Cyclists and drivers in road interactions: A comparison of perceived crash risk

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Cyclists and drivers in road interactions: A comparison of perceived crash risk
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  AccidentAnalysisandPrevention 50 (2013) 1176–1184 ContentslistsavailableatSciVerseScienceDirect Accident   Analysis   and   Prevention  journalhomepage:www.elsevier.com/locate/aap Cyclists   and   drivers   in   road   interactions:   A   comparison   of    perceived   crash   risk Nadine   Chaurand ∗ , Patricia   Delhomme TheFrenchInstituteofScienceandTechnologyforTransport,DevelopmentandNetworks(Ifsttar),LaboratoryofDriverPsychology,France a   r   t   i   c   l   e   i   n   f   o  Articlehistory: Received14December2010Receivedinrevisedform6August2012Accepted6September2012 Keywords: PerceivedriskCyclistsDriversRoadinteractionsPerceivedskill a   b   s   t   r   a   c   t Today’s   increase   in   the   number   of    cyclists   hastriggered   a   change   in   the   interactions   to   be   handled   byroad   users.   However,   few   studies   have   investigated   crash   risk   perceived   bycyclists   interacting   with   otherusers,and   few   have   compared   cyclists’   and   drivers’   perceptions   of    crash   risk   in   bike–car   interactions,the   most   dangerous   situation   for   cyclists.   Our   aims   here   are   to   study   perceived   crash   risk   (no   matter   theseriousness   of    the   crash)   in   six   common   road   situations   during   which   cyclist   crashes   are   frequent   and   alsotostudy   cyclists’   and   drivers’   perceived   risk   in   bike–car   interactions,   in   comparison   to   other   interactiontypes   (cyclist   vs.   cyclist   and   driver   vs.   driver).   We   predicted   that   perceived   risk   of    being   involved   in   acrashduring   a   particular   interaction   would   be   greater   when   in   interaction   with   acar   than   with   a   bike,   andthat   drivers   would   perceive   more   risk   than   cyclists   would.   We   also   predicted   that   perceived   risk   woulddecrease   with   drivers’   and   cyclists’   experience   of    their   transportation   mode   and   their   perceived   controlover   the   interaction   situation.   We   ran   an   online   survey   ontwo   samples,   experienced   cyclists   ( N    =   336)andnon-cyclist   car   drivers   ( N    =92).   Participants   evaluated   their   personal   risk   –ascyclists   or   as   drivers   –ofbeing   involved   in   aroad   crash   if    they   were   in   an   interaction   with   abike   or   a   car   for   each   of    six   riskyroad   situations.   Experience   was   measured   in   terms   of    years   of    vehicle   driving   and   driven   km;   perceivedcontrol   was   measured   in   terms   of    perceived   skill   and   responsibility   for   the   risky   behavior.   The   resultsvalidated   our   hypotheses:   perceived   risk   was   higher   for   car   drivers   than   for   cyclists   and   for   interactingwith   acar   thanwith   abike.   The   implications   of    these   results   for   interventions   to   improve   road   safety   forboth   cyclists   and   car   drivers   are   discussed. © 2012 Elsevier Ltd. All rights reserved. 1.Introduction 1.1.Increaseinbikes Theincreaseinthenumberofbikesonurbanstreetscanbeseenasasolutiontocertainproblemsencounteredincitiesinmodernsocieties.Indeed,ecologicalissuesconcerningtheenvi-ronmentalconsequencesoftheuseofmotorizedtransportation,concernsabouttheimpactofcaruseonhealth,orproblemsintermsofcostandtimelossduetotrafficcongestionareleadingpeopletochangetheirtransportationmode(SafetyNet,2008).This dynamicisencouragedbypublicpolicies,throughcampaignsinfavorofsustainabletransportation(Martens,2004;Pucheretal.,2010;RietveldandDaniel,2004)andthroughrentalbikeservicesinmorethan150majorcitiesintheworld(DeMaio,2010).Sur- veysestimatethatalthoughbikesarestillaminoritytransportationmode,therateofcyclistcommutershasslowlyincreasedoverthelastdecadeinmostdevelopedcountriessuchasmostofEurope(Bassettetal.,2008;Héran,2012),USA(CensusBureau’sAmerican ∗ Correspondingauthorat:Ifsttar,LaboratoryofDriverPsychology,25alléedesMarronniers,Satory,78000Versailles,France.Tel.:+330130843955. E-mailaddress: nadine.chaurand@ifsttar.fr (N.Chaurand). CommunitySurvey,2009),orAustralia(AustralianBureauof  Statistics,2009).However,thisnewdistributionofroadusersrequiresmodifi-cations,indescriptivenormsconcerningtraffic,inroadstructures(creationofbicyclepathsandbicyclelanes),andintrafficlaws(e.g.,the2010lawinFranceallowingbikestorideinbothdirectionsonlimited-speedone-waystreets).Suchmodifications,inturn,necessitatethatallroadusersadapttheirexpectationsaboutthebehaviorsofpeopleondifferenttransportmodes,theiranticipa-tionsofpossiblerisksources,andtheirbehaviors.Indeed,cyclistsanddriversdiffersignificantlyfromeachotherintermsofspeed,size,weight,andvulnerability,sothatinteractingwithoneortheotherimpliesadaptingourperceptionsandourbehaviortothesedifferences.Cyclistsanddriversmustlearnhowtodealwiththenewtrafficmakeup,howtoshareroadspacewithdifferenttypesofvehicles,andhowtobetterindicatetootherroaduserswhattheirnextmovewillbe,formiscommunicationsandincor-rectexpectationsabouttheotheruser’sbehaviorappeartobeanimportantfactorinexplainingcrashesresultingfrombike–carinteractions(Basfordetal.,2002;Bíletal.,2010;Jiaetal.,2008;RäsänenandSummala,2000;TaylorandDavis,1999).Althoughthenumberofcyclistfatalities,aswellasthatofallothervehicledrivertypes,hasdecreaseddramaticallyinEuropeoverthepast15years,thistendencyhasslowedwithinthelast2yearswhileother 0001-4575/$–seefrontmatter © 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.aap.2012.09.005  1178  N.Chaurand,P.Delhomme/AccidentAnalysisandPrevention 50 (2013) 1176–1184 increaseofthenumberofcyclists)oracardriver(whichisobjec-tivelythesituationinwhichthemostcyclistfatalitiesoccur)whilepayingparticularattentiontocyclist–driverinteractionseemstobecrucial.Thepresentstudystartstoaddressthesequestions. 1.4.Aimsandhypotheses We   hadfourmajoraims.Thefirstwastoexplorehowexperi-encedcyclistsperceiveriskwhenoneofanumberofriskybehaviorsisexecutedinasituationwherethecyclistisinteractingwithanothervehicle(bikeorcar).Thesecondwastoexplorehowdriversperceiveriskinthesesamesituations.Ourthirdaimwastocom-pareriskperceptionamongthesetworoadusertypes,inordertodeterminewhichriskybehaviorselicitthegreatestdifferenceinperceivedriskbetweencyclistsanddrivers,soastobeginthinkingaboutwhichcharacteristicsintheproposedriskybehaviorcausethesedifferences.Ourfourthaimwastofindoutwhetherperceivedriskmatchestoobjectiverisk,forcyclistsaswellascardrivers.Morespecifically,wewantedtolookintotheimpactofthevehi-cledrivenbytheparticipant(cyclistvs.cardriver),thevehicletheyencountered(bikevs.car),andthecontroltheyhadovertheriskybehavior(definedintermsofwhocommittedtheriskybehavior,eithertheparticipantortheuserwiththeothervehicle).Inlinewithpreviousliteratureandrelatedtheories,wepredictedthat(a)perceivedriskwouldbegreaterwhentheothervehiclewasacarbut(b)cyclistswouldgenerallyperceivelessriskthandriverswould.We   alsoexpected(c)participantstoperceivelessriskiftheywereresponsibleforit.Furthermore,weexaminedhowperceivedskill,experience,pastviolations,etc.,affectperceivedriskasperceivedamongcyclistsanddrivers.We   alsostudiedhowthesevariablesmoder-atetherelationshipbetweenthevehicletheparticipantsareusing(bikeorcar)andtherisktheyperceive.We   expectedthatthemore(d)perceivedskill,(e)experienceand(f)trafficlawviola-tionsincrease,themoreperceivedriskdecreases,forbothcyclistsanddrivers. 2.Pretests  2.1.Dependentvariablesandroadsituations We   measuredperceivedriskastheprobabilitythatpeoplethinktheymightbeinvolvedinacrash,duringthenext3years,iftheyfoundthemselvesinagivenroadsituation.Thesituationsproposedwereinteractionsbetweentheparticipantandanotherroaduser,withoneofthetwoprotagonistscommittingatrafficviolation.Wefocusedoninteractionssincemostroadfatalitiesoccurbecauseof acollisionbetweenvehicles,andonviolationssincesuchbehaviorsobjectivelycreateriskandaregenerallyeasytorepresentforpar-ticipants.Moreover,wefocusedonviolationstobeabletostudythecrashresponsibilityvariable.Moreover,roadriskscannotbestudiedbytakingintoaccountonlyoneroadsituationbecausesuchsituationsvaryonagreatnumberofdimensions.Forthisreasonwepretested10riskysitu-ationschosenfortheinteresttheyhavereceivedinpreviousworkandofficialstatistics(Choetal.,2009;Crundalletal.,2012;Johnsonetal.,2011;Kimetal.,2007;Räsänenetal.,1999;Rettingetal.,1999;Summalaetal.,1996;ThomandClayton,1992).Thetensit-uationswere:“failingtoyieldtherightofway,”“goingthrougharedlight,”“goingthroughayellowlight,”“overtakingwithoutvisibilityinfront,”“notsignalingtothevehiclebehindwhentur-ningintoaprivatedrive,”“swervingtotherightwhenturningatahighspeed,”“tailgatingthevehiclejustaheadwhosedriversud-denlyslamsonthebrakes,”“riding/drivingatahighspeedwhenthevehicleaheadslowsdown,”“notcheckingtrafficontheleftwhenturningatanintersection,”and“notcheckingtrafficontherightwhenturningatanintersection.”Thepreteston30participantsledustoeliminatefourofthesituations–namely,“goingthroughayel-lowlight,”“overtakingwithoutvisibilityinfront,”“riding/drivingatahighspeedwhenthevehicleaheadslowsdown,”and“notcheck-ingtrafficontherightwhenturningatanintersection”–becausetheyeitherexhibitedaflooreffectontheriskmeasureorhadtoomuchinternalinconsistency.  2.2.Experienceandperceivedcompetence We   studiedriding/drivingskillviatwo   aspects:objectiveexpe-rienceandperceivedskill.Inordertobeabletocomparecyclists’anddrivers’answers,we   usedobjectiveexperiencemeasuresthathadanequivalentmeaningforthetwotypesofvehicles:frequencyofuse,averageweeklytimespentusingthevehicle,andaverageweeklydistancecoveredwiththevehicle(withproposeddistancerangesfordriversrepresentingfivetimestheproposeddistancerangesforcyclists).Wecreatedaperceivedskillscalewithtwo   versions,oneforcyclistsandonefordrivers.Afterseveralpretests,weobtainedascalecomprising17items,suchas“Wheninmycar/onmy   bike,Icancontrolmy   driving/ridingnomatterhowfastI’mgoing,”“Icandrive/ridewellevenwhenI’mtired,”and“SometimesIdon’tseemotorcyclesormopedswhenontheroad”(seeAppendixA).Cron- bach’salphawas.77forthecyclistversion,.86forthedriverversion,and.81forthewholepopulation.Factoranalysesidentifiedthreefactors,forbothcyclistsanddrivers:perceivedcontroloverthevehicle(6items, ˛ cyclist =.81, ˛ driver =.85, ˛ global =.82),overconfi-dence(5items, ˛ cyclist =.80, ˛ driver =.81, ˛ global =.82),andperceivedincompetence(6items, ˛ cyclist =.52, ˛ driver =.73, ˛ global =.59). 3.Method Thestudywasrunbyadministeringanonlinequestionnaire.Thisquestionnaireconsistedoftwo   versions:inthefirstversion,itemswereadaptedtocyclists,inthesecondversion,itemswereadaptedtodrivers.Forsimplicitypurposes,weconsiderthepar-ticipantsthatfilledinthefirstversion(thecyclists)areourSample1,andthattheparticipantsthatfilledinthesecondversion(thedrivers)areourSample2.We   willpresentthetwoversionsofthequestionnaireandtheircorrespondingsampleseparately.  3.1.Participants 3.1.1.Sample1–cyclists Theparticipantswere336cyclistslivinginParisoritssub-urbs(221men,88women,and27gendernotindicated;meanage=45.55,SD=11.83).Themeanfrequencyofbikeusewas5.51(outof7).Duringanaverageweek,participantsusedtheirbikesonmorethan5days;themedianweeklytimespentonbikewasbetween5and10h,andthemediandistancecoveredinaweekwas   between20and50km.  3.1.2.Sample2–cardrivers Theparticipantswere92driverslivinginParisoritssuburbs(51men,22women,and19gendernotindicated;meanage=43,SD=12.42).Themedianfrequencyofcarusewasfourtosixtimesaweek.Themediantimeparticipantsdrovetheircarduringanaver-ageweekwasbetween2and5h,andthemediandistancecoveredwas   between50and100km.   Theyusedabikeatmaximumonceaweek.  N.Chaurand,P.Delhomme/AccidentAnalysisandPrevention 50 (2013) 1176–1184 1179  3.2.Recruitment  3.2.1.Sample1–cyclists Thecyclistswererecruitedthroughmessagestomembersof themailinglistofaParisiancyclistassociation,onforumsspe-cializingintransportationandcycling,andviaflyersdistributedinpublicplaces(trainstations,parkinglots,etc.).Afterconnectingtothestudywebsite,participantsindicatediftheyhadadriver’slicense.Iftheyansweredno(11participants),theywereinformedthatthestudywasreservedforpeoplewithadriver’slicense.If theyansweredyes,theywentontothequestionnaire.Theythenindicatedonasix-pointscalehowfrequentlytheyusedabicycletogotowork.Iftheygaveananswercorrespondingtomorethanonceaweek,theycouldcontinuewiththequestionnaire.  3.2.2.Sample2–cardrivers Thedriverswererecruitedthroughmessagesonforumsspe-cializingintransportationandcars,aswellasviaflyersdistributedinpublicplaces(trainstations,parkinglots,etc.).Theyfollowedthesameprocedureasthecyclists,wererequiredtohaveadriver’slicense,andwereincludedonlyiftheysaidtheyusedabicycletogotoworkonceaweekorless.  3.3.Questionnaire 3.3.1.Sample1– cyclists TheonlinequestionnairewascreatedusingSurveyMonkey.Cyclistswereaskedtoimaginethemselvesonabikeintown.Thisinductionwasrepeatedatthebeginningofeachofthefourpartsof thequestionnaire,andalsointheitems,whichmentionedspecifi-cally“youareridingabike”(exceptdemographicitems).Thefirstpartofthequestionnaireaskedcycliststoimaginethemselvesinthesixsituationswheretheywereinteractingwithanothervehicle,withoneofthetwopersonsadoptingapotentiallyriskybehavior.Thesixsituationswere:“failingtoyieldtherightofway,”“goingthrougharedlight,”“notsignalingtothevehiclebehindwhenturningintoaprivatedrive,”“swervingtotherightwhenturningatahighspeed,”“tailgatingthevehiclejustaheadwhosedriversuddenlyslamsonthebrakes,”and“notcheckingtrafficontheleftwhenturningatacrossroads.”Foreachofthesesituations,threeconfigurationswerepresented:theparticipantshadfirsttoimaginetheywereinteractingwithsomeoneonabikewhoexecutedtheriskybehavior,thenwithsomeoneinacarwhoexecutedtheriskybehavior,andfinallywithsomeoneinacar,buttheyweretheonewhoexecutedtheriskybehavior.Forexample,thesituation“failingtoyieldtherightofway”waspresentedasfollows:“Accordingtoyou,howlikelyisitthatyouwillbeinvolvedinacrashwhilecyclingduringthenext3yearsif:–anothercyclistfailstoyieldtherightofwaytoyouataninter-section–acardriverfailstoyieldtherightofwaytoyouatanintersection–youfailtoyieldtherightofwaytoacardriveratanintersection”Foreachofthese18possibilities,participantsuseda7-pointscaletoindicatetheprobabilitythattheywouldhaveacrashif theyfoundthemselvesinthedescribedsituationduringthenext3years.Inthesecondpartofthequestionnaire,participantsusedfive-pointscalestoindicatethefrequencyatwhichtheyadoptedeachof thesixriskybehaviors.Thethirdpartwastheperceivedskillscale.Itmeasuredparticipants’perceivedabilitytoridetheirbikeinanurbancontext,using17seven-pointitems,suchas“Iridemybikesafely”and“Icancontrolmy   bikeregardlessoftheweather.”Inthefourthpart,participantsgaveinformationconcerningtheirrealuseofbikesandcars:possessionornot,frequencyofuse,weeklyamountoftimeused,andweeklydistancecovered.Finally,partic-ipantsindicatedtheirgender,age,andprofession.Afterwardstheywerethankedandtoldhowtoobtaintheirgift(aUSBflashdrive).  3.3.2.Sample2–cardrivers Thisquestionnaireusedtheitemsfromthequestionnaireof Sample1,afteradaptingthemtocarswhileretainingthemean-ingasmuchaspossible.Participantswerethusaskedtoimaginethemselvesdrivingacarintown.Again,thisinductionwas   repeatedatthebeginningofallpartsofthequestionnaire,aswellasintheitemsthatspecificallymentioned“youaredrivingacar”(exceptdemographicitems).Thethreeconfigurationsforeachsituationwereadapted:participantshadtofirstimaginetheywereinterac-tingwithsomeoneinacarwho   executedtheriskybehavior,theninteractingwithsomeoneonabikewhoexecutedtheriskybehav-ior,andfinallyinteractingwithsomeoneonabike,buttheyweretheoneexecutingtheriskybehavior.Forexample,thesituation“failingtoyieldtherightofway”was   presentedasfollows:“Accordingtoyou,howlikelyisitthatyouwillbeinvolvedinacrashwhileinacarduringthenext3yearsif:– anothercardriverfailstoyieldtherightofwaytoyouwayatanintersection– acyclistfailstoyieldtherightofway   toyouwayatanintersection–youfailtoyieldtherightofwaytoacyclistatanintersection”Finally,participantsgaveinformationconcerningtheirrealuseofcars. 4.Results Foreachparticipant,wecomputedanoverallviolationscorebyaveragingthefrequencywithwhichtheparticipantadoptedthesixriskybehaviors,andthreecompetencesubscorescorrespond-ingtothethreesubscalesoftheperceivedskillscale.We   thusranrepeatedmeasuresANOVAswiththelevelofperceivedriskasadependentvariable,typeofquestion(“othervehicle”,“samevehicle”,“participantresponsible”,etc.)asawithin-participantsindependentvariable,anddemographicandattitudinalvariablesasbetween-participantsindependentvariables.ForeachANOVA,werantheoverallanalysisbyconsideringthesixriskysituationsasarepeatedvariableandweranthesixsituationalanalysesbyconsid-eringeachriskysituationseparately.Foreaseofreading,whentheresultsofthesituationalanalyseswereallsignificantandcorrob-oratedtheresultsoftheoverallanalysis,wedonotpresenteachofthesixsituationalresults,butgivethesmallesteffectoutofthesixandsaythatallofthesixeffectsaregreaterthanthisminimum.ThemainresultsfortheoverallanalysisaredisplayedinTable1,andtheperceivedscoresforeachofthesixsituationsaredisplayedinTable2. 4.1.Sample1– cyclists Thesituationperceivedasthemostriskywas“tailgating”,whereastheleastriskywas“notsignalingwhenturning”(seeTable2).Asexpected,regardlessofthesituation,cyclistsperceivedmoreriskwheninteractingwithacar( m =3.32)thanabike( m =2; F  (1,335)=854.877,  p <.001,  2 =.72;fortheanalysisbysituation,all F  (1,335)>200,all  p <.001,all  2 >.385).Moreover,wheninterac-tingwithacar,theyperceivedthesituationaslessriskyiftheyweretheonecommittingtheriskybehavior( m =3.02; F  (1,335)=32.22,  p <.001,  2 =.088;intheanalysesbysituation,except“failingtoyield”,all F  (1,335)>18,all  p <.001,all  2 >.05).Intheanalysesincludingexperience,perceivedskill,andtrafficviolations,neither
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