Evaluation Methods for the Impacts of Shared Mobility: Classification and Critical Review

Abstract

In recent years, shared mobility services have had a growing presence in cities all over the world. Developing methodologies to measure and evaluate the impacts of shared mobility has therefore become of critical importance for city authorities. This paper conducts a thorough review of the different types of methods that can be used for this evaluation and suggests a classification of them. The pros and cons of each method are also discussed. The added value of the paper is twofold; first, we provide a systematic recording of the state of the art and the state of the practice regarding the evaluation of the impacts of shared mobility, from the perspective of city authorities, reflecting on their role, needs, and expectations. Second, by identifying the existing gaps in the literature, we highlight the specific needs for research and practice in this field that can help society figure out the role of urban shared mobility.

Full text

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Sustainability2020,12,10504;doi:10.3390/su122410504www.mdpi.com/journal/sustainability
Article
EvaluationMethodsfortheImpactsofShared
Mobility:ClassificationandCriticalReview
AnastasiaRoukouni*andGonçaloHomemdeAlmeidaCorreia
Transport&PlanningDepartment,FacultyofCivilEngineeringandGeosciences,
DelftUniversityofTechnology,Stevinweg1,2628CNDelft,TheNetherlands;g.correia@tudelft.nl
*Correspondence:a.roukouni@tudelft.nl;Tel.:+31‐613248875
Received:19November2020;Accepted:14December2020;Published:15December2020
Abstract:Inrecentyears,sharedmobilityserviceshavehadagrowingpresenceincitiesalloverthe
world.Developingmethodologiestomeasureandevaluatetheimpactsofsharedmobilityhas
thereforebecomeofcriticalimportanceforcityauthorities.Thispaperconductsathoroughreview
ofthedifferenttypesofmethodsthatcanbeusedforthisevaluationandsuggestsaclassificationof
them.Theprosandconsofeachmethodarealsodiscussed.Theaddedvalueofthepaperistwofold;
first,weprovideasystematicrecordingofthestateoftheartandthestateofthepracticeregarding
theevaluationoftheimpactsofsharedmobility,fromtheperspectiveofcityauthorities,reflecting
ontheirrole,needs,andexpectations.Second,byidentifyingtheexistinggapsintheliterature,we
highlightthespecificneedsforresearchandpracticeinthisfieldthatcanhelpsocietyfigureoutthe
roleofurbansharedmobility.
Keywords:sharedmobility;transportationimpacts;evaluationmethods;cities;cityauthorities
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1.Introduction
Inacontinuouslyurbanizedworld,thecomplexityofurbandwellers’needsisalsogrowing.
Citiesallovertheworldarefacingdifferentchallengesandneedtodevelopnewsolutionstofulfil
theircitizens’changingneeds,whilestrivingtowardsthegoalsofthe2030AgendaforSustainable
Development,andespecially“SustainableDevelopmentGoal11:tomakecitiesandhuman
settlementsinclusive,safe,resilientandsustainable”[1].Ontopofthat,currently,accordingtothe
UnitedNations,“duetoCOVID‐19,anunprecedentedhealth,economic,andsocialcrisisis
threateninglivesandlivelihoods,makingtheachievementoftheGoalsevenmorechallenging”[2].
Withmorethan90%ofCOVID‐19caseslocatedinurbanareas,citieshavebeenurgentlyforcedto
comeupwithnovelapproachesinordertosurvivethetempest[2].
Overthepastyears,sharedmobilityserviceshavehadagrowingpresenceincitiesalloverthe
world;thisphenomenonisbeingfacilitatedbytheincreasingadoptionofinformationand
communicationstechnology(ICT),whichistranslatedintothewideuseofsmartphones,social
media,anddigitalplatforms[3].Intheaftermathofthepandemic,therefore,itismoreimportant
thaneverforcitiestobeabletounderstandandassesstheimpactsofsharedmobility,asthiswill
helpthemplacesharedmobilityinthebiggerpictureofmakingaplantowardsanefficient,
sustainable,resilient,andpeople‐orientedurbantransportsystem.Inthiscontext,theresearch
presentedhereinaimsatprovidingacomprehensiveandstructuredcriticalreviewofthestateofthe
artandstateofthepracticeofevaluationmethodsthatcanbeusedbycitiestoassesstheimpactsof
sharedmobility.Wehavereviewedacademicliteratureaswellasso‐calledgreyliterature—reports,
whitepapers,newsarticles,blogs,andwebsites—duetothefactthatthereisnolargevolumeof
researchyetfocusingontheyoungestmembersofthesharedmobilityfamily,suchasdockless
systems,transportationnetworkcompanies(TNCs)ande‐scooters.Theobjectiveofthispaperis
hencetoprovideavaliddescriptionofthekeydimensionsofheterogeneitywithinresearchand

Sustainability2020,12,105042of22
practiceonthetopicoftheevaluationoftheimpactsofsharedmobilityandtoprovidethebasisfor
thefuturedevelopmentandapplicationofmethodstosupportcitiesintheirdecisions.
Asplaceswherepeople,ideas,andresourcesaregathered,citiesareattheforefrontofthe
transitiontowardsasustainablefuture.Theyalsooftenactasincubatorsforinnovationandtheyare
increasinglyembracingnoveltechnologies[4,5].Acrucialcomponentforthesuccessofthistransition
iscertainlytheurbantransportsystem.Environmentalpollution,trafficcongestion,parking
difficulties,longcommutingtimes,andlossofpublicspaceareonlyafewoftheurbanmobility‐
relatedchallenges[6,7].Urbanmobilityhasbeenexperiencinganeraoftransitionaswell,moving
towardsapersonalized,intelligentfuturethatisexpectedtobringtogetherthreemainmobility
trends—sharedmobility,electricmobility,andautonomousmobility[8,9].
Thegrowthofsharedmobilityispartoftheoverallboomingtrendoftheso‐calledsharing
economy,whichhasbeenflourishingsignificantlyinagrowingnumberofcitiesduringthelast
decade,andhasgatheredalotofattentionfromacademicsindifferentfields(e.g.,see[10–13]),
practitioners,aswellasthemedia.AccordingtotheFinancialTimes,weareenteringanerainwhich
consumerswillvalueaccessoverownershipandexperiencesoverassets[14].Theconceptofshared
mobilityreferstoprovidingaccesstoadestination,insteadofowningthevehiclethattakesyouto
thatdestination[15].
Itcantakeseveraldifferentforms,varyingfromsharingthetimeavailableforusingavehicleto
sharingaridewithothercommutersinthesamevehicle.Fromcarsharingandbikesharing,services
thatdatebackseveralyearsago,tothedisruptiveintroductioninthe2010softransportationnetwork
companies(TNCs)andmostrecentlytotheemergenceofsharedmicromobility,reflectedintheinflux
ofe‐scootersinnumerouscitiesaroundtheglobe,sharedmobilitypresentsaplethoraofoptionsfor
peopletotravelinurbanareas.Severalstudiesexistthatfocusontheimpactsofsharedmobility,
examiningthemunderthelensofallthreepillarsofsustainabledevelopment—environment,
economy,andsociety.Developingmetrics,models,andmethodologiestomeasureandevaluatethis
widerangeofimpactsisofmajorimportanceforcitiesbecauseitisessentialtounderstandthemto
beabletoguidepublicpolicydevelopment[16,17].
Cityauthoritieshavethusimportantdecisionstomake.Theyhavetodecidewhetherthe
introductionofasharedmobilityservicewillbebeneficialfortheircityand,incasesinwhichsome
potentialdrawbacksareexpected(orestimated),theymustfindifthepositiveimpactsthatare
foreseenarestrongenoughtooutweighthenegativeones[18].Asthespectrumofavailableshared
mobilityoptionscontinuestogrow,boostedbytheprivatesector’sinnovations,thepublicsector
shouldrespondwithpoliciesandguidelinesthataimatthemaximizationofbenefitsthatthesenew
sharedservicescanbringtothecityandthecitizens[19].
In2020,afterasharpdecreaseinridershipthathasbeenreportedbymostsharedmobility
serviceprovidersduringtheinitialperiodoflocallockdownsandsocial‐distancingmeasures
implementedduetoCOVID‐19,sharedmodesarenowbeingconsideredbymanycitiesasastrong
allyinsupportingurbanmobilityinthepost‐pandemicerathatliesahead.Moreandmorecities
worldwidearetryingtogiveadditionalspacetoactivemodesoftransport,inanattempttorelieve
pressureandavoidcrowdedsituationsinpublictransit,encouragingthiswayforpeopletowalkand
cyclemorewhilebeingabletomaintainaphysicaldistancefromoneanother.
Theremainderofthepaperisstructuredasfollows.Initially,anoverviewoftheexistingshared
mobilitymodesandservicesispresented,togetherwithsomeinsightsregardingtheirevolutionand
growthtrends.Theimpactsofsharedmobilityarethenintroducedandcategorizedintodifferent
groups.Thenextsectiondiscussestheroleofcityauthoritiesandthekeychallengestheyfacewhen
consideringtheintroductionofanewsharedmode/serviceintheirterritory.Thisisfollowedbya
presentationofthestateoftheartandthestateofthepracticeinmethodsthatarefoundinthe
literaturefortheevaluationoftheimpactsofsharedmobility,withacriticalview,discussingthe
strongpointsbutalsothedrawbacksand/ortheissueswhichrequirefurtherresearch.Thepaper
endswithgeneralconclusionsandperspectivesforfuturework.


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2.SharedMobility:Modes/ServicesandEvolution
Thereisalargevarietyofmodesandservicesfallingintothewidecategoryofsharedmobility.
Figure1presentsthesevenmaincategoriesofsharedmobilityaccordingtotheliterature—car
sharing,bikesharing,ridesharing,on‐demandrideservices,(shared)micromobility,alternative
transitservices,andcouriernetworkservices.

Figure1.Sharedmobilitymodesandservices(Basedon:[15,19]).P2P:peer‐to‐peer.
2.1.CarSharing
Carsharingprogramshavealonghistory,especiallyinEurope,wheretheyfirstappeared
aroundthe1950sinSwitzerland,withtheUnitedStates(U.S.)andAsiafollowingafewdecadeslater.
Nowadays,carsharingserviceshaveapproximately32millionusersandcanbefoundinalmost50
countriesaroundtheglobe(2018data)[20].Asharpincreasingtrendwasnoticedafter2012,
especiallyinAsianmarkets[20].Variouscarsharingmodelsexist,havingstartedfromthestation‐
basedround‐tripmodelandhavingevolvedintomanyalternativeschemes—one‐way,free‐floating,
andpersonalvehiclesharing(whichcanbefurtherdividedintopeer‐to‐peer(P2P),hybridP2P—
traditionalmodel,P2Pmarketplace,andfractionalownership)[19].
2.2.BikeSharing
BikesharingsystemsbeganinAmsterdam,theNetherlands,in1965,withaprogramknownas
“whitebikes”.Severalbicycles,paintedwhite,wereofferedtothepublictouseforfreebutthe
programstoppedshortlyafterwards,duetoproblemsrelatedtotheftandvandalism[21,22].From
theeraoftheso‐called“first‐generation”ofbikesharinguntilnow,ahugeevolutionhastakenplace
inthefield,reachingthepresent“fourth‐generation”ofbikesharing—highlyflexibledockless
systems,operatedusingICT,globalpositioningsystem(GPS)devices,andsmartphones,whichhave
revolutionizedbikesharingmarketsinrecentyears[21,22].Asof2018,morethan1600publicbike
sharingsystemsexistedallovertheworld,fromonly17in2005,withover18millionbicycles[19].In
additiontothedistinctionbetweendockedanddockless(free‐floating),bikesharingsystemscanalso
beofferedonaclosedcampus(e.g.,see[23]),aspersonalvehiclesharingsystems(P2P/marketplace),
orasbike‐leasesystems(e.g.,seetheDutchSwapfietssystem,[22]).
2.3.Ridesharing
Ridesharingenablespeoplewhoareheadingtothesamedestinationortodestinationslocated
closetooneanother,andwhosestartingpointsarealsoadjacent,tosharetheridethere[19].Although
onceagainnotamoderninvention,ithasmetwithgrowingpopularityduringthelastdecade,dueto
Shared
Mobility
Car sharing
Station-based Free-floating
(dockless)
Personal
Vehicle
Sharing (PVS)
Round-trip
One-way
P2P Car sharing
Hybrid P2P – Trad itional
Car sharing model
P2P Marketplace
Fractio nal Ownershi p
Bike sharin g
Station-based
Round-trip
One-way
Free-floating
(dockless)
Closed
Campus
Personal
Vehicle Shari ng
(PVS)
P2P Bike sharing
P2P Marketplace
Ridesharing
Carpooling
Vanpooling
On-dem and
ride services
Ridesourcing/
TNCs Ridesplitting E-hail
(Shared)
Micromobility
E-scooters E-bikes (E)-mopeds
Alternative
Transit
Services
Shuttles
Microtransit
Courier Network
Services (CNS)
P2P Delivery
Services
Paired on-demand
passenger ride and
courier services
Bike leasing

Sustainability2020,12,105044of22
theincreasinguseofonlineplatformsandaspartoftheoveralltrendofthesharingeconomy[24].In
theU.S.,carpoolingwasfirstintroducedasaregulationpolicytodecreasefuelconsumptionduring
WorldWarII.Itsusepeakedinthe1970s,withapproximately20%ofallcommutetripsbeing
performedbycarpool.Nowadays,carpoolingisaverypopularmodeoftransportforworkcommuters
intheU.S.,comingsecondonlytosingle‐occupancyvehicles[25].Vanpoolinguseslargervehicles,
typicallyforupto15people,andtheuserscansharethetripcostsandsometimesalsothedrivingtime
[15].
2.4.On‐DemandRideServices
On‐demandrideservicesusedigitalplatformsandapplicationstoconnectdriverswith
passengers.Thiscategorycanbefurtherdividedintoridesourcing,orasitismostoftencalled,
transportationnetworkcompanies(TNCs),ridesplitting,ande‐hailservices.Thedifferencewith
ridesharing(describedabove)isthatinthecaseofridesourcing,driversdonotjusthappentogothe
samedestinationasthepassengersanddecidetocombinetheride.Rather,theyheadtowhichever
locationsthepassengersdemand,asiftheyweretaxidrivers.Ridesourcinghasdisplayedafastand
massivegrowthduringthelastdecadeandthushasprovidedtriggersforintensedebatesoverits
impactsonfutureurbandevelopment[19,26,27]).Thee‐hailserviceswereintroducedbytaxi
operatorsasaresponsetoTNCs.Withe‐hail,apassengercancallataxithroughanapplicationvery
similartotheridesourcingones.Nevertheless,thepriceinthiscaseisfixedanddependsonthelocal
taxicharges;itisnotdemand‐driven,asinthecaseofTNCs[19].Ridesplittingcanbeconsidereda
combinationofridesourcingandcarpooling;itworkswithdifferentpassengerswhoseoriginand
destinationhappentobesimilarlocations,andthereforetheydecidetosharearidesourcingrideto
saveonthefee.Usuallythepassengersinthiscasehavetowalktoapick‐uppointsomemetersaway,
wheretheymeetthedriverandtheirfellowtravelers[27].
2.5.Micromobility
Micromobilityisatermthathasbeenincreasinglyusedsince2017,whenthefirstsharede‐
scootersappearedincities(inthispapertheterme‐scootersreferstostandinge‐scooters,whereas
othere‐scootersarereferredtoase‐mopeds).Micromobilityservicesareadvocatedmostlybythe
youngergenerations,whousedifferentoptionsinthewaytheytravel,comparedtotheirantecedents
[28],andwhoarenaturallymorephysicallyskilledintheuseofthesevehicles.Despiteitsexplosive
popularityincitiesallovertheworld,thereisnotyetaclearconsensusamongresearchersonwhat
exactlycomprisesmicromobility.Accordingtosomedefinitions,“sharedmicromobilityistheshared
useofabicycle,scooter,orotherlow‐speedmodes”(see[29]).Otherresearchersconsiderthatone
shouldnotincludebikesharinginthecategoryofmicromobility,asithasamuchlongerhistoryin
citiesallovertheworld,thereforeitshouldformaseparatecategoryofitsown.Thisistheapproach
wefollowinthisarticle,adoptingthefollowingdefinition—“Microvehiclereferstotheclassoftiny
vehiclessuchase‐bikesande‐scooters,excludingsolelyhuman‐poweredvehicleslikepedal‐only
bikes.Micromobilityreferstothetravelmodecategorythatusesmicrovehicles”[30].
In2018,45milliontripsweremadeusingsharede‐scootersande‐bikesintheU.S.,surpassing
bikesharingtrips(36.5million)forthefirsttime[31],whereasinEuropethenumberofcurrente‐
scooterusershasreached20million[28].FromMarch2020,micromobilityservicesworldwidehave
experiencedaconsiderabledropinridership,inlinewiththegeneraldeclineindemandthatthe
measurestakenbygovernmentstofighttheCOVID‐19pandemichadinitiallybroughttoallmodes
ofsharedmobility.Nevertheless,theyareexpectedtohaveakeyrole,togetherwithbikesharing,in
thepost‐pandemicmobilityera,asmoreandmorecitiesintroducenewbikecorridors,aswellas
discussingstrategiesandlegislationtosupportactivetransportandrelievepressurefrompublic
transitnetworks.


Sustainability2020,12,105045of22
2.6.AlternativeTransitServices
Alternativetransitservicescaneitherrefertomicrotransitorshuttleservices,whichoperate
simultaneouslyandoftencomplementarytopublictransportoptions,buttheycanhavesome
flexibilityintermsofitinerary(timeand/orroute).Theycanoperateonademand‐responsivebasis
and/oronmorefixed‐routeconnections[19].Alternativetransitservicescanalsoincludeinformal
sharedparatransitservicesthataremetinthedevelopingworldsuchasamaphelainSouthAfrica
[32],danfosinNigeria[33],trotrosinGhana[34],winsinThailand[35]orthepost‐Sovietminibuses,
knownasmarshrutkas,inGeorgia[36].
2.7.CourierNetworkServices
Asharedservicethathasseensignificantgrowthrecentlyiscouriernetworkservices(CNS).
CNSoperateonthesamebasisasTNCs,usingadigitalplatformthatconnectssupplyanddemand.
Inthiscase,insteadofpassengers,driverscanconnecttoconsignersandagreetodeliveroneormore
packagestotheconsignees.Thecourierscanusetheirpersonalvehicles(cars/motorcycles)orbicycles
toperformthetransfer,andsometimesCNSandTNCservicescanco‐existinthesameride.Aswe
haveseenwithcarsharingandbikesharing,P2Pserviceshavestartedtoevolveinthiscategoryas
well[19].Thepresentpaperfocusesonpassengertransport;therefore,wearenotgoingtoelaborate
furtherontheroleandimpactsofCNS,remainingawarethatanintriguingdimensionfor
forthcomingresearchwouldbetoexpandthepresentresearchstreamtosharedfreightandlogistics.
3.CategorizingtheImpactsofSharedMobility
Beforediscussingtheavailablemethodsandapproacheswithwhichtheimpactsofshared
mobilitycanbeevaluated,itisimportanttohaveacomprehensiveunderstandingofwhattheterm
“impacts”entailsinanurbancontext,asitcanrefertonumerousdifferentthings.
Anumberofstudieshavedealtwiththewaysbywhichsharedmobilitycanaffectacity,and
thevolumeofliteratureisbeingcontinuouslyenrichedwiththelaunchofnewsharedmodeslike
sharede‐bikesande‐scooters.Theimpactsofthemorerecentoneshavebeeninvestigated,as
expected,toamorelimiteddegreesofar,incomparisonwithmoreestablishedsharedmodesthat
havebeenoperatingfordecadesalready,suchascarsharing,ridesharing,andtraditionaldocked
bikesharing.Evenregardingthesamemodes/services,therearedifferencesinthenumberofexisting
studies,dependingonthetypeofbusinessmodel.Forinstance,station‐basedroundtripcarsharing
hasbeenstudiedforalongertimethanfree‐floatingcarsharing,whichisamorerecentvariation.
Thesameholdsforstation‐basedandfree‐floatingbikesharing,respectively.Theboostedpopularity
ofon‐demandrideserviceshasledtoseveralresearchersstartlookingattheirimpactondifferent
aspectsoftheurbanrealm.
Itshouldbekeptinmindthatalthoughthereismuchevidenceintheliteraturethatshared
mobilityhasthestrongpotentialtobringnumerousbenefitsandpositiveeffectstocities,itisalso
clearfromtheresearchperformedsofarthatsharedmobilityisnotandshouldnotbetreatedasa
panaceaorsomekindofsilverbullettoalltheurbanchallengesdiscussedinSection1ofthispaper.
Somestudieshavefoundthattheintroductionofasharedmobilitymode/servicehasresultedinfact
insomeundesirableconsequences,suchasadditionalvehiclekilometerstraveledandtrafficjams,
leadingtoariseinemissions,incitieswhereTNCsbegantheiroperations(e.g.,see[37–39]).In
addition,therehavebeencaseswheretheintroductionofanewsharedmobilitysystemhasbeen
provenunsuccessfulinanareaanditceasedoperationshortlyafteritsimplementation(e.g.,see[40]).
Therefore,potentialreboundeffectsshouldnotbeoverlooked.
Asthefocusofthispaperisnottoprovideadetailedreviewoftheliteratureregardingthe
impactsthemselves,butrathertoprovidethoroughinsightsonthewaysbywhichtheseimpactscan
beevaluated,inthefollowingparagraphswearegoingtosummarizethekeyareasofimpactby
placingtheminwhatweconsidertobethesixmaincategories,namely,environment,travel
behavior,builtenvironment,society,trafficconditions,andeconomy.Fromthesebroadcategories,
thehighestnumberofstudiesandreportsbelongstothecategoriesofenvironmentandtravel

Sustainability2020,12,105046of22
behavior.Themaincategoriesofimpactsandthekeyareasthatbelongtoeachofthemareillustrated
inFigure2.

Figure2.Maincategoriesandkeyareasofimpactsofsharedmobility.VKT/VMT:vehiclekilometers
traveled/vehiclemilestraveled.
3.1.ImpactontheEnvironment
Theimpactofsharedmobilityontheenvironmentisundoubtedlycrucial,asminimizingthe
environmentalimpactoftransportationingeneralhasacentralroleinensuringasustainablefuture
forcities.Investigatingthiscanbeviewedaspartoftheoverallresearchstreamthatcallsforthe
decarbonizationofcitiesandsearchesfornewwaysofachievingthisgoal.Somestudieshavelooked
intotheimpactofsharedmobilityonCO2/greenhousegas(GHG)emissions[41–43],energy
consumption[44,45],airquality[46],andnoisepollution[47,48].Althoughthemajorityofstudies
examinetheimpactontheenvironmentofmainlycarsharing,bikesharing,ridesharing,andmore
recentlyridesourcingschemesoracombinationofthose,theenvironmentalimpactofnovelshared
mobilityservices,suchase‐scooters[49,50]ande‐bikes[51],hasonlyrecentlystartedtobeaddressed.
3.2.ImpactonTravelBehaviorandtheBuiltEnvironment
Regardingtheimpactofsharedmobilityontravelbehavior,therearestudiesthatexaminehow
modechoiceisaffectedwhensharedmodesbecomeanavailableoptionandwhetheramodalshift
isobservedandtowardswhichmode(s)[22,52–54].Otherresearchhasinvestigatedtheroleofshared
mobilityinfirst‐ andlast‐mileconnectivitywiththeurbanpublictransportnetwork[55–58].The
impactonvehicleownership,whichcanbereflectedinthewillingnessofsharedmobilityusersto
skiporpostponeacarpurchaseortostopusing/sellacartheyalreadyownhasalsobeendocumented
byseveralresearchers,andsohastheimpactonthevehiclekilometerstraveled/vehiclemilestraveled
(VKT/VMT)[43,45,59–61].Otherresearchershavelookedintotheimpactsandpotentialsynergiesof
sharedmobilitywiththepromotionofactiveandmulti‐modaltransport[48,56,62–64].Asforthe
impactonthebuiltenvironment,threemainthemeshavebeenthetopicofresearchsofar—the
potentialimpactsonparkingsupply[65],landuse,andurbanaesthetics[66,67].
3.3.ImpactontheEconomy
Impacts of
Shared
Mobility
Environment
Travel behavior Built
environment
Society
Economy
Mode choice
Vehicle ownership
GHG Emissions
Air quality
Lifestyle
Environmental
awareness
VKT/VMT
Health
Traffic
conditions
Congestion
Car fleet size
Transportation
Equity
Number of
accidents
Parking supply
Energy
consumption
Individual and
household leve l
costs
Travel time
Employment
Multi-modality
Economic activity
near hubs
Active transport
Land use
Trip generation
First/last mile
connections
Urban
aesthe tics

Sustainability2020,12,105047of22
Theuseofsharedmobilitycanimpacttheeconomyinvariousways;itcanleadtocostsavings
onanindividualandhouseholdlevelbecausepassengerssharevehiclesandrides,anditcanalso
reducetheneedforvehicleownership,leadingtomoresavingsandthusallowingcitizenstohavea
largeramountofmoneyavailableforothergoodsandservices.Thisway,itcanalsohaveanimpact
ontheoveralleconomicactivityoftheareanearthesharedmobilityhubs.Furthermore,shared
mobility,andespeciallyTNCsandCNS,influencetheemploymentlevelsofanarea,withthe
recruitmentofdriversinanon‐demandbasis[44,66].
3.4.ImpactonTrafficConditionsandTransportationEquity
Theimpactofsharedmodesoftransportontrafficconditionscanbefurthersubdividedintothe
impactsoncongestion[42],tripgeneration[68],carfleetsize,traveltime[69],andtheimpacton
safety,whichisusuallyreflectedonthenumberofaccidents[48].Intermsofthesocietalimpactof
sharedmobility,animportantcomponentistheimpactontransportationequity[65].Somestudies
arealsostartingtolookattheeffectontransportationequityofthenewestmembersoftheshared
mobilityfamily—[26],docklessbikesharing[21]anddocklesssharede‐bikesande‐scooters[70].
Otherresearchershaveinvestigatedtheimpactthatsharedmobilitycanhaveonthehealthofcitizens
[44,70],ontheirlifestyle,aswellasonthecreationofenvironmentalawareness[71,72].
3.5.ImpactofShared(Autonomous)ElectricVehicles(S(A)EVs)
Asmentionedintheintroductionofthispaper,inadditiontosharedmobility,theothertwo
majortrendsthatareexpectedtohaveanincreasinglyessentialroleinurbanmobilityintheyearsto
come,especiallywhencombinedwithsharedmobility,areelectricandautonomousvehicles.There
isagrowingsegmentoftherecentliteraturethatfocusesontheimpactsofthisspecificcomponent
ofsharedmobility—sharedelectricvehicles(SEVs);sharedautonomousvehicles(SAVs);andthe
combinationofthetwo,sharedautonomouselectricvehicles(SAEVs).Thesevehiclescanbepartof
carsharing,ridesharing,on‐demandrideservices,and/oralternativetransitservicefleets.
TherearestudiesthatinvestigatetheimpactsofSAVs,SEVs,and/orSAEVsonallthecategories
discussedonthissection:theenvironment[73–77],travelbehavior[76,78–80],thebuiltenvironment
[77,81],society[82,83],trafficconditions[84–87],andtheeconomy[88].Foracomprehensivereview
ofexistingup‐to‐dateworkregardingtheimpactsofsharedautonomousvehicleservices,see
Narayananetal.[89].
4.TheRoleofCityAuthorities
Cityauthorities’initiativescanhelpinenhancingsharedmobility’suseandacceptanceamong
citizens[90].Cityauthoritiescansupportsharedmobility,forinstancebyprovidingdesignatedon‐
streetparkingspotsforcarsharingvehiclesandbyestablishingagreementswithcarsharingservice
providersregardingpublicoff‐streetparking.Moreover,whenofferingsupport,theauthorities
shouldalsomakedecisionsonadditionalissuessuchastheintegrationofsharedmobilitywiththe
existingurbantransportationsystem[91].
Researchonsharedmobilitycanassistlocalauthoritiesanddecision‐makersinobtainingamore
concreteideaoftheimpactsofsharedmodes,andintryingtoenhancethepositiveimpactsandlimit
thenegativeones.Differencesinservicemodels,localcircumstances,datacollection,anddata
analysismethodscanneverthelessleadtoinconsistencies,especiallywhenthedataavailabilityis
limited,andtheanalysisisperformedonanaggregatelevel[48].Therefore,accordingtoShaheen
andCohen[48],“itcanbechallengingtoprovideacomprehensiveandunbiasedpicture”.
BondorováandArcher[47]emphasizethatwhentheimpactassessmentsofsharedmobilityare
performedbysharedmobilityprovidersthemselvesorbycompaniesthathavebeenemployedby
themtodoso,theresultshavetobeinterpretedcarefullybecausetheyoftenlackindependenceand
theyalsomightnotprovidethoroughinformationabouttheirmethodologicalapproach.Someofthe
mostindependentandcomprehensiveevaluationsthathavetakenplacesofarhavecitiesintheU.S.

Sustainability2020,12,105048of22
astheirfocus,andthereforetheirfindingsarenotnecessarilyrepresentativeofthesituationin
Europeancities[47].
Oneoftheveryfewattemptssofar—tothebestofourknowledge—forthedevelopmentofa
tooltocontributetothebetterunderstandingofsharedmobilityservicesandtheirimpactandto
supportcityauthoritiesindefiningsuitablepoliciestomaximizethebenefitsinvolvedwas
undertakenbytheShared‐UseMobilityCenterintheU.S.Thisorganizationhaspublishedthebeta
versionofanonlinetoolcalledtheSharedMobilityBenefitsCalculator.TheSharedMobilityBenefits
Calculatorwaslaunchedasatooltoestimatetheemissionsbenefitsfromdeployingvariousmodes
ofsharedmobilityanditsdevelopersclaimthatitcanbeusedtosetandmonitorgoalstowards
reducingcongestion,householdtransportationcosts,andcarbonemissionsfrompersonalvehicles.
ThetoolisbasedonlyonU.S.cities,anditincludescitieswithmorethan100,000residents[92].
Itappearsthatlocalauthoritiesinmanycitiesarenotwellpreparedtomanageandregulate
suchdisruptiveservices[93].Theextremelyfastadoptionratesofsharede‐scootersinurbancontexts
aroundtheworldhashighlightedthelackofregulatoryframeworksforemergingmobilitymodes.
Theresponseofcitiestothetrendofsharedmicromobilityvariesalot,fromcompleteprohibitionin
somecasestototalopennessinothers,withmanyin‐betweensolutionsaswell[28].
Citiesallovertheworldarefacingdilemmasrelatedtohowbesttodealwithsharedmobility,
andhowitcanbepartoftheirstrategiesfortacklingthechanging,complexurbanchallengesrelated
tomobilityandlanduse.Thisiscurrentlymoreurgentthanever,forreasonsrelatedtothe
achievementoftheUNSustainableDevelopmentGoalsandtheaftermathoftheCOVID‐19
pandemic,asdiscussedinSection1.Thereisthusanundeniablyincreasedinterestinimplementing
sharedmodesincities,initiatedbynewcompaniesappearingonthemarkettooffersuchmobility
services,butoftenalsobythewishesofthetravelersthemselveswhoexperiencesimilarservices
elsewhere.Citieshavetomakesurethattheintroductionofnewsharedmodeswillindeedfitthe
needsofthecityandcitizens,andnottheotherwayaround.
Manycitiesarethusfacingchallengesinunderstandingwhethersharedmobilitywouldbeable
toeffectivelybringanysubstantialbenefittotheirterritories,andhowtheexistingurbantransport
systemwouldreactwhendemandforthenewmode(s)startstogrow.Thedifficultyinforecasting
andevaluatingtheimpactsofsharedmobilitycancreatestressforthedecision‐makersandcanlead
totheintroductionofblurredpoliciestoavoid“stayingbehind”.Therefore,thereisaclearneedto
providetherightmethodsandtoolstosupportthemintheirdecisions.
5.DiscussionoftheAvailableMethodsfortheEvaluationofSharedMobilitybyCity
Authorities
Ageneralobservationthatcanbederivedfromourliteraturereviewisthatthereisalarge,
heterogeneouspoolofdifferentapproachesthatresearchershaveusedtotrytoevaluatetheimpactsof
sharedmobility,butaconsiderablepercentageoftheexistingstudiesarecase‐specificandexploratory,
andtheyshouldthereforebecarefullyinterpretedwhentryingtoscaleuportransfertheirresults.
Moreover,thescopeofthisworkistolookattheevaluationprocessfromacityperspective,inthe
directionofassistingthedecision‐makersinthechallengingprocessofdecidingonthemostsuitable
methodorcombinationofmethodstoapplytoassesstheimpactsofsharedmobility.
Inthatsense,wearenotinterestedinofferingaclassificationofallthevariationsofthemethods
thathaveeverbeenusedbyacademics,researchersandpractitionerstoevaluatesharedmobility’s
perksandpitfalls.Weclassifythemaincategoriesofoptionsthatcanbeusedtoevaluatetheimpact
ofsharedmobilityinaclearformatthatismeaningfulnotonlytoacademicsandresearchersbutalso
tocityauthoritiesanddecision‐makers—thepeoplewhooftenfacethedifficultdecisionsregarding
theimplementationofsharedmobilityprograms.
Wedividedtheevaluationmethodswhich,accordingtoourviews,arethemostrelevantonesthat
canbeofinteresttocitiesintoseveralmaincategories,andthenseparatedthesecategoriesintotwo
groups,basedonthetimeframeinwhichtheycanbeemployed—thosethatcanbeusedbeforethe
introductionofanewsharedmobilitymode/servicetoacity(ex‐anteevaluation)andthosethatcanbe
usedafterthenewmode/servicehasbeenimplemented(ex‐postevaluation).Thatbeingsaid,several

Sustainability2020,12,105049of22
citieschoosetorunpilots,whichentailshort,try‐outperiodsfortheimplementationofasharedmode,
towitnesswhetherthenewserviceprovidedwillhaveapositiveimpactonthecity,inarelativelymore
“safe”environment,withlowerrisksinvolvedduetothetemporarynatureofthepilot.
Figure3illustratesthemaincategoriesofevaluationmethods,classifiedbasedonthetimeframe
inwhichtheycanbeused,inlinewiththedistinctiondescribedabove.ItcanbenoticedinFigure3
thatsomeofthecategoriesappearinbothtimeframes,astheycanbeemployedeitherfortheex‐ante
ortheex‐postevaluationoftheimpactsofsharedmobility.Adiscussionofeachoneofthecategories
mentionedinthediagramfollowsbelow.

Figure3.Classificationofthemainmethodsavailablefortheevaluationoftheimpactsofshared
mobility.
5.1.Ex‐AnteEvaluation
5.1.1.StatedPreference/StatedChoiceSurveys
Statedpreference(SP)orstatedchoice(SC)surveyshavebeenwidelyemployedfordecadesin
transportandotherfieldstoidentifybehavioralresponsestosituationsofchoicewhichhavenotyet
beenrevealedinthemarket[94].Theyhelptoidentifyindividualpreferenceswithoutrequiring
excessivecognitiveeffortbytherespondents.ThishasmadeSPsurveysoneofthemosteffectiveand
widespreadwaystostudybehavioraldecisions[95].SPsurveyscanbevaluableincollecting
informationaboutnewpolicies,forinstance,theintroductionofanewtransportmodeoraroad
pricingscheme[96].Thistypeofsurveyusuallyincludesquestionsrelatedtosocio‐demographic
characteristicsoftherespondents,followedbyquestionsaimingatselectinginformationaboutthe
travelpatternsandpossiblyfrequentlyrepeatedorigin‐destination(OD)pairs.Then,theyrequest
responsestoquestionscorrespondingtohypotheticalsituationswhichinvolveatransportoption,
notyetavailablewhenthesurveyisconducted,with“whatwouldyoudoif…?/whatwouldbeyour
choice?”typeofquestions.
Before the introduction (ex-ante)
Pilot
Implementation (ex-post)
Benchmarking
Stated preference/
Stated choice surveys
(shared mode specific)
Transport modeling
Analysis of da ta from mobilit y servic e
providers (standardized or/and not
standardized)
Revealed preference surveys
(shared mode specific)
How can cities evaluate the impacts of shared mobility?
Implementation of new
shared mobility
service(s)
Analysis of oth er data (e.g. number of accidents,
complaints, activity data, feedback from focus
groups/stakeholder and cit izen en gagement etc.)
Transport modeling/
Data analysis
Household Travel surveys/
Mobility surveys
Available methods
Household Travel surveys/
Mobility surveys

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AftertheinformationiscollecteduponcompletionoftheSPsurvey,somefirstconclusions
regardingtheexpectedattitudesoftheparticipantstowardsthenewtransportoptioninquestioncan
bedrawnbyperformingasimpledescriptivestatisticalanalysistocomeupwiththepercentagesof
peoplethatarelikelytoembrace/rejectthenewservice.Thedatagatheredcanthenbeusedby
researchersasaninputtodifferenttypesofmoresophisticatedmodelingtechniques—whichusually
belongtothefamilyofdiscretechoicemodeling—torevealmorecomplex,hiddeninteractionsamong
theexaminedvariables.ExamplesofsuchmodelsthathavealreadybeenusedtoanalyzeSPsurvey
datainthefieldofsharedmobilityaremixedlogitmodels[97],mixednestedlogitmodels[53],and
orderedprobitmodels[78,98].
SPsurveyscanbeusedtoexaminetheimpactthatsharedmodes/servicesareexpectedtohave
onthetravelbehaviorofcitizens.Morespecifically,thewillingness‐to‐usesharedmodescanbe
estimated(e.g.,see[80])aswellasthemodalshiftpatternsbetweensharedmodesandprivatecars,
publictransport,and/orcycling(e.g.,see[97]).Inaddition,SPsurveydatacanbeusedtoexamine
whichcharacteristicsofasharedmodeareconsideredvaluableforpotentialusersandwould
thereforebevitalforitsadoption(suchasconvenientaccesstothesharedvehicles,parking
availability,etc.)(e.g.,see[53,97]).Theimpactoncarownership[98]andtheadoptionratesofshared
vehiclescanalsobeestimatedusingtheSPdataunderdifferentpricingscenarios[78].
OneoftheimportantstrengthsofSPsurveysisthefactthattheoptionsofmodesorservicesare
notlimitedtotheavailableonesatthetimethatthesurveyisconducted,butthedesignersofthe
surveyhavethefreedomtobecreativeandinvestigatemanydifferentpotentialscenariosifthey
wish.Becauseofthis,itispossibletogatheralargervolumeofinformation,comparedtosurveys
thatfocusonlyonexistingoptions[99](asinthecaseofrevealedpreferencesurveys[99],whichwe
describeinSection5.2.1).
However,asallsurvey‐basedstudiesexploringthesphereofhumanbehavior,theSPapproach
issubjecttocertainlimitations,mostlyconcerningself‐reportedandself‐selectionbias,whichshould
beconsideredwheninterpretingtheirresultstoavoidvalidityissues.Self‐selectionbiascanoccurin
caseswhenmanyofthepeoplewhoagreetoparticipateinasurveyaboutaparticularmode,bike‐
sharingforinstance,couldbecyclistenthusiasts,whichcouldleadtoabiasedoutcomeinfavorof
bikesharing,whichmaynotnecessarilyreflecttheperceptionsofthemajorityofthecommunitythat
thesurveysampleissupposedtorepresent[70].Self‐reportedbiascanarisebecausepeople
sometimesdonotprovidefullyaccurateinformationregardingtheirtravelbehavior;e.g.,intermsof
theextentorfrequencyoftravel,theexacttimesanddaysthatacommutetookplace,etc.[48].InSP
surveysthereisalsothepossibilityoftheexistenceofhypotheticalbias.Thisbiasreferstothe
tendencyofrespondentstoreportawillingness‐to‐paythatexceedswhattheyactuallypayusing
theirownmoneyinreal‐lifeexperiments[100].Cautiousdesignandimplementationofthesurvey
contributestoreducingtheriskofoccurrenceofsomeoftheaforementionedbiases,butsomeothers
areintrinsicandthusmoredifficulttoeliminate[99].Forthesereasons,theuseofsuchaninstrument
hastobecarefullyconsidered,makingsurethatitispossibletocontrolforthesourcesoferrorand
preferablycombiningitwithrevealedpreference(RP)dataifavailable(seeSection5.2.1).
5.1.2.Benchmarking
ComparedtoSPsurveys,whichhavebeenaroundfordecadesalready,theconceptof
benchmarkingismorerecent.Camp[101]definedbenchmarkingas‘‘thesearchforindustrybest
practicesthatleadtosuperiorperformance”.Inthecontextofcityplanning,benchmarkingis“a
systematicandcontinuousmethodthatconsistsofidentifying,learningandimplementingthemost
effectivepracticesandcapacitiesfromothercitiesinorderforone’sowncitytoimproveitsactions”
[102,103].Focusingonurbantransport,benchmarkinghasproventobeabletoenhanceandimprove
performancethroughlearningfromothercitieswithsuperiorperformance[104].
Inthecontextofsharedmobility,benchmarkingstudiescanbeconductedtohelpavoid
duplicativeresearch,toreduceoverallcosts,aswellastoaccelerateimprovementstotheurban
transportationsystem.Theapproachusuallycomprisesthreesteps—aliteraturereview,interviews
andmeetingswithexpertsinselectedcities,andsynthesisoftheinformation.Typically,thecitiesare

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selectedbasedonfactorssuchasthesizeandscaleoftheirsharedmobilitysystemsandtheexistence
ofpoliciesrelevanttothecitythatisinterestedinimplementingthesharedmobilityprograms[105].
Benchmarkingappearstostillhaveroomtodeployitsfullpotentialinexploringtheprosand
consofsharedmobility,asnotmanyexamplesofapplicationsofcomprehensivebenchmarking
studiesfocusingonsharedmobilityhavebeenfoundintheliterature.Inpractice,acommon
phenomenoninEuropeancitiesthatareinvolvedindifferentEU‐fundedprojectsinthewiderarea
ofsustainablemobilityisthecreationofnetworkstoexchangeexperiencesandlessonslearnedand
trytoimprovetheirurbanmobilitysystemsbystudyingthesuccesses(andfailures)oftheir
counterparts.Thiscanbeseenasakindofbenchmarking,withoutnecessarilybeingclassified
officiallyassuch.
SomeexamplesoftheaforementionednetworksinEuropeincludethePOLISnetwork,the
CIVITASForumNetwork,andthenetworksoftheURBACTprogram.ThePOLISnetworkconnects
localandregionalauthoritiesacrossEurope,whichcanthenworktogethertopromotesustainable
mobilitythroughthedevelopmentofinnovativetechnologiesandpolicies[106].TheCIVITASForum
Network“isaplatformfortheexchangeofknowledge,ideasandbestpracticeamongEuropeancities
regardingsustainableurbantransportpolicies”[107].TheURBACTprogramisaEuropean
TerritorialCooperationprogramwiththeobjectiveof“enablingcitiestoworktogetheranddevelop
integratedsolutionstocommonurbanchallenges,bynetworking,learningfromoneanother’s
experiences,drawinglessonsandidentifyinggoodpracticestoimproveurbanpolicies.”Withinthe
URBACTtherearenetworksfocusingondifferenttypesofurbanchallenges,suchasurbanmobility
(thecurrentnetworksfocusingonurbanmobilityareRiConnect,Space4People,andThrivingStreets)
[108].
However,beforeapplyingbenchmarkingorbeingengagedinanykindofprocessthatinvolves
comparingtheperformanceoftheirurbanmobilitysystemwiththatofothers,citiesshouldalsobe
awareofsomelimitations,firstandforemosttheoneresultingfromthenatureofthemethoditself—
studyingtheimpactoftransportservicesondifferentgeographicalcontextscaninvolvecrucial
differencesinissues,rangingfromexistingregulations,legislation,andpoliciestosocio‐
demographicindicators,densityofneighborhoods,livingconditions,citizens’behavior,traditions,
andculture,tonamejustafew.
5.2.Ex‐PostEvaluation
5.2.1.RevealedPreferenceSurveys
Revealedpreference(RP)surveysinvestigatechoicesthathavealreadybeenmadeby
individualspriortothetimethatthesurveyisbeingconducted.Inthefieldoftransportation,the
revealedinformationcanincludeorigin,destination,transportmode,trippurpose,etc.Incontrast
withthestatedpreferencesurveysdescribedpreviously,theexaminedscenariosinthiscaseare
existingandnothypothetical[109].RPsurveyscanbeaddressedtousersornon‐usersofashared
mobilityservice.Theobjectiveistoobtainabetterunderstandingoftravelbehaviorandthe
motivationalfactorsinfluencingit.AswithSPsurveys,differenttypesofchoicemodelscanbe
appliedtothecollecteddata,whichcanleadtoin‐depthconclusions,e.g.,binomiallogitmodels[42],
multinomiallogitmodels[55],andmixednestedlogitmodels[53].
InthecaseofSPsurveys,theselectionofquestions,asmentionedearlier,canbedonewith
higherflexibilityasthequestionsrefertohypotheticalsituations,whereasinRPsurveysthereisless
controloverthat,astheavailablemodes/servicesisthemajordecisivefactorthatdefinesthetypeof
informationthatcanbecollected[99].Inthecontextofsharedmobility,RPsurveyscanbeusedto
examinechangesinmobilitypatterns,modalshiftdynamics,aswellastheinfluentialfactors
concerningdifferentsharedmodes/services(e.g.,see[22,91,110]).Furthermore,theimpactonpublic
transportridershipandkilometerstraveledcanbeestimatedthroughtheuseofRPdata(e.g.,see
[27]),aswellastheimpactoncarownership(e.g.,see[42]).Theresultingeffectsofsharedmobility
onVKT(e.g.,see[59,61])andonCO2emissions(e.g.,see[43])canalsobeexaminedusinganRP
survey,ascantheimpactonfirst‐/last‐miletrips(e.g.,see[55]).

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Itshouldbetakenintoaccountthat,fallingintothecategoryofself‐reportedstudies,RPsurveys
arealsosubjecttosimilarbiasesandlimitationsastheonesalreadydiscussedforSPsurveys.
Moreover,whenRPsurveysareaddressedtousersofasharedmode,thereisalsotheriskthatthe
youngergenerationsaswellasthosewithahigherincomeareoverrepresentedinthesurvey,asthe
averageuserofsharedmobilitytendstohavetheseattributes,andthusthesurveyresultscanfailto
includevitalinputfromlargepartsofthepopulationwhodonothavetheaforementioned
characteristics[70].Notwithstandingtheselimitations,fortheforeseeablefuture,surveysare
anticipatedtomaintaintheiressentialroleinassessingthecausalfactorsrelatedtotravelbehavior
changesthatresultfromsharedmobility[48].
Thecombineduseofasurveybeforetheintroductionofanewtransportmodeandasurvey
aftertheintroductionisoftencalleda“before‐and‐after”survey.Thistermcanrefereithertoastated
preferenceandarevealedpreferencesurvey(e.g.,see[53]),ortotwohousehold/mobilitytravel
surveysconductedattwodifferentperiodsintime(e.g.,see[70]).
5.2.2.AnalysisofDatafromSharedMobilityServiceProviders
Inadditiontoself‐reporteddatacollectedbythesurvey‐basedmethodsdiscussedabove,high‐
qualitydatamadeavailablebymobilityserviceproviderscanbeanalyzedandinterpretedbycity
authorities.Thishasgreatpotentialintheevaluationprocessoftheimpactsofsharedmobility,asit
cancontributetotheeliminationofsomeofthelimitationsofsurvey‐basedmethods.Thereare
ongoingdiscussionsincitiesworldwideaboutwhethersharedmobilityserviceprovidersshouldbe
requiredtoprovidecityauthoritieswithmobilitydataandinwhichformat(standardizedornot)
thesedatashouldbepresented.
Regardingstandardizeddata,therearetwokeydataspecificationsthatmanycitiescurrently
requiretobeemployedbymobilityserviceprovidersoperatingintheirterritory:theGeneral
BikeshareFeedSpecification(GBFS)introducedin2015bytheNorthAmericanBikeshare
Association,andthemorerecentMobilityDataSpecification(MDS)createdbytheLosAngeles
DepartmentofTransportationin2018.Theyarebothbasedontheuseofapplicationprogramming
interfaces(APIs)[111].Morethan80citiesandpublicagenciesaroundtheworldarecurrentlyusing
theMDS,mostlycitiesintheU.S.,andveryrecentlysomecitiesinEuropeincludingZurich,Helsinki,
andLisbon[112].
Dataspecificationsaimtoprovideastandardizedwayformunicipalities/regulatoryagenciesto
receive,compare,andanalyzedatafrommobilityserviceproviders.However,whenitcomesto
usingamobilitydataspecification,therearesomechallengesinvolved.TheintroductionoftheMDS
hasfueledanongoingdebateabouttheprivacyofusers.Agrowingbodyofresearchdemonstrates
thatanonymousmobilitydatacanpotentiallystillbeusedtore‐identifyspecificindividualsand
activities[113,114]andtherefore,forcitiesinEuropeforinstance,compliancewiththeGeneralData
ProtectionRegulation(GDPR)shouldbethoroughlyconsideredbeforeproceedinginimplementing
adataspecification.
Anotherquestionthatarisesiswhethercityauthoritieshavetheabilityandknowledgetostoreand
analyzethedata(computer,personnel,etc.),oncetheyreceivethem,orwhethertheyneedtohire
“intermediarybodies”todealwiththeanalysisontheirbehalfandpresentthemdirectlywiththeresults.
Somestart‐up/mobilitydatacompanieshavealreadyexpressedinterestinactingasthe“middle‐man”in
suchcases.Otherreasonsfornotsupportingdata‐sharingcanincluderealandperceivedcompetition,
privacyandethics,theregulatoryenvironment,cybersecurity,interoperability,andliability[115].
Ifobtained,datafromsharedmobilityserviceproviderscanbeusedinvariousways.For
example,bycombiningpick‐upanddrop‐offdatafromride‐hailingproviderswithinformationon
trafficflow,pedestriansflow,andparking,citieswouldbeabletodynamicallymanageandregulate
theuseofstreetcurbsandpavementstolimitdwelltimesandalleviatecongestion[115].Inaddition,
bybeingabletoanalyzedatafrombikesharingprovidersandsharedmicromobilityproviders,city
authoritiescanbecomeawareofwhichpublictransportstationsattractmoreusersofsharedbikes
andsharedmicrovehicles,andthiswouldallowthemtoidentifypotentialpromisinglocationsfor

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multimodalmobilityhubsandwouldalsomagnifythepotentialofmobility‐as‐a‐service(MaaS)
applications[116].
Anotherwaythatdatafrombikesharingandsharedmicromobilityserviceproviderscanbe
usedistorevealareaswithinthecitythathaveincreasedsafetyrisks,duetotheco‐existenceofa
high‐frequencybuscorridorandmanye‐scootertrips,forinstance.Developingnewinfrastructure
solutionsintheseareastoensurethesafetyandcomfortofriderscanthenbeconsideredbythecity
authorities[116].Thecityauthorities,byhavingaccesstothedata,wouldalsobeabletoseewhether
sharedvehiclesarebeingdeployedequitablyacrossneighborhoods.Iftheyarenot,thedecision‐
makerscanthenplannewpoliciesincollaborationwiththesharedmobilityserviceproviders,to
promotetransportationequityinthecitybyincreasingtheavailabilityofsharedvehiclesinareas
whereunderprivilegedcommunitiesreside.Inthecaseoffree‐floatingsystems,inparticular,data
fromsharedmobilityproviderscanhelpcityauthoritiesmonitorthesafetyandcomfortofvulnerable
streetusers,bycheckingifdocklessbikesande‐scootersareparkedinsafeandsuitableparkingareas
andnotblockingsidewalksorbikepaths,forexample[112].
5.2.3.AnalysisofotherDataSources
Therearealsosomecasesinwhichothertypesofdata(i.e.,notcomingfrommobilityservice
providers)canbeanalyzed,withmethodsthatdonotbelongtoanyofthemaincategoriesofthis
classification,thatneverthelessprovideinterestinginsightsontheimpactsofsharedmobilityand
thatcanbeusedbycitiesintheirassessmentstrategies.Someexamplesofanalysesof“otherdata”
arepresentedbelow.
Abefore‐and‐afteranalysiswasconductedbyAmatunietal.[41]toexploretheimpactofcar
sharingonGHGemissions,inwhichtheycomparedtheoverallemissionscausedbymobilityofthe
samegroupofpeoplebeforeandaftertheystartedusingcarsharing.Theydidnotbasetheir
calculationsonself‐reporteddata;instead,theyusedthelife‐cycleemissionfactorsforalltransport
modesandthenumberofkilometerstraveledbytheparticipantswitheachofthemforawholeyear.
Gössling[117]usedcontentanalysisofnewsitemswhichheaccessedonline,includingmaterial
publishedinnewspapers,TV,andradiowebsites,toexaminewhathappenedafterane‐scooter
sharedservicestartedoperatingintenlargecitiesacrosstheworld.Localmediareportsbeforeand
afterthee‐scooterskicked‐offinthesecitieswereanalyzedandinterpretedqualitativelytosee
whethernewpoliciesfore‐scooterswererequired.Othertypesofqualitativemethods(semi‐
structuredinterviewsandfocusgroups)wereusedbyJainetal.[71]tounderstandpotentialchanges
inthewaypeoplechoosetoliveandtravelwhencarsharingbecomesanoption.Asimilarapproach
comprisinginterviewswithpolicymakers,experts,researchers,andoperatorsandfocusgroupswith
driverswasappliedbyMohamedetal.[93],focusingonaridesplittingserviceinLondon.
5.3.BothEx‐AnteandEx‐PostEvaluation
5.3.1.HouseholdTravelSurveys/MobilitySurveys
Householdtravelsurveys(HTS)areamajorinstrumentforgatheringinformationonpassenger
traveldemandthatiscriticalforregionaltransportplanning.Suchsurveyscantakeplaceona
countryoracity/regionallevelonaregularbasis(every1,2,orsometimesmoreyears),although
therearealsoseveralcasesworldwideinwhichtheHTSdoesnotoccuratspecific,pre‐decidedtimes
[118].Mobilitysurveysrefertoasimilarconcept;theyaremoregenericsurveysaimingtocapture
the“overallmobilitypicture”ofanarea,withquestionsthatcanincludebutarenotrestrictedto
sharedmobility.Theydifferfromhouseholdsurveysonlyinthefactthattheycanberealizedwitha
sampleunrelatedtothehouseholdasaunit(theycanbepostedonsocialmediaandaskforthe
participationofeveryinterestedperson,forexample,orbedistributedtospecificcommunities,e.g.,
studentsandemployeesofauniversity).
ThedifferencebetweenthesesurveysandtheSPandRPsurveysdiscussedaboveisthatthese
arestructuredtowardsgatheringinformationaroundaspecifictransportintervention(e.g.,the
introductionofanewsharedmobilityservice),whereasthehouseholdtravelsurveysandthe

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mobilitysurveyshelpincharacterizingmobilitypatterns,ofwhichthe