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