THE FUTURE OF TRAFFIC mAnAgEmEnT - Robert L....

THE FUTURE

OFTRAFFIC

mAnAgEmEnTState of the Art,

Current Trends and Perspectives for the Future

1. The Social and economic Urgency of Traffic managemenT

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2. Traffic managemenT: how doeS iT work?

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3. STaTe of The arT and cUrrenT TrendS

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4. PerSPecTiveS for The fUTUre

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5. There iS STill work To do

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6. fUTUre reSearch agenda

COnTEnTS

BACkground TRAFFIC mAnAgEmEnT In THE nETHERlAndS

Traffic management applies measures to adjust the demand and capacity of the traffic network, in time and space, to better “match” the traffic demand and supply (capacity).

Examples of traffic management measures in the Netherlands are:

• Rampmetering • Dynamicrouteinformation • Dynamiclanemanagement • Queuestorage • Nationaldatawarehouse • Incidentmanagement • Tapering • Variablespeedlimits • Peak-hourlanes(hardshoulderrunningduringpeakhours) • Pluslanes(dynamicleftlane) • Sectioncontrol(variablespeedlimitandenforcement) • Queuetailwarning

At least eight entities are used for traffic management, which deter-

mine the total traffic system, and which are constantly interacting:

• Trafficmanagementcenter/emergencymanagementcenter • Measures • Controlprinciples/scenarios • Vehicles • Road/infrastructure • Roaduser • Organization • DataandInformation • Roadinspectors • Serviceproviders/police/emergencyservices

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1. THE SOCIAl And ECOnOmIC URgEnCy OF TRAFFIC mAnAgEmEnT

In just a few years, traffic management has been transformed from an everyday, passive task for the highway authority to an important policy instrument. This transformation is not without reason.

Traffic management has improved the safety and operations on our roadways, while it is relatively inexpensive, flexible and rapidly deployable. Transportation professionals are also convinced that

the potential of traffic management is far greater than previously imagined.

Weknowthattherearecriticalproblemsthatcallfortrafficmanagementsolutions.DespitethefactthattheNetherlandsboaststhehighestmotorwaydensityintheEuropeanUnion,westillspendabout65millionhoursperyearincongestion.Theeconomiccostofthiscongestionises-timatedatanamountbetween2.5and3.4billioneuroseachyear.

Becauseourroadnetworkalongkeyroutesisalreadyheavilyloaded,eachper-centincreaseintrafficflowcompoundstheproblem.

Promising SolutionsSolutionstoimprovemobility,accessibilityandreliabilityarethereforenecessaryandverymuchdesired.Trafficmanagementisobviouslynottheonlyapproachtowardsolvingcongestionandmobilityproblems(seealsothepage9),butitiscertainlyoneofthemostimportant,cost-effectiveandpromisingtoolsinourtoolbox.

Whatdowemeanbytrafficmanage-ment?Definitionsvaryslightly,butsimplyput,wetrytoinfluencesupplyanddemandwithtrafficmanagement,suchthatthetraf-

ficdemandandthesupply(capacity)ofthenetworkbettermatch,alongboththedi-mensionsoftimeandspace.Theproblemsthatoccurontheroadprimarilyconcernspecificbottlenecks(pointsinspace)andspecificmomentsintime(peakperiods,incidentsandspecialevents).Theaimistospreadboththetrafficdemandandthesupplyofinfrastructure(capacity)inordertoadaptdynamicallyandthusmakebetteruseoftheexistingroadnetwork.Thefieldoftrafficmanagementincludesbothtrafficcontrolandtravelerinformation.

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Typicaltrafficmanagementmeasuresin-cluderampmetering,dynamicspeedlimits,peakhourlanes(hardshoulderrunning),andtravelerinformationdisplayedonvari-ablemessagesignsabovetheroadwayorviaotherchannels.Themeasureshavebeenprimarilyintendedtoimprovemobil-ity,accessibility,andreliability,buttheyarealsoincreasinglydeployedtoimproveroadsafety(forexample,congestionorqueuewarningsviathevariablespeedlimitsigns)ortoimprovelivability(forexamplebyspeedrestrictions).

Benefits of Traffic ManagementWearestillworkingonthequestionofexactlyhoweffectivetrafficmanagementmeasuresareinpractice,andthisisanimportantdiscussion.Weparticularlyneedtounderstandthecumulativebenefitsofthejointdeploymentofmultiplemeasures,whichisdifficulttodetermine.Butwearecertainthattrafficmanagementmeasuresleadtorealbenefitstosafety,mobilityandsustainability.Forexample,theNether-landsInstituteforTransportPolicyAnalysis(KiM)hasestimatedthatduringtheperiod

2000to2010trafficmanagementintheNetherlandssucceededinreducingdelaysby14%,withafractionofthecostoftheconstructionofnewroadways.

Itisexpectedthattrafficmanagementcanresultinaddedbenefitsbyencouragingandfacilitatingclosercooperationbetweenroad authorities, other transport entities, emergencyresponders,andtheprivatesec-tor,partlythankstotheavailabilityofnewtechnology.Giventhemobilityproblemsforbothpassengerandfreighttravelin

theNetherlands,weconsidertrafficman-agementtobesociallyrelevantandevenurgent.

Thereappeartobesufficientreasonstoconsiderthispolicyinstrumentmoredeeply.Whydoesitwork?Howisitcur-rentlydeployed?Whatkindsofneartermdeploymentsdoweenvision?Andhowcanweensurethatthepotentialbenefitsoftrafficmanagementarefullyrealized?Inthisdocumentwewilldiscusseachofthese topics.

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SOlUTIOnS BEyOnd TRAFFIC mAnAgEmEnT

Constructing new roads, improving bot-

tlenecks or widening existing roads are obviousapproachesforsolvingmobilityproblems.Theseareusuallyeffectiveandsometimesevennecessary.However,therearedrawbacks.Sometimesaddressingonebottlenecksimplyshiftsthebottlenecktoanotherlocation.Also,constructioninahighlydevelopedenvironmentisexpen-siveandtimeconsuming,anditselfhastrafficimpacts.Givenitsspatial,socialandenvironmentalconsequencesnewcapacityshouldonlybeconsideredwithcaution.

The rational pricing of the infrastruc-

ture, such as road pricing and distance

basedcharging,isanotherpossiblesolution.Oneapproachistodevelopachargingsystemthatisconstantintimeandspace.Itisalsopossibletovarythepricingratesintimeandspacewhichwillmakepeakperiodtravelandcongestedrouteslessattractiveandtherebyreducecongestion. road pricing is seen as of-feringinterestingpossibilities,butsofarthemajorpoliticalhurdleshaveproventoodifficult.Onepossibleexplanationisthatcomplexdecision-makingmustbehandledbyonegovernment,whiletheimplementationandmanagementdependsonthepoliciesofthenextgovernmentad-

ministration.Inanycase,suchasolutionwilllikelynotbeintroducedintheNeth-erlandsintheshortterm.

Transportation demand management in-cludeseffortsbygovernmentagenciesandemployerstoreducetravelbyusingmeas-uressuchasteleworkingortelecommut-ing,measurestoshiftthetravelmodetowalking,cyclingandpublictransportation,andmeasurestoshifttraveltooff-peakperiods.Transportationdemandmanage-mentisoftenusedasameasuretosupportlarge-scaleinfrastructureconstructionormaintenanceprojects,butdoesoffermorepossibilities.

Traffic management is not the only tool for maintaining mobility, accessibility and reliability.

What other solutions are there?

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Driverstypicallychoosetheirpreferredoroptimalroutesfromtheiroriginstotheirdestinations.Aslongastrafficislight,transportationsystemusersdonotcauseanysignificantdisruptionstooneanother.Onthemotorway,driverswillspreadthemselveseffectivelyacrossthelanes,leadingtoasynchronizedsituation.Thegreatthingisthatindividualchoicesofsystemusersalsoresultinabalancedsituationatthenetworklevel,inwhichtheavailablespaceisusedefficiently.

Butthisself-organizationhasitslimits.Astrafficbecomesheavierorthereareunforeseenincidents(suchasacrash,abreakdown,orotherrandomevents),thetrafficsystemcanbecomeunstable.Injustafewminutes,trafficconditionscantransitionfrom“runningsmoothly”to“severedelays.”

What Can Go Wrong Fortrafficmanagementmeasurestopost-pone or prevent the onset of congestion, it

isimportanttounderstandtheunderlyingprocesses.Inotherwords:whatexactlyhappenswhencongestionarises?

Onephenomenonthatarisesistheca-

pacity drop.Capacityismeasuredasthemaximumnumberofvehiclesthatcanpassagivenpointovertime(usuallyinvehiclesperhour).Whencongestionoc-curs,thecapacitytypicallydropsanaver-ageof14%,sometimesasmuchas30%.Thishappensatfixedbottlenecksbutalsofrequentlyinmovingshockwaves.Shock-

Most of the time, traffic can organize itself. But as traffic gets busier, the system is confronted with phenomena such as spillback and capacity drop. Through careful

intervention aimed at optimizing traffic flow – traffic management – we aim to prevent or at least mitigate problems.

2. TRAFFIC mAnAgEmEnT: HOw dOES IT wORk?

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wavesoccurwhen,forexample,adriverbrakessharply,resultinginaqueueform-ingbehindwithhigherdensityandlowerspeed.Theshockwaveactslikeawaveofbrakelightsmovingagainstthedirectionthattrafficismoving,withaspeedofap-proximately18km/h.Theshockwavecansometimespersistlongerthanonehour.

Onceweobservethecapacitydrop,itistoolate–congestionhasformedanditwilltaketimetodissipate.Thechallengehereistoactuallyanticipatetheformationofcongestionandtherebypreventorpost-ponethelostcapacity.

The sub-optimal route choices of indi-vidualtravelerscanalsocauseproblemsforotherusers.Obviouslynotwhentrafficislight.Ifyouthenchoosealessoptimalroute,atmostitleadstoalongertraveltime(plusaddedfuelconsumptionandemissions)foryourself.Butiftrafficisheavy,oneperson’schoicewillimpacttheothers’–travelerBspendsmoretimeinthequeuebecausetravelerAspendsmoretimeonthenetwork.Sincemostroadusersreceivenoinformationabouttheconsequencesoftheirroutechoice,they

continuetomakeinefficientchoices.Afinalprocessthatwewanttohigh-

lightisspillback.Thisoccurswhenaqueueemanatingfromabottleneckatonelocationobstructstrafficflowatanother(upstream)location.Theabovefigureshowsanexampleofspillbackonamotorway.Thereissomuchtrafficen-teringthemotorwayatrampAthatthisleadstotheformationofaqueueonthemotorway.Thequeuegrowsandgrows,propagatingupstreamuntilexitBisblocked.TheresultisthatmotoristswhowanttouseexitB(andsohavenothingtodowithrampA),areblocked.Thisjust

causesthetrafficjamtocontinuegrowingasitspreadslikeanoilslickacrossthenetwork.Justremember:weshouldneverblockanexitwherepeopleactuallywanttoleavethesystem!

Fundamental Diagram Thephenomenadescribedabovearegoodexamplesofwhytrafficcanbecomeun-stable.Therearemoreprocessesworkingtogether,buttheendresultisalwaysthesame:ataparticularmomentthesystemwillcollapseanditwilltakehourstore-cover.

Atthenetworklevelthiscanbede-

ExitB RampA

Exampleofspillback

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scribedbyaverysimplerelationship,knownasthefundamental diagram. This diagram,asshowninthefigureonthispage,showstherelationshipbetweenthenumberofvehiclesinthenetworkandthe“production”(thenumberofvehiclesleav-ingthenetworkperunittime).Iftrafficislight,anincreaseinthenumberofvehiclesinthenetworkleadstoaproportionalincreaseintheproduction.Butbeyondacertainpointwhentrafficbecomesheavier,productivityincreaseslessrapidlyandataspecificpointitevenstartstodecrease.Inthatregion,anincreaseinthenumberofvehiclesleadstofewervehiclesleavingthenetwork.Wecallthisstagnation!

Traffic Management SolutionsThisfundamentaldiagramisinfactabasicbuildingblockforalltrafficmanagementstrategies.Ifthenumberofvehiclesinanytrafficnetworkapproachesthecriticalpointandyoufailtointervene,theproblemsquicklybegintomultiply.

Ofcourseitisimportanttointervenecor-rectly.Thegoodnewsisthatthepreviouslydiscussedcausesandphenomenaprovide

usefulguidanceforthedevelopmentofin-telligentwaysofmanagingtrafficinanet-work.Wecanidentifyfourbasictypesofsolutionsinthefieldoftrafficmanagement:

1. Increase ThroughputOnewaytocombatcongestionistoin-creasetrafficflowatcriticallocations.Forexample,youcanadjustcapacitytemporar-ilybyusinganadditionallaneduringthepeakperiod.Combatingthecreationofshockwavesisanotherwayofincreasingtrafficflow.Congestionleadstoacapacitydrop.Ifyoueffectivelycombatshockwaves

(byslowingthetrafficthatisdrivingto-wardsashockwave)thisincreasestheca-pacityandthusthethroughput. 2. Effectively Distribute Traffic Across the NetworkThesecondkeyapproachisthebetterdis-tributionoftrafficoverthenetwork.Thisisimportantbecausethesub-optimalchoicesoftravelersleadtoanunbalancedandinef-ficientuseoftheinfrastructure.Thismeansthatoneroutemaybecomesignificantlyoverloadedwhileotherroutesremainfreelyflowing.Byprovidinghelpfulinformation

Production

Numberofvehiclesinthenetwork

Ifitbecomesbusier,thentheproductionwilldecreasemoreandmore

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touserssothattheycanmakebetterdeci-sions,theentirenetworkismoreefficientlyutilized. 3. Regulate the Inflow of TrafficThethirdsolutioninvolvesregulatingtheinflowoftrafficsothatthenumberofroaduserstravelingintoanarearemainsbelowthecriticalnumber–belowthetippingpoint.Consideramotorwayringaroundacity–keepingtheringmovingcanbecru-cialformaintainingaccess.Onepossibilityistoregulatetheinflowontheringwithmeasuressuchasspeedlimitsonaccessroads,trafficsignals,orrampmetering(“onevehiclepergreen”)aton-ramps. 4. Prevent SpillbacksThefourthandfinalapproachispreventingspillback.Thiscanbeaccomplishedinsev-eralways.Inthesituationoutlinedonpage12youcanregulatetheinflowtothebottle-neckusingrampmetering.Thiswouldpre-ventthequeuefromformingatthatpoint

andfrompropagatingupstreamtoexitB.Weshouldbearinmindthatthismaycauseaqueuetobackupontotheunderlyingnetwork.Butthattrafficcanbetemporarilystoredinabufferareainalocationwhereaqueuewillnotdisruptlocalroadways.Traf-ficinthebuffermustwaitforashortwhile,butthesystemasawhole,andultimatelyalltravelers,arebetteroff.

Inaddition,wenotethattheabovefoursolutionsfocusonimprovingtheperfor-mance(theefficiency)ofthetrafficflow.IntheDutchframeworkofSustainableTrafficManagement(GGB),otherkeyobjectivesarerelevantsuchasimprovingroadsafetyandreducingtheemissionsandfuelcon-sumption.Torealizetheseobjectivesothersolutionsemergesuchas:•Managingorcontrollingthespeedof

traffic.•Improvingthesafetyofvehicles(such

measuresfallundertheconceptsof eSafety).

•Improvingthesafetyoftheroadwayinfra-

structure(suchashighrisksitemanage-ment).

Is More Possible?Theabovesolutionsarefairlycommoninthetransportationandtrafficengineer-ingcommunities.Mostroadauthoritiesaredevelopingtheirtrafficmanagementprogramsalongtheselines.Aswehavepointedout,thesetechniqueshavebeenrelativelysuccessful(intheNetherlandsan14%decreaseindelayhasbeenreportedduetotrafficmanagementimprovementsbetween2000and2010).Buttrafficexpertssuggestthatthereisstillmorepossiblewithtrafficmanagement,forexamplewithare-gional,coordinateddeploymentofmutuallycomplementaryandreinforcingmeasures.Animportantissueisalsothatthefieldoftrafficmanagementisconstantlychangingalongtechnologicalandsocietaldimen-sions. To ensure thattrafficmanagementiseffectiveinthefuture,itisimportanttorespondorbetteryet,anticipate.

2. TRAFFIC mAnAgEmEnT: HOw dOES IT wORk?

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mEASURES In RElATIOn TO THE mAIn SOlUTIOnS

ThetrafficmanagementmeasuresthatwearefamiliarwithandapplyintheNetherlandscanbelinkedtothefourtypesofmainsolutionsdescribedabove.Inthetableonthispageweillustratethisforarangeofspecifictrafficmanage-mentapplications.Notethatthemeasuresshowncangenerallybeusedtoaddressmorethanoneproblemandsointhatrespectaremultifunctionalandcomplemen-tary.

mAIn SOlUTIOnS RAmp mETER TRAvElER InFORmATIOn

pEAk HOUR SHOUldER lAnES

dynAmIC SEpARATIOn OF THROUgH And lOCAl TRAFFIC

InCREASE THROUgHpUT

Effective capa-cityincreasebypostponingqueueformation

- Increasecapacitybyopeninganextralaneduringpeakperiods(shoulderand/orre-striping)

Increaseinca-pacitybydecre-asingweavingmovements

EFFECTIvEly dISTRIBUTE TRAFFIC

Reducecut-throughtraffic(ratrunning)

Informdriversaboutrouteswithresidualcapacity

- -

REgUlATE InFlOw Regulateente-ringtraffictomainroadway

Informdriverswhichon-rampto use if options areavailable

- -

pREvEnT SpIllBACkS

Prevent queue spillbackonthemainroadwaytoanupstreamexit

Informdriverstochooseexitifoptions are avai-lable

Preventspillbackbybufferingtraffic

Preventspillbackbychannelingexitingtraffictodedicatedlanes

Relationship between traffic management measures and primary solutions

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3. STATE OF THE ART And CURREnT TREndS

STATE OF THE ARTWehaveappliedtrafficmanagementintheNetherlandsforseveraldecades.Whatbeganinthe1980sasasingleinitiativeofRijkswaterstaat(executiveagencyoftheMinistryofInfrastructureandtheEnviron-ment)hasnowbecomeabroadfieldwithmultipledifferentplayersandawiderangeofsolutions,measuresandtechnologies.

MeasuresForcontrollingandmanagingtrafficflows,road authorities have a range of instru-ments:rampmetering,adaptivetrafficsig-nalcontrolsystems,greenwaves,roadsidepanelsfordynamicrouteinformation,and

dynamicdedicatedlanes.Mostofthesesystemsareprimarilyfocusedonimprovingtrafficflow,butsomehavebeendevelopedwiththebenefitsofimprovingsafety,liv-abilityandsustainability(includingreduc-ingfuelconsumptionandemissions).Ex-amplesofthisincludethemotorwaytrafficmanagementsystem,andthequeuetailwarningsystemandvariablespeedlimits(toimproveairquality)whicharepartofthat.

Travelerandtrafficinformationisavail-ableviaradio,television,computer,smart-phoneandin-vehiclenavigationsystem.Theinformationitselfischangingfrompre-tripexpectationstoreal-timepre-tripand

en-routeinformation(insomecasesevenmultimodal).Wenowareaimingtowardmeetinguserexpectationsbyprovidinginformationthataccuratelydescribesthecurrentandfuturetrafficconditions,andisaccessiblesafely,anytime,andanywhere.Thistransitionisnotyetcomplete–inparticularweneedtoimprovetheaccuracyandpersonalizationoftravelerinformation.

Collecting Traffic DataCurrentlyitisprimarilytheroadauthoritiesthatcollecttrafficdata,typicallythroughinfrastructure-basedsensorsofdifferentkinds,includinginductiveloops,radar,videoandBluetooth.IntheNetherlands,

It is clear that traffic management works and will continue to be effective in the future. But what does that future look like? To provide such a vision, it is important to describe the current state of the art first. In other words, where do we stand with traffic management?

A look at the trends will then provide insights into the direction we’re heading.

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thedataarearchivedintheNationalDataWarehouseforroaddata(NDW)andmadeavailableforafeetoserviceproviders.

However,moreandmoretheprivatesectorisactivelycollectingadditionaldatafrommultiplesourcesincludingvehiclesandsmartphones.Thesedatamostoftenincludeposition,speedandtraveltime.Thechallengeishowtobringthesecom-plementarydatasourcestogether.

PlayersGovernmentagencies–intheNetherlandsincludingRijkswaterstaat,theprovinces,andmunicipalities–havetheresponsibilityforcontrollingandmanagingtraffic.Thisisdonefromthedifferenttrafficmanagementcenters.Theprivatesectorplaysaleadingroleininformingroadusers.Thatsubdivi-sionofresponsibilitiesisnotentirelyacci-dental.Bycontrollingandmanagingtraffic,governmentagenciesareinvolvedinpri-marily“communityinterests”suchasac-cessibility,qualityoftheenvironmentandsafety,andthoseinterestsaretraditionally

providedbythegovernment.Theprivatesectorisdrivenbytheprofitmotiveandthereforefocusesmoreontheindividualinterestsofroadusers:trafficinformationservicestohelpcustomersavoidtrafficjams,providingalternateroutesandrealtimeinformation.

CooperationThecooperationandcollaborationbetweengovernmentagenciesforcontrollingandmanagingtrafficisreasonabletogood.Thetrafficmanagementapproachwasuntilre-cently“locationbased,”wherethevariousroadauthoritiesfocusedmainlyonisolatedbottlenecksandontheroadswithintheirparticularjurisdictions.Withtheincreaseinthenumberandcomplexityofmobilityproblems,ithasbecomeclearthatamoreregionalapproachisrequired,includinginthetrafficmanagementcenters.ThankstomethodologiessuchasSustainableTrafficManagement(GGB),thefocushasshiftedtoamorenetwork-orientedapproach.Trueoperationaltrafficmanagementatthere-

gionallevelisstillrare,butinmanyregionsthere is good cooperation on the strategic andtacticallevels.Alsoduringmajorroadconstruction,cooperationisfine(e.g.,co-ordinatingworkanddetoursondifferentjurisdictions’roads).

However,whenwelookatthecoopera-tionbetweengovernmentagenciesandtheprivatesector,inotherwordsbetweencon-trollingandmanagingononehand,andinformingontheother,thepictureislessclear.Thedomainsdonotalwaysreinforceoneanother–andsometimestheyevenworkagainsteachother.Takeforexam-ple,thegrowinggroupofroaduserswho,thankstothetrafficinformationontheirin-vehiclenavigationsystems,avoidsprob-lemsonthemainnetworkbychoosinganalternativeroutevialocalroads,sometimesthroughvillagecenters.Inthatcasethereisaconflictbetweentheindividualinter-estofroadusersandthecollectivepublicinterest(qualifyoflifeandsafety)wheregovernmentagenciesandroadauthoritiesareresponsible.


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CURREnT TREndSIncomingyearswewillseemanychang-esinthefieldoftrafficandtransporta-tion.Societalanddemographictrends,technologicalandeconomicdevelopments–theywillall,toacertainextent,impactthedevelopmentandapplicationoftrafficmanagementsolutions.Inthefollowingwewillhighlightthemostrelevantinflu-encingfactorsforthenext10to25years.

Societal TrendsSocietywillfurtherpersonalize,within-creasingemphasisonindividualcitizensandtheirfreedomofchoice.Atthesametime,however,citizenswillexpectgovern-mentagenciestopursuethesocialgoalsofsafety,accessibility,livability,andsus-tainability.

road users have access to accurate andintelligenttrafficinformation,andwillthereforebeabletomanagetheirindividualobjectives(includingcomfortandoptimaltraveltime).Futuretrippur-posesandtravelpatternswillcontinuetochange,partlyasaresultofdemographicshifts,theagingpopulationandsocialme-

dia(“GenerationY”).Thesechangesmayleadtolesstraditionalcommuting,buttomoreleisureandrecreationaltrafficandmorepublictransportuse.Theinterestforflexibleworkenvironments(teleworking,teleconferencingandhoteling)willgrowaccordingly.Thishasimplicationsforresidentiallocations,departuretimes,andcommutingdistances.Astrafficvolumescontinuetoincrease,discussionsabout

roadpricing(payingfortheuseofinfra-structure)willlikelyreturn.

Organizational TrendsFromthetrafficengineeringandadmin-istrativeperspectiveweseeanincreasingintegrationofmajorroads,provincialroadsandurbannetworks.Thisincludesdatacollection,trafficmanagementplan-ningactivitiesandimplementation.

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Public-privaterelationshipswillalsochangeinthecomingyears.WithDesign,Build,Finance,MaintainandOperate(DBFMO)contracts,forexample,newgovernmentandprivatesectorroleswillemerge.Theresponsibilityformainte-nance,administrationandmanagement

willfallincreasinglyontheprivatesector.Alsowiththegrowthintheuseofin-vehicletechnologies(suchasnavigationsystemsandmoreadvancedcooperativesystems)theprivatesectorcouldultimate-lytakeonmoretrafficmanagementtasksthanjustprovidinginformation.

Finally,fortheNetherlandsthereisthefurtherinternationalizationoftranspor-tationpolicies.Europe’stransportationpoliciesaredeveloping,andthisalsohasimplicationsfortrafficmanagement.TheNetherlandswillhavetotakeintoaccounttheEuropeanCommission’sActionPlanfortheIntroductionofIntelligentTrans-portSystemsinEurope(ITSActionPlan,2008)andtheITSDirective(2010).Forexample,withthisDirectivetheECmayissuebindingspecificationsforintelligenttransportationsystemsinthefuture.

Technological DevelopmentsTechnologicalinnovationsinthefieldoftrafficinformation,driverassistancesystemsandinterventioninhazardoussituationswillmakeitpossibletodevelopfurthertrafficmanagementinnovations.Forexample,imaginetheenormousop-portunitiesofferedbythecommunicationbetweenin-vehicleandroadsidesystems.Newcooperativesystemswillbeplatformsforservicesbeyondtravelerinformation


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alone–suchasindividualguidance,rout-ing,hazardwarningsandcrashavoidance.Givensufficientpenetrationintothevehiclefleet,newtrafficmanagementsystemswillbepossibleduetothepresenceofincreas-ingproportionsofprobevehicleswithmoreaccuratepositioningdataleadingtopreventative intervention. Secure and con-venientfinancialtransactionswillalsobepossiblethroughsuchaplatform,usefulforanykindofpricingmechanismdesiredinthe future.

Forintelligenttransportationsystems(ITS)tobeeffectivelyusedasatrafficman-agementmeasure,asufficientlyhighpen-etrationrateof30to70%isnecessary.Theautoindustryassumesthatin-vehiclesys-temswillbestandardforallnewvehicles.Governmentagenciescanactivelysupportthisdevelopment.Standardizationisarequirement–thiswillfacilitatethedevel-opmentofnewfunctionalitiesandservicesandthusacceleratetheimplementation,reduceunitcostsandincreaseconfidenceininvestments.StandardizationcanbeorganizedfromtheEU,butalsofromthe

automotiveandsupplierindustries.Thede-velopmentsinothermajormarkets(Japan,U.S.)willcertainlyplayarole.

Itisnotyetcleartowhatextentin-vehiclesystemscomplimentarytoroadsidesystemscanandwillbeusedforregulationandenforcement.

Economic TrendsThereisastrongrelationshipbetween

trafficdemandandeconomicdevelop-ment.Economicfluctuationscanthereforeleadtosubstantialchangesinthedeploy-mentoftrafficmanagementstrategies.Particularlyinagrowingeconomyitwillbenecessarytousetheexistingcapacityoftheroadnetworkaseffectivelyaspos-sible.Theeconomicsituationalsoaffectstheinvestmentclimateandbusinessop-portunitiesformobilityservices.

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TREnd AnAlySIS COnClUSIOnS

Relationships between trends and developments, supply and demand, goals and traffic management.

The above discussion provides a glimpse

into the current and foreseeable

problems around traffic and mobility, along with various trends and possible

future developments. The adjacent figure

outlines these developments and shows the

relationships between the trends, goals,

demand, supply and traffic management.

Technological developments

Economictrends

Trafficmanagement

(incl. instruments)

Supply

Goals

Demand

Aging population, “Generation Y”Teleworking and teleshopping

Acceptance of road pricing

Cooperative systems Development of traffic management instruments

Stronger role of the marketRegional approach

In-car technology

Economic development

Focus on economicallyimportant zones

Energy guaranteeEconomic development

IndividualizationImportance sustainabilityPerspective mobility

Societaltrends

Organizational trends

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Itisclearthatweexpectsignificantshiftsintrafficdemandasaresultofsocialandeconomictrends,butalsointhemobilityobjectives.Forexample,weforeseemorefocusonsustainability.Atthesametime,wehavesubstantialopportunitiesforincreasingtheeffectivenessoftrafficmanagement.Cooperativesystems,furtherdevelopmentofthetoolsfordynamictrafficmanagement,andnewperformancemeasuresandmethodsareallpossible.Alsoattheorganiza-tionallevel,wewillbeabletogainbenefitsfrombet-terregionalcooperation,furtherdevelopmentsintheprivatesectorandfuturepublic-privatepartnerships.

Asideeffectofpersonaltrafficinformationandtherolethattheprivatesectorplays,isthatroadus-ersarebecominglesseasytoinfluence,forexample,withqualityoflife,livability,orsafetyasobjectives.Thismeansthatinthefutureitisevenmoreimpor-tantthatthegovernmentandtheprivatesectorwork

togetherininforming,managingandcontrollingtraf-ficstreams.Individualinterestsrepresentedbytheprivatesectorandsocialinterests(government)mustbereconciled.Ifnot,thegovernmentwillneedtobe-comemorestrictinpreventingunwantedbehaviorofknowledgeableusers–forexample:travelthroughatowncenterbecauseitisjustalittlefaster.

Finally,inthefuturechangesinmobilityobjec-tivesmayberequiredinordertoallowamoreflex-ibledeploymentoftheinfrastructureandaproactiveinfluenceonthetrafficdemand.Thisleadsalmostautomaticallytoanextensionoftheroleoftrafficmanagement.Ifweaddtheeconomicdevelopmentandsocialrestraintsontheconstructionofnewinfra-structure,thenitbecomesclearthattheopportunitiesandpossibilitiesfortheeffectivedeploymentoftrafficmanagementwillonlyincreaseinthecomingyears.


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4. pERSpECTIvES FOR THE FUTURE

Theprimarytaskoftrafficmanagementistheappropriateoptimizationandmatch-ingoftrafficsupplyanddemandaccord-ing to infrastructure constraints. Even nowthisistheprimarytask,buttheim-portanceofthesupply/demandalignmentwillonlygrowinthecomingyears.

Thefirstlevelofoptimizingormatch-ingtransportationsupplyanddemandoccursatthenetworkplanninglevel.Theregularpatternofdemand,insofarasitexists,willestablisha“baseload”forthenetwork,definingthequantityoftraffic

thatneedstobeaccommodated.Acertaindegreeofcongestionisallowedduetothepeakingphenomenon.Whatexactlyisal-lowed,determinesthenecessityofroadcapacity.

Oncethenetworkcapacityhasbeenes-tablished,thenthebalancebetweensup-plyanddemandisanoperationalissue,withtrafficmanagementasanimportantinitialinstrument.Trafficmanagementmakesitpossibletodynamicallyrespondtotheever-changingtrafficsupplyanddemand.Trafficmanagementisalso

particularlycriticalduringnonrecurrentandunexpectedsituations,suchasroadconstruction,specialeventsorincidents.Thiswillleadtoabetterbalancebetweenindividualinterestsandtheinterestsoftheroadauthorityandsociety.Individualchoicesmustbeadjustedsothattheen-tirenetworkwillbenefit.

High DemandsIfwewanttrafficmanagementinhighdemandsituationstobesufficientlyeffec-tive,themeasuresmustbepowerfuland

Traffic management of the future needs to be especially flexible, cooperative and proactive. We should be able to quickly respond to changes

in supply and demand, to deploy coordinated measures and manage the different networks as a whole. What is required? One requirement is that road authorities, private sector partners and research/education institutes

should work together and cooperate more closely.

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impactful.Withmoreflexiblemanage-mentofsupplyanddemand,therewillbegreateropportunitiesforcoordinationandthusforcombatingcongestion.Thisrequiresahighdegreeofinstrumentationonrouteswheretrafficcanbeguidedanddirected(includingmotorways,arterialsandlocalroads).Wemustalsoconsiderwhattypesofmeasuresarerequired:themechanismsforinforming,controlling,andmanagingaswellasthepenaltiesandrewardsthatareavailable.Themeasuresshouldbewellcoordinatedandshouldberapidlydeployable.Inaddition,atransi-tionfromreactivetrafficmanagementtoproactivetrafficmanagementisnecessary.Thisrequiresagreaterroleforrouteguid-anceandtrafficcontrolundernormalandincident-relatedconditions.Predictionisanimportantcomponentofthisvision.

ConclusionInsummarywecansaythatthetrendsanddevelopmentsdescribedhereofferexcellentopportunitiesfortrafficmanage-ment.Buttrafficmanagementmustmeetanumberofimportantrequirements:

•Trafficmanagementofthefuturemustbemoreflexibleinhandlingchangesinsupplyanddemand.

•Measuresmustbecoordinatedandusedacrossthenetwork.

•Trafficmanagementmustbeproactiveandcanbeusedtoachievearangeofpolicyobjectives.

•Roadauthorities,privatesectorparties

andresearch/educationinstitutionswillneedtostrengthencollaborations.

Onlythencanwecontinuetodelivertraf-ficmanagementasaconstructivecontri-butiontothequalityofthetransportationsystem.

27

5. THERE IS STIll wORk TO dO!

Flexibility in Supply and DemandFortrafficmanagementtobereallyeffec-tive,itisnecessarytoinfluenceboththedemandandsupply.Atpresent,allroadauthoritieshaveavarietyofmeasurestoaccomplishthis.Buttotakeasignificantstepforward,thescopeofthesemeasuresshouldbeincreased.

Influencingtravel demandischalleng-ing.Dynamicroadpricingisapotentiallyeffectiveinstrument,butintheNeth-erlandsdeploymentislimitedtostatic

tollingandcurrentlyitisnotdeployedfortrafficmanagementpurposes.Therearealsoinitiativesthatrewardroadusersfortravelingoutsideofthepeakperiods.Thisformofpricinghasbeentestedex-perimentally.Itmaybesuitablefortem-porarysituations,suchaslarge-scaleroadconstructionwithcapacityimpacts.Amuchbroaderdeployablesolutionsuchasanoverallkilometercharge,hasthusfarbeenprovenpoliticallyinfeasible.There-fore,intheshorttermitisappropriatetoexplorewhetheralimitedpricingmeasure

suchashighoccupancytoll(HOT)lanes(wheresingleoccupantvehiclescanpaytoenteracarpoollane,withstaticordy-namicprices)ashavesuccessfullybeenimplementedintheU.S.,canbeeffectiveintheNetherlands.

Anotherwaytoinfluencedemandisbyprovidingtrafficinformation.Thiswayyoucanencouragetravelerstoreconsidertheirmobilitybehavior.Theinformationmustbeofhighqualityandtailoredtotheindividual.Thenitmaybepossibletoen-courageuserstotravelatadifferenttime,

We now understand the promise of proactive traffic management in the Netherlands. But we have also established that there will be significantly more required of traffic management in the future. How can we elevate the field of traffic management to the

next level in the coming years? What steps are needed?

30

change their route, choose a different des-tinationoradifferentmode,orworkandshopfromhome.

on the supply sidethereismuchthatcanbedonetoincreaseflexibility.Therehasbeeneffectiveuseofpeakandpluslanesaswellasrampmeteringinstal-lations,butthesecanbedeployedevenmoreintelligently.Thesesystemscanbeimplementedinatrulydynamicwaysothatactualconditionsaremeasuredinordertodeterminewhentheyshouldandshouldnotbeactivated.Inadditionthedifferentinstallationscanbecoordinatedmorefully.Anotherpossibilityistoex-pandthenumberofreversiblelanesandbufferlanes.Othercountries,suchastheU.S.,applythesemeasuresmorebroadlythantheNetherlands.

When designing the infrastructure it isimportanttotakeintoaccounttheap-plicationofthefullrangeoftrafficman-agementmeasurestobeapplied.Theroadnetworkshouldberobustenoughtodealwithrecurrentconditions.Inaddi-tion,preciselybecausethenetworkinthe

Netherlandsisoverloadedandsovulnera-ble,itisimportantfortrafficmanagementmeasurestodealwithnonrecurrentandunexpectedsituations–incidents,events,constructionandotherunusualcircum-stances.Currentlywedeploytrafficman-agementmeasuresatroadconstructionsites,butitneedstobemorecomprehen-siveandmoreeffective.Theabilitytoab-

sorbfluctuationsindemandisenhancedbybuildinginflexibilityandredundancyintothenetwork.Therefore,whenextracapacityisneeded,thereisanopportunitytoaccommodatethedemand.

More CooperationWithaviewtoeffectiveness,itisimpor-tantfortrafficmanagementtobecoordi-

31


natedanddeployednetwork-wide.Onlythencanwereallysolveproblemsinsteadofshiftingbottlenecksandproblemstodifferentlocations.Suchanetwork-wideapproachrequirescooperationamongroadauthoritiesandbetweenroadau-

thoritiesandserviceproviders(theprivatesectorpartiesthatprovidetrafficinforma-tion).Giventhelargenumberofstake-holders,thisisnotasimpleprocess.

Fortunately,thepartiesconcernedintheNetherlandsarealreadyorganizedin

variousways.Thereisaplatformwheregovernmentagenciesandprivatesec-torpartiesconsiderthepossibilitiesandapplicationsoftrafficmanagement,andthereareregionalcollaborationsthattargetregionaltrafficproblems.Inordertoconsiderfuturestrengthenedcollabora-tion,itmaybeusefultolookatincidentmanagement:thecooperationiseffective,thereareclearagreementsinplace,lead-ingtoabetter“product.”

Itisalsousefultolookinternation-ally.Forexample,intheU.S.,therearemanycollaborativepartnershipsbasedonMemorandaofUnderstandingandtrustineachother’sgoodintentions.Thereisquiteoftenacommongoal,whichmakesiteasiertosharefunding(pooledfunding)forajointprojectorresearch.IntheU.S.,thefocusismainlyoncorridors,butthemethodcanequallywellbeappliedtore-gionalnetworks.

Apositivedevelopmentisthatthereis increasing coordination and coopera-

32

tionbetweenthevariousroadnetworks(motorways,provincialroads,andurbanroads).However,thetrafficengineeringaspect of this deserves further investiga-tion:howcantrafficmanagementmeas-uresbefullycoordinatedanddeployed?Therehavebeensomeinstancesofco-ordinationofmeasuresonarouteorinaportionofanetwork,buttherearenotmanycontrolconceptsavailablethatcanhandlethis.Therefore,theseconceptsmustbedevelopedandextensivelytested,bothinsimulationsandinfieldtrials.

Anotherissueisthebalanceamongmodesoftransportation(road,rail,publictransport,cycling,pedestriansandwater)andbetweenpassengerandfreighttrans-portation.Onthatleveltherehasbeenlit-tleprogress:thefocusisstilltoomuchonthebetterusewithinasinglemode. Cooperative SystemsWiththeadventofcooperativesystems–whereinfrastructureandvehiclesys-temscommunicatecloselyasonesystem–therewillbemoreopportunitiesforcoordinationinthenearfuture.In-vehicle

systemsalreadyplayasmallroleintraf-ficmanagement.Navigationsystemsandqueuemessagesontheradiocaninflu-encetheroutechoiceofaroaduser.Ifve-hicle-infrastructurecommunicationisadd-ed,thesemeasureswillbecomemoresig-nificantastoolsforinformationandcon-trol.Thisisexpectedduetotheincreasedvehicle-vehicleandvehicle-infrastructure

communicationsinthefuture.Thefactthatthevariouscomponentsofthetraf-ficsystemcancommunicatemeansthatthesystems(comparedwithstand-alonesystemsinvehiclesandinfrastructuresys-tems)aremoreintelligentandbasedonmorethanjustcurrentinformation.Thereisinasensecooperation–ormaybeitisbettertotalkofnegotiation–amongve-

33

hiclesandtheinfrastructure(oracentraltrafficcenterorbackoffice).Thus,newandmoreefficient,predictivemeasureswillbepossible.Examplesarecoopera-tiveadaptivecruisecontrolandintelligentnavigationsystemsthatprovideadvicere-

gardingthecurrent(andpredicted)trafficandparkingsituations,possiblyincludingmultimodaltravelinformation.Alltrafficmanagementstakeholders(governmentagencyandprivatesector)seeopportuni-tieswithcooperativesystems.Itisimpor-

tanttoconsiderhowcooperativesystemsshouldbedesigned:whatsystems,howtotestthem,andhowtoorganizethedevel-opment,deploymentandmaintenance.

Vehicle-to-vehicle(V2V)applicationsinvolvingdedicatedshortrangecommu-nication(DSRC)areexpectedtobedevel-opedmainlybytheprivatesector,whilegovernmentagenciesaretypicallymoreinterestedinvehicle-to-infrastructure(V2I)applications.Forbothpartiesques-tionsremain:whopaysandwhobenefits?Forgovernmentagenciestherearefurtherquestionssuchas:inwhichequipmentdoweneedtoinvest,whatexistingequip-mentmustbereplaced,andifsowithwhat?Therearestillbottlenecksonthetechnicallevel(forexample,standardiza-tionandsecurity),organizationallevel(forexample,privacy),therelationshipwithroadusers(forexample,useraccept-ance)andscaleability(suchascomplexityandmanageability).


34

Proactive Traffic Management“Preventionisbetterthancure,”sotrafficmanagementshouldpreferablybeproac-tive.Asafirststep,itisnecessaryforthe“traditional”reactivetrafficmanagementmeasurestobeinplace.Withtheadventofmoredata,betterforecastingmodelsandsmarterconceptsfornetwork-widemanagement,progresscanbemadeto-wardproactivetrafficmanagement.Inpracticethiswillmeanthatwepreventspillback,distributetheflowbetteracrossthenetwork,regulatetheinflowoncer-tainvulnerablepartsofthenetwork–allbeforetheproblemsreallystart.

Tomovetrafficmanagementintherightdirection,inthefutureastrongerprogramofcontrolandrouteguidancewillbeneededthanisnowthecase.Currentlythemajorityoftheeffortsareaimedatprovidingtrafficinformationandadvice,andifanactionisneededitisprimarilylefttotheroaduser(ahighdegreeofself-organization).Butaswehaveseen,self-organizationonlyworksuptoacertainpoint.Duringpeakperiods,withhightraf-ficdemand,andduringnonrecurrentcir-

cumstances,itwouldbemoreefficientforacentraltrafficauthoritytomanagetraf-fic,forexample,providingdynamicrout-inginformationtoroadusers.Thiskindofsystemmusttakeintoaccountwhattheroaduserwillfinddesirable,comfort-ableandacceptable.Thisrequiresdeepinsight into the preferences of users and a carefuldesignoftheuserinterface(inthe

vehicleandalongtheroadside).Afterall,ifroadusersdonotseetheusefulnessofthemeasureitselforseedisadvantages,theywillnotfollowtheguidance.Knowl-edgeofhumanfactorsplaysanimportantrole.Aninformation-ergonomicapproachshouldbefollowedtodevelopsafeanduserfriendlysystems.

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Optimize for Multiple Policy GoalsTheincreasinginterestin–orrathercon-cernabout–thesocietaleffectsoftrafficmeansthattrafficmanagementmusttakeintoaccountmorediversegoalsthanbe-fore.Itisnolongersufficienttooptimizesolelyontotalflowortraveltime,butitisalsonecessarytoconsiderimprovementsinsafetyandqualityoflife(includingairquality,noise,andenergyconsumption).Inotherwords,amulti-objectiveoptimi-zationapproachisnowrequired.

Tomanagetrafficaccordingtomultipleobjectives,datacoveringthetrafficflow(speeds,traveltimes,vehicledelayhoursandreliabilityoftraveltime)arerequired,butwealsoneeddataonroadsafetyandqualityoflife/livability.Theobjectivesmustbequantified,andweneedmeth-odologiesthatmakeitpossibletounder-standandcommunicatethetrade-offs.

Integrated ApproachTrafficmanagementmustbepartofanintegratedapproach,inwhichtrafficman-agementtakesitsplacenexttomobilitymanagement,infrastructureplanningandspatialplanning.Forexample,ifitisnec-essarytoinfluencethetrafficdemandtoenableeffectivetrafficmanagement,thismustbealignedwithmobilitymanage-mentmeasuresthataimtoinfluencethenumberoftripsinanareaoronaparticu-larroute.Ashifttoothermodescanalsohelp.

Linkingtrafficmanagementtospatialplanningisimportantandcanhavemoreofaninfluenceonthestrategiclevel.Aspreviouslynoted,awell-designednetworkisthebasisforeffectivetrafficmanage-ment.Forexample,takingintoaccountthetrafficvolumesacrossthenetworkcanhelptoformanunderstandingofwhereflexibleinfrastructurefeaturessuchaspeak,plus,HOV,HOTorreversiblelanesare needed.

OrganizationRegardingtheorganizationoftrafficmanagement,therearealreadymanycomponentsinplaceintheNetherlands.Regionalcooperationcanneverthelessbestrengthenedfurther,whichisimpor-tantforthedeploymentofcoordinatednetwork-widetrafficmanagement.

Anotherissueisthewayinwhichgovernmentagenciesandtheprivatesec-torworktogether.Thisinvolvesmakinggood,clearagreements:whoisresponsi-bleforwhatandunderwhatconditions?Forsuchaclosecooperationtherearesomeinspiringexamples.Forexemple,governmentagenciesandprivatesectorhavegoodworkingarrangementsinthefieldofincidentmanagement.WecanlookabroadtoconsiderhownationalITSorganizations(withpublicandpri-vatemembers)havebeenestablishedandwhattheprosandconsoftheseap-proaches are.

Intermsoforganization,anumberof


36

behavioralaspectsandhumanfactorsplayimportantroles.Cooperationbetweenvariousorganizationsandbetweendiffer-entteamsrequiresnewwaysoforganiz-ing.Cooperationinthefieldofoperationaltrafficmanagementmust,forexample,beinitiatedatthetrafficmanagementcenter.Buthowdoyoustart?Fullintegrationoftrafficmanagementtasksondifferentlev-elsoftheroadnetworkhierarchymaybedifficult.

Anotheraspectrelatedtoorganizationconcernsinnovation.Incurrentpractice,afteralongdevelopmentalprocess,in-cludingsuccessfulfieldtrials,itisstillrarethatameasureisimplementedonalargescale.Theimplementationpathforinnovationscanbebetterorganized,andagainthereneedstobeclosecoopera-tionbetweenpublicandprivateparties.Moreover,trafficmanagementmeasuresthathavethepotentialtogeneraterev-enuehavenotreceivedmuchattention.Whilethetrafficsituationisconstantlychanging,littleeffortisexpendedinthefunctionalmaintenanceoftrafficmanage-mentmeasures.

Finally,thereisanimportantroleforresearch and education institutions. Both publicandprivatepartiescouldtakebet-teradvantageoftheknowledgedevelop-mentthattakesplaceintheNetherlands.InthefieldofITS,forexample,resultsfrommanyEuropeanresearchprojectscouldbetranslatedtotheDutchsituation,whichcancreateinterestingnewmeas-

uresandsystems.Theresearchatuni-versitiesintheNetherlandsatthispointisamongthebestintheworld.Itwouldbemutuallybeneficialforallpartiestostrengthenexistingpartnershipsandex-aminenewjointventures.

Training and EducationNomatterhowwellthetrafficmanage-

37

mentsystemisorganized,theworkisultimatelycarriedoutbyindividualem-ployees.Trainingandeducationforthesestaffmembersalsodeserveattention.Thisrelatesnotonlytoresearchers,engineersandplanners,butalsotothefieldperson-nel,suchasroadinspectors,maintenanceemployeesandoperators,trafficengineersandtrafficcoordinatorsintrafficmanage-mentcenters.Ifweindeedwishfortrafficmanagementtobemoreproactive,broad-erandbettercoordinated,thisrequiresnewcompetenciesandskillsfortheseemployees,obtainedthroughcontinuingeducation and training.

Basic FacilitiesArchitectureAbasicprovisionforthehighqualityand(wherenecessary)uniformapplica-tionoftrafficmanagementisthetraffic management architecture. This consists ofadescriptionofallstepsneededtoachieveeffectiveregionaltrafficmanage-

ment:appliedtechnology,organization,funding,interoperability,legalaspects,etc.Whensuchaframeworkisinplace,aclearoverview,structureandaparticu-larstandardization(everyoneusesthesamedefinitions)emerge.Anarchitecturealsoprovidesinsightintherelationshipsbetweendevelopmentsintrafficmanage-mentinthemediumandlongterm.

Clearly,simplyhavinganarchitectureisnotenough–italsoneedstobeused.Itisespeciallyimportantthattrafficengineer-ingfunctionalitiesandrequirementsarelinkedtotechnicaldevelopments,sothatdevelopmentsbettermatch.Thatlinkisalreadypartlyimplementedintheexistingtrafficmanagementarchitecture.However,therearestillassumptions,forexamplewithregardtolife-cyclepenetrationandeffectiveness,whichshouldbefurtherclarified.

Onewell-knownexampleofa(sub)architectureistheSustainableTrafficManagement(GGB)approach,whichde-

scribesindetailthestepstowardajoint,broad-basednetworkvisionandanarea-wideregionaltrafficmanagementstruc-ture.GGBhasalreadyprovenitsvalueinpracticeinmanyregionsintheNether-lands,butsomegapsinthearchitecturehaveemerged.Therefore,nowGGBPlus hasbeendevelopedwithamajornewcomponentconsistingofthefunctionalclassificationoftheroadnetwork.InGGBPlustheroadsareclassifiedaccordingtotheirfunctioninthenetwork,suchas“mainhighway”or“urbanroad.”Thisoffersopportunitiestoemphasizeaspectssuchassafetyandlivability. MonitoringHighquality,timelyandcompletetraf-ficdataareessentialfortheprovisionoftimelyandcorrecttrafficinformationtoroadusersandforthedeploymentoftraf-ficmanagementmeasures.IntheNether-landsweobtainthevastmajorityofdatafrominductiveloopdetectorsintheroad.


38

Thereareminorquantitiesofotherdetec-tionsystemsdeployedandalsovehiclesplaytheroleofsensor,butthatisstillnotadominantfeaturefordatacollection.Therefore,datafusion,whichincludesmethodstocombinedatafromdifferentsources,isofinterest.Thiscallsformoreintelligenceingatheringandprocessingthedata.Thedatamustbecollectedattherightplaces,measuredwiththecor-recttechniquesandthedatacollectedmustbewellcombined.Definingthedataqualityrequirementsdependsonwhatisdonewiththeinformation.Datafortraf-ficmanagementforexamplehasdifferentrequirementsthandataforpolicydevelop-ment.Itiscertainlynotnecessaryforalldatatobecollectedwiththesamequalityrequirements.Itisimportanttoviewthesensing,aggregating,qualityassessment,archivinganddistributionofsensordataholistically;atpresentthesecomponentsarehandledinafragmentedmanner.

Anotherissueistrafficinformationaround nonrecurrent events and incidents. Informationisnowavailable(trafficde-mandatevents,durationofincidents,

andalternativeroutes),butisagaintoofragmented.Atthistime,moreintegrationisneededamongtheserviceprovidersforprovidingtheinformation,inordertoim-proveresponsetimesandtheabilitytore-spondquicklytochangingcircumstances.Forthistooccuritisbetterthattheroadauthoritiesacceptgreaterresponsibil-ity.Thisisparticularlytrueinsituations

wheretrafficinformationcanbecrucial,suchasdisasters,majorincidents,events,andsevereweatherconditions.Anaddi-tionaladvantageisthattheroadauthorityismorevisibletotheroaduser. Models and PredictionWithtrafficmodelsitispossibletopro-vide quantitative insight into the effects

39

oftrafficmanagementmeasureson,forexample,safety,mobilityandtheenviron-ment.However,itisimportanttousethecorrecttypeofmodelforeachsituation.Forexample:fortheassessmentofpolicyleveloptions,staticmodelsareoftenused,evenifthepolicyoptionistrafficmanagement.Butstaticmodelsarenotsuitabletodeterminetheeffectsoftrafficmanagement.Dynamicmodelsneedtobedeployedforthispurpose.

Inthefuturemodeldeveloperswillneedtotakeactiontoimprovethissitua-tion.Theremustbeabetterlinkbetweenstaticanddynamicmodels.Thefunc-tionalityofdynamicmodelsshouldbeextended,sothatitispossibletoassesscertainpolicyoptions.Itisalsoimportantformodelresultstobepresentedwellandclearlyexplained.Onlyinthiswaywillpolicymakersandadministratorstakemodelresultsseriouslyintoconsiderationwhenmakingdecisions.

Alsothereal-timeapplicationoftraffic

modelsisofinterest.Wehavepreviouslyconcludedthatinordertoallowproactivetrafficmanagement,weshouldbeabletopredictthetrafficflow.Trafficmodelsareessentialforthispurpose,buttheyneedtobeimproved.

Finallywesuggestthatbehavioralmod-els–behavioralsimulationsofeconomic,psychologicalandsocialdecision-makingprocesses–requireextraattention.Thesefeaturesshouldbecomemoreprominentingenerictrafficmodels.Examplesofap-plicationsincludedeterminingtheeffectsofhabitualbehavior,thepotentialforpriceincentivestochangebehaviorandtheimpactofpersonalizedinformation.Further understanding is needed regarding the interdependence of these processes. Forexample,howcanweencouragemod-ificationofhabitualbehaviorusingintelli-gentandpersonalizedinformation?Afur-therunderstandingofthiswouldneedtobebasedonthelatestinsightsonhumanfactors.Thatinfluenceisnotlimitedtoa

specificbehaviorallevel(strategic,tacti-cal,operational).Sothechallengeistoex-ploittheinteractionsbetweentheselevels:e.g.departuretime,speed,routechoiceandmodechoice.Theseinteractionsalsorequireconnectionsbetweenthemacro-,meso-andmicroscopicmodels. Traffic Management Centers

Thefieldoftrafficmanagementhasdevel-opedinitiallyfromtheneedsandrequire-mentsofroadauthorities.Butsincethenalothaschanged:theprivatesectorisplayinganincreasinglylargerrole,therearein-vehiclesystemstobetakenintoac-countandthepossibilitiesofmobilecom-municationareincreasingexponentially.Thesechangeshaveledtoarangeofnewtoolsandopportunitiesfortrafficinforma-tionandtrafficmanagement.Theroleandnecessityoffacilitiesalongandabovetheroad,intermsofeffects,time,costsanddepreciation,havebecomepointsofdiscus-sion.Fortrafficmanagementcentersthis


40

hasanumberofimportantconsequences:

•Trafficmanagementcenterswillbedeployedinthenearfuturefornet-workwidetrafficmanagementofallroadauthoritiestogether.Theywillthereforebeattheserviceofregionalcooperation–andnotattheserviceofonlyoneroadauthority.

•Trafficmanagementcenterswillincreasinglyfocusontheinterplaybetweeninforming,controllingandmanagingtrafficflows.

•Trafficmanagementcentersinthefuturewillbeinextricablylinkedwithcooperativesystems,includingvehicle-to-vehicleandvehicle-to-infrastructuresystems,withroadsidedevicesandin-vehiclesystems.

•Trafficmanagementcenterswillinthefuturebetheplatformfromwhichbothroadauthoritiesandservicepro-vidersoperate.Bothpartiesshouldworkfromacommonplatform.

Thetrafficmanagementcenterofto-morrowwillalsoplayasignificantrolefortheapplicationofpredictionmodelsanddecisionsupportsystems.Thesetoolssupportthetrafficmanager,forexample,inthepreparationoftrafficmanagementscenarios.Inthisnewcontext,theques-tionsofeducation,traininglevelandtheworkloadofthetrafficmanagerwillrequire further attention. We need to con-sidertheoptimalwaysfortheworktobeaccomplishedandforthetrainingtobeprovided,sothatthetrafficmanagerscandotheirworkaseffectivelyaspossible.

Further InnovationIntheprecedingsectionsmanytopicswerediscussed,butitisimportanttocontinuetolookforfurtherinnovationsoutsidethetrafficworldthatmaybeofinterestfortrafficmanagement.Forexam-ple,wetrytomakefulluseofnewinfor-mationandcommunicationstechnology(ICT)developments.Sofartherehasbeen

littlerigorousfocusontheinfluenceofsocialmediaontheuseoftrafficinforma-tion.

Inaddition,itisprudenttokeepaneyeopenfordevelopmentsinothersectors.Astudyofanalogiescandeterminewhetherdevelopmentsandinnovationselsewheremayalsobeusefulforapplicationintraf-ficmanagement.


41

6. FUTURE RESEARCH AgEndA

Inthischapterweidentifythevariousresearchthemesresultingfromthediscussionabove.Wehavegroupedtheresearchthemesunderseveralcategories.Theboldthemesarethemosturgent.Toindicatewherethegreatestinterestmaylieinaparticularresearchquestion–andwhichkindoforganizationwouldmostlikelyleadtheresearcheffort–wehaveassignedeachresearchtopictofourcategories:

Strategic/Policy These are themes that are par-

ticularly important for policy.

Operational/ Road Authorities

Themes that are important

for the road authority.

Knowledge ApplicationThemes that are important

both for policy and road au-

thorities and for which the

knowledge is present to apply

them.

Knowledge Development

Research topics for which it is

difficult to find a direct client

and so could be advanced by

universities or research or-

ganizations.

If we want to fulfill the true future potential for traffic management we must take the necessary steps forward. This is not a simple matter. Most of the first steps require further investigation. That is why we close this brochure about the future of traffic management

with a recommended research agenda.

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Flexibility in Supply and Demand

Flexible infrastructure (more flexible deployment of the available capacity) is an effective way to temporarily address capacity shortages or spikes in traffic demand. But where and when exactly is it useful to deploy flexible infra-structure?

Dynamic road pricing is potentially a powerful tool to influence demand, but it is also politically sensitive. It is therefore necessary to explore what other less far-reaching possibilities there are to apply pricing. Perhaps a high occu-pancy toll (HOT) lane is an option.

Mobilitymanagementisusedsuccessfullyatroadcon-structionsites.Mobilitymanagementforrecurrentconditionsand/ornonrecurrent/incidentconditionsshouldbeexamined,suchthatbettertuningispossiblebetweentrafficmanagementandmobilitymanagement.

More Cooperation

Much is expected from coordinated network-wide traffic management. There are already actions in place aimed at im-plementing this, but further examination and development

is needed. Network-wide traffic management also has con-sequences for the design and organization of traffic manage-ment centers.

Inthenearfutureweexpectagreatdealfromcooperativesystems.Buthowwillthesesystemsactuallycontributetoabet-tertransportationsystem?Whichspecificapplicationsareonthehorizonandwhenwilltheybeintroduced?Whoisresponsibleandwhatistherelationshipbetweenroadsidedevicesandin-vehiclesystems?

IntheU.S.thereisawell-establishedsystemforpoolingresearchfunds(seewww.pooledfund.org).Regionalpartiesto-gethercreateafundtotackleaspecificproblemortoconductresearch.ThequestionnowishowthisfinancingmechanismcanbeadoptedintheDutchsituation.

Morecoordinationisneededbetweenthevariousroadnetworks(motorways,provincialroads,urbanroads)andmodesoftransport(car,publictransport,bicycle).Itisnecessarytoexaminehowtheinterfacesbetweentheroadnetworksandthenetworksoftheothermodescanbebetterplanned,designed,managedandoperated.

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Proactive Traffic Management

To achieve the desired coordinated network-wide traffic management we need prediction. Further research is needed to determine which concepts can be used and what further development is needed for forecasting models.

Thequalityofthetrafficinformationcanbeimproved.Weshouldexamineunderwhatcircumstanceswhichparticularinformationisnecessaryanduseful,andwhichtrafficdatamustthereforebeobtained.

Operationaltrafficmanagementisextremelyimportantinnonrecurrentsituationsandincidents.Inthatrespect,thequal-ityofdecisionsupporttoolsintrafficmanagementcentersmustbeenhanced.Thisincludesaneedtobetterassessandpredictthetrafficsituation.Theeffectsofmeasureswouldneedtobeincluded.

Optimize for Multiple Policy Goals

Multi-objective traffic management would consider

more than just mobility but also accessibility, safety and quality

of life. What methods are available for such an integrated assess-

ment, and what optimization techniques are suitable?

Integrated Approach

More research into the role of human factors is impor-tant to ensure that road users understand and comply with the traffic management measures that are applied. Human factors knowledge should therefore be included in traffic management by default. Research is needed in this area, for example in the development of systems, the implementation of operational measures and the application of traffic manage-ment.

Therobustnessofthenetworkhastodowiththecoordi-nationbetweentheplanningoftheinfrastructure(thestructureoftheroadnetwork)andtheoperationalapplicationoftrafficmanagement.Itisnecessarytoexaminehowcoordinationcanbeimproved,forexamplebyexploringwhereintheDutchnet-workredundancyisneeded.


Strategic/Policy

Operational/Road Authorities

Knowledge Application


45

Thereisagapbetweenthedesiredtrafficengineeringfunctionalitiesandtechnicaldevelopments.Itisnecessarytoexaminehowabettermatchbetweenthesetwodo-mainscanbeachieved.Ononehand,itinvolvesabetteruseofavailabletechnologies,andontheotherhand,toletthedesiredfunctionalitydrivethetechnologicaldevelopments.

Itisalwaysusefultoexaminedevelopmentsinotherfieldsandseeifthereareanyanalogieswithtrafficmanagement,inparticularaboutthewayinwhichtransport(particlesandinfor-mation)isregulatedandmanaged.

Thefunctionalmaintenanceoftrafficmanagementcompo-nentsisanimportantissue.Butwhataretheoptimalinvestmentlevelsinfunctionalmaintenance?

Organization

In the Netherlands the effectiveness of traffic management is sometimes doubted. In the U.S. it appears that this is less of a problem. In some states and metropolitan regions “branding” for traffic management is a normal course of action. The question is how important the application of traffic management in Netherlands is and how we can shape a branding initiative in the Netherlands.

There is currently discussion about the roles of road authorities and the private sector on the distribution of traffic information. An important research question is under what circumstances it is useful and desirable for a road authority to provide information. What would be the quality requirements of that information and what is the most appropriate division of responsibilities between government agencies and the pri-vate sector? What business models are needed?

Notonlyinprovidingtrafficinformation,butalsoinap-plyingtrafficmanagementinitiativestheprivatesectorwillplayalargerrole.Itisnecessarytoexaminehowtherolesandresponsibilitiesbetweengovernmentagenciesandtheprivatesectorcanbedividedandharmonized.Towhatextentcaninter-nationalITSorganizationsserveasexamples?

46

Basic Services and Other

Traffic management uses all kinds of data and data sources. It is important to examine how the data can be gath-ered, analyzed and combined more intelligently, taking into account the differences in quality. Improvement is needed quickly given current inefficiencies in the system that relies on fixed sensors (for example, during conditions of low flow, incidents or poorly tuned sensor controllers).

Thereisinsufficientinsightintothevalidityofmodelsandtherefore,thereisalotofdebateabouttheresultsofmodel-basedstudies.Researchintotheaccuracyofdriverbehav-iormodelsisneeded.Thisincludesmultiplelevels(forexample,lanechangingandroutechoicebehavior)andtheinteractionsbetweenthem.

Inmodelingthereissometimesagapbetweenpolicyandpolicy-supportingmodels.Ononehand,fromthepolicysidebettermodelsshouldbedeveloped,whileontheotherhand,theresultsofmodel-basedstudiescanbebetterpresented.Thequestionishowthatcouldbedone.

Socialmediaarestronglyontherise.Wehavetothinkabouttheroletheycouldplayinprovidingtrafficinformationsafelyandeffectively,bothoutsideandinthevehicle.


Strategic/Policy

Operational/Road Authorities

Knowledge Application


47

Publication Information

Text:

prof.dr.ir.SergeHoogendoorndr.ir.HenkTaaleir.IsabelWilminkprof.dr.RobertL.Bertinidr.ir.RonaldvanKatwijkprof.ir.BenImmersir.HenkSchuurman

Illustrations:

EwoudLuppens

Editing and design::

EssenciaCommunicatie,TheHague

© 2012 TrafficQuest

Nopartofthispublicationmayberepro-

ducedinanywaywhatsoeverwithoutthe

priorwrittenpermissionofthepublisher.

Thegreatestpossiblecarehasbeentakenin

compilingthedatainthispublication.The

publishercannotacceptliabilityforanyerrors

oromissions.

48

About TrafficQuest

TrafficQuest, the Center of Expertise in

traffic management, is a collaboration

between Rijkswaterstaat, TNO and TU

Delft.

In the world of traffic management a lot is happening and developmentsmove quickly. Traffic Quest helps to keep track of these developments by systematically collecting, developing and transferring knowledge. The part-ners in TrafficQuest together cover the entire spectrum including the funda-mental, theoretical knowledge about traffic management, and the opera-tional expertise about the application of traffic management in practice. The activities of TrafficQuest consist of an-swering specific questions, giving ad-vice on projects, conducting research on specific topics and to establish and disseminate knowledge.

www.traffic-quest.nl

THE FUTURE OF TRAFFIC mAnAgEmEnT - Robert L....

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