Review of safety and mobility issues among older pedestrians

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Contents lists available atScienceDirect

Accident

Analysis

and

Prevention

j o u r n a l h o m e p a g e :w w w . e l s e v i e r . c o m / l o c a t e / a a p

Review

of

safety

and

mobility

issues

among

older

pedestrians

Isabelle

Tournier

a,b,∗

,

Aurélie

Dommes

b

_,

_Viola

_Cavallo

b

a_INSIDE,_University_of_Luxembourg,₁₁_porte_des_sciences,_L-4366_{Esch-sur-Alzette,}_Luxembourg b_LEPSIS,_IFSTTAR,₂₅_allée_des_Marronniers,_F-78000_Versailles,_France

a

r

t

i

c

l

e

i

n

f

o

Articlehistory:

Received14September2015

Receivedinrevisedform9February2016 Accepted29February2016 Keywords: Pedestrians Aging Safety Mobility Functionalchanges Recommendations

a

b

s

t

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Althougholdpeoplemakeupanextremelyvulnerableroad-usergroup,olderpedestrians’difficulties havebeenstudiedlessextensivelythanthoseofolderdrivers,andmoreknowledgeofthisissueis stillrequired.Thepresentpaperreviewscurrentknowledgeofolder-adultproblemswiththemain componentsofpedestrianactivity,i.e.,walkingandobstaclenegotiation,wayfinding,androad cross-ing.Comparedtoyoungerones,oldpedestriansexhibitdecliningwalkingskills,withawalkingspeed decrease,lessstablebalance,lessefficientwayfindingstrategies,andagreaternumberofunsaferoad crossingbehaviors.Thesedifficultiesarelinkedtoage-relatedchangesinsensorial,cognitive, physi-cal,andself-perceptionabilities.Itisnowknownthatvisualimpairment,physicalfrailty,andattention deficitshaveamajornegativeimpactonolderpedestrians’safetyandmobility,whereastherolesof self-evaluationandself-regulationarestillpoorlyunderstood.Alltheseelementsmustbetakeninto con-sideration,notonlyindevelopingeffectivesafetyinterventionstargetingolderpedestrians,butalsoin designingroadsandcars.Recentinitiativesarepresentedhereandsomerecommendationsareproposed. ©2016ElsevierLtd.Allrightsreserved.

1. Introduction

Acommondesire among olderadults isto stay wherethey

areastheyage,whileremainingmobileintheirfamiliar

environ-ment(LordandLuxembourg,2006).Theabilitytostayconnected

tocommunityservicesandtomaintainsocialinteractionsis

con-sideredtodaytobecrucialtowell-beingandsuccessfulaging(for

areview,seeYenandAnderson,2012).Beyondtheneedfor

mobil-ity,walkingisknowntobethemostcommonphysicalactivityof

olderadults(McPhillipsetal.,1989)andtohavepositiveeffects

onhealth,cognition,andwell-being(seee.g.,Foxetal.,2007;for

areview,seeKramerandErickson,2007).However,walkingmay

bedangerousbecauseitexposesthewalkertoaccidentrisksand

falling.

Withinthelastfew decades,researchhasmostlyfocusedon

the safety of older drivers. The study of older pedestrians is

more recent and more limited, even though a largeportion of

pedestrianaccidentsinvolveanolderadult.Forexample,inItaly,

Greece and France, more than half of all pedestrians killed on

theroadareover 65years of age,whereas this agegroup

rep-resentsamuchsmallerpart(17–20%)ofthepopulation(ONISR,

∗ Correspondingauthorat:INSIDE,UniversityofLuxembourg,Maisondes Sci-encesHumaines,11portedessciences,L-4366Esch-sur-Alzette,Luxembourg.

E-mailaddress:[email protected](I.Tournier).

2006;SafetyNet,2009).Thesamepatternofover-implicationof

olderadults in pedestriancasualtiesand injuries hasalsobeen

observedinnon-EuropeancountriessuchasNewZealand(Keall,

1995).

Being hit while crossing a street is not the only safety risk

encounteredbypedestrians:theriskof fallsalsoincreases

dra-maticallywithaging.Aboutonethird ofadults age65 orolder

have experienced a fallwithin thepast year(for a review, see

Lordetal.,2001).Morethanhalfofallfallsinindependentolder

community-dwelling peopleoccuroutsidethehome(Fothergill

etal.,1995;Lordetal.,2001).Althoughthedataarescarce,astudy

conductedontheUSpopulationreportedthat77.5%ofpedestrian’s

nonfatal injurieswere linkedtoa fall;accidentswhile crossing

the street (15%) and overexertion (5.8%) were the other main

causes(Naumannetal.,2011;seealsoAbou-RayaandElMeguid,

2009).

The aimof the present paper was tocomprehensively

por-tray older pedestrians’ safety difﬁculties in carrying out three

main tasksinvolved in travelonfoot, i.e.walkingand obstacle

negotiation,navigation, and streetcrossing. To provide a more

general understanding of these difﬁculties,we also report the

underlyingfunctional changes thatoccur withaging(sensorial,

cognitive, and physical) and theirconsequences on pedestrian

safety and mobility. Identifyingrisky situations and theirmain

causesis apreliminarysteptowarddevelopingefﬁcientactions

aimingat improvingthe safety and mobility of older

pedestri-http://dx.doi.org/10.1016/j.aap.2016.02.031

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ans. Some of these programs are presented at the end of the paper.

2. Walkingandobstaclenegotiation

Directlylinkedtotheriskoffalling,walkingandobstacle

negoti-ationaretwomajorcomponentsofpedestrianmobilitythatchange

duringaging.

2.1. Walkingandgaitcharacteristics

Adecreaseinwalkingspeed duringagingisa typical

obser-vation, and older women are generally reported towalk more

slowlythanoldermen(seee.g.,Asheretal.,2012;Knoblauchetal.,

1996;Romero-Ortuno,2010;Romero-Ortunoetal.,2010).

Simi-larly,theaccelerationcapacityalsoreduceswithaging(Buckley

etal.,2009).Whenrequiredtochangefromwalkingatone’s

pre-ferredspeedtowalkingquickly,theelderlyfailtoachievethesame

increasesinspeedandstridelengthasthoseachievedbyyoung

adults(Shkuratovaetal.,2004).

Severalparametersotherthanwalkingspeedalsochangewith

advancingage,whereweﬁndshorterstridelengths,greater

stand-ingwidthsandmoretimespentonthedoublesupportphase(i.e.,

bothfeetontheground),abentposture,andalessvigorousforce

developmentatpushofftime(Salzman,2010;Winteretal.,1990).

Thesechangesarecommonlynotedasearlyasage65,butbecome

moremarkedandlimitmobilitytoagreaterextentaftertheageof

85.Cautiouswalkingandstandingbehaviorsmayreﬂectadaptation

toage-relatedchangesaffectingthesensory,motor,andcognitive

systems(forreviews,seee.g.,Al-Yahyaetal.,2011;Salzman,2010),

andmayalsomainlyexpressfearoffalling(seee.g.Espyetal.,

2010).Althoughsuchgaitdisturbancesarefrequentinolder

per-sonsandareoftenanearlymanifestationofasubclinicaldisease,

about20%ofolderadultsarefoundtoretainnormalgaitpatterns

intoveryoldage(i.e.,over85;seethereviewbySalzman,2010).

Amongthevariousphasesinvolvedinwalking,gaitinitiation

andcessationarethemostriskyperiodsduetothecomplex

pos-turaladjustmentstheyrequire(Uemuraetal.,2012).Bothwalking

initiationandcessationslowdownwithaging(e.g.,Caoetal.,1998;

Hallidayetal.,1998;Winteretal.,1990).Thisslowingseemsto

bepartlyexplainedbythemorecautiousstrategyofolderadults,

whoneedtobecarefuloftheirgait(Muiretal.,2014;Tiroshand

Sparrow, 2004). It seemsthat olderadults prefer stability over

speed (Buckley etal., 2009)and placingpriorityonthis

senso-rimotorperformancemayevenbedetrimentaltootherkindsof

performance(see e.g.,Shumway-Cooketal.,1997).Withaging,

gaitcannotbeconceivedofastheoutcomeofaseriesof

identi-cal,automaticsteps.Instead,gaitperformancebecomesacomplex

taskthat placesdemands onthesensoryandcognitivesystems

(Sheridan andHausdorff, 2007).Giventheirfear offalling (e.g.,

Schefferetal.,2008)andtheirneedtokeeptheirbalancewhen

walking(WoollacottandTang,1997),olderpedestriansseemto

allocatemoreattentiontowatchingtheirstepsastheycross,

caus-ingthemtoatleastpartlydisregardapproachingtrafﬁc(Avineri

etal.,2012).Thepresenceofcurbsatthebeginningandendofa

street-crossingtaskmayaddsupplementarycognitiveandmotor

demandsthatveryfewstudieshaveexaminedinadetailedmanner

(seee.g.,Naveteuretal.,2013).

Theuseofcanesorawalkerisaneffectiveadaptivemeansof

reducingtheriskoffalling(forareview,seeAlexander,1996).

Log-ically,olderpedestriansusingcanesorwalkerswalkmoreslowly

thanolderpedestrianswhoarenotusingsuchdevices,andagain,

inthecaseoftheuseofcanes,olderwomenappeartowalkmore

slowlythanoldermen(ThompsonandMedley,1995),althoughthis

gendereffectisnotalwaysobserved(ArangoandMontufar,2008).

2.2. Obstaclenegotiation

Walkingisalsochallengedbythepresenceofobstaclessuchas

unevensurfaces(e.g.,cobblestone,stones,cracks),butalso

obsta-clestobeavoided(e.g.,otherpedestrians,benches)ortostepover.

Trippingoveranobstacleisactuallyoneofthemostcommoncauses

offallsamongolderadults(Blakeetal.,1988;Campbelletal.,1989).

Avoidinganobstacleisriskytoo:havingtochangeone’sdirection

whilewalkingisassociatedwithmoregaitvariabilityandariskof

fallingamongolderpeople(Meinhart-Shibataetal.,2005).

Severaladaptivestrategiesareusedbyolderpedestrianswho

areconfrontedwithobstacles.Olderadultstendtoadoptaslower,

moreconservativeobstacle-negotiationstrategythatgivesthem

moretimetoadjusttheirfoottrajectory(forareview,seeGalna

etal.,2009).Inthepresenceofunevensurfaces,forexample,they

havebeenshowntodecreasetheirwalkingspeedandtheirstep

lengthmorethanyoungeradultsdo(MarigoldandPatla,2008).

Moreover,olderadultshavebeenfoundtospendmoretimelooking

atthegroundduringobstacleavoidance,whereasyoungeradults

spendmoretimegazingstraightahead(PaquetteandVallis,2010).

Finally,themaintenanceofalargepersonalspacebetween

them-selves and other pedestrians is another strategy used by older

adults toreduce therisk of bumpinginto someoneand falling

(Gérin-Lajoieetal.,2006).

Oneofthemain obstacle-negotiationsituationsencountered

bycity-dwellingpedestriansishandlingsidewalks.Despiteefforts

fromlocalauthoritiestoprovideloweredsidewalksatpedestrian

crossings,movingfromasidewalkintothestreetisfrequently

asso-ciatedwithguttersandlevelorsurfacechangesthatchallengeolder

pedestrians.Whilespeciﬁcstudiesonsidewalknegotiation

dur-ingstreetcrossingbyolderpedestriansarescarce,someinsights

havebeenprovidedbystudiesaboutclimbingstairsandstepping

overobstacleswithaging.Indeed,goingupanddownstairsisrated

byolderadultstobeamongthemostdifﬁculttasksintheirdaily

life(WilliamsonandFried,1996).Fallsarethreetimesmore

fre-quentduringdescentthanascent(Svanström,1974;Tinettietal.,

1988),whichseemsoftentobeexplainedbyadeclineinthe

abil-itytoregulatebodyswayduringthestair-to-ﬂoortransitionwhen

descending(Lee andChou,2007).In responsetothesechanges,

olderadultsadoptcautionarybehaviorsinstaircases,suchas

low-eringtheirspeed,watchingtheirfeetwhilewalking,andusingthe

handrails(HamelandCavanagh,2004).

3. Wayﬁnding

Wayﬁndingisanotherimportantpedestrianactivity.Itcanbe

dividedintopreparingforthejourney(i.e.,planning)and

navigat-ingwhilewalking(i.e.,movingandorientation).

3.1. Planningthejourney

Efﬁcient navigationrequires makingdecisions abouthow to

reachagivendestinationwhilesatisfyingvariousconstraintssuch

asavoidinghavingtowalkoverlylongdistancesoravoiding

bar-riers(SalthouseandSiedlecki,2007).Thisabilityistypicallytested

withlaboratorytaskssuchasthemultipleerrandtest(Shalliceand

Burgess,1991)orthezoomaptask(Wilsonetal.,1996),which

requireusingamapprovidedtocarryoutcertainactivities(e.g.,

shopping,visitingpeople).Olderadultsaregenerallyfoundtobe

lessefﬁcientthanyoungonesatdeterminingthecomplexcourseof

actionsneededtoreachthepredeﬁnedgoal;theymakemore

mis-takesandtakemoretimetopreparethejourney(Allainetal.,2005;

SanderandSchmitter-Edgecombe,2012).Theseﬁndingsare

prob-lematic, becausebeforenavigating toan unfamiliarplace, older

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theriskofgettinglostandtheanxietythatensues(Phillipsetal.,

2013).Age-relatedplanningdeﬁcitsarenotasgreat,however,for

morecommontasks(e.g.,Gardenetal.,2001;Phillipsetal.,2006),

whicharemoresimilartodailylifesituationsinafamiliar

environ-ment.Thissuggeststhatlife-spanexperienceinwayﬁndingatleast

partlycompensatesforsomeoftheage-relatedcognitivedeclines

thataffectplanning(Kliegeletal.,2007).

Inplanningtheirjourneys,olderadultsarenotalways

inﬂu-encedbythedesiretoreducethedistancetraveledonfoot.The

shortestwayisnotnecessarilythechosenone,sinceseveralfactors

linkedtophysicalaccessibilityandcomfortmayaffectroutechoice

infamiliarenvironments.Forexample,olderpedestrianshavebeen

showntobemorelikelywalkalongstreetswithwide,comfortable

sidewalksandnohillsorstairs,andalongstreetswithpedestrian

devicessuchaszebracrossingsortrafﬁc-freezones(e.g.,Borstetal.,

2008;Mollenkopfetal.,1997;Ståhletal.,2008).Moreover,older

adultsreportapreferenceforroadswithlittlecarandpedestrian

trafﬁcbecausetheyareoftenafraidofbeingpushed

(Huguenin-Richard,2012).Thesesafechoicesaresometimescompromised,

however,byillnesses thatlimit a pedestrian’swalkingdistance

andjustifycloserchoicesthatareoftennotassafe(Bernhoftand

Carstensen,2008;Huguenin-Richard,2012).Anotherpointisthe

needforrestingtime, which increasesthenecessityofoutdoor

benchesandseatswithweatherprotection(Carlsson,2004).

3.2. Navigatingandorientating

Thesecondkeycomponentofwayﬁndingiskeepingtrackof

one’sdirection and location while moving around in the

envi-ronment.Globally, theability tonavigateand orientate oneself

declinewithaging(forreviews,seeKlencklenetal.,2012;Moffat,

2009).Thislesserefﬁciency,whichleadstomoreerrorsandlonger

executiontimes,isobservednotonlyinsituationswherea

prede-ﬁnedplanexists(SandersandSchmitter-Edgecombe,2012;butsee

Allainetal.,2005),butalsointheabsenceofapredeﬁnedplan,e.g.,

inreal-lifeorinunknownvirtualenvironmentssuchasamedical

centerorasupermarket(e.g.,HeadandIsom,2010;Kirasic,1991;

Wilknissetal.,1997;Zakzanisetal.,2009).

Thisage-relateddecline hasbeen explainedin terms of

dif-ﬁculties selectingand learning thefeatures needed tokeep on

course,andproblemslearningthetemporospatialorderofrelevant

landmarks(e.g.,Wilknissetal.,1997).Thepresenceofprominent

landmarks(e.g.,postofﬁce,trafﬁclights)ishelpfulforolder

pedes-triansnavigatinginbothfamiliarandunfamiliarenvironments.In

contrast,inanewenvironment,theuseofaprintedmapproviding

anaerialviewoftheneighborhoodseemstobelesshelpfulforolder

adultsthanforyoungerones(e.g.,Goodmanetal.,2005;Sjölinder

etal.,2005).Recently,however,theoppositeresultwasobtainedby

YamamotoandDeGirolama(2012),whoshowedthatsomeolder

adultsareabletomaintaintheirmap-readingskillsrelativelywell

inunknownenvironments.

Manystudieshavealsotakenaninterestinnavigation

strate-gies.Amajordistinctioninthesestudiesistheoppositionbetween

egocentricnavigation(i.e.,referencetospatiallandmarksandone’s

currentlocationanddirection)andallocentricnavigation(i.e.,use

ofamentalmap).Studiessuggestthepreferentialuseofegocentric

ratherthanallocentricstrategiesamongtheelderly,probablydue

tospatialmemorydeﬁcitsand executivedeclines(fora review,

seee.g.,Tailladeetal.,2014).Theage-relatedimpairmentinthe

allocentricstrategy,and alsotheability toswitchfrom

egocen-tricroute-followingtoallocentricwayﬁndingstrategiesseemsto

explain why older adults were outperformed by younger ones

whentryingtoﬁndnovelshortcutstoattainapreviouslylearned

goallocationinarealisticbutvirtualtownenvironment(Harrisand

Wolbers,2014).

Navigationinfamiliarenvironmentsappearstobelessimpaired

withagethannavigationinnovelenvironments(Rosenbaumetal.,

2012).Althoughtheimpactoffamiliarityonpedestrian

naviga-tionhasnotbeenstudiedmuch,someﬁndingsonolderdrivers

suggest that theyavoid unfamiliar routes (Brydenet al., 2013;

Burns,1999).Wayﬁndingtoolsoffering“step-by-step”instructions

andlandmarkstofollowcouldbeaneffectivemeansofhelping

olderpeoplenavigateinunfamiliarenvironments(e.g.,Fickasetal.,

2008;Goodmanetal.,2005;Mayetal.,2003).Thesetoolscould

atleastpartlycompensate forage-relatedcognitivedeclinesby

reducingthecognitiveloadofnavigationtasks.However,when

askedaboutwhichkindofwayﬁndingstrategiestheyused,55.1%

ofolderdriversreportedpullingovertocheckthemap,butonly

9.9%reportedregularlyusinganavigationsystem(Brydenetal.,

2013).Thisreluctancetousenavigationaidscouldbelinkedeither

toalackofconﬁdencein newtechnologies(e.g.,Barnardetal.,

2013)ortooverloadedcognitiveresources(e.g.,dividedattention)

whenusingthemtodrive.

4. Streetcrossing

Crossingastreetisacomplextaskthatrequiresseveralactions

(Baileyetal.,1992).First,pedestrianshavetoselectanadequate

crossingplace,approachthecurb,andlookforoncomingvehicles

and/ortrafﬁclights.Ifthereisnotrafﬁclight,pedestriansthenhave

toselectanadequatemomenttocrossbyjudgingtheavailablegaps

intheﬂowoftrafﬁc.Fromthere,theyhavetoadapttheirstart-up

timeandcrossingtimetotheamountoftimeavailableforcrossing,

bycalibratingtheirwalkingspeedtothevisualfeedbackcoming

fromapproachingtrafﬁc.

4.1. Selectingaplacetocross

Awareness of one’s vulnerability with advancing age may

explainwhyolderpedestrians,ascomparedtoyoungerones,

pre-ferto usepedestrian crosswalks and intersections withsignals

(BernhoftandCarstensen,2008).Itshouldbenotedthattherisk

ofcollisiononcrosswalkswithoutsignalsislinkedtoincautious

behavioronthepartofpedestriansbutalsotothefailureofdrivers

tostopatpedestriancrossings(Harruffetal.,1998;Koepselletal.,

2002).

Choosingasafeplacetocrossisparticularlychallengingforolder

pedestriansbecausetheyoftensufferfromphysicalimpairments

thatreducetheirabilitytogettoapedestriancrossingthatistoo

faraway.Consequently,theysometimesevendecideto“jaywalk”,

i.e.,crosswhere thereis nocrosswalk.Despitetheirpreference

forcrosswalks,themajorityofolderpedestriansreportregularly

crossingthestreetattheircurrentposition,especiallywhen

visi-bilityisgoodortrafﬁcissparse(BernhoftandCarstensen,2008).

Thisbehavior is riskybecausecomplex roadenvironments and

infrastructuresimposeahighcognitiveloadaswellas

substan-tialphysicaldemandsonolderpedestrians.Thisexplainswhythe

riskofaccidentsis higher,forexample,intwo-way trafﬁcthan

inone-waytrafﬁcsituations(FontaineandGourlet,1997;Oxley

etal.,1997).Olderpedestrians’difﬁcultycrossingwidestreetsor

busyintersectionsmaybecausedbyproblemsrapidlyscanning

trafﬁccomingfromvariousdirectionsatthesametime(Bernhoft

andCarstensen,2008).

4.2. Explorationofthevisualenvironment

Accuratelookingbehaviortocheckforongoingtrafﬁcis

nec-essaryforcrossingstreetssafely.Inthepresenceofatrafﬁclight,

thelookingbehaviorofolderandyoungeradultsisquitesimilar

(forareview,seeDunbaretal.,2004).Incontrast,intheabsence

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approachingthestreetappearstodeclinewithage.The

decision-makingprocessappearstobeslowed,assuggested,forexample,by

thefactthatolderpedestrianspauseonthesidewalkforalonger

timebeforecrossing(Oxleyetal.,1997).Thisageeffectisespecially

observedforcrossingtwo-waystreets,butnotforone-waytrafﬁc

situations(Oxleyetal.,1997).

Whileolderpedestriansseemtospendmoretimeatthecurb,

thetotalnumberofheadmovementswhilewaitingtocrossappears

tobesimilarinyoungandolderpedestrians.Thiswasobserved

inaﬁeldstudybyOxleyetal.(1995)andinasimulated

street-crossing taskbyDommes et al.(2014). Morespeciﬁcally,older

womenwereshowntolookbothways lessoftenthanyounger

adultsand oldermendid,although thisgendereffect seemsto

decreasewithdrivingexperience(HollandandHill,2010).A

differ-encebetweenolderwomenwithandwithoutdriver’slicensecould

beduetodriving-relatedknowledge:drivingexperiencemayhave

animpactonanumberofcrossingskillssuchasvisualsearching

(Underwoodetal.,2002)andjudgingvehiclearrivaltimes(Carthy

etal.,1995).Butacohorteffectresultingfromsocio-economicand

educationaldifferencescouldalsoexplainthisgendereffect,

inso-farastheoldestwomenrecruitedinrecentstudiesgenerallynever

learnedhowtodrive,anddrivingwasmostoftenreservedformen

inthesegenerations.Thisgenerationeffectistendingtodisappear

todaybecauseyoungandmiddle-agedwomennowdriveasmuch

asmen.Inanycase,theseoverallﬁndingssuggestthatolder

pedes-trianshavetroubleprocessingalargeamountofinformationatthe

sametimeandneedmoretimetodecideontherightmomentto

cross.Consequently,thesimilarnumber ofheadmovementsby

youngandolderadultsdoesnotguaranteethatthequalityofthe

informationtakeninwhenexploringthevisualsceneissparedin

olderpedestrians.Thestudyofthenumberofheadmovementsmay

thereforenotbesufﬁcienttoassesstheefﬁciencyoflooking

behav-iors.Directionof gaze,thenumber andtypeof objectschecked

inthevisualscene,lookingtime, andthespeed ofhead

move-mentsmaybemoreinformativeforassessingscanningbehavior

withaging.

4.3. Choosingatimegapforcrossing

Choosing a safe time gap for crossing involvesdetermining

whetherthetimeavailablebetweentwovehiclesexceedsthetime

neededtocross.Thiscomparisonrequiresassessingboththearrival

timeoftheapproachingvehiclesandone’sowncrossingtime(see

alsoSection5.4).

Twostudiescomparingthestreet-crossingdecisionsof

differ-entagegroupsrevealedthatolderadults(70–80yearsold)chose

alargermediantimegapthanyoungeronesdid(20–30and60–70

years old)forcrossing asimulated one-waystreet(Lobjoisand

Cavallo,2007,2009).Thisﬁndingsuggeststhatolderpedestrians

attempttocompensatefortheirslowerwalkingspeed.Butseveral

virtual-realitystudieshavealsoshownthatolderadults’decisions

arebiasedbytheapproachingvehicle’sspeedandthattheaccepted

timegapdropsasspeedincreases,leadingtosmallersafetymargins

andmoreunsafedecisionswhenvehiclespeedishigh(Dommes

andCavallo,2011;LobjoisandCavallo,2007,2009;Oxleyetal.,

2005).Olderpedestriansseemtousesimpliﬁedheuristicsbasedon

vehicledistance:foragivenavailabletimegap,olderpeoplemore

oftendecidetocrosswhenvehiclesaremovingathighspeedsthan

atlowonesbecausethedistanceoftheapproachingcarsisalso

greater.Theyoverestimatethetimeavailableforcrossingandthus

aremorelikelytoexperiencedifﬁculties.

Adetailedinvestigationofaccidentstatisticsalsosuggeststhat

olderpedestrians aremorelikelytogethitonthefarsidethan

onthenearsideofatwo-waystreet(FontaineandGourlet,1997;

Oxleyetal.,1997;Dommesetal.,2014;Dommesetal.,2015).The

greaterriskonthefar-sideofthestreetseemstobepartlyexplained

bytheslowwalkingspeedoftheelderly(HoxieandRubenstein,

1994):thefarlanemayhavebeenclearwhenthecrossingwas

initiatedbutbecomesbusybeforeitiscompleted.Anadditional

explanationisrelatedtoinadequatejudgmentsoffar-sidetrafﬁc.

Asimulatorstudyinvestigatingvisualexplorationstrategies

sug-gestedthatolderpedestriansmakecrossingdecisionsmainlyon

thebasisofthegapavailableinthenearlane,whileneglectingthe

farlane(Dommesetal.,2014).However,otherstudieshaveshown

thatpedestrians,andparticularlytheoldestones,aremoreoften

involvedinaccidentsintheearlypartofthecrossings(Dunbar,

2012,2005;Wardetal.,1994).Therelativeriskinessofnear-side

accidentsseemstofollowareverseJ-shapedcurveacrossthe

lifes-pan,fallinginlatechildhoodandcontinuingfalluntilitrisesagain

afterage85(Dunbar,2012).Theriskofnear-sideaccidentshas

alsobeenshowntobehighinpedestrianssufferingfrom

dement-ingdiseasessuchasAlzheimer’sdisease(Gorrieetal.,2008).This

riskmaybeduetoattentionalfailuresaffectingtheabilitytocheck

andeffectivelydetectpotentialhazards,evenonthenearsideofa

two-waystreet.

4.4. Start-uptimeandcrossingtime

Start-uptimecorrespondstothetimebetweenthedecisionto

crossandtheﬁrststepintothestreet.Aslowstart-upwilldelay

thecrossingandincreasetheriskofstillbeingontheroadwhena

vehiclearrives.Inlaboratorytasks,start-uptimeisrarelyisolated

frommeasuresofcrossingtimeordecision-makingtime(seee.g.,

Oxleyetal.,2005),ormeasuresofinitiationtime(timebetween

themomentwhenthepedestrianbeginstocrossandwhenthe

car openingthegappassesinfront ofhim/her, seeLobjoisand

Cavallo,2007,2009;Hollandand Hill,2010).Ina seriesofﬁeld

studies,Knoblauchetal.(1996)observedthatthestart-uptimes

ofpedestrianswaitingforagreenwalksignwereslightlylonger

forolderadultsthanforyoungerones:theaveragetimewas1.9s

for younger adults and 2.5sfor older ones. Similarly,

observa-tionsofreal-lifecrossingbehaviors(Oxleyetal.,1997)aswellas

resultsfromindoorexperiments(HollandandHill,2010)havealso

revealedthatolderpedestrianstakeabout1slongerthanyounger

adultsdo.Thisincreasemaybeduetotheslowingofmotorspeed

andreactiontimewithaging(Oxleyetal.,1997),butalsotothe

age-relatedincreaseindecision-makingtimeinadultsage75yearsor

over(Oxleyetal.,2005).

4.5. Calibrationofwalkingspeedtotrafﬁcperception

Afterstarting to cross thestreet, pedestrians can still make

some adjustments (i.e., increasing or decreasing their walking

speed)basedonvisualfeedbackprovidedbyapproaching

vehi-cles.Walking-speedadaptation isprobably animportant factor

thathelpsavoid collisionsduringstreetcrossing.Tomaintaina

satisfactorysafetymargin,youngpedestrianshavebeenshownto

increasetheirwalkingspeedduringsimulatorexperimentswhen

everthetimegapbetweenvehiclesdecreases,whereasthis

adjust-mentisnotobservedinolderpedestrians(Dommesetal.,2014;

LobjoisandCavallo,2009).LobjoisandCavallo(2009)suggested

thatthecrossingdecisionsofyoungeradultsaremuchmoreﬁnely

tunedtotimegapsbecausetheyusevisualfeedbackwhilecrossing.

Olderadultsmayhavetroublecalibratingperceptionandaction.

Dommesetal.(2014)alsoobservedfewchancesfor

compensa-tionbywalkingfaster.Beyondthewell-knownmotordeclineswith

aging(seee.g.,Shkuratovaetal.,2004),theabsenceof

compensa-tionfordecision-makingerrorsbywalkingquicklycouldalsobe

linkedtooldpeople’sneedtovisuallycontroltheirgaitand

bal-ance;thispreventsthemfromwatchingapproachingtrafﬁcwhile

walking.Severalstudieshaveclearlyshownthatoldpeopleneedto

(5)

2012).Thissensorimotor-performancepriority(seee.g.,

Shumway-Cooketal.,1997)islikelytobedetrimentaltothevisualmonitoring

ofapproachingvehicles(seeSection2.1).

5. Functionalchangesaffectingolderpedestrians’safety

Many componentsof pedestrianactivity areaffected bythe

normalagingprocessandmaythereforehaveanegativeimpact

onolderpedestrians’safetyandmobility.Theseoverallfunctional

changespertaintosensory,cognitive,andphysicalabilities,aswell

asself-perception.

5.1. Impactofsensorychanges

Becausewalking,navigatingandstreetcrossingarehighlyvisual

(forareview,seeShinarandSchieber,1991),thevisualdeclines

associated with thenormal aging process and age-related

dis-easeslikecataract,glaucoma,andmaculardegeneration,maybe

importantfactors in explaining thegreater mobility difﬁculties

ofolderpedestrians, suchastheirincreasedlikelihoodof

mak-ingunsafecrossingdecisions.Whereastheeffectofvisionlosson

safetyhasbeeninvestigatedmuchmoreofteninolderdriversthan

inolderpedestrians,somedataareavailable.Therisk offalling

increaseswithdeclinesinvisualacuity(forareview,seeHarwood,

2001;Iverset al.,1998),adaptationtothedark (McMurdo and

Gaskell,1991), the binocularvisualﬁeld (Coleman etal., 2007;

Freemanetal.,2007),andcontrastsensitivity(Iversetal.,1998;

Lordetal.,1991).Visualacuitylosshasalsobeenshowntocause

problemsindiscriminatingvehiclesfromtherestoftheroad

envi-ronment(Oxleyetal.,1995),anddeclinesincontrastsensitivity

arethoughttohindertheperceptionofﬁxedormovingobjects

suchassidewalksoroncomingvehicles(Oxleyetal.,1995).The

declineofvisualmotionsensitivityin olderadults (e.g.,Sekuler

etal., 1980;Snowden and Kavanagh,2006)hasbeenproposed

todirectlyaccountfor theuseofdistance-basedheuristics and

theensuingincreaseinunsafecrossingdecisionswhenvehicles

movingatahighspeedareapproachingapedestriancrossingthe

streetonafull-scalesimulator(Dommesetal.,2013;Dommesand

Cavallo,2011;LobjoisandCavallo,2007):theslowangularvelocity

ofthevehiclesisdifﬁculttoperceiveandisevensometimesbelow

theperceptualthreshold,causingvehiclespeedinformationtobe

neglected.

Regardingpathologicalage-relatedchanges,theriskoffallingis

greaterinthepresenceofglaucoma(Haymesetal.,2007),

macu-lardegeneration(Szaboetal.,2008),andcataract(McCartyetal.,

2002). It is not completely clear yet whether cataract surgery

reducesthisincreasedriskoffalling(forareview,seeDesapriya

et al., 2010). Finally, glaucoma is associated with poorer

self-reportedmobility(Blacketal.,2011;Friedmanetal.,2007).

Visionisnottheonlysensorymodalitythatdeclinesinolder

people.Hearinglossalsoincreaseswithaging.Around30–75%of

adultsage75oroverpresentahearingloss,accordingtothe

deﬁ-nitioncurrentlyineffect(Salonenetal.,2011;Smithetal.,2008).

Althoughhearingimpairmentcouldhaveasigniﬁcantimpacton

pedestriansafety,investigationsarescarcecomparedtostudieson

vision.Hearingmayhelpinthespatiallocalizationofvehicles,so

olderpeoplewithhearingimpairmentsmayhavetroublelocating

approachingvehiclescomingfrombehindthemorturning(fora

review,seeDunbaretal.,2004).Inonestudyusingquestionnaires

(HollandandRabbitt,1992),olderadultswhofelttheirhearinghad

deterioratedoverthepastfewyearswereshowntoreport

avoid-ingwalkingalongstreetswithnosidewalks.Hearingimpairments,

moreover,havebeenproventobeclearlyassociatedwithalarger

riskoffalling(Grueetal.,2009;Lopez etal.,2011),poorer

self-reportedphysicalhealth(Lopezetal.,2011),andpoorergeneral

mobility(Viljanenetal.,2009).Adiminishedauditorycapacityis

alsolikelytohaveanegativeimpactonstreet-crossingsafety:the

absenceofauditoryinformation,asstudiedinasimulator

exper-iment,hasbeenshowntogiverisetomoreriskystreet-crossing

decisionsinbothyoungandoldpedestrians(Rodriguesetal.,2012).

In addition to the visual and auditory systems, the

pro-prioceptive and vestibular systems are involved in standing

uprightandmovingthrough space.Efﬁcient posturalregulation

requiresintegratinghighqualitysensoryinformationcomingfrom

somatosensory,visual,andvestibularafferences(Gauchardetal.,

2001).Theage-related decline of proprioceptive and vestibular

afferencesappearstoaccountfortheimpairedsenseofbalance

andtheincreasedriskoffallingfoundinolderpedestrians(seee.g.,

Gauchardetal.,2001;Pateletal.,2010).Forexample,olderadults

arehinderedmorethanyoungeradultsbyvibrationsofskeletal

musclesortendons(Pateletal.,2010)orbyvisualdistortionswhile

walking(Huitemaetal.,2005).Moregenerally,anincreaseinthe

taskdemandsimposedontheproprioceptiveandvestibular

sys-tems(i.e.,closed eyes,movement oftheexperimentalroom) is

associatedwithmorebodyswaysamongolderthanyoungadults

(Priolietal.,2006).

5.2. Impactofcognitivechanges

Oneofthemoststrikingage-relateddeclinesisinprocessing

speed,i.e., therateatwhichthebrain andnervoussystemcan

processsensory information (Salthouse, 1996).This decreasein

processingspeed hasbeenshowntobeassociated withaslow

walkingspeedand a higherrisk offalling(Holtzeretal.,2007;

OwsleyandMcGwin,2004;Rosanoetal.,2012;Welmerinketal.,

2010).Aslowerprocessingspeedmayalsopartlyexplainpoorer

navigationperformancewithaging(Kliegeletal.,2007;Salthouse

andSiedlecki,2007).Finally,becauseprocessingspeedisnecessary

formakingtimely,correctdecisions,itcouldalsoexplainthelonger

start-uptimesofolderpedestrians,aswellasthelinkobserved

betweenthesafenessof street-crossingdecisionsmade in

sim-ulatorexperimentsandscoresontheUFOV® _test_(Dommes_and

Cavallo,2011;Dommes etal.,2013,2015).TheUFOV® _test_is _a

computer-basedtestofrapidvisual-sceneperceptionthat

mea-surestheusefulﬁeldofview(i.e.,theareafromwhichonecan

extractvisualinformation atabriefglancewithoutheadoreye

movements)andthereforeinvolvesprocessingspeedand visual

attention(BallandOwsley,1993).

Anothermain cognitive changewithaging is the decline of

executivefunctions,i.e.,thecapacityforupdatingandmonitoring

informationin workingmemory,inhibitinginconsistentor

use-lessinformation,and shifting(Salthouseet al.,2003).Inhibition

declineshavebeenshowntobeassociatedwithagreater

num-beroffalls(Ansteyetal.,2009).Thisassociationcanbeexplained

bytheroleofinhibitionongaitcontrolandmultitask

coordina-tion(forareview,seeLiuetal.,2014).Moreincorrectdecisions

havealsobeenobservedonafull-scalestreet-crossingsimulator

withinhibitiondeclines(DommesandCavallo,2011).Likewise,the

age-relateddeclineoftheabilitytoswitchlinesofreasoningand

actionsinordertoperceive,process,andrespondtosituationsin

aﬂexibleway(i.e.,shiftingskills)havebeenshowntobea

signif-icantpredictorofstreet-crossingcollisions(Dommesetal.,2013):

inacomplex,two-waystreetenvironment,olderpedestrianswith

poorshiftingskillsseemtohavedifﬁcultyswitchingtheir

atten-tionbetweentrafﬁcapproachingfromtwodifferentdirections,and

selectingthemostrelevantinformationsources.

Theimpactofexecutivefunctionsonroadsafetyhasoftenbeen

investigated usingthe dual-taskparadigm,which requires

per-formingtwotasksatthesametime. Inreality,insteadofdoing

severaltaskssimultaneously,theindividualhastoquicklyshift

(6)

concomitantaccomplishmentofasecondarytask,suchasa

mem-orytaskorproducingspontaneousspeech,isgenerallyassociated

withslowerwalkingspeed(Lindenbergeretal.,2000;

Plummer-D’Amatoetal.,2011),narrowersafetymarginswhensteppingover

obstacleswhilewalking(Harleyetal.,2009),anincreasedriskof

falling(Faulkneretal.,2007;Lundin-Olssonetal.,1997),and

street-crossingimpairmentssuchasagreaterriskofbeinghitandlonger

crossingtimes(Nagamatsuetal.,2011;Neideretal.,2011).These

negativeconsequencesonmobilityandsafetyaregreaterinolder

thaninyoungadults,andsuggestthatwalkingisnolonger

auto-maticwithaging:itrequiresadditionalattentionalresources(e.g.,

Laessoeetal.,2008;SheridanandHausdorff,2007)andthe

involve-mentofexecutivefunctions(forreviews,seeAl-Yahyaetal.,2011;

BeurskensandBock,2012).Olderadultshavebeenshowntoplace

priorityonmotorcontrolduringdual-taskwalking,soastoavoid

fallingbutattheexpenseofwalkingspeed(Hollmanetal.,2007)or

talking(forareview,seeBeurskensandBock,2012;Sparrowetal.,

2002).Inthisline,thegreaterdeclinesofexecutivefunctionsin

mildcognitiveimpairmentandAlzheimer’sdisease(daCostaetal.,

2013)maybewhythesemedicalconditionsarestronglyassociated

withahigherriskoffalling(Delbaereetal.,2012;Sheridanand

Hausdorff,2007),ahigherriskofbeinginjuredduringstreet

cross-ing(Gorrieetal.,2008)andnavigationdifﬁcultiesinreal-lifeor

simulatorstudies(e.g.,Kliegeletal.,2007;SalthouseandSiedlecki,

2007;Tailladeetal.,2013).

Lastbutnotleast,memorydifﬁculties–oneofthemost

impor-tantcomplaintsofolderpeople–haveamajorimpactonspatial

navigation(forareview,Klencklenetal.,2012).InastudybyGras

etal.(2012),olderadultswereshowntobeslowerandlessaccurate

thanyoungeronesinrealroutelearning.Thispoorerperformance

wasinpartexplainedbyepisodic-memoryandworking-memory

declines.Thedeclineinvisuo-spatialworkingmemorywithaging

couldbelinkedtoareducedabilitytoinhibitirrelevant

informa-tionthatusesupsomeoftheworking-memoryresources1_needed

to learn complex new routes (Mammarella et al., 2009).

Difﬁ-cultylearningnewroutesanddisorientationaregreaterandmore

prevalentin patientssufferingfrom mild cognitiveimpairment

(Cushmanetal.,2008;Hortetal.,2007)orAlzheimer’sdisease(Liu

etal.,1991;Rainvilleetal.,2001;Zakzanisetal.,2009).

5.3. Impactofphysicalchanges

Mobilityandsafetyarealsochallengedbyage-relatedphysical

changesaffectingmuscles,bones,andjoints.Skeletalmusclemass

andstrengtharehighlyaffectedbythesechanges,withadecrease

duringagingwhiletheproportionofbodyfatincreases(Spirduso

etal.,2005;Fakhourietal.,2012;forareview,seeVisser,2011).

Thedeclineofmusclestrengthwithageisassociatedwithslower

walkingandstandingupfromasittingposition(Asheretal.,2012;

Spirdusoetal.,2005),andanincreaseintheriskoffalling(Landi

etal.,2012;Pijnappelsetal.,2008).Obesity,oftenconcurrentwith

thedeclineofskeletalmusclemass,isalsoassociatedwithahigher

riskofacquiringwalkingdisabilities(Stenholmetal.,2007)and

falling(Fjeldstadetal.,2008;HimesandReynolds,2012).

How-ever,fatlossbycaloricrestrictionduringagingmaylowermuscular

strengthandbonemassbycausingunder-nutrition(seethereview

byMillerandWolfe,2008).Consequently,anincreaseinphysical

activityshouldbepreferred,accompaniedbynutritional

supervi-sion(forareview,seeDarmon,2013).

The low bone mineral density associated with osteoporosis

increases with aging and represents an important fall-related

1_According_to_the_literature_review_by_Hasher _and_Zacks₍₁₉₈₈₎_, _inefﬁcient

inhibitorymechanismswillallowmoreirrelevantinformationtoenterworking memory,overloadingitsstoragecapacity.

riskoffracture,notably inolderwomen(Harris,2002;Lipsand

Van Schoor,2005).Anotherriskof osteoporosis isthat it

exac-erbatestheover-curvatureofthethoracicvertebrae,acondition

calledkyphosis(Arnoldet al.,2005).Kyphosisincreasesduring

aging,andexcessivekyphosisisassociatedwithpoorwalkingand

stair-climbingperformance,poorposturalcontrolduringobstacle

avoidance,andahigherriskoffalling(Arnoldetal.,2005;Katzman

etal.,2011;Sinakietal.,2005).Kyphosiscouldalsohaveanegative

effectonvisualexplorationoftheenvironmentduringstreet

cross-ingbecauseoftheassociatedimpairmentofcervicalmobility(Quek

etal.,2013).Similarly,osteoarthritis,acommoninﬂammatoryjoint

disorderinolderpeople,isassociatedwithdifﬁcultywalkingand

climbingstairs,aswellasahigherriskoffalling(Guccioneetal.,

1990;Hanlonetal.,2002;Hochbergetal.,1995).

5.4. Impactofself-perceptionandself-regulation

Anage-relatedawarenessofone’sreducedfunctionalabilities

andfrailtyinthestreetisanimportantelementofself-regulation

that may help older people adjust their behavior accordingly.

Morespeciﬁcally,peopleawareoftheirlimitationscanuse

self-regulationtodealwiththeenvironmentaldemands.Conversely,

individualswholackawarenessoftheirfailingabilitiesand

limi-tationsareshowntobemoreatriskofengaginginbehaviorsthat

compromisetheirsafety(MarottoliandRichardson,1998).

The self-perception of age-related walking-speed reductions

mayprompt self-regulatorybehaviors.It mayalsoexplainwhy

older pedestrians prefer to use signalized pedestrian crossings

morethandoyoungpedestrians(BernhoftandCarstensen,2008).

However, olderadults oftenunderestimate thetime theyneed

tocross the street: theiractualcrossing times aresigniﬁcantly

longerthanthecrossingtimestheyestimatebeforeoraftercrossing

(Naveteuretal.,2013;Zivotofskyetal.,2012).Thiskindof

under-estimationoccursespeciallyforyoungerolderadults(60–74years

old)whereasolderadults(75yearsoldormore)tendto

overesti-matetheircrossingtime(HollandandHill,2010).

Awarenessofone’sdecliningeyesightisalsousefulfor

develop-ingself-regulationbehaviors.Usingaquestionnaire,Hollandand

Rabbitt(1992)showedthatolderpedestrianswhofeltthattheir

eyesighthaddeterioratedover thepast10 yearsavoided

cross-ingthestreetatnight.Olderpedestrianswhoperceiveddifﬁculties

seeinginthedarkoratduskreportedavoidingcrossingthestreet

outside apedestriancrosswalkand walkingalonga streetwith

nosidewalk.Olderpedestrianswhoreporteddifﬁcultiesseeingin

brightlightorglaredeclaredavoidingcrossingthestreetunder

theseconditions,andﬁnally,olderpedestrianswhoreported

dif-ﬁcultyreadingroadsignstendedtosaytheyavoidedcrossingat

complexintersections,crossingoutsideapedestriancrosswalk,and

crossingwiththesunintheireyes.

Impairedposturalcontrolisalsoknowntoprovokeseveralkinds

ofself-regulation.Withaging,astheriskoffallinggrows,thefear

offallingincreasestoo(forareview,seeLegters,2002).Overall,

olderpeoplewithfearoffallingavoidsituationsknowntobe

difﬁ-culttohandleorwithahighriskoffalling(forareview,seeZijlstra

etal.,2007).Forexample,comparedtoolderpedestrianswhoare

lessafraidoffalling,oneswhoaremoreafraidhavebeenshown

tolookmoreatthepavementandtheirfootsteps,andtherefore

paylessattentiontocrossingintrafﬁc(Avinerietal.,2012).Older

pedestriansareespeciallylookingforsidewalksalongtheirroute

andsmoothsurfacesforwalking(BernhoftandCarstensen,2008).

Asaconsequence,andsomewhatcounterintuitively,older

pedes-triansoftenexpressconcernsaboutfallingorfeelingunstableon

tactilepavingclosetofootpathsorstairstoassistblindand

vision-impairedpedestrians(I’DGO,2010)andsomeofthempreferto

walkaroundit.Pavedstreetsandsidewalks,whicharefrequentin

(7)

andreluctance.Anothertopicof concernispavementsthat are

slipperyduetorain,dryleavesorsnow.Olderpedestrianshave

beenshowntobeworriedaboutice and/orsnowonsidewalks

(Wennbergetal.,2009)andwalkmoreslowlywhenitissnowing

(Knoblauchetal.,1996).

Itisnoteasytodeterminehowaccuratethesefearsand

self-perceptions are. Self-evaluation accuracy is important because

inaccurateself-perceptionsmayhavenegativeconsequenceson

themobilityandsafetyofolderpeople.AccordingtoTinettiand

Powell(1993),48%ofolderadultsage75yearsorolderwhohad

fallenwithinthepreviousyearreportedfearoffalling,but27%of

thosewhohadnotfallendidalso.Previousfallsthusseemtobe

linkedtoanincreaseinthefearoffalling,butnotstrictly.Some

studieshaveactuallysuggestedthatthegait-parameterchanges

observedwithagingarebetterexplainedbythefearoffallingor

agingstereotypesthanbyagingitself(seeChamberlinetal.,2005).

6. Recommendationsforimprovingsafetyandmobility

Thestudiesreviewedabovehaveshedlightonthemaincauses

ofolderadultpedestrian’s highrateofinvolvementinfatalities

and injuries. Someof thesefactors arelinked tothe roaduser

him/herself(i.e.,declinesinsensory,cognitive,andphysical

abil-ities, and incorrect estimation of one’s own capabilities). Risk

factorslinkedtotheroadenvironmentplayanimportantroletoo

(e.g.,complexityofroadinfrastructures,vehiclespeed).However,

despitethisaccumulatedknowledge,littleempiricalevidencehas

beenpublishedabouthowtohelpolderpedestriansmore

particu-larly.

6.1. Trainingprogramsforolderpedestrians

Oneofthemostdirect waysofenhancingolderpedestrians’

safetyistotrytomodifytheirbehaviorsandstrategiesthrough

training. However, systematic evaluations or even attempts to

examine training efﬁciency are still scarce and requirefurther

investigation.

Physicaldeclinesaretargetedbytraining programsaimedat

improvingbalance,ﬂexibility,velocity,and cardiovascular

func-tion. Such gains, with long-term effects, have been observed

aftertrainingviaheavyweightmuscleexercises,stretching,Tai-chi

movements,and/orwalkingprograms(Cristopoliskietal.,2009;

GattsandWoollacott,2006;Giné-Garrigaetal.,2010;forareview,

seeGranacheretal.,2008;Malatestaetal.,2010).Thereported

beneﬁtsofphysicaltrainingprogramsongaitandbalancecould

improvethesafetyandmobilityofolderpedestrians,particularly

bydecreasingboththeriskandthefearoffallingoutsideofthe

home,and maybebyincreasingwalkingspeed for crossingthe

street.In thepresent stateof ourknowledge,physical exercise

appearstobeoneofthemostefﬁcientapproachesforolder

pedes-trians.Recentpapershaveshowninparticularthatengagement

inphysicallysimulatedsportgamesenhancesthecognitiveand

physicalabilitiesdirectlyinvolvedinthedailylivingactivitiesof

olderadults(Maillotetal.,2012).Thebeneﬁcialeffectsofphysical

exerciseoncognitiveperformanceinolderadultshavebeenclearly

established(seee.g.themeta-analyticreviewsbyColcombeand

Kramer,2003,andAngeravenetal.,2008).Incontrast,supporting

evidenceoftheimpactofcognitivetrainingforolderpedestrians

isstill scarce, although sometraining programs targetingolder

drivershaveindicatedsomebeneﬁts(e.g.,Roenkeretal.,2003).

However,arecentstudyusingUFOV-trainingofolderpedestrians,

whilesigniﬁcantlyenhancingprocessingspeedandtheusefulﬁeld

ofview,didnotproducenotableimprovementsintheacceptance

ofsafegaps(CavalloandDommes,2014).

Unlike physical and cognitive training programs which are

aimedatimprovingtheabilities andskills ofolderpedestrians,

theobjectivesofeducationalandbehavioralprogramsistomake

pedestriansmoreawareoftheirpossiblelimitationsandofwhat

safebehaviorstheyshouldadopt.Regardingfallprevention,

edu-cationalprogramsaregenerallycombinedwithsomeotherkindof

training(e.g.physicaltraining),whichseemstoeffectivelyenhance

knowledgeoftheriskoffalling(Schepensetal.,2011).Untilnow,

anddespiteseverallocalandgovernmentalinitiatives(forareview,

seeDunbaretal.,2004),onlyonestudyhasfoundevidencethat

educationaltrainingcanimprovethesafetyofolderadults’

street-crossingdecisions(CavalloandDommes,2014).Notethatstudies

onolderdrivershaveshownthateducationalprogramsimprove

knowledge,buttheexistenceofsafetybeneﬁtshasnotbeenproven

(forareview,seeKorner-Bitenskyetal.,2009).Consequently,more

studiesthatevaluatetheeffectivenessofeducationalinterventions

arerequiredforolderpedestrians.

Anotherapproach is to combineeducational programs with

behavioraltrainingthatdirectlyaddressesbehaviorandknow-how

throughrepeatedpracticeinrealorsimulatedenvironments.In

recentyears,studiesaimedattrainingpeoplethroughtheuseof

simulatorsandvirtualrealityhaveemerged intheﬁeldofroad

safety.Thesetoolshavealreadyprovenpowerfulastrainingdevices

forpreventingchildpedestrianinjury(e.g.,McComasetal.,2002;

Thomsonetal.,2005)orforteachingbasicdrivingskillstoolder

adults(forareview,seeBootetal.,2014).Butforolder

pedestri-ans,behavioraltrainingstudiesusingvirtualrealityarestillrare.

Tworecent simulator studies combiningrepeated street

cross-ings,explicitfeedback,anddiscussionsobtainedpositive effects

onthesafety ofolder pedestrians’crossing decisions(Dommes

andCavallo,2012;Dommesetal.,2012).Ithasevenbeenshown

thatbehavioraltrainingonasimulatoralonecanmakeforsafer

gapacceptancelevelsduringstreet-crossing(CavalloandDommes,

2014).Inanotherrecenttrainingprogram,olderadultsweretaught

tojudgevehiclespeedmoreaccuratelyandwerefoundtoimprove

gap-acceptance accuracy in real-world conditions (Hunt et al.,

2011).However,thatexperimenthadnofollow-upphaseorcontrol

groupanddidnotincludeanactualcrossing.Futurelongitudinal

studiesshouldgobeyondthesemethodologicallimitationsinorder

todeterminewhetherthiskindofmethodcansuccessfullypromote

long-termimprovementsinolderadults’street-crossingbehaviors.

Thisbeingsaid,agingmaybeassociatedwithrigidstrategiesand

habitsthataredifﬁculttochange(Rosenbloometal.,2015),as

high-lightedbyastudythatfailedtoimproveon-roadhazarddetection

inolderpedestrians.

Finally,interventionsshouldalsobegearedtootherroadusers,

not just older adults. The safety of pedestrians requires safe

behaviorsfromallroad-usergroups.Morerespectfulbehaviors,

especiallytowardolderpeopleanddisabledindividuals,couldbe

increasedbymediacampaignsandlocalornationalgovernment

actions(BoyceandGeller,2000;VanHoutenetal.,1985).Not

stop-pingforpedestriansatcrosswalksshouldberegardedasaserious

offensepunishablebysevereﬁnes,justlikeotherroadviolations.

6.2. Ergonomicdesignofroadenvironmentsandcars

Thereareanumberofimprovementsinroadenvironmentsthat

coulddecreasetheriskoffallsandcollisions, andalsopromote

themobility ofolderpedestrians. Wide,ﬂat,non-slippery

side-walkswithoutobstaclesreducetheriskof falling(Bernhoftand

Carstensen,2008;Liu,2015).Leavesandsnowshouldberemoved

promptlyfromsidewalksandcrosswalks.Inaddition,the

inves-tigationofalternativedesignsforpedestrianrampsisrequiredto

preventthebottomoftherampsfrompoolingwithrainorice(Li

etal.,2013).Anotherimportantpointforurbandesignersistocheck

(8)

benches)aswellaspublicrestrooms(Carlsson,2004).The

pro-visionofshadyrestingplacesandwaterfountainsisparticularly

importantforhotsummerdays.

Regardingnavigation and thefear of gettinglost, signs

giv-ingdirectionsandotherindicationsshouldbeincludedbyurban

plannersanddesigners(Phillipsetal.,2013).Thesecouldinclude

signsshowingdistances,thepurposeofvariousplaces,and

impor-tantlandmarks.Navigationinnewplacesbypeoplewithcognitive

impairmentscouldbegreatlyimprovedbytheuseofhigh-quality

GPSsindicatingsigniﬁcantlandmarksandstep-by-steporientating

instructions.However,thesetechnologicaltoolsmustbecarefully

designedtoavoid asensoryand/orcognitiveoverloadforolder

users.Forexample,toomanycognitivelydemandingdeviceshave

beenshowntoincreasegaitirregularitiesinolderadults(seee.g.

Schellenbachetal.,2010).Consequently,GPSsneedtobeﬂexible

andspeciﬁcallydesignedforandtestedonolderadults,notonlyby

assessingtheirnavigationalbeneﬁtsbutalsobyexaminingtheir

possiblenegativeimpactonotherareasof theolderpedestrian

activitysuchasbalanceandcognitiveresources(Schellenbachetal.,

2010).

Safety and comfort during street crossing could also be

improvedbyprovidingasufﬁcientnumberofwell-designedand

well-placedcrosswalks(Koepselletal.,2002).Inthecaseof

cross-walkswithouttrafﬁcsignals,thepresenceofcar-freeislandsin

themiddleoftwo-waystreetsisrecommendedbecauseitallows

pedestrianstocrossintwostagesandtherebylightensthe

cogni-tiveload(Dommesetal.,2014;ITF,2012).Crosswalkswithtrafﬁc

signalsshouldbepreferred,however.Thepresenceofcountdown

displaysgivingthetimeleftforcrossingisaneffectivewayof

pro-vidingfeedbacktoolderpedestrians.Previousstudieshaveshown

thatcountdowndisplaysincreasethetrafﬁc-signalcomplianceof

olderpedestrians(Lipovacetal.,2013).Overall,thetimeallowedby

trafﬁclightsforpedestrianstocrossthestreethasbeenshowntobe

insufﬁcientformostolderpeople(Amosunetal.,2007;Asheretal.,

2012;HoxieandRubenstein,1994).Theneedtohurryisfrequentin

olderadultsandisassociatedwithanxiety,despitethepresenceof

trafﬁclights(Amosunetal.,2007;HoxieandRubenstein,1994)and

thismayprovokereluctancetocross.Trafﬁclightsshouldtherefore

bedesignedtoofferolderadultsenoughtimetocrosssafelyand

calmly.

Anotherefﬁcientactionistousesidewalksthatextendouttothe

edgeoftheparkinglane.Thisreducesthedistancetocrossand

con-sequentlythetimespentinthestreet(ITF,2012).Speed-reduction

measuresforcars,suchasspeed rampsorstreetnarrowing,are

alsopromisingwaystodecreasetheriskofcollision(Dommesand

Cavallo,2011)andthegravityofinjurieswhenapedestrianishit

(RosénandSander,2009).

Finally,improvingon-boardtechnologiesandthedesignofcars

(bumper, hood, windshield) are other means of improvingthe

safety of older pedestrians (Jermakian, 2011; for a review, see

Crandalletal.,2002).

7. Conclusion

Walkingisthecheapest,easiest,andmostsustainablewayto

getaround.Everytripbeginsandendsbywalking,whichisthe

commonlink in themultimodal travel chain.While walking is

themostcommontransportationmodeusedbyolderpeople,it

isalsoaparticularlyriskyactivityforthis population.Although

populationagingand urbanization,and in particularthe

devel-opmentof “global age-friendly cities” (WHO,2007), have been

identiﬁedastwoofthemostimportantchallengesofthepresent

century,researchandpublicpolicywithinthepastfewdecades

havefocusedonolderdrivers,therebyneglectingolder

pedestri-ansandtheirtravelrequirements.Moregenerally,thereisstillan

importantneedinourdevelopedsocietiestorecognizethe

signif-icanceofmobilityforolderpeople,andtobetterunderstandnot

onlythemobilitychangesthatoccurinlaterlife,butalsothe

abil-ityoftheelderlytostaymobilethroughnormalandpathological

aging.

Toanswertheagingchallenge,alongwithissueslinkedto

cli-matechange,pollution,andhealthingeneral,publicauthorities

shouldhelpolderpeople’stravelina“multimodal”,“sustainable”,

and“adapted”way,i.e.,byensuringthegreaterandsaferuseof

walkingandpublictransportation,andalsothecontrolleduseof

individualcars.

Infutureresearch,itwouldbeworthwhiletofurther

investi-gatetheimpactoffunctionaldeclines,andespeciallyolderpeople’s

awarenessoftheirdecliningabilitiesandtheirpositiveand

nega-tiveeffectsonsafetyandmobility.Thisknowledgewillpermitthe

implementationofefﬁcientandsuitableprogramsaimedatolder

pedestriansandroadenvironments.

A lot remains to beaccomplished in thearea of effectively

assessing theactions taken.Anincreasing number of localand

governmentalinitiativesarebeingimplementedtoaddressolder

pedestriansafety(e.g.,modiﬁcationofinfrastructuresand

equip-ment, educational training) but most of them have not been

evaluatedinasystematicway.AsmentionedbyHusband(2010)

inareviewregardingasimilarproblemforolderdrivers,thelack

ofevaluationmaybeduetotimeconstraintsorinsufﬁcient

knowl-edgeorresources.Thissituationhighlightstheneedtotightenthe

linkbetweenresearchersandlocalandgovernmentalauthorities

sothatinterventionswillbesystematicallyandobjectively

evalu-ated,usingavalidmethodology.Cooperationbetweenresearchand

transportation-relatedpublicpolicy-makersisanecessarypartof

improvingtheabilityofolderadultstoremainmobileandsafe,

whichisessentialtotheirwell-being,autonomy,andsocial

inte-gration.

Acknowledgements

TheworkwasfundedbyDGMove,throughtheSAMERUproject

(agreement number

MOVE/SUB/2010/D3/300-1/SI2.565668-SAMERU),aimedatinvestigatingthesafetyandmobilityofelderly

roadusers.TheauthorswouldliketothankVivianWaltzforthe

Englishediting.

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