過飽和狀態(tài)交通信號控制優(yōu)化原理及仿真

過飽和狀態(tài)交通信號控制優(yōu)化原理及仿真

0u3000公車法urafficmortiagestrafege家族value公務(wù)員的基本生活服務(wù)體系管理。如上所述，通過基本生活服務(wù)體系、基本生活服務(wù)體系、職業(yè)人口統(tǒng)計（痕跡研究）、hcm（高線空間）的基本控制軟件，以及基本生活服務(wù)體系的基本控制軟件（生命的相互分離）和scot（生命的相互分離）。對于任何工作場所的異常行為，參與緩慢的非正義控制，以及人類的分散。改革進(jìn)展緩慢的移動時間是從哪里來的。改革進(jìn)展緩慢的系統(tǒng)有50個等級，而官方的區(qū)域控制系統(tǒng)沒有注冊，并且可以采取計劃中的區(qū)域控制。這封信是屬于馬蹄形的。這是一個由扭曲運動統(tǒng)治的城市網(wǎng)絡(luò)。Trafficcontrolstrategiesunderover-saturatedconditionsarefirstlyimplementedforisolatedintersections.Specificcoordinatedtrafficsignalcontrolstrategiesforthearterialandroadnetworkarethendevelopedforthepurposeofdealingwithcongestionstatus.Beginningwithdistinguishingtheconceptionsofapproachingsaturation,saturationandover-saturation,theover-saturatedtrafficcontrolstrategiesforvariousscalesaresummarizedandevaluated.Asapartoftheadvancedtrafficmanagementsystem(ATMS),adaptivetrafficsignalcontrolsystemswiththecapabilitiesofhandlingover-saturatedflowarealsodiscussed.1que資源統(tǒng)一whiceTrafficstatusisgenerallydeterminedbytrafficintensity,i.e.V/C(volume/capacity)ratio.Foraroadsection,approachingsaturationusuallyreferstothesituationofV/Cratiolargerthan0.9,andover-saturationisthetrafficstatuswithV/Cratiogreaterthan1.0,thesaturationstatushasaV/Cratioexactlyequals1.0.Theconceptionsoftrafficconditionsatintersectionaresimilartotheconceptionsatroadsection.Ifthetrafficdemandofoneapproachoftheintersectionexceedsitscapacity,thisintersectionisunderover-saturatedstatus.AsshowninFig.1,becauseitisdifficulttomeasuretheactualtrafficdemandandcapacitywhenthetrafficsystemiscongested,theoversaturationatsignalizedintersectioncanbedefinedastheconditionofhavinganapproachwithresidualqueue.Thequeueinformationcanbedirectlyestimatedbyloopdetectors,mobilesensorsorvideodatabyusingshockwavetheory.Trafficflowwillbecomeunstableunderoversaturationorapproachingsaturationconditions.Asmallfluctuationfromanyvehicleinaplatoonmaycauseadverseconsequencesandreducetheefficiencyoftrafficsystemsharply.Thelowstabilityofsaturatedtrafficflowputsforwardmorestringentrequirementstothetrafficcontrolsystem.Generally,over-saturatedconditionwillfirstlyappearatoneorseveralisolatedintersectionswithrelativelyhighsaturationdegrees.AsshowninFig.2,whenintersectionBcanue10btdischargethequeue,itturnsintoover-saturatedstatus.ThequeuewillcontinuallygrowuntilitexceedstheroadsectionbetweenintersectionsAandB.AtthemomenttheresidualqueuereachintersectionA,bothintersectionsareundertheover-saturatedconditions.Noeffectivetrafficcontrolstrategyexistsatthismoment,buttopreventanyvehiclefromenteringover-saturatedroadsection.Thisdetrimentaleffectisnamedspillback,whichshouldbeavoidedinthefirstplace.Intersectionsalongtheroutewithlargertrafficvolumesmayspreadthecongestionmuchfasterthanotherroutes.Finally,thewholeroadnetworkwillbecongested,evenunderalock-outstatus.Itisimportanttoimplementtrafficsignalcontrolstrategiestopreventover-saturatedconditionsinthefirstplace,ratherthantoreacttotheissuesafterthefact.Oncethetrafficdemandgoesbacktothenormallevel,thefrequentlyusedtrafficcontrolstrategywillmakethepractitionersmanagethetrafficfloweasily.Thecauseofover-saturatedstatusindicatesthatthedeclineofcapacitycausedbydetrimentaleffectsisacriticalinterferingfactor.Therefore,theessenceoftrafficcontrolstrategiesunderoversaturatedstatusistoeliminatethedetrimentaleffectsbyadjustinggreentime,cyclelengthandoffset.2就業(yè)服務(wù)的繼承2.1內(nèi)插領(lǐng)養(yǎng)兒童2.1.1為系統(tǒng)論和utikizraince系統(tǒng)論SinceWebsterconnectedtheaveragedelaywiththesignaltimingparametersandtheobservedvariablesbyusingcumulativediagram,theseparameterscanbeoptimizedbyminimizingthedelayofsignalizedintersection(knowingasTRRLmethod).SimilartoTRRLmethod,manyoptimizationobjectivesarealsoappliedinsignaltimingoptimizationprocess,suchasminimizingcyclefailures,minimizingstopsandminimizingaveragesaturationdegree.However,becauseoftheprincipleofalgorithm,theycanhardlybeutilizedunderover-saturatedconditions.Althoughthecoordinatetransformationmodelandthedeterministicmodelwereestablishedtoestimatethedelayorqueueinthesignalizedintersectionwithrelativelyhighsaturationdegree,thetrafficsignalcontrolcandonothingbuttoallocatemoregreentimetoreducethedelay.2.1.2u3000spindexedraftingmo產(chǎn)品pensiptenWhenthegreentimebecomesflexible,switchingofgreenisthefirstandsimplesttrafficcontrolstrategyfortheover-saturatedintersections.Thisstrategycanallocatetheunusedgreentimefromun-congestedphasetoover-saturatedphasetoensuretheeliminationofresidualqueue.Byapplyingthiscontrolphilosophy,thetotaldelayscanbeminimizedbymaximizingintersectionproductivity,whilekeepingthequeuesue10bdevelopmentwithinacceptablelevelsatthesametime.Amaximumgreentimeisgiventothemovementwiththehighersaturationflowuntilthequeueisdissipated,whileothermovementsreceivetheminimumgreentime.Widelyusedtechnologiesofthisstrategyincludesemi/fullactuatedcontrol,NEMAue10bs(nationalelectricalmanufacturesassociation)ring-barrierphasemodelinNorthAmerica,andphasestagemodelinEurope.Intheactuatedcontrolsystem,controllercanextendorterminatethecurrentphasetoallocatetheunusedgreentocongestedphase.NEMAue10bsring-barrierphasemodelextendstheideaofactuatedcontrol.AsillustratedinFig.3,thedualringcontrolunitcangivemorepriority(i.e.moregreentime)totrafficflowofspecificintersectionapproachbyadjustingthebarriersbetweenphases1,5(3,7)and2,6(4,8).Phasestagemodelcangroupalltheun-conflictedmovementsandorderthembypriorities.Thephaseassociatedwithcriticalmovementgroupcangetmoregreentime.Theswitchingofgreenstrategydoesimprovetheefficiencyoftrafficsignalsystem,especiallyforthesituationofintersectionwithonlyoneortwomovementsbeingcongested.However,whenthevolumesofallmovementsexceedtheircapacity,thesealgorithmswillextendallphasestomaximumgreentime.Atthattime,trafficcontrolsystemhasnodifferenceswithfixedtimecontrol.Ingeneral,minimizingdelayviasplitswitchingisnotanon-linehighlyresponsivepolicy,butanoptimizationpolicybasedonadvancedmathematicsandthedetailedknowledgeofdemand.2.1.3n鞣inci生物cuespinvi結(jié)構(gòu)處理Thenatureofgreenadjustmentpoliceistore-allocatethetemporalresourcesforthepurposeofimprovingtheirefficiencies.However,whentheroadspacebecomestherestrictionofthesystem,maintainingqueueratioshouldbeselectedastheoptimizationobject.Underthisstrategy,thegreentimeshouldbeadjustedtobalancethequeuesatintersectionue10bsapproaches.Theobjectiveistominimizethenumberofblockedintersectionsbymanagingqueuesofcriticalintersection.Thisstrategyinvolvestheuseofsampledloopdataateachintersectionormobilesensorsdata.Recentstudiesindicatedthatthesignalizedintersectionwonue10btmaximizeitscapacityandminimizeitsdelayatthesametimeunderapproachingsaturatedorover-saturatedconditions.Inthisway,signaloptimizationobjectivesshouldbeswitchedtothemeasuresofreducingthequeuelengthatthebottleneckandminimizingthedetrimentaleffectsunderoversaturatedstatus.Theseoptimizationobjectivesinvolvethethroughputmaximizationorthequeueminimizationofcriticalroute.2.2Simulationbasedevaluation2.2.1vissimsotvissimsoteInordertoevaluatetheperformanceoftrafficcontrolstrategiesforover-saturatedisolatedintersection,fixedtimingmethod(TRRLmethod),Synchromethod(HCMmethod),actuatedcontrolmethod,NEMAue10bsdualringcontrolunit,phasestagemodelandqueueratiomaintenancemethodareevaluatedintheprevailingmicroscopictrafficsimulationenvironmentbasedonVISSIMsimulationsystem.TheadvantagesofVISSIMoverothersimulationpackagesincludesomeaspectsasfollows.(1)VISSIMprovidesthelargestflexibilityforuserstocalibratedrivingbehaviorsandtrafficconditions.(2)VISSIMisdevelopedunder.NETframework,whichbringsflexibilityforadd-onprogramdevelopment.(3)VISSIMprovidesthebesttoolsforthedevelopmentofsignalcontrolstrategies,suchasNEMAcontrolleremulator,vehicleactuatedprogramming(VAP)language,signalcontrolapplicationprogramminginterfaces(SCAPIs),etc.VISSIMSCAPImethodisusedtodevelopsignalcontrolemulatorinthisresearch.SCAPIsarewritteninC++/CLRlanguageandtheoriginalversionofSCAPIscontrollerrequiressignalcontrolalgorithmsbeembeddedintoasingledynamiclinklibrary(DLL)file.Tofacilitatethedevelopment,amiddlewareisdeveloped,whichcansynchronouslycollectallthereal-timedetectors/phasesstatesfromtheVISSIMnetworktothecontrolleremulatorthenreturnthenewdesiredphasestatesbacktotheVISSIMnetwork.Ateachtimestep,controllerrunsthealgorithm,makesdecisionsaccordingtothecurrentstate,thenreturnsthenewdesiredphasestatestotheVISSIMnetwork.TheconceptofthissimulationenvironmentisillustratedasinFig.vissim軟件Asimplefourwayintersectionisselectedtoevaluatetheselectedalgorithms.ThegeometriccharacteristicsoftheintersectionareshowninFig.5.TheexperimentalconfigurationsarelistedinTab.1.AlltheneededdatacanbedirectlyobtainedfromtheVISSIMsoftware.Alltheinputparametersareoptimizedinadvance,andthenareinputtotheVISSIMenvironment.TheVISSIMsoftwarehasabuilt-infixedtimecontrollertoachieveTRRLmethodandHCMmethod.TheCrossingsoftwareandVisVAPmoduleinVISSIMareappliedtoprogramtheactuatedcontrolmethod,phasestagemodelandqueueratiomaintenancemethod.TheVISSIMstandardNEMAeditorisutilizedtoevaluatethedualringcontrolunit.2.2.3perfogenfici能夠生長Eachscenariorunsfor50timestoconductstatisticalanalysis.Throughputvehiclesandaveragequeueratioareselectedtocomparetheselectedtrafficcontrolmethods.AsshowninTab.2,itcanbeindicatedthatundernormalconditions,theactuatedcontrolmethod,theNEMAmethodandthephasestagemethodallhavesimilarperformances.Theflexiblegreencontrolstrategies,suchasactuatedcontrol,NEMAandphasestage,haverelativelybetterperformancethanthefixedtimingcontrolstrategies(TRRL,HCM).Althoughthequeueratiomaintenancemethodhasgoodperformanceinmanagingthequeueratio,thiscontrolstrategyisnotthemostefficientoneundernormalconditions.However,underover-saturatedconditions,thequeueratiomaintenancemethodhasbetterperformancethanallotherstrategies,andthus,itissuitabletobeutilizedundercongestedconditions.Ifthetrafficdemandcontinuestogrow,specifictrafficcontrolstrategiesforlargerrangeareneededtobeconcerned.3內(nèi)省的根本變異3.1內(nèi)插領(lǐng)養(yǎng)兒童系統(tǒng)3.1.1通過外引并式方法參加了..3.4和.3.4和.......與whichin...................................................3.3Signalcoordinatedcontrolstrategiestrytoseekforthemaximumprogressionbandbyadjustingtheoffsetsbetweengreenphasesundersteadytrafficconditions.Withpredefinedmaximumlikelihoodoffsets,coordinatedtimingplansaregenerallydesignedfortrafficflowundersteadystates.Astheintersectionsbecomemoresaturated,residualqueuesstarttodisruptmovementatupstreamintersections.Then,theprogressionbandisnotapplicableanylonger.Iftheover-saturatedconditionlastsforaconsiderabletimeperiod,fixed-timingsignalcoordinationislikelytoaggravatemovementdisturbance,whichmaycausespillbackintoupstreamintersections.Variable-bandwidthprogressionisthenestablishedtoadjusttheoffsetsaccordingtothetraveltimeinformationinrealtime.AsshowninFig.6,thevariable-bandwidthprogressionimprovestheefficiencyofcoordinatedcontrol,andmakesitworkatmostconditions.TheMonteCarlomethodcanbeutilizedtooptimizethebandwidthtopreventtheearlystartedcoordinatedgreenphaseintheactuatedsignalsystem.Underoversaturatedconditions,thereal-timeinformationishardtoobtain.Meantime,inordertomakemorevehiclespassthroughtheprogressionband,thebandwidthstendtobelarge,whichmakessignaltimingtobefixed(maximumgreenatthecriticalrouteandminimumgreenatotherroute).3.1.2u3000服務(wù)平臺Insteadofsearchingthemaximumprogressionband,thestrategyofmaximumstoragecapacitiesofapproachesisutilizedtooptimizequeuesatintersectionapproaches.Thismethodrespondstotherestrictionsofroadspaceundertheoversaturatedconditions,andtriestomakeefficientuseofupstreamlinkue10bsstoragecapacity.Theprocedureofusingsimultaneousoffsetsalongthearterialandnegativeoffsetswithflaringofgreenalongcrossroadsisthentestedundertheoversaturatedarterialnetwork.Becauseofmarkedlydecreasedspillbackblockages,theprocedureofoffsetsettinghaslargerthroughputvehiclenumberthantraditionaloffsetsetting,andwitha20%reductioninoveralltraveltime.Withthepossibilityofhigh-resolutiontrafficdata,recentresearchesdescribedsimplecontrollerlogicfortruncatingaphaseearlywhenfacedtoadownstreamrestrictionofflowandtoavoiddetrimentaleffectlike“spillback”or“de-factored”.De-factoredassumesthatnoflowonadetectorwhenthelightisgreenindicatingthatthereisnowhereforthevehicletogo,andthusitisbetterforoverallintersectionoperationstomoveontoanotherphase.3.2內(nèi)臟器官3.2.1interity分工Anarterialisselectedtoevaluatetheperformanceofmaximumprogressionbandstrategy,variablebandwidthprogressionstrategy,andmaximumstoragecapacitiesstrategy.Thearterialisabout8.85kmlong,fourwaysfortwodirections,andsixsignalizedintersections.Fig.7showsitslayoutandtrafficmovementcounts.Thefiledobservedtrafficiscongestedorclosetocongested.AllsixsignalizedintersectionsarecontrolledbytheEconoliteASC/3signalcontrollersandinductiveloopdetectorswithfour-waypedestrianphases.TheVISSIMSCAPImethodisalsoutilizedtoevaluatethecoordinatedtrafficcontrolstrategies.TheoriginaltrafficsignaltimingplanisgeneratedbySynchro,aprevailingsignaltimingoptimizationpackageinNorthAmerica,usingmaximumprogressionbandstrategy.Fig.7alsoshowstheoptimizedfixedtimingplansoftheselectedintersections.Thevariable-bandwidthprogressionstrategyandmaximumstoragecapacitiesstrategyareimplementedbyCrossingsoftwareandVisVAPmodule.3.2.2queueclearing.u...............3.3inderace................................................3.3.3.Duringtheprocessofevaluation,eachscenariorunsfor50timesandsummarizestheaveragevalue.Wheneverthetimingplansareupdatedandaplatoonisidentified,onlyphasesplitsareadjustedwhereasthecyclelengthsandoffsetsarekeptunchanged.Thereforethecoordinationwillnotbedestroyedonthemainline.Sincetheexpectedadvantagesofthemaximumstoragecapacitiesstrategyincludeprovidingsignaltimingstoavoidqueuespillbackandqueueclearancewithoutdestroyingcoordination.ThefollowingMOEs(measuresofeffectiveness)arechosentoevaluatetheperformanceoftheACScontrolstrategy:linktraveltime,totalstops,theaveragecontroldelay,andthemaximumqueueratioonthemainline.Tab.3summarizestheMOEsforallthethreetrafficcontrolstrategies.FromTab.3,itisclearthatthemaximumstoragecapacitystrategycanreducethelinktraveltimeandvehiclestoponthemainlinebyfrom5%to15%.However,thevariable-bandwidthprogressionstrategyhasissuesonoptimizingthesignalofsouthboundtraffic,andcauseseriouscongestionduringsimulation.Althoughtheperformanceofnorthboundisslightlybetterthanthefixedtimescenario,thevariable-bandwidthprogressionstrategyisnotsuggestedtobeutilizedunderover-saturatedconditions.Themaximumstoragecapacitystrategydoesnotsignificantlyreducethemaximumqueueratioorcontroldelaysatintersections,becausethedistancesbetweenintersectionsarerelativelylongandtheconstraintsregardingtherelationshipoftheestimatedmaximumqueuelengthandlinklengthbarelyplayaroleduringtheoptimization.Itisexpectedthatmorebenefitofqueuespillbackavoidancewillbeacquiredifmaximumstoragecapacitystrategyisdeployedatclosely-spacedintersections.4u3000etis/which國際專利產(chǎn)品,作品本.“非價值”的strafes.kues.agie和whichi-roune.關(guān)于聯(lián)邦域,聯(lián)邦strage-strage-strage-strage-strage-strage-strage-strage-strage-strage-strage-strage-strage-stratestrage-strage-strage-strage-strage-strage-strage-strage-strage-strage-strage-strage-strage-strage-strage-strage-strage-strage-strage-strage-rouneThesignalcontrolstrategiesintheroadnetworklevelaretheextensionofthestrategiesforcoordinatedintersections.Similartothestrategiesforcoordinatedintersections,thestrategiesforroadnetworkcanbedividedintoadaptivesignalcontrolandmetering/gatingpolice.Theadaptivecontrolstrategiestrytoseekforarelativelybetterallocationofthepassagetimeatthenetworklevelbyapplyinghillclimbingmethodorotherheuristicalgorithms.Whentheroadspacebecomesalimitationfortrafficsignaloptimization,itissuggestedtodistributethetrafficdemandoverthenetwork,andmakefulluseoftheentireroadspacewithintheselectedarea.Themeteringpoliceextendsthequeuemanagementstrategy.Thisstrategyimpedestrafficinputatasuitablepointorpointsupstreamtopreventthedemandfromreachingcriticallevelsatcriticaldownstreamlocations.Itcanmanagetherateofflowintoandwithinhigh-trafficdensitynetwork.Onewell-knownreal-timetrafficcontrolpolicyforcongestedarterialsisRT/IMPOST(real-time/internalmeteringpolicytooptimizesignaltiming),whichisdesignedtocontrolqueuedevelopmentoneverysaturatedapproachbysuitablemeteringtraffictomaintainstablequeues.AtrafficcontrolstrategyforintersectiongroupunderoversaturatedconditionfurtherdevelopedtheRT/IMPOSTstrategybyaddingcriticalroutelayer.Thisprocedureensuresthecriticalrouteistheprimaryoptimizationobjectforover-saturatedintersectiongroup.Inordertoaccomplishtheroadnetworkcontrolstrategies,anumberofmodelsweredevelopedtoidentifythequeue,queuedischargetime,availabledownstreamstorage,etc.5u2004公車使用第203.3—Adaptivetrafficsignalcontrolsystemforover-saturatedconditionsForthereasonthattheoptimizationobjectsunderover-saturatedconditionsaredifferentfromtheonesatsteadystates,specifymodulesorfunctionsareneededtobuiltinthetrafficsignalcontrolsystemtodealwiththeover-saturatedconditions.Generally,anadaptivetrafficsignalcontrolsystemwiththecapabilityofworkingunderover-saturatedconditionsshouldcontaintrafficstatusidentificationmodule,congestioncauseidentificationmoduleandseveralsignalcontrolparametersue10boptimizationalgorithms.Commonlyusedcommercialadaptivetrafficcontrolsystemsgenerallyhavethecapabilityofcalculatingsaturationdegreeinapproximatelyrealtime,suchasthesaturationpercentageinSCOOT,orthedegreeofsaturationinSCATS.However,becauseofthereasonthatnospecifyalgorithmisdesignedforover-saturatedconditions,whenthesaturateddegreeapproaches1,thestabilityofthesesystemsdropssharply.Todealwiththetrafficcongestionmanagementproblem,someadaptivetrafficcontrolsystemsaredesignedtoavoidcongestionorover-saturatedconditions,suchasSCOOTMC3,MOVA,TUC,andMOTION.DetailmeasuresappliedinthesesystemsaresummarizedinTab.4.6“which”信號聯(lián)Accordingtotheoptimizationprinciples,thetrafficsignalcontrolstrategiescanbedividedintotwocategories:theallocationoftemporalorspatialresources.Understeadystates,theefficiencycanbeimprovedby