ChrisSchwarz,Ph.D. 9/1/2016

TransferfromHighlyAutomatedtoManualControlPerformance&Trust

Adrivingsimulatorstudywasperformedwith20participantstostudytransfersofcontrolinhighlyautomatedvehicles.Weobserveddriverperformanceandmeasuredcomfortasanindicatorofthedevelopmentoftrustinthesystem.Onescenariousedanautomationsystemthatwasabletorespondtomosteventsbyslowingorchanging

lanesonitsown.Theotherstudydriveissuedtakeoverrequests(TORs)inallcases.Thustherewasachangeinreliabilityoverthecourseofthestudydrives,wheresomeparticipantsexperiencedthemore-capable

systemfirstandotherstheless-capable.

Studyeventsincludedaworkzone,asectionwithmissinglanelines,anelevatedrampcurve,aslowleadvehicle,andanexitrampasthefinalevent.Extraeventswithleadvehiclesthatchangedspeedservedasexamplesofsuccessfulautomationinterventions.

Atriviataskfromwww.triviaplaza.comwasusedtoengagetheoperatorwhileinautomatedmode.Ratherthanbeingasecondarytask,thiswastheprimarytaskduringperiodsofautomation.

ExperimentalSetup

Automated-modeiconandimminenttakeoverrequest

NADS-1motionbase

LongitudinalmeasuresLongitudinalMeasuresComfortMinimumspeedMeanspeedSteeringreversalrateStd.dev.lanepositionHigh-frequencysteeringPercentroadcentergaze

Transferofcontrolexampleswithvariedexpectation Expected UnexpectedLowertoHigher Buttonpress CollisionavoidanceHighertoLower Grabwheel Automationfailure

ChrisSchwarz,Ph.D.

TakeoverrequestsweremodeledaftertheinterfacesusedinrecentNHTSAresearchonlevel2/3automation(Blancoetal.,2015).

Weobservedthreetypesofpeoplewithrespecttotheircomfortprofilesoverthecourseoftheirthreedrives.Somestartedoutverycomfortable,otherstookalongtimetobecomecomfortable,andothersincreasedincomfortfairlyquickly.

Takeoversweresplitintophysicaltakeover,visualattention,andvehiclestabilization.Wedidnotattempttoquantifythetimerequiredtoregainfullsituationalawareness.Driverswereabletophysicallytakecontrollessthanfivesecondsafterbeingrequestedto.However,responsetimeandperformancemeasuresshowedthattherewasa15-to25-secondperiodbetweenthephysicaltakeoverandareturntonormaldrivingperformance.Thisconfirmssomeobservationsinpreviousstudiesontransferofcontrol(Goldetal.,2013;Meratetal.,2014).

NoothereventexposeddifferencesbetweenthestudygroupsaswellastheslowleadvehicleeventinDriveB.Womenwereseentoachievelowerminimumspeedsthanmen.Menspentmoretimeinmanualmodethandid

women.YoungerdrivershadalowerSRRandlargerSDLPthandidtheoldergroup.Finally,whendriversexperiencedthiseventintheirfirstdrive,theytendedtohavelargeramountsofhigh-frequencysteeringthanwhentheyexperienceditintheirseconddrive.

References

Blanco,M.,Atwood,J.,Vasquez,H.M.,Trimble,T.E.,Fitchett,V.L.,Radlbeck,J.,Fitch,G.M.etal.(2015).HumanFactorsEvaluationofLevel2andLevel3AutomatedDrivingConcepts.FinalReportDOTHS812182.Washington,D.C.:NHTSA.

Gold,C.,Damböck,D.,Lorenz,L.,&Bengler,K.(2013).‘Takeover!’Howlongdoesittaketogetthedriverbackintotheloop?”ProceedingsoftheHumanFactorsandErgonomicsSocietyAnnualMeeting57(1):1938–42.

Merat,N.,Jamson,A.H.,Lai,F.C.H.,Daly,M.,&Carsten,O.M.J.(2014).Transitiontomanual:Driverbehaviourwhenresumingcontrolfromahighlyautomatedvehicle.TransportationResearchPartF:TrafficPsychologyandBehaviour.

“Thereisa15-to25-secondgapbetweenphysicaltakeoverandvisualattention/stabilizationduringwhichthedrivermaybevulnerabletomissingasafety-criticaleventataninopportunemoment.”