technology demonstration study final report-v16€¦ · technology demonstration study focused on...

1NARRATIVE REPORT: YEAR 1

University of Iowa Technology

Demonstration Study

TECHNICAL REPORT

December 1, 2016Ashley B. McDonald Michelle L. Reyes Cheryl A. Roe Julia E. Friberg Kayla S. Faust

Daniel V. McGehee Principal Investigator

TransporTaTion and Vehicle safeTy research program

2401 Oakdale BlvdIowa City, IA 52242319-335-6819http://www.nads-sc.uiowa.edu

TheNational AdvancedDriving Simulator

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TableofContents

KeyFindings...........................................................................................................................3

ExecutiveSummary................................................................................................................4

Introduction...........................................................................................................................5

PurposeandResearchObjectives...........................................................................................5

Methodology..........................................................................................................................5IdentificationofLearningOutcomes.................................................................................................6StudyRecruitment...........................................................................................................................8StudyMethods...............................................................................................................................10DataManagementandSecurity.....................................................................................................18

Results..................................................................................................................................18ADASTechnologyKnowledge.........................................................................................................19ADASTechnologyPerceptionRatings.............................................................................................19LearningPreferences......................................................................................................................23

Discussion.............................................................................................................................30

Limitations............................................................................................................................31

Conclusion.............................................................................................................................32

Acknowledgements...............................................................................................................32

References............................................................................................................................33

Correspondenceshouldbedirectedto:DanielV.McGehee,PhD,PrincipalInvestigatorNationalAdvancedDrivingSimulatorIowaCity,IA2401OakdaleBlvdIowaCity,IA52242Tel.(319)335-6819Email:daniel-mcgehee@uiowa.eduPleasecontacttheresearchteamtorequestaccesstotheTechnologyDemonstrationStudyFinalReportAppendix.

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KeyFindingsThisreportcontainstheresultsoftheUniversityofIowa’sTechnologyDemonstrationStudy.Thestudyevaluateddrivers’attitudestowardandknowledgeaboutfiveadvanceddriverassistancetechnologiespriortoandafterlearningaboutthetechnologiesbycompletingoneoffourlearningprotocols.Thelearningprotocolsincludedreadinganowner’smanualand/orobservingadriverusethetechnologiesduringaride-alongdemonstrationdrive.TheTechnologyDemonstrationStudyfocusedonthefunctionsperformedbyadaptivecruisecontrol,blindspotmonitor,lanekeepingassist,parallelparkingassist,andrearcrosstrafficalert.

Ø Participantknowledgeofthefivetechnologiessignificantlyincreasedattheendofthestudy.Onaverage,knowledgescoresincreasedabout170%.

Ø Participantratingsofusefulnessofavehicleequippedwiththefunctiondescriptionsofadaptivecruisecontrolandparallelparkingassistsignificantlyincreasedattheendofthestudy.Ratingsfortheusefulnessoftheothertechnologiesinthestudywererelativelyhightobeginwithanddidnotchangesignificantlyattheconclusionofthestudy.

Ø Participantratingsoftrustforthefunctiondescriptionsofadaptivecruisecontrol,lanekeepingassist,parallelparkingassist,andrearcrosstrafficalertallsignificantlyincreasedattheendofthestudy.

Ø Ratingsofapprehensionofusingavehicleequippedwitheachtechnologyfunction

significantlydecreasedattheendofthestudyforallfivetechnologies.

Ø Participantsreportedthattheowner’smanualandtheride-alongdemonstrationdrivebothindividuallycontributedtotheirlearningaboutthepurposeandhowtouseeachADAStechnology.However,participantsassignedtothetwolearningprotocolsthatincludedbothreadingtheowner’smanualandcompletionofthedemonstrationdrivereportedthatthedrivecontributedmoretotheirlearningthantheowner’smanual.

Ø Aftercompletingthestudy,participantshadsignificantlygreaterinterestinpurchasinga

vehiclethatperformedadaptivecruisecontrolandparallelparkingfunctions.

Ø Beforecompletingthestudy,participantssaidtheywouldprefertolearnaboutadvanceddrivertechnologiesthroughamethodthatincludedademonstrationmorethan80%ofthetime.Attheendofthestudy,participantsoptedforalearningmethodthatincludedademonstrationdrivemorethan90%ofthetime.

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ExecutiveSummaryAdvanceddriverassistancesystems(ADAS)aremakingstrikingandrapidmarketpenetrationintheconsumervehiclemarket.However,manyconsumershavelittletonoexperiencewiththesetechnologiespriortofindingthemselvesbehindthewheel.ResultsfromtheNationalConsumerSurveyofDrivingSafetyTechnologiesconductedbytheUniversityofIowa(UI)founddriveruncertaintyabouttechnologiesthatarenotonlynewandemerging,butalsowithADAStechnologiesthathavebeenstandardforseveralyears.AsADAStechnologiesquicklyevolveandintegratewithotherin-vehiclefeatures,thismayleaveconsumerswithouttheeducationandinformationneededonhowtomosteffectivelyusethesetechnologies.TheMyCarDoesWhatnationaleducationcampaign,ledbytheUIandtheNationalSafetyCouncil,seekstoeducatetheAmericandrivingpubliconhowtomosteffectivelyuseADAStechnologieswhenbehindthewheelofavehicleequippedwiththesefeatures.DesignedtosupportthebroaderMyCarDoesWhatcampaigneffort,theTechnologyDemonstrationStudy(TDS)wasconductedtoprovideinsightsandunderstandingintodriverattitudestowardandknowledgeaboutseveraloftheemergingADAStechnologies.FocusingondriverswhodidnothavepriorexperienceorexposuretoseveraloftheADAStechnologiesincludedinthestudy,atotalof120participants,evenlysplitbygender,wereexposedtofourdifferentlearningprotocolsforfivedifferentADAStechnologies:adaptivecruisecontrol,blindspotmonitor,lanekeepingassist,parallelparkingassist,andrearcrosstrafficalert.IntheTDS,eachparticipantexperiencedoneoffourdifferentlearningprotocolsduringasitevisit:

• Readingtheowner’smanual• Experiencingaride-alongdemonstrationdrive• Experiencingaride-alongdemonstrationdrivefollowedbyreadingtheowner’smanual• Readingtheowner’smanualfollowedbyaride-alongdemonstrationdrive

AllparticipantscompletedaSiteVisitandPre-andPost-VisitSurveysthatmeasuredtheirknowledgeaboutandattitudestowardusingthetechnologies.Thisreportdetailstheoverallstudyobjectives;methodologiesforrecruitingtheparticipantsample,surveyinstruments,andlearningprotocols;andpreliminaryresults.TheTDSisthefirststudyofitskindtocomprehensivelymeasuredriverattitudestowardandknowledgeaboutthefiveADAStechnologiesincludedthestudy.TheTDSgreatlyaddstothescientificknowledgebaseofdriverunderstandingandhumanfactorsissuestobeconsideredforfutureevaluationasthesetechnologiescontinuetoincreaseinmarketpenetration.TheTDSwillserveasamodelbasetocontinuetomeasureandevaluatedrivers’attitudestowardandknowledgeaboutcurrentandfuturevehicletechnologies.

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IntroductionAdvanceddriverassistancesystems(ADAS)aremakingstrikingmarketpenetrationonAmericanroadways.MostADAStechnologiespromiseincreasingsafetybyprovidingdriverswithwarningsoralertsofpotentialhazardsorevenvaryinglevelsofvehiclecontrol.However,littleisknownabouthowadriver’strustisaffectedwhenanADAStechnologydoesnotperformasexpectedoranticipated.

PurposeandResearchObjectivesThepurposeoftheTDSwastoevaluatewhetherdriverattitudesandknowledgeaboutADAStechnologiesareaffectedbythewaysinwhichtheylearnaboutthetechnologies.TheTDSincludedfiveADAStechnologies:adaptivecruisecontrol(highwayandin-townscenarios),blindspotmonitor,lanekeepingassist,parallelparkingassist,andrearcrosstrafficalert.TheprimaryresearchquestionsoftheTDSwere:

1. DodriverswhoareunfamiliarwithADAStechnologiesexperienceachangeintheirknowledgeaboutandattitudestowards(includingtrust,usefulness,apprehension,andinterestinpurchasing)thosetechnologiesaftertheyhavelearnedaboutthemby:

a. Readingaboutthetechnologiesinanowner’smanual;b. Observingthosetechnologiesinuseduringaride-alongdemonstrationdrive;orc. Bothreadingaboutandobservingthetechnologies?

2. HowdodriversprefertolearnaboutdifferentADASanddotheirpreferenceschangeafterthestudy?Howdideachlearningprotocolcontributetotheirlearning?

TheTDSwascreatedtoprovideadditionalinsightandscientificdatafortheUI’sMyCarDoesWhatcampaignthatseekstoeducatedriversonADAStechnologiesthatareintheirvehiclestoday,aswellasthoseavailableintheoverallAmericanfleet.FindingsfromtheTDSwillassistthecampaignandresearchteaminidentifyingcriticalgapsindriverknowledgethattheMyCarDoesWhatteamcanaddressintheirpublicallyavailablematerialsandoverallcampaignmessaging.

MethodologyTheTDSwasdesignedtomeasuredriverknowledgeaboutandattitudestowardfiveADAStechnologies.Thesetechnologiesincluded:adaptivecruisecontrol,blindspotmonitor,lanekeepingassist,parallelparkingassist,andrearcrosstrafficalert.Thesesystemswerespecificallyselectedfortheirrecentincreaseinmarketpenetrationandrelativelylowlevelofknowledgeamongstconsumers.Itisworthnotingthat,throughouttheTDS,thetechnologieswerereferredtobytheirgenericormostcommonnameintheindustry.Insomeinstances,thetechnologynamereferredtointheTDSdifferedfromthenameusedbytheoriginalequipmentmanufacturer(OEM),asmanyOEMsuniquelymarketandbrandtheirindividualin-vehiclesafetysystemstodistinguishtheirproductsfromcompetitors.Inordertopreventanybiasorconfusion,theresearchteamusedthemoststraightforward,common,andgenericnameofthetechnology.

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Thefinalstudysampleincluded60maleand60femaledriverswhowereunfamiliarwithADAStechnologies.AllparticipantscompletedPre-andPost-VisitSurveysthatmeasuredtheirknowledgeaboutandattitudestowardusingthetechnologies.AllstudyprocedureswereapprovedbytheUIInstitutionalReviewBoard(IRB).IdentificationofLearningOutcomesToensureknowledgeofADAStechnologieswasmeasuredsimilarlyforallparticipants,regardlessofwhichlearningprotocoltheyexperienced,theresearchteamidentifiedaseriesoflearningoutcomes.Thelearningoutcomesaddressedthepurpose,function(howthesystemworks),andlimitationsofeachsysteminmostvehiclesonthemarket(i.e.,howtheADAStechnologiesworkingeneral,notjustintheTDSresearchvehicle).ForeachofthefiveADAStechnologiesintheTDS,theresearchteamobtainedtheowner’smanualsformakesandmodelsthathadallfiveADAStechnologiesanddraftedthelearningoutcomestobeapplicableacrossvehicles.Theresearchteamensuredthatboththeowner’smanualandtheride-alongdemonstrationdrivelearningprotocolsincludedalltheinformationdirectlyrelevanttothelearningoutcomes.Theresearchteamdrafted22multiplechoiceknowledgequestionsbasedonthelearningoutcomestoassessparticipantknowledgeofADAStechnologiesbeforeandaftercompletingthelearningprotocol.ThefollowingtablesbelowdisplaythelearningoutcomesdevelopedbytheresearchteamforeachADAStechnologyincludedintheTDS.

Table1:Generaldriverassistancesystemslearningoutcomes

Technology Purpose Function Limitations

DriverAssistanceTechnologies(ingeneral)

Areintendedtosupportthedriverbyprovidinginformation,alerts,orminimallevelsofcontrol

Useradar,sensors,and/orcamerastodetecttheenvironmentaroundthevehicle

Theradar,sensors,andcamerashavelimitationsthatcanaffectsystemperformance

RequirethedrivertostillpayfullattentiontothedrivingenvironmentCanvaryagreatdealbetweendifferentvehiclemakesandmodelsintermsofcapabilityandoperationCaneachbeturnedoffbythedriver

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Table2:AdaptivecruisecontrollearningoutcomesCaneachbeturnedoffbythedriverTechnology Purpose Function Limitations

AdaptiveCruiseControl(ACC)

Anadvancedversionofcruisecontrolthatnotonlymaintainsasetspeed,butasetdistancefromthevehicleaheadaswell

Providessomelimitedamountofbrakingthatvariesbetweenmanufacturers

Willonlyrespondtovehiclesthatthesystemhasrecognized

Requiresthedrivertosethis/herspeedandtimeintervaldistance.Thetimeintervaldistance(followingdistance)variesinseconds,butmostvehiclesgenerallyhaveashort,medium,andlongdistancetheymaintainfromthevehicleahead.

May"losetrack"ofvehiclesaroundcorners,sharpcurves,andiftheroadwayelevationchanges

Whenactivated,ACCtakesoverspeedcontrolfromthedriver

Table3:BlindspotmonitorlearningoutcomesWhenactivatedbythedriver,ACCtakesoverspeedcontrolfromthedriver

Technology Purpose Function Limitations

BlindSpotMonitor

Alertsthedriverwithawarningwhenavehiclemaybelocatedinhis/herblindspot(warningvariesbymanufacturer-maybeanilluminatedsymbol,sound,orvibration)

Onlyalertsthedriver,doesnottakecontrolofthevehicleinanyway

Manysystemsarenotdesignedtodetectvehiclespassingthroughtheblindspotatextremelyfastspeeds

Somesystemsprovideanescalatedwarningifavehicleislocatedintheblindspotandthedriver'sturnsignalison

Maynotdetectmotorcycles,bicycles,orpedestriansinadriver'sblindspot

Table4:Lanekeepingassistlearningoutcomes

Somesystemsprovideanescalatedwarningifavehicleislocatedintheblindspotandthedriver'sturnsignalison

Maynotdetectmotorcycles,bicycles,orpedestriansinadriver'sblindspot

Technology Purpose Function Limitations

LaneKeepingAssistDesignedtopreventcrashescausedwhenavehicleunintentionallydriftsoutofthelane

Detectswhenthevehiclemaybedriftingoutofthelaneandwillgentlysteerthevehiclebacktothelane

Notdesignedtoworkwithmarkingsthatarefaded,covered,indisrepair,orareoverlycomplicated

Designedtobeusedathighwayspeeds Ifthevehicle'stiresleavethelane,thesystemwillalertthedriverwithawarning(tone,icon,orvibration)

Temporarilytakescontrolofsteeringtotrytokeepthevehicleintheoriginallane

Reliesonpaintedlanemarkingstooperateeffectively

WillnotactivateifaturnsignalisonandthedriverisdriftinginthesamedirectionasthesignalThedriver'shandsmustbeonthesteeringwheelinorderforthelanekeepingassisttofunction

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Table5:Rearcrosstrafficalertlearningoutcomes

Table6:Parallelparkingassistlearningoutcomes

Purpose Function Limitations

Temporarilytakescontrolofsteeringthevehicleduringtheparallelparkingmaneuver

Searchesforasuitableparallelparkingspot,notifiesthedrivertobraketoastopandshiftthevehicleintoreverse

Theparallelparkingsystemwillbecancelledifthebackingspeedistoofastorifatirebeginstospinorlosetraction

Thedrivermustmaintaincontrolofthebrakeandthespeedofthevehicleduringthemaneuverandshiftthevehiclewhenthesystemdirectshim/hertodosoThesensorsonthevehiclewillalertthedriverasitisgettingclosertovehiclesorobjectsaroundthevehicleUsesacameratoshowtheenvironmentaroundthevehicleIfthedriverwantstostopthemaneuver,he/shecanturnthesteeringwheelorpressabutton(usuallyonthecenterdisplayorsteeringwheel)tocancel

StudyRecruitmentStudyEligibilityThebasicstudyeligibilityrequirementsweredefinedbyparticipantageandexposuretoselectedADAStechnologies.Thefollowinginclusioncriteriaweredefined:

• 30-55yearsold• Mustpossessacurrent,validUSdriver’slicenseandmusthavebeenalicenseddriver

foratleastthreeyears(validateduponsitevisit)• Mustdriveatleast90minutesperweek• Vehiclesinthepotentialparticipant’shouseholdunequippedwithanyofthefiveADAS

technologiesincludedintheTDS

Purpose Function Limitations

Alertsthedriverifoneormorevehiclesareabouttoenterthevehicle'sbackingpath

Ifthesystemisturnedon,itwillactivatewhenthevehicleisshiftedintoreverse

Hasreducedfunctionalityinangledparkingsituations

MostusefulwhenbackingoutofaperpendicularparkingspacewherethedrivercannotseeothervehiclesthatmaybecomingfromtherightorleftWarningtone,flashinglightonthemirrors,ordashboardalertthedriverthereisadetectedvehicleOnlyalertsthedriver,doesnottakecontrolofthevehicleinanyway

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TDSRecruitmentTheresearchteamconductedamulti-facetedrecruitmentplantoadvertisethestudytopotentialparticipants.Recruitmenttacticsincludedane-mailtoUIfacultyandstaff,ane-mailtotheNationalAdvancedDrivingSimulator(NADS)participantregistry,aCraigslistposting,andwordofmouth.RecruitmentbeganonJune1,2016,andextendedthroughSeptember11,2016.PotentialparticipantsaccessedtheTDSEligibilitySurveythroughthewebsitelinkincludedinallrecruitmente-mailsandpostings(referenceAppendixAfortheIRB-approvedrecruitmente-mailandonlinestudyannouncement).Afterremovingoutlierresponsetimes,theEligibilitySurveytookanaverageoffourminutestocomplete.ImmediatelyaftercompletingtheEligibilitySurvey,respondentswereinformedoftheireligibilityfortheTDS.Participantswereexcludedfromthestudyiftheydidnotmeetalltheinclusioncriteria,ifthey’dhadexposuretoadaptivecruisecontrol,blindspotmonitor,orlanekeepingassistasadriverorpassengerinanyvehicle,oriftheyhadpreviouslyparticipatedinresearchstudiesinvestigatingnewin-vehicletechnologiesinthepast.RespondentswhocompletedtheEligibilitySurveybutdidnotqualifyfortheTDSwereaskediftheywouldbeinterestedinaddingtheirnametoaregistryofpotentialparticipantsforfuturestudiesconcerningADAStechnologies.Atotalof112respondentsthatwereoriginallyineligibleforthestudynotedtheywouldliketheirnameaddedtotheregistry.Additionally,participantswhocompletedthefullstudyprotocolwerealsoaskediftheywouldliketobeaddedtotheregistry.Ofthosethatcompletedtheentirestudyprotocol,119respondedtheywouldliketheircontactinformationaddedtotheregistry.Table7providesthetotalstudyenrollmentandcompletionnumbersfromthetimepotentialparticipantsaccessedtheEligibilitySurveythroughthecompletionoftheTDS.Pleasenote,the“Ineligiblenumbers,InvitedtothePre-VisitSurvey,CompletedEntireStudyProtocol,FinalStudySample”arereflectiveofthe“EligibilitySurveyTotal”(426respondents).Thenumberbelow“EligibilitySurveyTotal”reflectsrespondentsthatclickedonthelink,butdidnotcompletethesurvey.

Table7:Totalstudyenrollmentandcompletionnumbers

EligibilitySurveyTotalAccessedtheEligibilitylinkbutdidnotcompletethesurvey

426108

Ineligible 178

InvitedtothePre-VisitSurvey 147

CompletedthePre-VisitSurvey 125

CompletedEntireStudyProtocol 122

FinalStudySample 120

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StudyMethodsPre-VisitSurveyOncepotentialparticipantsweredeterminedeligible,theyreceivedane-mailinvitationtocompletethePre-VisitSurveywithin30days.ThePre-VisitSurvey(AppendixB)includedquestionsassessingtheparticipant’sknowledgeabouttheADAStechnologypurposes,functions,andlimitations,aswellasquestionsrelatingtoparticipant’sattitudestowardsADAStechnologies,includingusefulness,trust,apprehension.Questionswerealsoaskedtoaddressparticipants’interestinpurchasingvehicleswiththesetechnologiesandhowtheywouldprefertolearnhowtousethem.PreviousresearchbytheUIfoundmanydriversdidnotknowwhataspecificADAStechnologieswerewhenreferredtobyname.Toaddressthis,someitemsinthePre-andPost-VisitSurveysprovidedadescriptionoftheADAStechnologyfunctionratherthanthenameofthesystem.Table8:providesthesevenADAStechnologydescriptionsusedintheTDSPre-andPost-VisitSurveystodescribethefiveADAStechnologiesincludedinthestudy(threedescribedthefunctionsofadaptivecruisecontrol).

Table8:DescriptionsofADAStechnologyfunctionsusedinthePre-andPost-VisitSurvey

ADASTechnology ADASTechnologyFunctionDescriptionParallelparkingassist SteersmyvehicleintoaparallelparkingspaceLanekeepingassist KeepsmyvehicleinmylaneifIbegintodriftoutofitBlindspotmonitor WarnsmeofvehiclesinmyblindspotAdaptivecruisecontrol AdjustsmyspeedwhileI’mfollowingavehicleAdaptivecruisecontrol BrakesmyvehicletoacompletestopwhileI’mfollowingavehicleAdaptivecruisecontrol AcceleratesmyvehiclefromastopwhileI’mfollowinganothervehicle

Rearcrosstrafficalert AlertsmewhencrosstrafficapproacheswhileI’mbackingoutofaparkingspace

UponcompletionofthePre-VisitSurvey,participantswerecontactedforthestudysitevisit.Aparticipant’ssitevisitwasschedulednoearlierthanleastsevendaysafterthecompletionofthePre-VisitSurvey.SiteVisitThesitevisittookplaceattheNADSfacility.Allsitevisitswerescheduledduringdaylighthoursandlowerexpectedtraveldensities.Sitevisitswerecanceledandrescheduledduetohighwindsorheavyprecipitation.

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IntakeSurveyUponarrival,participantsreviewedandsignedadministrativedocumentsandcompletedtheIntakeSurvey,whichhadbeenuploadedontoaniPad.TheIntakeSurvey(AppendixC)includedatotalof68questionsonthefollowingsubtopics:exposuretoinformationabouttheADAStechnologiescoveredinthestudysincecompletingthePre-VisitSurvey,TechnologyReadinessIndex2.0©(ParasuramanandColby,2015;usedwithpermissionoftheauthors),locusofcontrol,drivinghistory,andpersonaldemographics.UponcompletionoftheIntakeSurvey,theparticipant’sassignedlearningprotocolwasinitiated.LearningProtocolsEachparticipantwasrandomlyassignedtoexperienceoneoffourlearningprotocolsduringtheirsitevisit.Twobaselearningmethodsweredesignedtoevaluatehowdrivers’knowledgeandperceptionsofADAStechnologiesareaffectedbythewaysinwhichtheylearnaboutthesetechnologies.Onebasemethodrepresentedatypicalmethodoflearningaboutin-vehicletechnologies—anowner’smanual—whiletheotherconsistedofobservinganexperienceddriverusingthetechnologiesduringanon-roaddemonstrationinconditionsthatthetechnologieswereintendedfor.Thesetwobasemethodswerecombinedtocreatethefourbetween-participantslearningprotocols:

• Readingaboutthetechnologiesinanowner’smanual• Observinganexperienceddriverusethetechnologiesduringaride-along

demonstrationdrive• Readingtheowner’smanualfollowedbytheride-alongdemonstrationdrive• Theride-alongdemonstrationdrivefollowedbyreadingtheowner’smanual

Owner’sManualLearningMethodTheresearchvehicleusedintheTDSwasa2016full-sizeSUVequippedwithseveralADAStechnologiescurrentlyavailableonthemarket.Noafter-marketsystemswereinstalledandnomodificationsweremadetoanyvehiclesystems.Informationforalloftheresearchvehicle’sADAStechnologieswascontainedinonechapteroftheOEMmanual.ThebeginningofthischapterdescribedthecameraandradarsystemsthatsupportedseveraldifferentADAStechnologies,withtherestofthechapterdescribingeachofthedifferentADAStechnologiesindetail.Usingthischapter,theresearchteamdevelopedanowner’smanualfortheTDS,specifictothefivetechnologiesincludedinthestudy.Referencestothemanufacturerwereremoved,aswasinformationpertainingtosystemsnotincludedintheTDS.TheTDSowner’smanual(AppendixD)consistedofsixsections,withintroductorymaterialforeachsectionwrittenbytheresearchteam.TheresearchteamalsoreviewedADAStechnologycontentfromotherOEMowner'smanualsinordertowritethisintroductorymaterial.Thefirst

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sectionaddresseddriverassistancetechnologiesingeneral,withaone-pageintroductionexplainingthepurposeandlimitations,followedbyOEMcontentdescribingthecameraandradarsystem.Afterthisintroduction,onesectionforeachofthefiveADAStechnologiesincludedintheTDSfollowed.Intotal,theTDSowner’smanualpresentedtotheparticipantscontained38pagesbasedontheoriginalcontentofthemanualandsixpageswrittenbytheresearchteamintroducingeachsection.Participantsweregivenasmuchtimeaswasnecessarytoreadthemanual.Themedianamountoftimeparticipantsspentreviewingtheowner’smanualwas40minutes.Ride-AlongDemonstrationDriveLearningMethodFortheTDSride-alongdemonstrationdrivelearningmethod,theparticipantsatinthefrontpassengerseatoftheresearchvehicleandobservedanexperienceddriver(referredtoasthedemonstrationdriver)usingthefivedifferentADAStechnologiesonapredeterminedrouteutilizedforallparticipants.Priortoenteringthevehicle,participantswerebrieflyintroducedtothevehicle,includingthecameraandsensorsthatsupportmanyoftheADAStechnologies.Atspecificpointsthroughoutthedrive,thedemonstrationdriverinstructedtheparticipanttouseaniPadtoplayaudiofiles(AppendixE).ThefirstpartofeachaudiofilepresentedinformationaboutthenextADAStechnologythatwouldbedemonstrated,explainingthegeneralpurposeofthesystem,howitfunctioned,anditslimitationsinanyvehiclemodel.Thesecondpartexplainedthespecificfunctionandlimitationsofthetechnologyintheresearchvehicle.Audiofilesrangedinlengthfromabout30secondstofourminutes.Inadditiontotheaudiofiles,participantswereprovidedareferencesheetthatdisplayedvariousicons,steeringwheelsettings,andbuttonsrelatedtotheADAStechnologiesaswasdeterminednecessarybytheresearchteam.Throughoutthedemonstrationdrive,thedriverprovidedbriefexplanationsonhowthevehicle’ssystemswererespondingastheyweredemonstratedduringthedrive.Throughoutthedemonstrationdrive,theparticipantwasallowedtoaskthedemonstrationdriverquestionsormakecommentsabouttheADAStechnologies.Thedemonstrationdriverrespondedtoparticipantquestionswhenitwassafetodoso.Tocapturetheseparticipantquestionsandcomments,aswellastorecordtheexecutionofthedemonstrationdrive,threeGoProHero4cameraswereinstalledintheresearchvehicle.Onecamerafacedintothecabinandcapturedtheparticipantanddriver,asecondcapturedtheviewovertheparticipant’sshoulder,includingthesteeringwheelandthein-vehicledisplay,andathirdcapturedtheforwardroadway.Amicrophonewasclippedtothesunvisoronthepassengersidetorecordaudio.Inadditiontothedemonstrationdriver,adriverinasecondvehicleassistedwiththedemonstrationdrive(referredtoastheassistdriver).Ahand-free(Bluetooth)cellphoneconnectionwasestablishedbetweentheresearchandassistvehiclessothattheassistdrivercouldhearthedemonstrationdriverandparticipantthroughoutthedrive.Bothdemonstrationandassistdriverswereblindedtothelearningprotocolassignedtoeachparticipant.

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ThefirstthreeADAStechnologydemonstrationswereparallelparkingassist,blindspotmonitor,andlanekeepingassist.Thentheadaptivecruisecontroldemonstrationoccurredintwoparts:adaptivecruisecontrolduringhighwaydrivingandadaptivecruisecontrolinstop-and-gotrafficsituations.RearcrosstrafficalertwasdemonstratedintheNADSparkinglotattheendofthedrive.Thedemonstrationdrivetookapproximately40minutes.TheroutestartedintheNADSparkinglotandcontinuedtoaresidentialarea,suburbanarterialstreets,aninterstate,andaUShighwaybeforereturningtotheNADSfacilitybyreversingtheroute(seeFigure1).

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Figure1:TDSroutefromtostarttofinish(IowaCity,IA)

ParallelParkingAssistDemonstrationPriortothedemonstrationdrive,aparallelparkingscenariowasstagedwiththeassistvehicleandanotherresearchvehicleonaresidentialstreetneartheNADSfacilitytocreateaparkingspaceapproximately22feetlong.Thevehicleinfrontoftheparkingspaceandtheassistvehiclewereparkedaboutonefootfromthecurb(Figure2).

ParallelParkingAssist

BlindSpot

Monitor

LaneKeepingAssist

AdaptiveCruiseControlonthe

Highway

AdaptiveCruiseControlinStop-and-Go

Traffic

RearCrossTrafficAlert

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Figure2:Parallelparkingassistdemonstrationstaging.Blackvehicleistheresearchvehicleandwhitevehicleistheassist

vehicle.

Attheparallelparkingassistdemonstrationsite,thedemonstrationdriverfollowedtheinstructionsprovidedbytheresearchvehicletoparallelpark,verbalizingtheseinstructionsfortheparticipantasthevehiclemaneuveredintotheparkingspace.BlindSpotMonitorDemonstrationAftercompletingtheparallelparkingassistdemonstration,theresearchvehicle,followedbytheassistvehicle,traveledtoafour-lanesuburbanarterialstreetwithadividingmedianwherethedemonstrationdrivermovedintotherightlanewhiletheassistdriverremainedintheleftlane.Thedemonstrationdriveraskedtheparticipanttolookatthedriver’ssidemirrorastheassistvehiclebegantoovertaketheresearchvehicle.Afterafewseconds,theturnsignalwasactivatedsotheparticipantcouldobservehowtheblindspotwarningindicatorchangedfromstaticilluminationtoflashingillumination.Theflashingilluminationcontinueduntiltheassistvehicleclearedoutoftheresearchvehicle’sblindspot.Afterasignalizedintersection,theroadwaywidenedtothreelanes.Theassistvehiclemovedtotherightlaneandreducedspeedsoitcouldbepassedbytheresearchvehicle.Thedemonstrationdriverinstructedtheparticipanttolookatthepassengersidemirrorandthenactivatedtherightturnsignalsotheindicatorwouldflash.Theblindspotmonitordemonstrationendedwhentheassistvehiclewasnolongerintheblindspot.LaneKeepingAssistDemonstrationAfterenteringontothefour-lanedividedUShighwayandpermittingtrafficapproachingfromthereartopass,thedemonstrationdrivergentlysteeredthevehicletowardstherightlaneboundarywhiletheparticipantobservedthesteeringwheelortheroadtoseehowthesystemattemptedtocorrectlaneposition.Thislanekeepingassistdemonstrationtotherightwasexecutedasecondtime.Thenthedriverdemonstratedthelanekeepingassisttowardstheleftlaneboundarytwice.

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AdaptiveCruiseControlontheHighwayDemonstrationTheadaptivecruisecontrolonthehighwaydemonstrationtookplaceoverfivemilesonafour-lanedividedUShighway.Afterenteringthehighway,thedriversettheadaptivecruisecontrolspeedto60mphandshowedtheparticipanthowthesystemwassettothelongesttimeintervalsetting(aboutthreeseconds).Afterpassingtheresearchvehicle,theassistvehiclethenenteredthelaneinfrontoftheresearchvehicleandmaintainedaconstantspeedof57mph,causingtheresearchvehicletoreducespeed.Whilethesetspeedwasthenincreased,thedemonstrationdrivershowedtheparticipantthatthisdidnotresultinachangetotheresearchvehicle’sactualspeedasitwasstillfollowingtheslower-movingassistvehicle.Thenthetimeintervalwaschangedtotheshortestsetting(aboutonesecond)andthevehicleacceleratedtoclosethegap.Finally,themiddletimeintervalsettingofabouttwosecondswasdemonstrated,withthedemonstrationdrivernotingthattheadaptivecruisecontrolwasagainreducingthespeedtoincreasethegapbetweenthevehicles.Duringtheadaptivecruisecontrolonthehighwaydemonstration,theassistvehicleacceleratedoutoftherangedeterminedbythetimeintervalsettingwhiletheadaptivecruisecontrolmaintainedthevehicle’ssetspeedof65mph.Topreparetoexitthehighway,theassistdriverreducedspeedand,asthegapbetweenthetwovehiclesclosed,theadaptivecruisecontroldeceleratedtheresearchvehicleaccordingtothetimeintervalsetting.Whileontheoff-ramp,thedemonstrationdriverputtheadaptivecruisecontrolsystemintostandbymode,concludingtheadaptivecruisecontrolonthehighwaydemonstration.AdaptiveCruiseControlinTownDemonstrationWhilestillfollowingtheassistvehicle,theresearchvehicleexitedtheinterstate.Afterturningofftheexit-rampontoamulti-lanesuburbanarterialstreet,thedemonstrationdriversettheadaptivecruisecontroltothespeedlimitof40mphandthelongesttimeintervalsetting.Thisroadhadthreesignalizedintersectionsthatcouldbeusedforthedemonstration.Ifanystoplightwasamberorred,theassistvehiclebraked,resultingintheadaptivecruisecontrolslowingtheresearchvehicle.Eachparticipantwasgiventheopportunitytoexperienceasuccessfuldemonstrationinstop-and-gotrafficatleastonceandnoparticipantexperienceditmorethantwice.Thebrakingdemonstrationwasconsideredsuccessfuliftheresearchvehicledeceleratedtoaspeedof5mphorless.Ifthefirsttwotrafficlightsdidnotprovideforasuccessfuldemonstration,analternateroutewasusedtoencounteranothertrafficlight.Ifthatwasunsuccessful,theroutecontinuedontoalow-volumestreetwithoutstoplights.Theadaptivecruisecontrolwassetto25mphandthelongesttimeinterval.Thentheassistvehiclesignaledforaleftturnintoaparkinglotandbrakedtoacompletestopbeforemakingtheturn.

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RearCrossTrafficAlertDemonstrationAftercompletingtheadaptivecruisecontrolinstop-and-gotrafficdemonstration,thereturnedtotheNADSparkinglot,pullingintoareservedperpendicularparkingspacewithamini-vanparkedintheadjoiningspaceonthepassengerside(seeFigure3).Intheparkingaisle,theassistdriverwaitedoutofviewoftheparticipant.

Figure3:Rearcrosstrafficalertdemonstrationstaging.Blackvehicleistheresearchvehicle,whitevehicleistheassistvehicle,

andgrayvehicleistheparkedmini-van.

Aftertheassistdriverwasinposition,thedemonstrationdriverannouncedtotheparticipantthattherearcrosstrafficalertsystemwouldbeactivatedwhenthevehiclewasbacking.Thedemonstrationdriverthenshiftedintoreverseandpausedbrieflybeforelettingtheirfootslowlyoffthebraketobeginbacking.Astheresearchvehiclebackedoutofthespot,theassistdriverdroveforwarddowntheparkingaisleataspeedbetween10-15mph.Astheassistvehicleapproached,therearcrosstrafficalertsoundedthroughtheresearchvehicle’sfrontandrearpassengersidespeakersandprovidedavisualwarningontheconsoledisplayandonthesideofthevehiclewheretheassistvehiclewascomingfrom.Aftertheassistvehiclepassedbehindtheresearchvehicle,thedemonstrationdriverpulledbackintotheparkingspaceandthedemonstrationwasrepeatedwiththeassistvehicleapproachingfromthedriver’sside.Post-VisitSurveyOnceparticipantshadcompletedtheentirelearningprotocoltowhichtheywereassigned,theywereshowntoanoffice(iftheyhadjustfinishedthedemonstrationdrive)andpresentedwithaniPadpreloadedwiththePost-VisitSurvey(AppendixF).

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ThePost-VisitSurveyincluded69questions.Thesurveyincludedquestionsassessingparticipants’knowledgeofADAStechnologypurposes,functions,andlimitations,aswellastheirperceptionsofADAStechnologieswererepeatedfromthePre-VisitSurveytoallowforcomparisonanalysis.ThesurveyalsoaskedparticipantsabouttheirlearningpreferencesoftheADAStechnologiesbasedonthelearningprotocoltheyexperiencedinthestudy.TheaveragePost-VisitSurveyresponsetimewasapproximately30minutes.ParticipantCompensationParticipantswerecompensated$10forcompletingthePre-VisitSurveyand$65forthesitevisitportionofthestudy.DataManagementandSecurityDataStorageThroughoutdatacollection,surveydatawasdownloadedforqualitycontrolmeasures.Alldatasetsforthisstudywerestoredinaccess-controlfoldersthatonlyTDSprojectstaffarepermittedtoaccess.Theresearchteammergedallsurveydataintoonelargedatasettoallowforcomprehensiveanalysisandcleanedthefinaldatasettoincludethe120participants.Theresearchteamconductedstatisticalanalysesforresearchquestions1and2,withresultsnotedinthefollowingsections.Boldedfontinthechartsindicatesstatisticallysignificantfindings.Alldemonstrationdrivevideowasdownloadedtoanaccess-controlledfolderandtranscribedforfurtheranalysis.ElectronicDataTheEligibilitySurveywaspubliclyavailabletoanyonewhoaccessedthesurveylink.TheEligibilitySurveylinkwashousedwithinQualtricsandthedatawasonlyaccessibletotheTDSadministrativeteamattheUIwhowereresponsiblefortherecruitmentandmanagementofparticipantenrollment.ThePre-VisitSurveyutilizedtheQualtricspanelmailerfunctiontosendanindividualsurveylinktoeligibleindividuals.Allfinaldatadatasetsincludede-identifieddatathatonlynoteauniqueidentifiermatchingthePre-VisitSurvey,IntakeSurvey,andPost-VisitSurveydataforeachparticipant.

ResultsAsmentioned,sevenADAStechnologyfunctiondescriptionswereusedinthePre-andPost-VisitSurveystodescribethefiveADAStechnologiesincludedinthestudy(pleasereferenceTable8).Thesedescriptionswereusedtoevaluatedriverattitudesoftrust,usefulness,apprehension,andinterestinpurchasingeachADAStechnology.Additionally,inthePost-VisitSurvey,eachtechnologywasspecificallyreferredbyitsnamereferencedinthestudytomeasuredriverattitudes(includingtrust,usefulness,apprehension,andinterestinpurchasing).Allknowledgequestionswerereferredtospecificallybythenameusedthroughoutthestudy.

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Theimagebelowrecallsthemainsubtopicsineachsurvey.

Figure4:MainsubtopicsineachTDSsurvey

ADASTechnologyKnowledgeParticipantknowledgeabouttheADAStechnologieswasmeasuredbycomparingparticipants’answersto22knowledgequestionsonthePre-andPost-VisitSurveys.Responsestoeachknowledgequestionwereconvertedtoscoresbyassigningavalueof1whenparticipantsselectedthecorrectanswerand0otherwise.Scoresweresummedacrossthe22itemstocreateacompositeknowledgescore.Compositeknowledgescorespossiblerangedfrom0to22.Onaverage,participantsgotsixknowledgequestionscorrectonthePre-VisitSurvey(Table9).Aftercompletingthesitevisits,theknowledgescoresincreasedonaverageby10pointstoanaveragescoreof16.45correctonthePost-VisitSurvey.Table9:NumberofcorrectanswersonADAStechnologyknowledgequestionsandresultsoftwo-waypairedsamplest-tests

Pre-Visit Post-Visit PairedSamplesTestVariable Mean SD Mean SD tstatistic pvalueCompositeKnowledgeScore 5.99 2.970 16.45 2.688 31.053 <0.001ADASTechnologyPerceptionRatingsAnumberofsubjectiveratingswereexaminedinthestudy.Thosewereratingrelatedtousefulness,trust,apprehension,andinterestinpurchasing.RatingsofUsefulnessRatingsofusefulnessweremeasuredbycomparingparticipants’answersto7questionsonthePre-andPost-VisitSurveys.Basedonfunctiondescriptions,eachparticipantratedhowmuch

Pre-VisitSurvey

• Trust• Knowledge• Interestinpurchasing• Learningpreferences• Personaldemographics

IntakeSurvey

• ExposuretoinformationabouttechnologiessincecompletingthePre-VisitSurvey

• TechnologyReadinessIndex2.0©

• Locusofcontrol• Personaldemographics• Drivinghistory

Post-VisitSurvey

• Trust• Knowledge• Interestinpurchasing• Learningpreferences

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theyagreedthatthesevenADAStechnologyfunctionswouldbeusefulintheirowndriving.Theratingsrangedfrom1(“stronglydisagree”)to7(“stronglyagree”).Table10showstheratingsforeachofthesevenADAStechnologyfunctions.ForthePre-VisitSurveyratings,theadaptivecruisecontrolfunctionsofacceleratingfromandbrakingtoastopwhilefollowinganothervehiclereceivedthelowestratings;onaverage,participants“slightlydisagreed”andwereneutralwhenconsideringtheusefulnessofthesesystems,respectively.They“slightlyagreed”thattheadaptivecruisecontrolfunctionofadjustingspeedwhilefollowingavehicleandtheparallelparkingassistfunctionwouldbeuseful.Aftercompletingtheirassignedlearningprotocol,participantsagreedmorestronglythatallthefunctionsperformedbytheadaptivecruisecontrolandthefunctionoftheparallelparkingassistwouldbeusefulintheirdriving(allpvalues<0.001).Ratingsforlanekeepingassist,blindspotmonitor,andrearcrosstrafficalertfunctionsindicatedthat,onaverage,participants“agreed”to“stronglyagreed”thatthesefunctionswouldbeusefulbeforetheycompletedtheirassignedlearningmethodprotocols,andtheratingsdidnotchangesignificantlybetweenthePre-andPost-VisitSurveys.Table10:RatingsofagreementwithstatementsabouttheusefulnessofsystemsthatperformADAStechnologyfunctionsand

resultsoftwo-waypairedsamplest-tests

Statement Pre-Visit Post-Visit PairedSamplesTestIwouldfindasystemthatdoesthefollowingusefulinmydriving:

Mean SD Mean SD tstatistic pvalue

Steersmyvehicleintoaparallelparkingspace

5.17 1.703 5.83 1.322 4.193 <0.001

KeepsmyvehicleinmylaneifIbegintodriftoutofit

5.79 1.424 5.97 1.414 1.366 0.175

Warnsmeofvehiclesinmyblindspot 6.62 0.751 6.46 0.933 -1.700 0.092

AdjustsmyspeedwhileI’mfollowingavehicle

4.65 1.734 5.56 1.642 4.987 <0.001

BrakesmyvehicletoacompletestopwhileI’mfollowingavehicle

3.94 1.962 5.17 1.620 7.189 <0.001

AcceleratesmyvehiclefromastopwhileI’mfollowinganothervehicle

3.26 1.734 4.71 1.727 7.658 <0.001

AlertsmewhencrosstrafficapproacheswhileIambackingoutofaparkingspace

6.49 0.925 6.62 0.797 1.285 0.201

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RatingsofTrustRatingsoftrustweremeasuredbycomparingparticipants’answersto7questionsonthePre-andPost-VisitSurveys.ParticipantsgaveratingsofhowmuchtheyagreedwithtrustingthefunctiondescriptionsofeachADAStechnologyonboththePre-andPost-VisitSurveys.BeforelearningabouttheADAStechnologiesparticipants,onaverage,wereneutralintheirratingsforthethreeadaptivecruisecontrolfunctions,“slightlyagreed”withtrustingsystemsperformingparallelparkingassistandlanekeepingassistfunctions,and“agreed”thattheytrustedsystemsperformingblindspotmonitorandrearcrosstrafficalertfunctions.Aftercompletingtheirassignedlearningprotocol,withtheexceptionofblindspotmonitorsystems,participants’ratingsoftrustinthesystemsallincreasedsignificantly(allpvalues≤0.002).TheblindspotmonitorfunctionhadaninitiallyhighratingoftrustinthePre-VisitSurveyandtheslightincreaseintheratingsforthePost-VisitSurveywasclosetobeingstatisticallysignificant(p=0.052).Table11:RatingsofagreementwithstatementsabouttrustingsystemsthatperformADAStechnologyfunctionsandresultsof

two-waypairedsamplest-tests

Statement Pre-Visit Post-Visit PairedSamplesTestIwouldtrustasystemto: Mean SD Mean SD tstatistic pvalue

Steermyvehicleintoaparallelparkingspace

4.82 1.638 5.62 1.413 5.152 <0.001

KeepmyvehicleinmylaneifIbegintodriftoutofit

5.18 1.387 5.63 1.489 3.904 0.002

Warnmeofvehiclesinmyblindspot 5.72 1.305 6.01 1.156 1.967 0.052

AdjustmyspeedwhileI’mfollowingavehicle 4.23 1.704 5.51 1.552 7.434 <0.001

BrakemyvehicletoacompletestopwhileI’mfollowingavehicle

3.62 1.716 4.74 1.657 6.027 <0.001

AcceleratemyvehiclefromastopwhileI’mfollowinganothervehicle

3.70 1.768 5.23 1.642 8.211 <0.001

AlertmewhencrosstrafficapproacheswhileIambackingoutofaparkingspace

5.58 1.321 6.09 1.030 3.341 0.001

RatingsofApprehensionParticipantsratedtheiragreementwithstatementsregardingfeelingapprehensiveaboutusingsystemsthatperformeachoftheADAStechnologyfunctiondescriptionsinthePre-VisitSurvey.Participants“slightlydisagreed”thatthetwofunctionsthatonlygivethedriverwarnings(i.e.,

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blindspotmonitorandrearcrosstrafficalert)madethemfeelapprehensive.They“slightlyagreed”thattheadaptivecruisecontrolfunctionsofacceleratingfromandbrakingtoastopwhilefollowinganothervehiclemadethemfeelapprehensive.AfterlearningabouttheADAStechnologiesinthestudy,ratingsaboutapprehensionforallsevenADAStechnologyfunctionsdecreasedsignificantly(allpvalues≤0.002,exceptforblindspotmonitorwhichhadapvalueof0.035).Table12:RatingsofagreementwithstatementsaboutfeelingapprehensiveaboutusingsystemsperformingADAStechnology

functionsandresultsoftwo-waypairedsamplest-tests

Statement Pre-Visit Post-Visit PairedSamplesTestIfeelapprehensiveaboutusingasystemthat:

Mean SD Mean SD tstatistic pvalue

Steersmyvehicleintoaparallelparkingspace 3.61 1.795 3.01 1.808 -3.129 0.002

KeepsmyvehicleinmylaneifIbegintodriftoutofit

3.45 1.637 2.68 1.721 -4.233 <0.001

Warnsmeofvehiclesinmyblindspot 2.53 1.573 2.14 1.358 -2.131 0.035

AdjustsmyspeedwhileI’mfollowingavehicle 4.44 1.709 3.09 1.824 -6.656 <0.001

BrakesmyvehicletoacompletestopwhileI’mfollowingavehicle

5.03 1.776 3.84 1.916 -5.123 <0.001

AcceleratesmyvehiclefromastopwhileI’mfollowinganothervehicle

5.09 1.664 3.26 1.908 -8.192 <0.001

AlertsmewhencrosstrafficapproacheswhileIambackingoutofaparkingspace

2.77 1.663 2.03 1.249 -3.928 <0.001

RatingsofInterestinPurchasingaVehiclewithADASTechnologiesInboththePre-andPost-VisitSurveys,participantswereaskedtothinkabouttheirnextvehiclepurchaseandratetheirinterestinsystemsthatperformeachofthefunctiondescriptions.BeforelearningabouttheADAStechnologiesincludedintheTDS,onaverage,participants“slightlydisagreed”orwereneutralintheirinterestinsystemsthatperformedparallelparkingassistoradaptivecruisecontrolfunctions.Aftercompletingtheirassignedlearningprotocol,interestinpurchasingthesesystemssignificantlyincreased(allpvalues≤0.01).Beforetheirstudyvisit,participantsagreedtheywereinterestedinlanekeepingassist(“slightlyagree”),blindspotmonitor(“agree”),andrearcrosstrafficalert(“agree”)functionswhenconsideringavehiclepurchaseinthefutureandtheseratingsdidnotchangesignificantlyafterlearningabouttheADAStechnologies.

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Table13:RatingsofinterestinpurchasingavehiclewithsystemsperformingADAStechnologyfunctionsandresultsoftwo-waypairedsamplest-tests

Statement Pre-Visit Post-Visit PairedSamplesTestThinkingaboutyournextvehiclepurchase,howinterestedareyouinsystemsthatdothefollowing:

Mean SD Mean SD tstatistic pvalue

Steersmyvehicleintoaparallelparkingspace 4.31 1.944 4.86 1.876 3.201 0.002

KeepsmyvehicleinmylaneifIbegintodriftoutofit

5.28 1.577 5.38 1.811 0.703 0.484

Warnsmeofvehiclesinmyblindspot 6.08 1.182 6.14 1.266 0.524 0.602

AdjustsmyspeedwhileI’mfollowingavehicle 4.28 1.963 4.90 1.880 3.033 0.003

BrakesmyvehicletoacompletestopwhileI’mfollowingavehicle

3.83 1.969 4.29 1.959 2.606 0.010

AcceleratesmyvehiclefromastopwhileI’mfollowinganothervehicle

3.32 1.749 3.91 1.896 3.307 0.001

AlertsmewhencrosstrafficapproacheswhileIambackingoutofaparkingspace

5.95 1.413 6.23 1.228 1.863 0.065

LearningPreferencesParticipantswereaskedbeforeandafterhowtheywouldprefertolearnabouteachADAStechnology.Attheendofthestudytheywereaskedtoassesshowmucheachlearningmethodtheyexperienced(manual,demo,orboth)contributedtotheirlearning.PreferredMethodsforLearningtoUseADASTechnologiesInboththePre-andPost-VisitSurveys,participantswereaskedwhichlearningprotocoltheywouldpreferiftheyneededtolearnhowtousethedifferentADAStechnologies.TheresultsareshowninTable14.ComparingthePost-VisitSurveyresponsestothePre-VisitSurveyresponsesacrossallparticipants,thenumberwhosaidtheypreferredtolearnonlybyreadingtheowner’smanualorbyreadingfirstandthenreceivingademonstrationdecreasedwhilethosewhosaidtheywouldprefertolearnaboutanewADAStechnologybyonlyreceivingaride-alongdemonstrationdriveorbyreceivingaride-alongdemonstrationdrivebeforereadingtheowner’smanualincreased.ThiswastrueforallfiveADAStechnologiesincludedintheTDS.CollectivelyacrossallfiveADAStechnologies,participantsmoreoftenpreferredtolearnthroughaprotocolthatincludedademonstrationdrive.Beforecompletingthesitevisit,only

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17%ofthetimedidparticipantsprefertoonlyreadtheowner’smanualcomparedwithjust8.5%attheendofthestudy.

Table14:Participants’Pre-andPost-VisitSurveyresponsesabouthowtheywouldprefertolearnaboutdifferentADAStechnologies

IfIneededtolearnhowtouse____,Iwould:

Readtheowner’smanual

Receiveademonstrationfromanotherdriver

Readtheowner’smanualandthenreceiveademonstration

Receiveademonstrationandthenreadtheowner’smanual

Other

Pre Post Pre Post Pre Post Pre Post Pre PostAdaptiveCruiseControl 15 7 25 40 38 29 32 44 10 0

BlindSpotMonitor 20 14 28 49 38 25 27 31 7 1

LaneKeepingAssist 21 10 27 50 36 24 29 36 7 0

ParallelParkingAssist 16 6 27 45 39 23 32 46 6 0

RearCrossTrafficAlert 24 14 27 52 33 20 29 34 7 0

Eachparticipant’sPost-VisitSurveylearningpreferenceswerecomparedtotheirPre-VisitSurveylearningpreferencestoseeiftheyhadchanged.Table15showsthepercentofparticipantswhoselectedadifferentlearningpreferenceattheendofthestudythantheydidinitially.Aftercompletingthestudy,about70%ofparticipantswhoinitiallysaidtheywouldliketolearnaboutdifferentADAStechnologiesbyreadingtheowner’smanualselectedadifferentlearningpreference.Approximately60%ofthosewhoinitiallysaidtheywouldliketolearnbyfirstreadingtheowner’smanualandthenreceivingaride-alongdemonstrationdriveselectedadifferentlearningpreferenceonthePost-VisitSurvey.TheparticipantsinthisstudywereveryinterestedinlearningaboutADAStechnologiesthroughdemonstrations.Priortotheirsitevisits,participantsindicatedthattheywouldprefertolearnaboutthefiveADAStechnologiesthroughamethodthatincludedademonstration83%ofthetime.Thisincreasedtomorethan91%attheendofthestudy.Afewcautionsmustbemadewheninterpretingtheseresults.Thefirstisthatifallfourlearningmethodswereequallypreferable,amethodincludingdemonstrationwouldbeselectedabout75%ofthetime.Additionalanalysesareneededtodetermineifparticipantpreferenceforamethodincludingdemonstrationissufficientlyoutsidetherealmofrandomchance.Asecondcautionistheeffectofself-selectionbias,thatis,thatthepeoplewhoexpressedinterestintheTDSandthendecidedtocompleteasitevisitmayhavedonesobecausetheywereveryinterestedinthepossibilityofseeingADAStechnologiesinaction.Asaresult,wecannotatthistimegeneralizethelearningpreferencesobservedinthisparticipantsampletoconsumersasawhole.

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Table15:PercentofparticipantsbyADAStechnologywhopreferredadifferentwayoflearningaftercompletingthestudy

LearningPreferenceReportonPre-VisitSurveyIfIneededtolearnhowtouse____,Iwould:

Readtheowner’smanual

Receiveademonstrationfromanotherdriver

Readtheowner’smanualandthenreceiveademonstration

Receiveademonstrationandthenreadtheowner’smanual

ADASTechnology N Percent N Percent N Percent N PercentAdaptiveCruiseControl 12 80.00 9 36.00 21 55.26 15 46.88

BlindSpotMonitor 14 70.00 10 35.71 24 63.16 14 51.85

LaneKeepingAssist 16 76.19 9 33.33 23 63.89 13 44.83

ParallelParkAssist 11 68.75 9 33.33 22 56.41 15 46.88

RearCrossTrafficAlert 17 70.83 7 25.93 20 60.61 15 51.72

Total 70 72.92 44 32.84 110 59.78 72 48.32AcrossallfiveADAStechnologies,atleast60%ofparticipantsassignedtotheride-alongdemonstrationdriveonlyprotocolortothedemonstrationdrive/owner’smanualprotocolchangedtheirlearningpreferences.Incontrast,57%ofparticipantsassignedtotheowner’smanualonlyprotocoldidnotchangetheirlearningpreferences.Thedifferencesintheproportionsofparticipantsinthedifferentlearningprotocolswhochangedtheirlearningpreferencesweresignificantlydifferentforadaptivecruisecontrol,C2(3)=8.48,p=0.037,andparallelparkingassist,C2(3)=8.12,p=0.047.Participants’learningresponsesbeforeandaftertheirsitevisitswereexaminedforeachADAStechnologyincludedintheTDS.TheresultsbelowdetailthefindingsforeachADAStechnology.AdaptiveCruiseControlOfthe15participantswhoinitiallysaidtheypreferredtolearnaboutadaptivecruisecontrolfromtheowner’smanual,80%(n=12)selectedadifferentlearningpreferenceattheendofthestudy.Halfofthese(n=6)selecteddemonstrationdrive/owner’smanual,25%(n=3)selectedowner’smanual/demonstrationdrive,andtheother25%selecteddemonstrationdriveonly.Ofthe25participantswhoinitiallypreferredtolearnaboutadaptivecruisecontrolfromthedemonstrationdrive,only36%(n=9)ofparticipantschangedtheiranswerattheendofthestudy.Sixofthese(67%)selecteddemonstrationdrive/owner’smanual.Ofthe38participantswhoinitiallysaidtheywouldpreferowner’smanual/demonstrationdrive,55%(n=21)selectedadifferentlearningpreferenceattheendofthestudy;twothirds(n=14)decidedtheywouldpreferdemonstrationdrive/owner’smanualand24%(n=9)changedtodemonstrationdriveonly.Fifteenofthe32whoinitiallypreferredtolearnaboutadaptivecruisecontrolbydemonstrationdrive/owner’smanualselectedadifferentoptioninthePost-VisitSurvey;60%(n=9)decidedthedemonstrationdriveonlywouldsufficeandonethird(n=5)optedforowner’smanual/demonstrationdrive.

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BlindSpotMonitorTwentyparticipantsinitiallysaidtheypreferredtolearnaboutblindspotmonitorfromtheowner’smanual;70%(n=14)selectedadifferentlearningpreferenceattheendofthestudywithaboutequalpreferencebetweendemonstrationdriveonly(n=5),owner’smanual/demonstrationdrive(n=5),anddemonstrationdrive/owner’smanual(n=4).Ofthe28participantswhoinitiallypreferredtolearnaboutblindspotmonitorfromthedemonstrationdrive,only36%(n=10)ofparticipantschangedtheiranswerattheendofthestudy.Fiveofthese(50%)selecteddemonstrationdrive/owner’smanual.Ofthe38participantswhoinitiallysaidtheywouldpreferowner’smanual/demonstrationdrive,63%(n=24)selectedadifferentlearningpreferenceattheendofthestudy;46%(n=11)decidedtheywouldpreferthedemonstrationdriveonly,and38%(n=9)changedtodemonstrationdrive/owner’smanual.Justoverhalf(n=14)ofthe27whoinitiallypreferredtolearnaboutblindspotmonitorbydemonstrationdrive/owner’smanualselectedadifferentoptioninthePost-VisitSurvey;71%(n=10)decidedthedemonstrationdriveonlywouldbepreferableandaboutonefifth(n=3)optedforowner’smanual/demonstrationdrive.LaneKeepingAssistTwenty-oneparticipantsinitiallysaidtheypreferredtolearnaboutlanekeepingassistfromtheowner’smanual;76%(n=16)selectedadifferentlearningpreferenceattheendofthestudy:demonstrationdriveonly(n=6),owner’smanual/demonstrationdrive(n=7),anddemonstrationdrive/owner’smanual(n=3).Ofthe27participantswhoinitiallypreferredtolearnaboutlanekeepingassistfromthedemonstrationdrive,onlyonethird(n=9)ofparticipantschangedtheiranswerattheendofthestudy.Fiveofthese(56%)selecteddemonstrationdrive/owner’smanual.Ofthe36participantswhoinitiallysaidtheywouldpreferowner’smanual/demonstrationdrive,64%(n=23)selectedadifferentlearningpreferenceattheendofthestudy;48%(n=11)decidedtheywouldpreferdemonstrationdrive/owner’smanualand43%(n=10)changedtodemonstrationdriveonly.Ofthe29participantswhoinitiallypreferredtolearnaboutlanekeepingassistbydemonstrationdrive/owner’smanual,45%(n=13)selectedadifferentlearningpreferenceoflanekeepingassistinthePost-VisitSurvey;85%(n=11)optedforthedemonstrationdriveonlylearningmethod.ParallelParkingAssistSixteenparticipantsinitiallysaidtheypreferredtolearnaboutparallelparkingassistfromtheowner’smanual;69%(n=11)selectedadifferentlearningpreferenceattheendofthestudy:55%(n=6)changedtodemonstrationdriveonlyand45%(n=5)optedfordemonstrationdrive/owner’smanual.Ofthe27participantswhoinitiallypreferredtolearnaboutparallelparkingassistfromademonstrationdrive,onlyonethird(n=9)ofparticipantschangedtheiranswerattheendofthestudy.Eightofthese(89%)selecteddemonstrationdrive/owner’smanual.Ofthe39participantswhoinitiallysaidtheywouldpreferowner’smanual/demonstrationdrive,56%(n=22)selectedadifferentlearningpreferenceattheendofthestudy;68%(n=15)decidedtheywouldpreferdemonstrationdrive/owner’smanualand27%(n=6)changedtodemonstrationdriveonly.Ofthe32participantswhoinitiallypreferred

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tolearnaboutparallelparkingassistbydemonstrationdrive/owner’smanual,47%(n=15)selectedadifferentlearningpreferenceinthePost-VisitSurvey;80%(n=12)optedforthedemonstrationdriveonlylearningmethodand20%(n=3)preferredowner’smanual/demonstrationdrive.RearCrossTrafficAlertInthePre-VisitSurvey,24participantsindicatedtheywouldprefertolearnaboutrearcrosstrafficalertbyreadingaboutitintheowner’smanual.Morethan70%(n=17)selectedadifferentlearningpreferenceonthePost-VisitSurvey.Almost60%(n=10)ofthosewhochangedtheiransweroptedforthedemonstrationdriveonly,24%(n=4)selectedowner’smanual/demonstrationdrive,and18%(n=3)chosedemonstrationdrive/owner’smanual.Ofthe27participantswhoinitiallypreferredtolearnaboutrearcrosstrafficalertwithademonstrationdrive,only26%(n=7)saidtheypreferredadifferentlearningmethodafterthestudy;sixofthose(86%)decidedtoselectdemonstrationdrive/owner’smanual.Thirty-threeparticipantsoptedforowner’smanual/demonstrationdriveonthePre-VisitSurvey;justover60%(n=20)hadadifferentpreferenceattheendofthestudy.Morethanhalf(55%,n=11)optedfordemonstrationdrive/owner’smanualand30%(n=6)selecteddemonstrationdriveonly.Ofthe29participantswhoinitiallypreferredtolearnaboutrearcrosstrafficalertbydemonstrationdrive/owner’smanual,justoverhalf(n=15)selectedadifferentlearningpreference;73%(n=11)selectedthedemonstrationdriveonlylearningmethod.EffectsofAssignedLearningProtocolonLearningPreferencesCrosstabsofassignedlearningprotocolbyPost-VisitSurveylearningpreferencewerecreatedforeachofthefiveADAStechnologiesandChi-squaretestsforindependencewereconducted.Forblindspotmonitor,lanekeepingassist,andrearcrosstrafficalert,thenullhypothesisofindependencebetweenassignedlearningprotocolandpreferredlearningmethodwasnotrejected.Foradaptivecruisecontrol,thenullhypothesisofindependencebetweenassignedlearningprotocolandpreferredlearningmethodwasrejected,C2(9)=20.92,p=0.013.Examinationoftheobservedandexpectedfrequenciesshowedthatparticipantsassignedtothedemonstrationdriveonlylearningprotocolmoreoftenpreferredtolearnaboutadaptivecruisecontrolwiththedemonstrationdrive/owner’smanualoption(63%,n=19),aseightmorepeoplethanexpectedselectedthatoption,whileonlyonepersonpreferredtheowner’smanual/demonstrationdrivelearningmethod,sixfewerparticipantsthanexpected.Thoseparticipantsassignedtotheowner’smanual/demonstrationdrivelearningprotocolpreferredthatlearningmethodoverdemonstrationdrive/owner’smanual,withaboutsixmorethanexpectedselectingtheformeroptionandsixfewerthanexpectedselectedthelatter.

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Table16:Cross-taboflearningprotocolassignedduringthestudyandpreferredmethodoflearningadaptivecruisecontrolreportedonPost-VisitSurvey.

Readtheowner’smanual

Receiveademonstrationfromanotherdriver

Readtheowner’smanualandthenreceiveademonstration

Receiveademonstrationandthenreadtheowner’smanual

Demonstrativedrive 2 8 1 19Demonstrationdrive/Owner’sManual

2 12 7 9

Owner’sManual 2 9 8 11Owner’sManual/Demonstrationdrive

1 11 13 5

Forparallelparkingassist,thenullhypothesisofindependencebetweenassignedlearningprotocolandpreferredlearningmethodwasalsorejected,C2(9)=19.12,p=0.0242.Onepersonassignedtothedemonstrationdriveonlylearningprotocoloptedfortheowner’smanual/demonstrationdrivelearningmethod,fivefewerthanexpected.Halfthoseparticipants(n=15)preferredthedemonstrationdrive/owner’smanualmethodoflearningaboutparallelparkingassistand47%(n=14)preferredtolearnwiththedemonstrationdriveonly.Oftheparticipantsassignedtotheowner’smanual/demonstrationdrivelearningprotocol,37%(n=11),aboutfivemorethanexpected,preferredtheowner’smanual/demonstrationdrivelearningmethodandonly20%(n=6)preferredthedemonstrationdrive/owner’smanuallearningmethod,aboutsixfewerthanexpected.

Table17:Cross-taboflearningprotocolassignedduringthestudyandpreferredmethodoflearningparallelparkingassistreportedonPost-VisitSurvey

Readtheowner’smanual

Receiveademonstrationfromanotherdriver

Readtheowner’smanualandthenreceiveademonstration

Receiveademonstrationandthenreadtheowner’smanual

Demonstrativedrive 0 14 1 15Demonstrationdrive/Owner’sManual 2 9 4 15

Owner’sManual 3 10 7 10Owner’sManual/Demonstrationdrive

1 12 11 6

RatingsofHowtheLearningProtocolsContributedtoParticipantLearningOnthePost-VisitSurvey,allparticipantswereaskedtoratehowmuchthelearningprotocoltheyexperiencedcontributedtotheirlearningofthepurposeandfunctionofeachADAStechnology.Forexample,everyoneassignedtoalearningprotocolthatincludedtheowner’smanualwasaskedtoratetheiragreementonascalefrom1(“stronglydisagree”)to7

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(“stronglyagree”)withthestatements,“Readingtheowner'smanualcontributedtomyunderstandingofthepurposeofAdaptiveCruiseControlonthehighway,”and“Readingtheowner'smanualcontributedtomyunderstandingofthefunctionofAdaptiveCruiseControlonthehighway.”Similarly,everyoneassignedtoalearningprotocolthatincludedthedemonstrationdrivewasaskedtoratetheiragreementwiththestatements,“ThedemonstrationdrivecontributedtomyunderstandingofthepurposeofAdaptiveCruiseControlonthehighway,”and“ThedemonstrationdrivecontributedtomyunderstandingofthefunctionofAdaptiveCruiseControlonthehighway.”RatingsofHowtheOwner’sManualContributedtoParticipantLearningRatingsofhowtheowner’smanualcontributedtoparticipants’learningofthepurposeandfunctionofeachADAStechnologyforthosewhoonlyreadtheowner’smanualwerecomparedtotheratingsofthoseassignedtothetwolearningprotocolsthatincludedboththeowner’smanualandthedemonstrationdrive.Theratingsgivenbythosewhoonlyreadthemanualwereverysimilartothosewhowereintheprotocolsthatincludedbothlearningmethods.Betweensamplestwo-wayt-testsconfirmedthattherewerenosignificantdifferencesintheratingsofhowtheowner’smanualcontributedtoparticipantlearning.Inaddition,ratingsbetweenthevariousADAStechnologypurposesandfunctionsweresimilar.Overalltheparticipantswhoreadtheowner’smanual“slightlyagreed”to“agreed”thatitcontributedtotheirlearning.RatingsofHowtheDemonstrationDriveContributedtoParticipantLearningRatingsofhowthedemonstrationdrivecontributedtotheparticipants’learningofthepurposeandfunctionofeachADAStechnologyforthosewhoexperiencedonlythedemonstrationdrivewerecomparedtotheratingsofthosewhobothreadtheowner’smanualandexperiencedthedemonstrationdrive.Theratingsgivenbythosewhoexperiencedthedemonstrationdriveonlywereverysimilartothosewhowereassignedtothelearningprotocolsthatincludedbothlearningmethods.Betweensamplestwo-wayt-testsconfirmedthattherewerenosignificantdifferencesinratingsbetweenthegroups.Inaddition,ratingsbetweenthevariousADAStechnologypurposesandfunctionsweresimilar.Overallparticipantswhoexperiencedthedemonstrationdrive“agreed”to“stronglyagreed”thatitcontributedtotheirlearning.ComparisonfortheGroupsExperiencingBothLearningMethodsEachparticipant’sratingsofhoweachlearningmethodcontributedtotheirlearningwerecomparedforthetwobetween-participantgroupsthatexperiencedbothlearningmethods,i.e.,thoseassignedtotheprotocolthatreadtheowner’smanualbeforeexperiencingthedemonstrationdriveandthoseassignedtotheprotocolthatexperiencedthedemonstrationdrivebeforereadingthemanual.Forexample,aparticipant’sratingforthestatement,“Readingtheowner'smanualcontributedtomyunderstandingofthepurposeofAdaptiveCruiseControlonthehighway”wascomparedtothatsameparticipant’sratingforthestatement,“ThedemonstrationdrivecontributedtomyunderstandingofthepurposeofAdaptiveCruiseControlonthehighway.”Apairedsamplestwo-wayt-testwasconductedforeachoftheADAStechnologyfunctionsandpurposestatements.TheresultsareshowninTable

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18.ForallthelearningcontributionstatementsforthepurposeandfunctionofalltheADAStechnologies,thedemonstrationdrivewasgivenhigherratings,indicatingthatacrosstheboardparticipantswhoexperiencedbothlearningmethodsratedthedemonstrationdriveascontributingmoretotheirlearningthantheowner’smanual.Table18:Ratingsofhowtheowner’smanualandthedemonstrationdrivecontributedtoparticipantlearningforthosewho

experiencedbothlearningmethodsandtheresultsofthepairedsamplestwo-wayt-tests

LearningMethod ReadingtheOwner’sManual

DemonstrationDrive PairedSamplesTest

Mean SD Mean SD tstatistic pvaluethepurposeofAdaptiveCruiseControlonthehighway

5.43 1.522 6.60 0.785 6.276 <0.001

thefunctionofAdaptiveCruiseControlonthehighway

5.63 1.235 6.73 0.516 6.846 <0.001

thepurposeofAdaptiveCruiseControlintown

5.18 1.467 6.23 1.079 6.221 <0.001

thefunctionofAdaptiveCruiseControlintown

5.27 1.287 6.47 0.812 7.227 <0.001

thepurposeofblindspotmonitor 5.62 1.290 6.48 0.948 5.595 <0.001

thefunctionofblindspotmonitor 5.62 1.277 6.68 0.537 6.172 <0.001

thepurposeoflanekeepingassist 5.67 1.336 6.48 0.892 4.986 <0.001

thefunctionoflanekeepingassist 5.62 1.303 6.67 0.542 6.101 <0.001

thepurposeofrearcrosstrafficalert 5.70 1.306 6.47 0.812 4.737 <0.001

thefunctionofrearcrosstrafficalert 5.58 1.418 6.63 0.581 5.504 <0.001

thepurposeofparallelparkingassist 5.47 1.512 6.45 1.016 5.364 <0.001

thefunctionofparallelparkingassist 5.32 1.384 6.63 0.610 7.064 <0.001

DiscussionAftercompletingtheirsitevisits,participantsintheTDShadsignificantlyhighertotalknowledgescores.Onaverage,knowledgescoresincreasedabout170%.FutureanalyseswilldeterminewhethertheincreaseinknowledgewassimilaracrossallfiveADAStechnologiesandwhethertheknowledgescoresvariedaccordingtotheassignedlearningprotocol.

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AfterlearningaboutADAStechnologies,participantshadincreasedtrustanddecreasedapprehensionaboutusingADAStechnologiesthatperformedallthespecifiedfunctions.Ratingsofusefulnessandinterestinpurchasingdidnotsignificantlychangeforblindspotmonitor,rearcrosstrafficalert,orlanekeepingassist—systemsthatonlyprovidealertsormomentaryinputtovehiclecontrol.However,learningaboutadaptivecruisecontrolandparallelparkingassist—systemsthattakeoverspeedcontrolandsteeringcontroltoperformaspecificdrivingtask—ledanincreaseinratingsofusefulnessandagreaterinterestinpurchasingavehicleequippedwiththosesystems.AcrossallADAStechnologies,asignificantproportionofparticipants(60-85%)whoinitiallysaidtheywouldprefertolearnaboutADAStechnologiesbyexperiencingademonstrationdriveandthenreadingtheowner’smanualchangedtheirlearningpreferencetodemonstrationdriveonly.Relativelyfewparticipants(<36%)whoinitiallysaidtheywouldpreferthedemonstrationdriveonlypreferredadifferentlearningmethodafterthestudy,butmostofthosewhodidchangetheirpreferenceoptedforexperiencingademonstrationdrivefollowedbyreadingtheowner’smanual.Thosewhoinitiallypreferredtoreadtheowner’smanualbeforeexperiencingthedemonstrationdriveweremorelikelytoselectademonstrationdrivebeforereadingtheowner’smanualforadaptivecruisecontrol,parallelparkingassist,andrearcrosstrafficalert.Additionally,thoseparticipantswereequallylikelytoselectdemonstrationdriveonlyorademonstrationdrivefollowedbyreadingtheowner’smanualforblindspotmonitorandlanekeepingassist.Additionally,theseobservationsdidnotseemtobeaffectedbywhichlearningprotocoltheparticipanthadbeenrandomlyassignedto.Participantsassignedtoalearningprotocolthatincludedboththedemonstrationdriveandtheowner’smanualindicatedthatthedemonstrationdrivecontributedmoretotheirlearningthantheowner’smanual.Itispossiblethattheseresultscouldreflectabiasintheparticipantswhoexperiencedbothmethods.Forexample,perhapsthedemonstrationdrivewasamoreenjoyabletaskcomparedtoreadingtheowner’smanualand,forthatreason,participantswhoexperiencedbothlearningmethodsmaybemorelikelytogivethedemonstrationdriveahigherrating.However,theparticipantswhoonlyreadtheowner’smanualsaiditcontributedtotheirlearningaboutthesameamountasthosewhoexperiencedbothlearningmethods.Likewise,thosewhoexperiencedonlythedemonstrationdrivesaiditcontributedtotheirlearningaboutthesameamountasthosewhobothexperiencedthedemonstrationdriveandreadtheowner’smanual.ThehighlevelofconsistencyintheseresultsacrossthedifferentlearningprotocolsandthedifferentADAStechnologieslendevidencethatthisissolidfinding.

LimitationsDriverunderstandingofADAStechnologiesisanemergingareaoffocuswithinvehiclesafetyandcollisionavoidanceresearch.DriverknowledgewillneedtocontinuetobeinvestigatedfurthertobetterunderstanddriverknowledgeofADAStechnologyuseandfunction,especiallyasthetechnologiesevolve.Additionally,theTDSsamplefocusedonthepopulationthatpreviousresearchhasshownisthemostlylikelytopurchaseavehicleequippedwithADAStechnologiesinthenearfuture.Futurestudiesshouldexpandtoadditionalpopulationsamples.Theeffectofself-selectionbiasshouldalsobetakenintoconsiderationwhenconsideringthese

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results.Forexample,peoplewhoexpressedinterestintheTDSandthendecidedtocompleteasitevisitmayhavedonesobecausetheywereveryinterestedinthepossibilityofseeingADAStechnologiesinaction.Finally,thesitevisitperiodforparticipantsthatreceivedboththeowner’smanualandride-alongdemonstrationdrivecouldhavelasteduptotwoandhalfhours,alengthoftimethatcouldhaveintroducedparticipantfatigue.Thisstudyalsohadparticipantsobserveratherthandriveanditispossiblethatactuallydrivingmayfurtherenhanceadriver’smentalmodelofADAStechnologies.

ConclusionTheTDSsoughttoevaluatehowthewaysinwhichdriverslearnaboutADAStechnologiesaffectstheirknowledgeandperceptionsofthetechnologies.Thestudyfocusedontwobaselearningmethodsthatareconventionalinthereal-world:readinganowner’smanualandexperiencingaride-alongdemonstrationdrive.TheTDSresultsshowincreasedratingsoftrustandusefulnessforseveralofthetechnologiesincludedinthestudy.Additionally,theTDSresultsshowdecreasedratingsofapprehensionofalltheADAStechnologiesandincreasedinterestinpurchasingavehicleequippedwithseveralofthetechnologiesinthestudy.Thesefindingssupporttheideathatexposuretothetechnologiesimpactsadriver’sattitudestowardandknowledgeofthetechnologiesinthefuture.TheTDSprovidedinsighttohowdrivers’trustisaffectedbytheirinitialexposuretothetechnology.Toourknowledge,theTDSprotocolisthefirstofitskindtomeasuredrivertrust,knowledge,andlearningpreferenceofdriverassistancetechnologies.TheUIbelievestheprotocolsdevelopedfortheTDScanbeexpandedtoincludevariousbrandsandtrimlevelsandbeadaptedtoincludenewandinnovativelearningmethods.Tobetterunderstandhowtobesteducateandinformthedrivingpublicabouttheseinstrumentallylife-savingtechnologies,researchers,policymakers,andtheindustrymustunderstandhowdriversarecurrentlylearningaboutthetechnologiesandhowthoselearningmethodsaffecttheirknowledgeandperceptions.ImproveddriverunderstandingwillsignificantlybetterAmericanroadways.

AcknowledgementsThankyoutoChristineBricker,CherCarney,KaylaFaust,ArielFrier,CristianMeier,andMadonnaWeissfortheirassistanceduringdatacollection.TheTechnologyDemonstrationStudywasfundedbytheToyotaSafetyResearchandEducationProgramSettlement.AllresearchisdevelopedindependentlybytheUniversityofIowa.Allcontent,viewsandconclusionsareexpressedbytheUniversityofIowaandhavenotbeensponsored,approved,orendorsedbyToyotaortheplaintiff’sclasscounsel.

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ReferencesMcDonald,A.,McGehee,D.,Chrysler,S.,Askelson,N.,Angell,L.,andSeppelt,B.,“NationalSurveyIdentifyingGapsinConsumerKnowledgeofAdvancedVehicleSafetySystems,”TransportationResearchRecord:JournaloftheTransportationResearchBoard,2559:1-6,2016.DOI:10.3141/2559-01.

Parasuraman,A.andColby,C.L.(2015)AnUpdatedandStreamlinedTechnologyReadinessIndex:TRI2.0.JournalofServiceResearch,18(1),59-74.DOI:10.1177/1094670514539730