidegatewayconditionyieldingincreasedto17%atthesouthrampandto13%atthenorthramp.Whenthenarrowgatewayconditionwasintroducedatthenorthramp,yieldingincreasedto31%,untilatruckstruckoneofthetemporarydelineatorsdestroyingit.Giventhelimitednumberoftemporarydelineatorsavailable,theWMUteamdecidedtoenddatacollectionattherampexitsites.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 42
Figure3-8.PercentageofdriversyieldingtopedestriansatthesouthandnorthentranceramptoI-94duringeachconditionoftheexperimentDiscussionAlthoughthewidegatewayplacedinthegutterpanatanentrancerampproducedsomeincreaseindriveryieldingtopedestriansinthecrosswalks,itwasnotsufficienttorecommendthegatewayforthisapplication.Althoughtherewasanincreaseinyieldingproducedbythenarrowconfigurationwithaddeddelineators,thelevelsobtainedwerestillfarlowerthantheeffectsobtainedatmidblocklocationsandatuncontrolledcrosswalksatintersectionswithastop-controlledminorcrossstreet.Heavytrucktrafficatfreewayentrancerampsalsomakeitunlikelythatanarrowconfigurationwouldsurviveatthistypeoflocation.Theonlyinstallationthatwouldlikelysurviveforlong-termusewouldbecurbtopplacementanditisunlikelythattheywouldproducemeaningfulincreasesinyieldingatthistypeofsite.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 43
Onereasonwhythegatewaywassoineffectiveatthistypeofsiteisthetendencyfordriverstowanttoincreasespeedtomatchtrafficonthefreewayatthetopoftheramp.Onceadriveristheprocessofaccelerationtheybecomelesslikelytomaketheefforttoswitchtheirfootfromtheacceleratorpedaltothebrake.Thisphenomenonisalsolikelyatworkatexitstoroundaboutswheredriversareintheprocessofaccelerating.
TRAILCROSSINGINSTALLATIONSLocationsThegatewaytreatmentwasexaminedattwotrailcrossinglocationsinPortage,Michigan.ThefirstsitewasamidblocktrailcrossingonOaklandStreetjustsouthofMilhamRoad.Thistrailcrossinghasarefugeisland.Thereisalsoaconstantflashingyellowbeaconinadvanceofthissiteandapushbuttonactivatedflashingyellowbeaconatthecrosswalklocation.ThesecondsitewasatrailcrossingonGardenLaneontheCeleryCreektrail.ThewidegatewayconfigurationatOaklandStreetisshowninFigure3-9.ThewidegatewayconfigurationatGardenLaneisshowninthelowerframeofFigure3-10.
Figure3-9.WidegatewayconfigurationonOaklandStreet
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 44
Figure3-10.WidegatewayconfigurationatthetrailcrossingonGardenLane.ResearchDesignAreversaldesignwasemployedatbothsites.Inareversaldesignatreatmentisintroduced,removed,andreintroducedinordertoreplicatetheeffectofthetreatmentondriver’sbehavior.ResultsTable3-1showstheaveragepercentageofdriversyieldingtopedestriansduringeachconditionatbothsites.Thepercentageofdriversyieldingright-of-waytopedestriansduringbaselinewas3%attheOaklandStreettrailcrossingand21%attheGardenLanetrailcrossing.AtbothcrossingsthenarrowR1-6gatewayproducedthehighestlevelofyieldingbehaviorwith39%yieldingattheOaklandStreetlocationand75%yieldingattheGardenLanelocation.ThewidetreatmentconditionwithdelineatorsplacedintothepositionusedfortheR1-6signsforthenarrowconditionwasassociatedwith18%yieldingattheOaklandStreetlocationand72%yieldingattheGardenlanelocation.BecausetherewasapedestrianactivatedflashingyellowbeaconattheOaklandsiteitwastestedaloneandwiththewideandnarrowR1-6gatewayconditions.Thepedestrianbeaconalonewasassociatedwith2%yielding,thewidegatewayconfigurationyieldingincreasedto23%andthebeaconwiththenarrowconfigurationwasassociatedwith57%yielding.ThelowerframeofFigure3-11showsyieldingattheOaklandStreetlocationandtheupperframeofFigure3-11showsyieldingattheGardenLanelocation.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 45
Table3-1.Thepercentageofdriversyieldingright-of-waytopedestriansduringeachconditionatthetwotrailcrossings.OaklandStreetTrailCrossing GardenLaneTrailCrossingCondition Percent
YieldingCondition Percent
YieldingBaseline 3% Baseline 21%R1-6gatewayWide 10% R1-6gatewayWide 67%R1-6gatewayNarrow 39% R1-6gatewayNarrow 75%RobustDelineatorAlone 5% RobustDelineatorAlone 61%R1-6gatewayWide+RDNarrow 18% R1-6gatewayWide+RDNarrow 72%Baseline+Beacon 2% Baseline+Beacon NAR1-6gatewayNarrow+Beacon 57% R1-6gatewayNarrow+Beacon NAR1-6gatewayWide+Beacon 23% R1-6gatewayWide+Beacon NA
Figure3-11.Percentageofdriversyieldingtopedestriansduringeachconditionatthetwotrailcrossingsduringeachtreatmentcondition.DiscussionThegatewaywashighlyeffectiveatoneofthetrailcrossingsbutonlymoderatelyeffectiveatthesecondcrossing,whichhadahigherADT(nearly17,000)andspeed(35mph).Thecrosswalk
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 46
onOaklandStreethadatrafficsignalnorthofthemidblocktrailcrossing.Itwasnoticedthatvehiclesacceleratingfromafreshgreensignalseemedtobelesslikelytoyieldasweredriversapproachingagreensignalfromtheoppositedirection.Observersalsothoughtmanyvehiclesweretravelingoverthespeedlimitatthissite.Thissitealsohadalargenumberofplatoonedvehiclesduetothecloseproximityofthetrafficsignalswhichreleasedthevehicleswhenthelightturnedgreen.Thismaybeafactorworthyoffurtherstudy.
INSTALLATIONATANRRFBLOCATIONAnRRFBisanotherwaytoincreasemotoristyieldingright-of-waytopedestriansatcrosswalks.AnotherpossibleapplicationforthegatewaytreatmentisatRRFBsites(8,11,26).PreviousresearchhasdocumentedtheefficacyoftheR1-6signusedaloneontheyellowlineorinagatewayconfigurationtoincreaseyieldingatcrosswalkscontrolledbyanRRFBorPHBatlocationswheretheRRFBorPHBproducedlessyieldingthanreportedinnationalstudies(9).LocationsThegatewayconfigurationwasexaminedwithaRRFBatamidblocklocationatasmallparkonMonroeStreetEastofChestnutStreetinAllegan,Michigan.Thecrossinghasapedestrianrefugeisland.Theedgesignsadjacenttotherefugeislandwereplacedinthegutterpanandthesignsadjacenttothecurbwereplacedonthewhitelanelines,asshowninFigure3-12.
Figure3-12.RRFBlocationinAllegan,Michigan.ResearchDesignAmultipleelementdesignwasemployedinthisexperiment.Duringthebaselinephasetwodatasetswerecollectedeachday,onewithoutandonewiththeRRFBactivated.Subsequently,thegatewaydeviceswereinstalledanddatacollectedwiththeRRFBactivatedandnotactivated.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 47
ResultsTheresultsofthisexperimentareshowninTable3-2.Driveryieldingduringthebaselineaveraged18%whenthedevicewasnotactivatedand65%whentheRRFBwasactivated.Thisresultissomewhatlowerthanthatfoundinnationalstudies(8,11,25).Afterthegatewaywasinstalled,yieldingwhentheRRFBwasnotactivatedincreasedto82%andaveraged96.5%whentheRRFBwasactivated.ItisinterestingtonotethatthecompletegatewayaloneinSeptemberwasmoreeffectivethantheRRFBbeforethegatewaywasintroduced.AsinpreviousstudiesthegatewayproducedamarkedincreaseintheefficacyoftheRRFB.OneoftheedgesignsonthelanelinewasdamagedbeforeOctober2015andNovember2015datawerecollected.Thisproducedadropinyieldingtothepartialgateway.Thissignwouldlikelyhavesurvivedifitwereplacedinthegutterpanorontopofthecurb.Table3-2.PercentofdriversyieldingatthemidblockcrosswalkinAlleganwhentheRRFBwasactivatedandnotactivated,duringbaselineandafterthegatewaywasinstalled.BeforegatewayInstalled AftergatewayInstalled
Sept Oct NovBaseline 18% gatewayalone 82% 50%* 57%*RRFB 65% gateway+RRFB 95% 98% 96%*TheRRFBonthenorthedgeofthecrossingwaslostduetoanimpact.
INSTALLINGAGATEWAYATONLYONELEGOFANINTERSECTIONSometimespedestrianexposureismuchhigheratthecrosswalkononesideofanintersectionthantheother.Thisstudyexaminedifagatewaytreatmentinstalledatthebusierlegproducedanincreaseinyieldingonthecrosswalkattheuntreatedlegoftheintersection.Thepurposeofthisstudywastodetermineifagatewayinstalledononelegofanintersectionhadaneffectonyieldingattheuntreatedlegoftheintersection.ParticipantsandSetting ParticipantsweremotoristsattheintersectionofMainStreetandBennettStreetnearthedowntownareaofThreeRivers,Michigan.Theintersectionconnectstwochurches,apark,andanelementaryschool.Thenorth-southtraffic(MainStreet)travelsintwolanes,withamiddleturnlane,withapostedspeedof3Omph.Theeast-westtraffic(BennettStreet)hasa25mphspeedlimitandiscontrolledwithstopsigns.Figure3-13showsadiagramoftheintersection.
Figure3-13.DiagramoftheintersectionofMainStreetandBennettStreetinThreeRivers,Michigan.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 48
ResearchDesignAreversaldesignwasusedtodeterminetheeffectivenessofagatewaytreatmenttoadjoiningcrosswalks.Followingabaselineconditiontoestablishthepercentageofdriversyieldingright-of-waytopedestrians,thegatewaytreatmentwasintroducedatonelegofthecrosswalkanddriveryieldingwasassessedatbothlegsofthecrosswalk.ResultsTheresultsarepresentedinFigure3-14showthatthegatewaytreatmentproducedanincreaseinyieldingatbothcrosswalksalthoughtheeffectonthecrosswalklegwiththegatewayissomewhatlargerthantheeffectoncrosswalklegwithoutthegateway.Bothincreasesinyieldingwerelarge.Onereasonwhythegatewayinfluencedyieldingatbothlegswasmayhavebeenbecausethegatewayreduceddriverspeedattheintersection.Thisreductioninspeedbenefitspedestrianusingboththegatewaytreatedlegandtheuntreatedleg.
Figure3-14.Percentofdriversyieldingatthelegofanintersectionwiththegatewaytreatmentandotherlegofintersectionthatwasnottreated.
0
10
20
30
40
50
60
70
80
90
100
Baseline GatewayLeg OtherLeg
Percen
tDriversYielding
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 49
CHAPTER 4 - POTENTIAL ROADWAY CHARACTERISTICS INFLUENCING THEEFFICACYOFTHEGATEWAYTREATMENT
Table4-1listscharacteristicsforeachexperimentationsiteswheregatewayinstallationswereinstalled.Mostofthesesiteswereinstalledduringthepresentstudy,buttheTrowbridgeRoadsite,theLivernoissiteandthetwoFarmingtonsiteswereinstalledduringanearlierMDOTcontract.Thesehavebeenincludedtoincreasethediversityofsites.AmapoflocationsisprovidedinFigure4-1.Thedatadoshowsometrends.Thegatewayseemstoworkbestatmidblockcrosswalksanduncontrolledcrosswalksatanintersectionwithaminorstreetwithstopsigncontrol.Itdoesnotseemtomatterwhetherthesitehasarefugeislandormedian,butitisknownthatthepresenceofthesefeaturesisassociatedwithacrashmodificationfactor.Itisalsothecasethatamorerobustgatewaycanbeinstalledatamidblocksitewitharefugeislandbyinstallingthesignsontherefugeislandontopofthecurbandthesignsontherightedgeoftheroadinthegutterpanorontopofthecurbunderpermissiontoexperiment.Roadwaycharacteristicsmayinfluencetheprobabilitythatdriverswillyieldright-of-wayatacrosswalklocation.Onecharacteristicisvehiclespeed,whichmayormaynotrelatetothepostedspeed.Theprobabilityofadriveryieldingright-of-waytoapedestrianisknowntobeafunctionofvehiclespeed.Onereasonwhydriversarelesslikelytoyieldright-of-waywhentheyaretravellingfastisthatittakesmoreeffortandtimetobrake.Anotherreasonisthatdriversshowincreasedtunnelvisionwithincreasingvehiclespeed.Undertheseconditionstheymaynotdetectpedestriansenteringthecrosswalkfromthesideoftheroadway.Unfortunately,wedonothavedataonoperatingspeedsonmostoftheroadsstudiedinthisseriesofexperiments.Speedseemstobethemajorfactorwith61%ofdriversonaverageyieldingtopedestrianson35mphroad,78%ofdriversyieldingonaveragetopedestrian’s30mphroads,and83%ofdriversyieldingon25mphroads.Anothercharacteristicthatmightinfluencewhetheradriveryieldsright-of-waytoapedestrianisADT.However,TheGatewayworkedverywellatseveralsiteswithahighADTandaspeedlimitof30mph(E.HuronSt.,TrowbridgeRd.,andLivernoisAve.)butitdidnotworkwellattwositeswithahighADTandaspeedlimitof35mph(OaklandRd.andWestnedgeAve.).Theaveragepercentageofdriversyieldingtopedestriansaveraged79%forwhenAADTwasbelow10,000,69%whenAADTwasbetween10,000and20,000,and71%whenAADTwasover20,000.OverallthiseffectsizeforADTwassmallerthanthatforspeed.Yieldingaveraged69%withonevehicletravellaneineachdirectionand76%withtwomotorvehicletravellanesineachdirection.Cautionshouldbeusedwheninterpretingtheseresultsbecausetheyarenotbasedonmanysites.However,itdoesappearthatspeedmaybealargerfactorthanAADTandthattheGatewaytreatmentmayworkbestonroadswitha25or30mphspeedlimit.Anothercharacteristicmaybethenumberofengineeringdevicespresentthatinfluencedriveryieldingright-of-waybehavior.Forexample,advanceyieldorstoplines,aRRFB,oraPHBusedinconjunctionwithasingleR1-6signoracompletegatewaytreatmentmayproducehigherdriveryieldingbehaviorthanthepresenceofonlyonesafetyfeature.Clearandconsistentevidenceexistsshowingacumulativeeffectofmultiplesafetyfeatures.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 50
Table4-1SelectroadwaycharacteristicsforMDOTproject120239(ResearchonComparisonofAlternativePedestrianCrossingTreatments)andMDOTproject114527(EvaluatingPedestrianSafetyImprovements)andyieldingresults
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 51
Figure4-1.StudyAreaMap
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 52
CHAPTER5–EVALUATIONOFTHELONGTERMEFFICACYANDSURVIVALOFTHEGATEWAYTREATMENTThischapterprovidesanexaminationofthelong-termpersistenceofdriveryieldingright-of-waytopedestriansandthelong-termsurvivalofthegatewaytreatment.Dataforlong-termefficacyofthegatewaytreatmentispresentedinTable5-1.Table5-1.Percentofdriversyieldingtopedestriansduringbaseline,initialtemporaryinstallation,andafterpermanentinstallationateachofthetreatmentsites.
PercentofDriversYieldingCrosswalkLocation
Baseline TemporaryInstallation
PermanentInstallation
FollowupPeriod X X 1Month 2Month 3MonthNixonRd.atBluettRd. 40 86 93 89 XS7thSt.midblockNorthofPioneerRd. 15 54 64 70 XS.DivisionSt.atE.JeffersonSt. 3 94 94 93 XE.HuronSt.westofN.IngallsSt. 40 86 X X XN.MainSt.NorthofE.MichiganAve. 6 X 64 53 50RoundaboutE.MainSt.at5thSt. 19 45 61 60 *33RoundaboutEMainatRiverviewDr. 9 43 44 44 44MarshallTrafficCircleNECrosswalk 13 54 71 71 50MarshallTrafficCircleSWCrosswalk 11 29 26 38 34S.WestnedgeatRanneySt. 0 59 33 29 *NAMonroeSt.eastofChestnutRRFBOff 6 X 82 *50 *56MonroeSt.eastofChestnutRRFBOn 65 X 95 98 96Mean 19 61 66 63 *Gatewayelementwasidentifiedasdamagedordestroyed
LONGTERMEFFICACYTheinstallationofthetemporarygatewayledtoanincreaseinthepercentageofdriversyieldingtopedestriansateachsite.Duringbaselineconditions,yieldingaveraged19%witharangeof0to40%.Atemporaryinstallationwasevaluatedafterthebaselineconditionateachsite.Whenthetemporarygatewaytreatmentwasevaluated,yieldingincreasedto61%witharangeof29%to94%.Oncethepermanentgatewaytreatmentswereinstalledforone-monthyieldingincreasedto66%witharangeof26%to95%.Twomonthsafterthepermanentinstallationyieldingwas63%witharangeof29%to98%.Datacollectedafterthefirsttwomonthsafterpermanentsignswereinstalledwasverysimilartodatacollectedwiththetemporarysigns.ThesignsinAnnArborwereinstalledonemonthlaterthanthesignsinsouthwestMichigansothereisnodataforthethirdmonthatthesesites.ThedatafromthesitesinsouthwestMichiganweresimilarforthethirdmonthwithexceptionoftwositesthathadelementsofthegatewaydamaged.ThesiteattheRoundaboutat5thinBentonHarborlostoneofthetwosignsplacedontheedgelanelineattheentrancetotheroundabout.Thissignwassheeredfromitsbase.AtthesiteatWestnedgeatRanneyinKalamazoo,thedelineatorwasseriouslydamagedreducingthegatewayeffect.Thissignshowedevidenceofmanymorestrikesthanothersigns.Manyofthesignsshowednoevidenceofbeingstruck.IfoneassumesthedatawillholdupforthethirdmonthinAnnArbor,themeanwouldbe65%,whichisthesameasthelevelproducedbythetemporarygatewayinstallations.Itshouldbenotedthatthesignsare
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 53
muchmoreeffectiveatsomesites.However,inallcasespedestriansdidnotneedtowaitlongtocrossafterthegatewaywasintroduced.Forexample,with50%yieldingeveryseconddriveryields;evenwith30%yieldingnearlyeverythirddriveryields.However,withlowbaselinelevelsof0%,3%,6%or9%,lessthanonedriverintenyields.
SURVIVALSignswerecheckedfordamageonaregularbasis.Manysignsshowednoevidenceofbeingstruck.Generally,signsmountedonacurbshowednoevidenceofbeingstruckandnoneweredamaged.Twoofthesignsinstalledintheroadwaywithflushmountedbaseswereseriouslydamaged.Onlyoneoftheflexibledelineatorpostswasdestroyedandthiswasatthesitewiththehighestnumberofstrikes.Preliminarydatasuggestthattheuseofacurbtypebasesmountedinthegutterpanorsignsmountedontopofthecurbmayshowgoodlong-termsurvival.Theuseoftheflexibledelineatorpostlookslikeitcansurvive,howeverthedataatWestnedgeandRanneyshowthissigncanbedestroyedifitisstruckonaregularbasis.Itshouldbenotedthatonesignthatwasdestroyedandtheotherthatwasseverelydamagedweresignswithflushmountedbaseslocatedontheedgelaneline.Thesedatasuggestthatsignsmountedflushtothestreetarelessrobustthanthesignsmountedoncurbtypebases.Itisunlikelythesesignswouldhavebeendamagediftheywereplacedontopofthecurb.Inclimatesthatrequireplowingsnowinwinter,itisnecessarytoinstallthesignsafterthesnowseasonendsandtoremovethesignsbeforethestartofthesnowseason.Becausetheinitialcostofinstallationisgreaterthanthecostofremovalandreinstallation,removalforwinteroperationsisnotlikelyamajorburdenfortheuseofthesesigns.Typicallypedestrianactivityisgreaterduringthespring,summerandfallthanduringwintermonths,particularlyinareaswithhightourismexposure.Thisiskeybecausetheonlysignsthatwouldlikelysurviveinwinterarethosemountedonthetopofthecurbattherightsideoftheroadandthosemountedontopofthecurbonarefugeormedianisland.However,itisnotcertainwhetherthesnowloadingfromtheplowcoulddamagethesignsifitpushesthemtotheside.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 54
CHAPTER6–TYPICALLYCOSTSFORINSTALLATIONANDMAINTENANCEOF
THEGATEWAYTREATMENT(NOTEINSTALLATIONCOSTMAYVARY)
Table6-1.CostsforinstallationandmaintenanceofthegatewaytreatmentCOSTOFVARIOUSGATEWAYELEMENTS
R1-6signmountedonacurbtypebase $300
R1-6signmountedabasecementedontopofthecurbbesidetheroad $200
Costofaflexibledelineatorpost,base,capandepoxy $130
INSTALLATIONTIME(MOBILIZATIONANDTRAVELNOTINCLUDED)R1-6Signonacurbbasemountedintheroadway 5min.
R1-6signonabasecementedtothetopofthecurb 5min.
FlexibleDelineatormountedintheroadway 10min.
INSTALLATIONMATERIALCOSTANDTIME,PERCONFIGURATION
FOUR-LANECROSSINGWITHREFUGEISLAND COST TIMEGateway,curbmountedR1-6signswithcurbbases $1,820 30min.
Gateway,curbmountedR1-6signs,robustdelineatoronwhitelanelines $1,480 40min.
THREE-LANECROSSINGWITHNOREFUGEISLAND
GatewaywithcurbmountedR1-6signswithcurbbases $1,210 20min.
TWO-LANECROSSINGWITHNOREFUGEISLAND
GatewaywithcurbmountedR1-6signswithcurbbases $910 15min.Note:Costforallconfigurationswouldbelowerwithedgesignsplacedontopofcurb.ThisconfigurationrequiresFHWArequestforexperimentation
INDIVIDUALINSTALLATIONCOSTITEMSR1-6Signmountedonacurbbase $190
R1-6signmountedontopofcurbbesideroadway $190
Flexibledelineatorpostinstalledonwhitelaneline $110
All signs can be removed and taken out for winter operation very quickly. The flexibledelineators come with a recessed cap that protects the base from water damage. The curb
bases are removable and the holes need to be filled with silicone caulking to protect theroadwayfromwaterfreeze/thawdamageduringwinter.
Table6-2.RemovalandreinstallationtimesforgatewaytreatmentRemovalofcurbtypebaseandsign 2min.
Reinstallationofcurbtypebaseandsign 2min.
Removalofsignmountedontopofcurb 1min.
Reinstallationofsignmountedontopofcurb 1min.
Removalofflexibledelineator,installcapforwinter 40sec.
Reinstallationofflexibledelineator,removecapinspring 90sec.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 55
CHAPTER7-CONCLUSIONSTheresultsofthefirstseriesofstudiesexploredseveralgatewayconfigurationsinfluencingtheefficacyofthegatewaytreatment.Onehypothesisthatwasconfirmedwasthatthenarrowness
ofthegapbetweenthesignswasinverselyrelatedtothetreatmenteffect.Thishypothesiswasconfirmed with narrow gaps leading to larger increases in driver yielding right-of-way topedestriansatseveraldifferenttypesofcrosswalkapplications.
Anotherhypothesistestedwaswhetherthesignmessageitselfhadaneffectondriveryieldingbehavior. It was found that the blanks configuration was significantly less effective than the
gatewayconfigurationwiththesignmessagepresent.A configurationanalysisalso showed that thepositionof the sign isa critical factor fordriver
yieldingbehavior.
• Gatewaytreatmentpositionsusedinisolationresultedinlowerdriveryieldingright-of-
waytopedestriansthanthefullgateway.• Signs placed on the white lane line alone exerted more control over driver yielding
behaviorthantheedgepositionsaloneatallsites,butlessyieldingthanthefullgateway
treatment.Itappearsthattheeffectisgreatestwhenmotoristsneedtodriveinalanebetweentwosigns.
However,theeffectsproducedbythepartialgatewaytreatmentshowthatifasignishitduringa season and not replaced until the signs are reinstalled after winter, the partial gateway
treatmentwouldstillbeofsomebenefittopedestrians.Another finding was the reduction in speed associated with the presence of the gateway
treatment.Driversbeganslowingatthedilemmazoneandweretravelling10mphslowerwhentheyentered thecrosswalkat theonly sitewhere speedwasmeasured.This speed reductionshould decrease the probability of hitting a pedestrian, as well as the seriousness of a crash
shouldoneoccur.Althoughthisstudyandpreviousstudies(9)demonstratethatthegatewaytreatmentproduced
changes indriveryieldingbehaviorat crosswalksonmultilane roads that can rival treatmentsoneandtwoordersofmagnitudemoreexpensivetoinstall,itisalsoimportanttoshowthatthistreatmentwillnotrequireexcessivemaintenanceefforts. In locationswhereplowing isnotan
issue thesignscanremainupyear round.However, inareaswheresnowremoval isan issue,the signswouldneed tobe removed inwinter.Mostof the signs testedcanbe removedandreinstalledquicklyaftertheinitialinstallation.Althoughin-streetsignsaredesignedtorebound
afterbeingstruck,signsurvivalwithmultiplestrikescouldbeanissue.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 56
Chapter 2 examined two configurations that could increase the survival of the gateway
treatment.Thetwoconfigurationstested,whichshowedincreasedsignsurvival,onlyproducedmoderatereductions intheefficacyofthegatewaytreatment.First, installationofthesignontopofthecurbfacewasassociatedwithonlyasmallreductioninthetreatmenteffectiveness.
Signsontopofthecurbfacearelesslikelytobestruckthansignsplacedinthegutterpananddonotpresentaproblemforsweepersordrainageissues.However,thistypeofconfigurationwouldbe lesseffectiveat locationswithon-streetparkingwhereparkedvehiclescouldscreen
theviewofasignaswellaspedestrians.Onesolutiontothisproblemwouldbetoinstallacurbextension. The curb extension would prevent parked cars from screening the view of thepedestrian,aswellasallowingtheinstallationofaR1-6edgesignsontopofthecurb.
Themostvulnerableelementofthegatewayconfigurationarethesignsplacedonwhite linesseparatinglanescarryingtrafficinthesamedirection.Theuseofarobustyellowgreenflexible
delineatordevicecanaddtothesurvivalofthegatewaytreatment.ThedelineatorselectedwastestedbytheTexasTransportationInstituteandfoundtotake100strikesat60mph.Thistypeofadeviceshouldhavea long lifespanonurbanroadswithspeed limitsof35mphor less. If
thereisamedianorrefugeisland,theuseofcurbtopplacementoftheR1-6edgesignsandadelineatoratthelanelineshouldprovideatroublefreeinstallationformanyyears.
Most of the applications studied in an earlierMDOT study examined the gateway treatmentefficacy at midblock crosswalks and crosswalks at uncontrolled locations on an arterial orcollector road at the intersection of a stop-controlled road. Chapter 3 examined the gateway
treatment in a variety of new crosswalk applications, including traffic circles, roundabouts,freewayentranceramps,andtrailcrossings.Theresultsofthisstudyshowedthatthegatewaytreatmentwaslesseffectiveattrafficcirclecrosswalks,particularlyatthewiderconfigurations.
The gateway treatment was also less effective at roundabout locations, particularly atcrosswalks exiting the roundabout. The treatment at freeway entrance ramps only producedmarginalincreasesinyieldingbehavior.Thegatewaytreatmentisthereforenotrecommended
forthistypeofapplication.Onereasonwhythegatewaytreatmentwasineffectiveatthistypeofapplication is thatdriversareacceleratingas theyapproachanentrance rampandare lesslikelytoyieldright-of-waytopedestrians.Thegatewaytreatmentwashighlyeffectiveatoneof
the two trail crossingsbutonlymoderatelyeffectiveat the secondcrossing thathadahigheroperatingspeed.
Preliminarydatasuggest:
• That the gateway treatment is most effective at midblock crosswalk locations,
uncontrolledcrosswalklocationsatanintersectionwithastop-controlledroad,andtrailcrossings.
• Data also indicated that a gateway installed at an RRFB location could bring yielding
behaviortoalevelthatcomesclosetothatproducedatatrafficsignal.• Dataalsosuggestthatthegatewaymaynotbeaseffectiveonroadswithaspeedlimit
above30mphiftheADTisover15,000.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 57
Chapter5providedpreliminaryevidenceof the long-termpersistenceofgateway increases indriversyieldingright-of-waytopedestriansovertimeandthelong-termsurvivalofthegatewaytreatment.Because the signswereonly installed for twoor threemonths, supplementaldata
will be required in order to provide clear results. However, the signs did maintain theireffectivenessinAnnArboroveratwo-monthperiodandatthesitesinthesouthwesternsideofthestateforathree-monthperiod.
Preliminary data on sign survival indicate that gateway signs mounted in the roadway oninstallablecurbbasesmaybemorerobustthanthoseinstalledflushwiththeroadway,andthat
therobustdelineator installedona lane linecansustainmanyhitsbutmaynotsurviveforanentireseasonatsiteswithhigherspeedsandADT.Atlocationswithon-streetparking,theedgesignsneed tobeplacedon theparking lane line.However suchplacementwouldmake them
very vulnerable to turning vehicle movements. Truck traffic hitting the signs likely woulddamagethesigns.Onealternativementionedabovewouldbetheuseofacurbextensionatthecrosswalk.Thiswouldallowforeithergutterpanplacement,curbtopplacementorplacement
intheroadwayattheleadingedgeofthecurbextension.Chapter6providedinformationonmaterialsandinstallationcostsforeachoftheelementsof
thegatewaytreatment.Thesedatashowthatthegatewaytreatmentisarelativelyinexpensivetreatment. Most items can be removed easily in winter and reinstalled easily in the spring.Estimatedremovalandreinstallationcostswerealsoprovided.
Although this treatment increases the percentage of drivers yielding to pedestrians atcrosswalkswithtwoormoretravel lanes ineachdirection, it isnotclearwhether itwouldbe
associatedwith a reduction in crashes at these sites.Oneway to increase the likelihood thatgatewaytreatmentreducescrasheswouldbetocombineitwithadvancestoporyieldmarkings(15,16,17,18,19).Itisalsoknownthatin-streetsignsareassociatedwithareductionofvehicle
speedatcrosswalks(7).Futureresearchshoulddeterminewhetherthefullgatewaytreatmentconsistentlyleadstoalargerspeedreductionthanasinglein-streetsign.Suchafindingwouldbeimportantbecausetherelationshipbetweenspeedreductionandreductionincrashseverity
hasbeenclearlyestablished(24).
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 58
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EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 60
APPENDIXASTATISTICALDATAANALYSIS
Thepurpose of this section is twofold. First, details regarding the statisticalmethods used to
analyze the outcomes of the studies are explained. Second, the outcomes themselves arepresented. Because the research was carried out at different Kalamazoo locations under avariety of conditions the research design, methods of analysis, and results are presented
separately for each of the following sites: (1) Rose Street at Kalamazoo Valley CommunityCollege(KVCC),(2)WestnedgeAvenueatRanneyStreet,and(3)RoseStreetatAcademy.
RoseStreet-KVCCSite
ResearchDesign
The data collected at the Rose Street-KVCC site were obtained under a 14-phase time-seriesdesignthatincluded68observationdays.ThesedataarepresentedinFigure1.Theconditionlabels for each phase in the 14-phase sequence are as follows: (1) Baseline, (2) Blanks, (3)
Gateway, (4)CityPost, (5)Gateway, (6)CityPost, (7)Gateway, (8)CityPost, (9)Baseline, (10)Blanks, (11) City Post, (12) Gateway, (13) Baseline, and (14) Blanks. This complex designprovideselaboratereplicationcomponentsthatallowrepeateddemonstrationsofintervention
effects.VisualAnalysis
Phases1,9,and13wereexposedtotheBaselinecondition.ItcanbeseeninFigure1thattheyieldingpercentagesareverylowbutsimilarforthesethreephases.TheBlanksconditionwas
appliedduringphases2,10,and14;eachofthesephaseshasayieldingpercentagethatcanbeseentobeapproximately30pointshigherthanduringadjacentbaselinephases.TheGatewayconditionwasappliedduringphases3,5,7,and12.Itcanbeseenthattheyieldingpercentages
duringthesephasesareover70pointshigherthanduringnearbybaselinephases.TheCityPostconditionwasappliedduringphases4,6,8,and11.Theyieldingpercentagesforthesephasesareover50pointshigherthanforbaselinephasesthatareneartheminthetimesequence.
Hence,avisualanalysisoftheresultsindicatesthatyieldingpercentagesareverylowduringallbaseline phases and that yielding is much higher for each non-baseline condition. Formal
statistical analyses that confirm these visual impressions and provide detailed quantitativeevaluationsaredescribednext.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 61
Figure1.YieldingPercentageDuring14Phases(RoseStreet-KVCCSite–Daytime).
StatisticalMethodsModelingApproach
Atime-seriesregressioninterventionanalysisofthetypedescribedinHuitema(2011;Chapters18-21) was carried out on the 14-phase design implemented at the Rose-KVCC site. This
modeling approach begins by fitting a complex model that accommodates several types ofintervention effects and errors; subsequent analyses are then carried out to evaluate thenecessityofretainingthevariousparametersintheinitialmodelandtoevaluatetheadequacy
ofpotentiallysimplermodels.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 62
The initial analysis involved fitting a complex (28-parameter) model; additional analyses
summarized in Table 1 were then carried out to determine if simpler models adequatelydescribethedata.
Table 1. Analyses Used in Model Identification and Evaluation (Rose Street-KVCC Site –
Daytime)
1.Model-comparisontest.ThecomparisonoftheinitialFullModel(includinglevelchangeandtrendchangeparameters)versustheRestrictedModel(includinglevelchangeparametersonly)yieldsF = 0.38 (df = 14, 40) andp = 0.97. It is concluded thatwithin-phase trend and trend
change parameters are not necessary and that the simpler (level change only) model issatisfactory.
2.Test forhomogeneouswithin-conditionphase levels. AnoverallF-test forequalityofphaselevelswithinallconditionsisrejected(p=0.04).Separatefollow-upF-tests(computedforeach
condition)revealthatthreeoffourconditionshavehomogeneouswithinconditionphaselevels.Onecondition(CityPost)hasstatisticallysignificant(p<0.04)heterogeneityofwithin-condition
phase levels,but thedegreeof theheterogeneity is insufficient to invalidatepooling. Hence,levelsamongphaseswithin the four treatmentconditionsare treatedashomogeneous in thefinalinterventionanalysis.
3. Testoftheassumptionof independenterrors. Autocorrelationamongresidualsofthefinal
analysis(a4-condition levelchangemodel) isnotpresent(r1=-0.09,Huitema-McKeantestp-value=0.98;Ljung-Boxtestonthecompleteautocorrelationfunctionthrough lag-17yieldsp-value = 0.85). Autoregressive parameters are not required in themodel because the errors
appeartobeindependent.
4. Testoftheassumptionofanormalerrordistribution. TheAnderson-Darlingtestappliedtothe residuals of the 4-condition level change model does not reject (p-value > 0.05) thenormalityassumption.Approximatenormalityisimplied.
5.Testoftheassumptionofhomogeneousofwithin-conditionvariances. Levene’stestrejects
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 63
(p<0.05)thehypothesisofvariancehomogeneity.Subsequenttestscomparingconditionlevels
are modified (using Welch-F and Games-Howell-q approaches) to accommodate thisheterogeneity.
ModelSimplification
One model simplification that is sometimes possible involves the removal of parametersdescribing trend within phases or conditions. The first test listed in Table 1 is a “modelcomparison”testthatdetermineswhethermeasuresoftrendwithinphasesarerequiredinthe
model.Becausethistestisclearlynotstatisticallysignificant(p=0.97)itisconcludedthatthedataarewellmodeledwithoutparametersdescribingtrendwithinphases.Theonlyparametersneededtodescribetheeffectsoftheinterventionsarethosethatdescribethechangeinlevel
fromonephasetothenext.A second concern in evaluating the adequacy of the initialmodel is the variation among the
phase levels within conditions. Therewere three Baseline phases, three Blanks phases, fourGatewayphases,andfourCityPostphases.Ifthelevelsofthethreeorfourphaseswithineachof these conditions are essentially homogeneous it is sensible to pool data. That is, on a
condition-by-condition basis, consolidate the data from the various phases within eachcondition.
Alternatively,ifthephaselevelswithinconditionsarenothomogeneousitmaybemisleadingtopoolthedata;todosointhiscaseistoimplythatasingleconditionisinvolvedwhenactuallyitmaybeimportanttoconsiderdifferentvariantsofacondition.Thedecisionmadewithrespect
topoolingleadstoamajordifferenceinthecomplexityofthefinalanalysisinthisexperiment.Without pooling there are 14 phases and 182 potential comparisons to be analyzed; withpooling there are just four conditions and six pairwise comparisons. This simplicity occurs
because a single parameter adequately describes a condition level regardless ofwhich phasewithintheconditionisinvolved.Forthesereasonsformalstatisticaltestsofthehomogeneityofthephaselevelswithinconditionswerecarriedout;theyaresummarizedasthesecondentryin
Table1.Theoveralltestrejectsthehypothesisthatwithinconditionphaselevelsarehomogeneous(p=
0.01). This implies that the phase levels are heterogeneouswithin at least one condition. Aseparate test of homogeneity of phase levels was then carried out for each of the fourconditions.ThesefourtestsrevealedthatonlytheCityPostconditionhasheterogeneousphase
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 64
levels. Homogeneity of the phase levels is present within the Baseline, Blank, and Gateway
conditions.Althoughstrictheterogeneityofphase levelswithintheCityPostconditionwas identified,the
more important issue isdecidingwhether theheterogeneity is largeenoughtobeofpracticalimportanceindescribingtheoveralleffectsoftheinterventions.Itturnsoutthatitisnot.ThiswasconcludedbecausethecomparisonofeachCityPostphaselevelwiththeoveralllevelsfor
the other three conditions yields the same pattern regardless of the phase chosen. That is,regardless of which City Post phase is chosen for comparison with the three remainingconditions (viz.,Baseline,Blanks,andGateway) theorderofeffectiveness isalways thesame:
Gateway>CityPost>Blanks>Baseline.AlthoughthispatternisnoteasilyobservedinFigure1,it is fairy obvious in Figure 2. Notice that the Baseline condition has the lowest yieldingpercentageregardlessofwhichofthethreeBaselinephasesisconsidered,theBlankscondition
is always second lowest, theCityPost yieldingpercentage is secondhighest regardlessof thephase,andtheGatewayconditionalwaysproducesthehighestyieldingpercentage.Thereisnoinstance in which this pattern does not hold. Because this ordering is constant for the four
phaseswithintheCityPostcondition,thesephaseswerepooled(justastheywerefortheotherconditions)toprovideasinglelevelestimateforthiscondition.
Figure2.YieldingPercentageDuringFourConditions(Rose-KVCCSite–Daytime).
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 65
FinalSimplifiedModelThemodelcomparisontestandthehomogeneitytestsdescribedabovewereappliedinorderto
justify simplifying the initial complex model. It was concluded from these tests that trendparameters were not necessary and that phases within conditions could be pooled. Thesedecisionsledtoafarsimplermodel,whichiswrittenasfollows:
where
Ytistheyieldingpercentagemeasuredondayt, β0 istheregressionintercept, β1 isthelevelchangebetweentheBaselineandBlanksconditions, D1t isthedummyvariableindicatingtheBlanksconditionondayt, β2 isthelevelchangebetweentheBlanksandGatewayconditions, D2t isthedummyvariableindicatingtheGatewayconditionondayt, β3 isthelevelchangebetweentheGatewayandCityPostconditions, D3t isthedummyvariableindicatingtheCityPostconditionondayt,and εtistheerrorofthemodel. Whereas the original 14-phase model has 28 parameters, notice that the simplified four-
conditionmodel has only four parameters. This simplification results in a more transparentinterpretationofparameters,increasedpoweroftheinferentialtests,andnarrowerconfidenceintervals.
After the simplified model was initially identified it was necessary to evaluate its adequacy.Entries 3, 4, and 5 in Table 1 focus on three issues relevant to evaluating thismodel. These
issues are all related to the assumptions regarding theproperties of theerrors of themodel.Theseassumptionsarerelevantbecausetheinferentialtestsrestonthem.
The first assumption is that the errors are independent. This assumption is violated if theresiduals are autocorrelated. It can be seen in Table 1 that the residuals of the fitted four-condition level-change model are not autocorrelated. Both the H-M and L-B tests for
autocorrelation yield very high p-values (viz., 0.98 and 0.85, respectively). This implies thatautoregressive parameters are not needed and that independence of errors of the adoptedmodelcanbeassumed.
Yt = β0 + β1D1t + β2D2t + β3D3t + ε t
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 66
The secondassumption is that thedistributionof themodel errors is normal. Table1 shows
that the Anderson-Darling test of normality does not reject this assumption; approximatenormality isaccepted. This implies thatneither transformationsof theoutcomemeasurenoralternativeestimationmethodsarerequiredforadequatetestsofinterventioneffects.
Thelastassumptionisthatofhomogeneouswithinconditionvariances.AscanbeseeninTable1 (last entry) this assumption is violated. It can be seen in Table 2 that the variance for the
Baselinecondition isconsiderablysmaller thanthevarianceassociatedwitheachof theotherthreeconditions.Forthisreasontheconventionaltestsappliedtoevaluateinterventioneffectsunder this model were modified (using Welch-F and Games-Howell-q methods) to
accommodatepotentialproblemsassociatedwithheterogeneousvariances.Insummary,allassumptionsexcepthomogeneityofvariancearemetfortheproposedoutcome
analysis. Plotsoftheresidualsofthemodel (notshownhere)confirmtheresultsof thetestssummarized above; it is concluded that the identified four-parameter intervention model isappropriateforthefinalanalysisifmodifiedteststhataccommodateheterogeneityofvariance
areused.Theresultsofapplyingthisanalysisarepresentedbelow.
ResultsMeasuresoftheeffectsofintroducingconditionchanges(Blanks,Gateway,andCityPost)atthe
RoseStreet–KVCCsiteareprovidedinthissection.Thesemeasuresarebasedontheidentifiedfour-conditiontime-series regression interventionmodel thatwas identifiedabove. Estimatesofthelevelandvarianceparametersassociatedwiththefourconditions(i.e.,Baseline,Blanks,
CityPost,andGateway)arelistedinTable2.Thelevelparametersareessentiallytheaverageyielding percentages for the four conditions. Notice that very large effects seem obvious bysimplyinspectingtheyieldingpercentagesshowninTable2forthefourconditions.
Inferentialtestsondifferencesamongtheconditionlevelsconfirmimpressionsbasedonsimpleinspection. The overall test for differences among the condition levels yields an F-ratio of
378.23andap-valuethatis<0.001.Hence,thereisnodoubtthatatleastoneconditionleveldifferssignificantlyfromtheotherthree.Pairwisecomparisonsamongthefourconditionswere
carriedouttoidentifythespecificconditionlevelsthatdifferedsignificantlyfromeachother.Table 3 lists the pairwise differences among the estimated levels, the results of inferential
multiple-comparison testson thesedifferences, and the standardizedeffect sizes.Notice thateach contrast of two conditions is associatedwith ap-value that is less than .005; hence, allpairwisecomparisonsarestatisticallysignificant.Moreimportant,thestandardizedeffectsizes
indicatethateachtwo-conditioncomparisoneasilyexceedsthedefinitionofalargeeffectsizeusingCohen’scriterion(viz.,≥.80).Similarly,verylargeeffectsoftheinterventionsarerevealed
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 67
bythe statistic,whichis0.906;thisisinterpretedastheproportionofthetotalvariationin
dailyyieldingbehaviorthatisexplainedbytheinterventionconditions.
AgraphicrepresentationoftheleveldifferencescanbeseeninFigure3asthedotsinthecenteroftheillustratedlines. Numbers1,2,3,and4inthisfigurecorrespondtothefourconditionspreviouslydescribedasBaseline,Blanks,Gateway,andCityPost, respectively. Hence,“2–1”
shown in the upper left of the figure identifies the row with a line that contains a dotcorrespondingtothedifferencebetweenthelevelofthefirstcondition(Baseline)andthelevelofthesecondcondition(Blanks).Noticethatthisdotfallsaboveapointontheabscissathatis
abouthalfwaybetween20and40;actually it isexactly30.34.(This isalsothevalueshowninTable3asthedifferencebetweenthelevelsforthetheseconditions.)Theleftandrightendsofthe lines in the figure indicate the lower and upper limits on the simultaneous 95 percent
confidenceintervals.Wecanbeatleast95percentconfidentthatthewholesetofintervalsiscorrect; that is,weareat least95percent confident that thewhole collectionof six intervalsindeed trap the true process effect (i.e., level differences) within the limits illustrated here.
Noticethatnoneoftheintervals isnearthezeroline;thismeansthatzeroisfarfrombeingacrediblevalueforthetruedifferencebetweenanypairoftrueconditionmeans.
Although theconventional confidencecoefficientof95percenthasbeenused inconstructingthe lines in this figure, themuchmore stringent confidence coefficient of 99.5 could also beused.Ifthisweredoneitwouldstillbefoundthatnoneoftheintervalswouldcontainzeroand
thesetof intervalswouldbeconsistentwith thesetof results shown incolumn3ofTable3.Notice that each p-value in this table is less than .005. This is simply an alternative way ofindicatingthateachofthesixpairwisedifferencesamongconditionlevelsfarexceedssampling
errorand,moreimportantly,representsalargeandpersuasiveeffectoftheinterventions.
Table2.YieldingLevelandVarianceforFourConditions(Rose-KVCCSite–Daytime)
Condition YieldingPercentageLevel Variance
1.Baseline 5.83 19.65
2.Blanks 36.17 96.92
3.Gateway 78.52 82.15
4.CityPost 59.82 112.96
η̂2
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 68
Table 3. Differences Among Yielding Levels, Familywise p-values, and Standardized Effect
Sizes(Rose-KVCCSite–Daytime)
Conditions
Compared
LevelDifference Familywise p-
value
Standardized
EffectSize
Blanks-Baseline 30.34 <0.005 3.38
Gateway –Baseline
72.69 <0.005 8.10
City Post -
Baseline
53.99 <0.005 6.02
Gateway-Blanks 42.35 <0.005 4.72
CityPost-Blanks 23.65 <0.005 2.64
City Post -Gateway
-18.70 <0.005 -2.08
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 69
Figure 3. Simultaneous 95PercentConfidence Intervals on LevelDifferences for EachPair ofConditions(Rose-KVCCSite–Daytime).
RoseStreetatKVCCSite(Night)Theanalysispresentedabove isbasedon thedaytimedatacollectedat theRoseStreet-KVCC
site; a second experiment was carried out at the this site at night. The nighttime data areanalyzedhere.
ResearchDesignThedesign used at night ismuch simpler than the daytime version because only four phases
(ratherthan14)areinvolvedandthenumberofdatacollectiondaysis18(ratherthan68).Datawerecollectedunderthreeconditions:Baseline(phasesoneandfour),Gateway(phase2),andCityPost(phase3).ThesedatacanbeseeninFigure4.
VisualAnalysis
ItisobviousinFigure4thattheyieldingpercentageisverylowduringtheBaselinephases(oneandfour)andthatbothexperimentalconditionsareassociatedwithmuchhigheryielding.Therankorderof theeffectivenessof thedifferentconditionsappears tobequiteconsistentwith
thefindingsreportedearlierforthemain(daytime)studyatthissite.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 70
Figure4. YieldingPercentageUnderBaseline,Gateway,andCityPostConditions (Rose-KVCCSite–Night).
StatisticalMethodsThestatisticalanalysisofthesedataissimilartotheapproachdescribedearlierindetailforthe
daytimedata. Thenatureofthenighttimedesign,however, leadstoseveralsimplifications inthedataanalysis.
ModelIdentificationAsummaryofthetestsusedtoidentifythemostadequatemodelareshownbelowinTable4.
Tests shown in the first two entries support the use of a three-condition level-changemodelwithpooledbaselinephases. Hence,thefinalmodelhasthreeparameters:onedescribesthelevel of the Baseline condition, one describes the level change from Baseline to Gateway
conditions,andonedescribes level change fromGateway toCityPostconditions. Thismodelalso provides information needed to evaluate the difference between Baseline and City Postconditions.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 71
Table4.SummaryofTestsUsedinModelIdentificationfortheRose-KVCCNighttimeData
1.Model-comparisontest.ThecomparisonoftheFullModel(includinglevelchangeandtrendchangeparameters)versustheRestrictedModel(includinglevelchangeparametersonly)yieldsF = 0.79 (df = 4, 10) andp = 0.56. It is concluded thatwithin-phase trend and trend change
parametersarenotnecessaryandthatthesimpler(levelchangeonly)modelissatisfactory.
2.Test for homogeneouswithin-condition Baseline phase levels. AnF-test for equality of thetwoBaselinephaselevelsisretained(p=0.37);thedifferencebetweenthetwoiseasilywithinthe rangeexpected fromsamplingerroralone.Hence, thedata fromthe twoBaselinephases
aretreatedashomogeneousinthefinalinterventionanalysis.
3. Testoftheassumptionof independenterrors. Autocorrelationamongresidualsofthefinalanalysis(a3-conditionlevelchangemodel)isnotpresent(Durbin-Watsonstatistic=1.74;H-M
statistic=1.31,p= .19;Ljung-Boxteston lag-1autocorrelationyieldsQ= .30,p-value=0.58).Autoregressive parameters are not required in the model because the errors appear to beindependent.
4. Testoftheassumptionofanormalerrordistribution. TheAnderson-Darlingtestappliedto
the residuals of the 3-condition level change model does not reject (p-value = 0.19) thenormalityassumption.Approximatenormalityisimplied.
5.Testoftheassumptionofhomogeneousofwithin-conditionvariances. Levene’stestrejects(p=0.05)thehypothesisofvariancehomogeneity.Subsequenttestscomparingconditionlevels
are modified (using Welch-F and Games-Howell-q approaches) to accommodate thisheterogeneity.
FinalSimplifiedModel
Testresultsshownasentries3,4,and5inTable4leadtotheconclusionthattheassumptionsof normality and independence of the errors are approximately met; the assumption of
homogeneous variances is not met. Consequently, the final tests for the identified three-parametermodelaremodifiedusingWelch-FandGames-Howell-qmethodsforaccommodatingvarianceheterogeneity.Theoutcomeofapplyingthesemethodsispresentednext.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 72
ResultsAninspectionoftheconditionlevels(Table5)andthedifferencesamongthem(Table6)leaves
nodoubt that largeeffectswereobtained. The standardizedeffect sizes listed inTable6areconsistentwiththisconclusion.Inaddition,mostofthevariationintheexperimentisexplained
bytheinterventions( statistic=0.96).
Inferential tests and confidence intervals essentially eliminate the argument that either theoverallresultsoranyindividualdifferencebetweenconditionlevelsmayhaveoccurredonlyasaresultofchance. TheWelch-Fomnibustestfordifferencesamongallcondition levelsyieldsa
valueof155.23 (p< .001). Hence, theobserveddifferencesamongthethreecondition levelsaremuchtoolargetobereasonablyattributedtosamplingerror. TheGames-Howellmultiplecomparisontestappliedtoeachindividualpairwisedifferencebetweenconditionlevelsreveals
astatisticallysignificant(p<.02)effectforeachcomparison.Correspondingly, the simultaneous 98 percent confidence intervals can be seen in Figure 5.
Notethatnoneoftheintervalstrapszero;wecanbe98percentconfidentthatthewholesetofintervalstrapthetruedifferencebetweenconditionlevels.Becausenoneoftheintervalstrapszeroitcanbeconcludedthatzeroisnotacrediblevalueforthetrueeffectofanycontrast.
Acomparisonoftheresultsofthedaytimeandnighttimeresultsrevealsamarkedconsistencyinboththeoverallpatternsandthespecificoutcomeeffects.InbothcasestheBaselineyielding
level is lessthansixpercent,theGatewaylevel isthehighest(roughly60-80percent),andtheCityPostlevelisintermediateatroughly35-60percent.
Table5.YieldingLevelandVarianceforThreeConditions(Rose-KVCCSite–Nighttime)
Condition YieldingPercentageLevel Variance
1.Baseline 1.49 6.22
2.Gateway 59.77 111.58
3.CityPost 38.92 16.35
Table 6. Intervention Effect Estimates, Familywise p-values, and Standardized Effect Sizes
(Rose-KVCCSite–Nighttime)
Conditions LevelDifference Familywise p- Standardized
η̂2
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 73
Compared value EffectSize
Gateway -Baseline
58.28 <0.02 9.76
City Post -
Baseline
37.43 <0.02 6.27
City Post -
Gateway
-20.85 <0.02 -3.49
Figure5.Simultaneous98PercentConfidenceIntervalsonDifferencesAmongConditionLevels.Condition:1=Baseline,2=Gateway,3=CityPost.(RoseStreet-KVCCSite–Nighttime).
WestnedgeAvenueatRanneyT-IntersectionSite
ResearchDesign
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 74
The data collected from theWestnedge Avenue at Ranney T-intersection site were obtainedunderaneight-phasetime-seriesdesignthatincludes37datacollectiondays.Theeightphasesarelabeledasfollows:(1)Baseline,(2)Edge,(3)Center,(4)FullGateway,(5)CityPost,(6)Edge,
(7)Baseline,and(8)CityPost.VisualAnalysis
Aconventionaltime-seriesplotoftheyieldingdatacollectedduringeachoftheeightphasesispresentedinFigure6.Itisobviousthattherearemajorshiftsfromphasetophase.Becausethe
designhaseightphasesbutonlyfiveconditions,someconditionshavemorethanonephase.Itmay be easier to visualize the overall differences in yielding between conditions in Figure 7,becausedifferentphasesbelongingtoagivenconditionareconnectedwithlines.Forexample,
nearthebottomofFigure7thefirstandseventhphasescontainthebaselinedata;thesephasesareconnectedwithastraightline.
It is obvious that there is essentially no yielding during the baseline condition (regardless ofphase)andthatallotherconditionshavehigheryielding.Morespecifically,itcanbeseenthatthehighestyieldingisassociatedwiththeFullGatewayconditionandthatthedataforallother
conditions fall between these two extremes. It appears that the Edge and Center conditionsresulted inminor tomoderate improvements,and theCityPost conditionhadamajoreffect,although the latter effect appears to be below that of the Full Gateway condition. Formal
statisticalevaluationsoftheeffectsarepresentednext.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 75
Figure6.YieldingPercentagebyPhase(WestnedgeatRanneySite).
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 76
Figure7.YieldingPercentagebyCondition(WestnedgeatRanneySite).
StatisticalMethods
ModelingApproachThe general modeling approach applied to theWestnedge-Ranney data is similar to the one
used for the Rose Street-KVCC site analyses. That is, a complex time-series regressionintervention model was initially estimated; tests were then used to determine whethersimplificationswerejustified,andthefinalmodelwasevaluated.Table7presentsasummaryof
thesetestsandtheassociatedresults.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 77
Table7. SummaryofTestsUsedinModel IdentificationandEvaluation(Westnedge-RanneySite).
1.Model-comparisontest.ThecomparisonoftheFullModel(includinglevelchangeandtrend
changeparameters)versustheRestrictedModel(includinglevelchangeparametersonly)yieldsF=0.754 (df=8,21)andp=0.65. It is concludedthatwithin-phase trendand trendchangeparametersarenotnecessaryandthatthesimpler(levelchangeonly)modelissatisfactory.
2.Testforhomogeneouswithin-conditionphase levels. Thetestfortheequalityofthephase
levelswithinconditions(F=.09,df=3,29,p=.98)isretained;poolingallthedatawithineachconditionisjustified.
3. Testoftheassumptionof independenterrors. Autocorrelationamongresidualsofthefinal
analysis (a5-condition level changemodel) isnotpresent (Durbin-Watsonstatistic=2.54,p>.05;H-Mstatistic=-.41,p=.68;Ljung-Boxtestforlag11throughlag-9autocorrelationyieldsQ=6.41, p-value = 0.70). Conclusion: Autoregressive parameters are not required in themodel
becausetheerrorsappeartobeindependent.
4. Testoftheassumptionofanormalerrordistribution. TheAnderson-Darlingtestappliedtotheresidualsofthe5-conditionlevel-changemodelrejectsthenormalityassumption(p-value<0.01). Approximate normality is not present. Amodified test insensitive to non-normality is
indicated.
5.Testoftheassumptionofhomogeneousofwithin-conditionvariances. Levene’stestrejects(p<0.05)thehypothesisofvariancehomogeneity.Subsequenttestscomparingconditionlevels
aremodified(usingrankbasedWelch-FandGames-Howell-qapproaches)toaccommodatethisheterogeneity.
ModelSimplificationThe initial eight-phase analysis contains 16parameters that includemeasures of level change
andtrendchangefromphasetophase. Testswerethencarriedouttodetermineifasimpler
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 78
modelisadequateforthesedata.First,amodelcomparisontest(reportedasthefirstentryin
Table7)supportsamodelthatdoesnotincludemeasuresoftrend,becausesystematictrendswerenotpresentwithinphases.Onlylevel-changeparametersarerequiredinthemodel.
Second, a testwas carried out to determinewhether it is appropriate to pool the data fromdifferentphaseswithinconditions.TheresultsofthistestarepresentedasthesecondentryinTable7. Thistest justifiespoolingthedata.Becausetheyieldingpercentagesbetweenphases
within conditions are essentially the same, these phases were combined. That is, the twobaseline phases were combined to form one condition. Similarly, the two Edge phases werecombinedtoprovidetheoverallEdgecondition,andthetwoCityPostphaseswerecombinedto
provide the overall City Post condition. Hence, even though there are eight phases in thedesign,themodelselectedforthefinalanalysisinvolvesthecomparisonofonlyfiveconditions(i.e.,Baseline(combined),Edge(combined),Center,FullGateway,andCityPost(combined).
FinalModel
Themodelidentifiedasmostappropriateforthesedataincludesfiveparameters.Itissimilartothe four-parameter model identified for the Rose-KVCC (daytime) site (described in detailearlier), but the present model includes one additional level-change parameter. The five
parameters measure the initial level during baseline as well as change from condition tocondition.Thelastthreeentries inTable7summarizeteststhatevaluatetheadequacyofthisfive-parameterlevel-changemodel.
All three testsof independence retain thehypothesisof independenterrors;hence, themostimportantassumptionappearstobemet.Thetestsfornormalityandhomogeneityofvariance
conclude that these assumptions are not met. These problems occur because the Baseline-condition data are essentially constant. An alternative analysis (a rank-based approachincorporating theWelch-F andGames-Howell-qmethods) that is little affectedbyeithernon-
normalityorheterogeneityofvarianceswasappliedtothedata;ityieldsthesameconclusionsregarding the effects of the interventions as does the originally selected level-changemodel.Forthisreason,onlytheresultsofthelatterarereportedhere.
ResultsAn inspectionof the condition levels (Table8)and thedifferencesamong them(Table9)leaves no doubt that large effects were obtained. The standardized effect sizes listed inTable9areconsistentwiththisconclusion.Allstandardizedeffectsizes,excepttheoneforthe Edge-Center comparison, exceed the criterion for a large effect. In addition,approximately90percentofthevariationintheexperiment(asmeasuredbythe statistic)is
explainedbytheinterventions.
η̂2
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 79
Inferential statistical tests and confidence intervals essentially eliminate the argument that
either the overall results or any individual difference between condition levels may haveoccurred only as a result of chance. The Welch-F omnibus test for differences among allconditionlevelsyieldsavalueof85.88(p<.001). Hence,theobserveddifferencesamongthe
three condition levels aremuch too large tobe reasonablyattributed to samplingerror. TheGames-Howellmultiplecomparisontestappliedtoeachindividualpairwisedifferencebetweencondition levels reveals a statistically significant (p < .05) effect for each of the 10 pairwise
differences,exceptforthe7.64-pointdifferencebetweentheEdgeandCenterlevels.Correspondingly, the simultaneous 95 percent confidence intervals can be seen in Figure 8.
Notethatnoneoftheintervalstrapszeroexceptthe“3–2”contrast,whichistheCenter–Edgecomparison. We can be 95 percent confident that the whole set of intervals trap the truedifferencebetweenconditionlevels.BecauseonlytheCenter-Edgeintervaltrapszeroitcanbe
concludedthatzeroisnotacrediblevalueforthetrueeffectinthecaseofanyoftheotherninecomparisons.
Table8.YieldingLevelandVarianceforFiveConditions(Westnedge-RanneySite)
Condition YieldingPercentageLevel Variance
1.Baseline 0.05 0.02
2.Edge 9.86 10.81
3.Center 17.50 67.50
4.FullGateway 89.14 250.81
5.CityPost 58.67 345.25
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 80
Table9.TenInterventionEffectEstimates,Familywisep-values,andStandardizedEffectSizes
(Westnedge-RanneySite).
ConditionsCompared Level
Difference
Familywise p-
value
Standardized
EffectSize
Edge-Baseline
9.81 <0.05 0.81
Center-Baseline
17.45 <0.05 1.44
FullGateway-Baseline 89.09 <0.05 7.37
CityPost–Baseline
58.62 <0.05 4.85
Center–Edge
7.64 >0.05 0.63
FullGateway–Edge 79.28 <0.05 6.56
CityPost–Edge
48.81 <0.05 4.04
FullGateway-Center 71.64 <0.05 5.93
CityPost–Center
41.17 <0.05 3.41
City Post – FullGateway
-30.47 <0.05 -2.52
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 81
Figure8.Simultaneous95PercentConfidenceIntervalsonthe10PairwiseDifferencesBetweentheFiveConditionLevels(Westnedge-RanneySite).1=Baseline,2=Edge,3=Center,4=Full
Gateway,and5=CityPost.
RoseStreetatAcademySite
ResearchDesign
A 19-phase time-series research design was used at the Rose Street & Academy site. Theoutcome data series consists of 87 observations (daily measures of yielding). One of the
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 82
followingsevenconditionswas ineffecteachday: (1)Baseline, (2)Narrow, (3)Blanks, (4)City
Post,(5)Wide,(6)Edge,or(7)Center.
VisualAnalysisThe yielding percentage data for the Rose Street-Academy site are illustrated in Figure 9 for
eachofthe19phasesinthisdesign.Itcanbeseenthatdatawereobtainedon87daysandtheconditionassociatedwitheachphaseisindicatedinthelegend.Itissomewhatcumbersometograsptheoveralloutcomefrominspectingthisfigurebecausetherearesomanyphases.
The outcome may be somewhat easier to comprehend in Figure 10, which identifies allobservations associated with a single condition using a line to connect the within-condition
phases. Although the observations associated with the Baseline, Blanks, and City Postconditionsarefairlyeasytotrack,thedataforsomeoftheremainingconditionsappeartoberathercommingled.
Figure11presentsboxplotsthatgreatlyclarifytherelativestandingoftheoutcomeunderthesevenconditions,althoughtheseplotseliminateinformationregardingthetimestructureofthe
data.Eachboxplothasalinerunningthroughtheboxthatindicatestheconditionmedian.Thebottomandtopportionsofeachboxcanbe interpreted,approximately,as the firstandthirdquartilesoftheindicatedconditiondistribution.
Inspectionof theseboxplotsmakes itclearthattheBaselineconditionhasthe lowestyieldingrate by far. The Narrow and Wide conditions appear to have the highest overall yielding
percentages, but the Narrow condition appears to have a somewhatmore consistent effect.Notice that the Narrow condition has less variation away from the center of the distributionthandoestheWidecondition(asindicatedbythedistancebetweenthetopandbottomofthe
box). Theother conditionsappear tohaveeffects thataremoremoderate than thoseof theNarrow and Wide conditions, but all of them are much better than the Baseline condition.These brief descriptive results are supplemented with a more thorough statistical analysis
below.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 83
Figure9.YieldingPercentagefor19PhasesIdentifiedbyCondition(Rose-AcademySite).
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 84
Figure10.YieldingPercentageforSevenConditions(Rose-AcademySite).
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 85
Figure11.YieldingPercentageBoxplotsforSevenConditions(Rose-AcademySite).
StatisticalMethods
ModelIdentification
Asummaryof the testsused to identifyandevaluate thebestmodel for theoutcomedata ispresented in Table 10. The first and second entries in this table indicate that (1) there is noneed for trend parameters in the model (i.e., level parameters are sufficient) and (2) the
variationbetweenphasemeanswithineachconditionissmallenoughtojustifypoolingalldata(from different phases) within conditions. The implications of the pooling are that the finalmodelevaluateschangesamong7conditionsratherthanamong19phases.Thisreductionhas
majordescriptiveandinferentialadvantages;amongthemissimplicity inthe interpretationofresults.Thereare21pairwisecomparisonsamongconditions(amanageablenumber)whereasthereare171pairwisecomparisonsamongphases.Table11liststhespecificphasesincludedin
eachconditionaswellastheconditionmeans.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 86
Thefinalmodel issimilartothemodelusedfortheanalysisoftheRose-KVCCdata,but ithassevenparameters insteadof four. The firstparametermeasures the initialBaseline levelandthe remaining six parameters measure change from one condition to the next and provide
informationneededtocompareallconditionswitheachother.
Table10.SummaryofTestsUsedinModelIdentification(Rose-AcademySite)
1.Model-comparisontest.ThecomparisonoftheFullModel(includinglevelchangeandtrendchangeparameters)versustheRestrictedModel(includinglevelchangeparametersonly)yieldsp > 0.05. It is concluded that within-phase trend and trend change parameters are not
necessaryandthatthesimpler(levelchangeonly)modelissatisfactory.
2. Test for homogeneous within-condition phase levels. Tests for the equality of the phaselevelswithinconditionshaveBonferroni-correctedp-values≥.14;thehomogeneityhypothesisisretained.Poolingdatafrommultiplephaseswithinconditionsappearsjustified.
3. Testoftheassumptionof independenterrors. Autocorrelationamongresidualsofthefinalanalysis (a 7-condition level changemodel) is not present (Ljung-Box test for autocorrelationbased on lags-1 – 22 of the autocorrelation function yields Q = 27.38, p-value = 0.20).
Conclusion:Autoregressiveparametersarenotrequiredinthemodelbecausetheerrorsappeartobeapproximatelyindependent.
4. Testoftheassumptionofanormalerrordistribution. TheAnderson-Darlingtestappliedtotheresidualsofthe7-conditionlevelchangemodeldoesnotrejectthenormalityassumption(p-
value=0.24).Approximatenormalityisassumed.
5.Testoftheassumptionofhomogeneouswithin-conditionvariances.Levene’stestrejects(p=0.03) the overall hypothesis of variance homogeneity. Consequently subsequent tests
comparing the seven condition levels are modified (using Welch-F and Games-Howell-qapproaches)toaccommodatethisheterogeneity.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 87
Table 11. Phases Pooled Within Each of Seven Conditions and Level Estimate for EachCondition(Rose-AcademySite)
Condition Phases Pooled Within EachCondition
PooledLevelEstimate
(1)Baseline 1,4,18 6.10
(2)Narrow 2,6,8,11,15 79.71
(3)Blanks 3,5,19 30.22
(4)CityPost 7,9 58.27
(5)Wide 10,12 78.81
(6)Edge 13,17 36.24
(7)Center 14,16 52.26
FinalModelEvaluation
The finalmodelwas estimated and the residuals from it were used to evaluatewhether theunderlyingmodelassumptionsaremet.Entries3,4,and5inTable10summarizetheresultsoftestsregardingtheassumptions. Entry3describesthetestoftheassumptionof independent
errors; the results of the Ljung-Box test imply that no additional parameters are required tomeasure dependency across time. The model errors appear to be correctly specified asapproximatelyindependent.Entry4describestheresultsofthetestforapproximatenormality
of the error distribution; this assumption appears to be met. The test described in Entry 5indicatesthattheassumptionofhomogeneousconditionvariancesmustberejected.Thistestresult does not invalidate the basic model or the estimation of effect estimates, but it does
change the methods required to provide valid inferential results. That is, the conventionalmethods for estimating error variances, hypothesis tests, and confidence intervals must bemodified to appropriately accommodate heterogeneous variances. Twomethods were used
here; they are known as the Welch-F omnibus test and the Games-Howell-q multiplecomparisontest.
Figure12 illustratesseveraldifferentwaysofplotting theresidualsof themodel. Theseplotsprovide visual confirmation of the test results described above. The plot in the lower rightquadrantofthefigureillustratesthebehavioroftheresidualsacrosstime.Itcanbeseenthat,in
general,thevalueofaresidualobservedononespecificdayisnotpredictiveofthevalueoftheresidualonsubsequentdays.ThisiswhytheLjung-Boxtestforautocorrelatedresidualsisnot
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 88
statisticallysignificant.Theplotsintheupperleftandlowerleftquadrantsprovidedescriptive
information regarding the normality assumption. The upper left “normal probability” plot isused to identifydepartures fromnormality;when thedotsdepart little fromthestraight line,approximatenormalityispresent. Becausemostdotsshowninthisplotarefairlyclosetothe
straight line it appears that approximate normality is present. The plot in the lower leftquadrant, which is simply the distribution of the observed residuals, can be seen to beapproximatelynormal.Theplotintheupperrightquadrantindicatestheresidualsforeachof
thesevenconditions. Thedistance from left toright represents theyieldingpercentage. ThedistributionofdotsthatappearontheleftoftheplotaretheBaselineresiduals.Noticethatthisdistribution has less variation than do the six other distributions (i.e., the non-Baseline
distributions). These discrepancies represent the variance heterogeneity that is identified byLevene’stest.
Figure 12. Residual Plots Indicating ConformityWith or Departure From Assumptions of the
FinalModel(Rose-AcademySite).
Theconclusionsofthemodelevaluationstagearethat(1)thedataconformtotwoofthethree
assumptionsofthefinalmodeland(2)thethirdassumption(homogeneityoferrorvariances)is
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 89
violated,butalternativestatisticalmethodsthataccommodatethisproblemareappropriatefor
theinferentialaspectsoftheanalysis. Theoutcomeofthestudy,basedonthefinalmodel, ispresentednext.
Results
TheaverageyieldingpercentageassociatedwitheachconditionisshowninthesecondcolumnofTable12. TheWelch-Fomnibus test fordifferencesamong these sevenmeansproducesa
valueof233.15(p< .001). Itcanbeconcludedthatdifferencesamongthesemeanestimatesare far too large to be explained as sampling fluctuation. Most of the variation in the
experiment isexplainedbybetweenconditiondifferences( =0.89). Becausethisevidence
supports the argument that overall intervention effects exist, more specific tests (and/orconfidenceintervals)evaluatingdifferencesbetweenpairsofconditionsareofinterest.
There are 21 pairwise comparisons in this seven-condition experiment. The two conditionsassociatedwitheachcomparisonarelistedininthefirstcolumnofTable13.Forexample,thefirstentryinthefirstcolumnis“Narrow–Baseline”andthevalueinthenextcolumnis73.61;
thelatteriscomputedastheNarrowmean(79.71)minustheBaselinemean(6.10). Thethirdcolumnliststhep-valueassociatedwiththetestonthedifferencebetweenthetwoconditionmeans, and the last column lists the standardized effect size. The standardized effect size is
simplytheeffectestimate(i.e.,thedifferencebetweenconditionmeans)dividedbythepooledwithin-conditionstandarddeviation(9.84).(BaselinedatawerenotincludedinthecomputationofthispooledvaluebecausetheBaselinestandarddeviationunderestimatestheerrorvariation
presentinallotherconditions.)
AnexaminationofthefirstsixrowsofTable13revealsthateachexperimentalconditionhasanaverageyieldingpercentage that ishigher than theBaselinepercentagebyat least24points.The range for the size of the effects is 24.12 points for the least effect condition (Blanks) to
73.61forthemosteffective(Narrow).Theorderoftheobservedeffectsofthesixactiveinterventionconditionsisasfollows:Narrow>
Wide > City Post > Center > Edge > Blanks. It should be pointed out, however, that thedifferencebetween theNarrowandWideeffectsarebothdescriptively trivialandstatisticallyunimportant. Similarly, both the (Blanks– Edge) and (Center - CityPost) differences arewell
within the rangeofvariation thatcanbeattributed tosamplingerror. Thiscanbeconcludedfromthenonsignificant(ns)p-valuesshownincolumnthree.
Analternative(andperhapsmoretransparent)analysisofthesamedatacanbeseenasthesetof confidence intervals presented in Figure 13. There are 21 intervals in this figure. Theseintervalsarepresentedinexactlythesameorder(fromtoptobottom)asthetestresultsshown
η̂2
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 90
Table13. Noticethatthreeconfidenceintervalstrapzero. Thesearetheconfidenceintervals
associated with the (Narrow – Wide), (Blanks – Edge), and (Center – City Post) differences.Whenan intervalcontainszerothismeansthatzero isacrediblevalueforthetruedifferencebetweenconditionmeans.
Just as 18 of the 21 familywise p-values in Table 13 are less than 0.05 (and therefore aredeclared statistically significant), 18 of the confidence intervals in Figure 13donot trap zero.
Bothapproachesleadtotheconclusionthatthese18differencesaretoolargetobeexplainedbysamplingerror.Theadvantagesoftheconfidenceintervalapproacharethat(1)thedegreetowhichanintervaldeviatesfromzerocanbeobserveddirectlyand(2)thewidthoftheinterval
provides a clear indicationof the amountof uncertainty associatedwith themeandifferenceestimate.
The intervals provided in Figure 13 are called “simultaneous 95 percent confidence intervals”becausetheprobability is0.95that thewholesetof21 intervalscontainthetruedifferences.Becausethisprobabilityvaluereferstothewholesetofintervals,thedegreeofconfidencethat
anindividualintervaltrapsthetruevalueisactuallymuchhigherthan.95.
Table12.YieldingLevelandVarianceforSevenConditions(Rose-AcademySite)
Condition MeanYieldingPercentage Variance
1.Baseline 6.10 8.40
2.Narrow 79.71 111.05
3.Blanks 30.22 59.00
4.CityPost 58.27 56.70
5.Wide 78.80 180.59
6.Edge 36.24 61.65
7.Center 52.26 110.50
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 91
Table13.InterventionEffectEstimates,Familywisep-values,andStandardizedEffectSizesfor21PairwiseConditionComparisons(Rose-AcademySite)
ConditionsCompared Difference BetweenMeans
Familywisep-value Standardized EffectSize
Narrow-Baseline 73.61 <0.05 7.48
Blanks–Baseline 24.12 <0.05 2.45
CityPost-Baseline 52.17 <0.05 5.30
Wide–Baseline 72.70 <0.05 7.39
Edge-Baseline 30.14 <0.05 3.06
Center–Baseline 46.16 <0.05 4.69
Blanks–Narrow -49.49 <0.05 -5.03
CityPost–Narrow -21.44 <0.05 -2.18
Wide–Narrow -0.91 >0.05(ns) -0.09
Edge–Narrow -43.47 <0.05 -4.42
Center–Narrow -27.45 <0.05 -2.78
CityPost-Blanks 28.05 <0.05 2.85
Wide–Blanks 48.58 <0.05 4.94
Edge–Blanks 6.02 >0.05(ns) 0.62
Center–Blanks 22.04 <0.05 2.24
Wide–CityPost 20.53 <0.05 2.09
Edge–CityPost -22.03 <0.05 -2.24
Center–CityPost -6.01 >0.05(ns) -0.61
Edge–Wide -42.56 <0.05 -4.32
Center–Wide -26.54 <0.05 -2.70
Center-Edge 16.02 <0.05 1.63
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 92
Figure13. Simultaneous95PercentConfidence Intervals for21PairwiseDifferencesBetween
SevenConditionMeans(Rose-AcademySite).
Thestandardizedeffect sizes listed in the final columnofTable13 for the first six rowsarguethattheeffectsoftheinterventionconditionsareofpracticalimportance.Eachofthesixvalues
easilyexceedstheconventionalcriterion(viz.,0.80)fordefininga“large”treatmenteffect.Moreimportantly,eventheleasteffectiveintervention(Blanks)hasayieldingpercentagethatis
fivetimesthesizeoftheBaselinepercentage,andthetwomosteffectiveinterventions(NarrowandWide)haveyieldingpercentagesthatareapproximately13timestheBaselinepercentage.Regardlessofthestatisticalmeasureusedtoevaluatethesizeorimportanceoftheoutcomethe
conclusionisthesame:largeeffectsaredemonstratedinthisexperiment.
EvaluationofR1-6GatewayTreatmentAlternativesforPedestrianCrossings 93
Also, the last15 rows in the last columnofTable13 indicate thatall comparisonsamong theactive (i.e., non-Baseline) intervention conditions except the previously mentioned (Wide-Narrow), (Edge-Blanks), and (Center-City Post) comparisons are statistically significant and
greatlyexceedthecriterionforalargeeffect.