交通工程學課件chp3traffic studies final

Chapter3

TrafficStudies（交通調(diào)查）PurposesofTrafficStudiesInventoriesofphysicalsystems,suchascontroldevices,etc.Investigatingtrendovertimesothatactionscanbeanticipated,identifiedandtaken(volume,speed,accidents,….)Calibrationofrelationsorparameters,suchasreactiontime,frictionfactor,…Assessingtheeffectivenessofimprovement,suchasaccidentreduction,HOV…TypesofTrafficStudiesVolumeStudySpeedStudyDensityStudyDelay/TravelTimeStudyCapacityStudyOriginDestination(O-D)StudyOtherSpecialStudiesAccidentParkingPedestrian3-1VolumeStudy（交通量調(diào)查）PurposesofVolumeStudyAnnualTrafficVolumeAnnualtraffictrend;estimateannuale(tollroads,收費道路)ADT/AADTTransportsystemvs.demand（需求）;improvementoffacilitiesHourlyTrafficVolumePeakhourtrafficflow;lackofcapacity;trafficmanagementmeasuresShort-termTrafficFlowFlowrate;variationoftrafficwithinthepeakhourVolumeStudyDataCategories(Two-way)VolumeDirectional（分流向）DistributionCapacityanalysis;signaltiming（信號配時）TurningMovementVehicleTypeVehicleoccupancy（占有率）PedestrianCordon（境界出入）andScreenline（分隔核查線）studiesVolumeStudyTechniquesTally（計數(shù)）SheetsMaximummanpowerHandCountersFloatingCar(ProbeVehicle）（浮動車）MechanicalCounters(e.g.,Pneumatictubecounters,壓力管式檢測器)PermanentCounters(e.g.,loopdetectors,線圈檢測器)OtherModernMethodsRadar,ultrasonic,imageprocessing,…FloatingCarMethod（浮動車法）ManualMethodorAutomatic(e.g.,floatingcellulardatatodeterminespeed)ManualMethodRequirements:onevehicle,onedriver,and3observersOneoftheobserverscountsing（對向）traffic(Xa)Anothercountsthenumberofvehiclespassing(Y1)orpassedby(Y2)thefloatingcar(Yc=Y1-Y2)Theotherrecordstimeandtraveltime(ta,tc)FloatingCarMethodEquationsVolumeAveragetraveltimeAveragespeedExample3-1,P42PneumaticTubesComponentsHollowrubbertubesVehiclecounterorclassifierFeaturesEasilyandquicklyinstalledInexpensiveReasonablyreliableInductiveLoops（感應線圈）ComponentsShieldedloopwireLead-incableDetectorunitConsiderationsMustsawthepavementFailurerateFixedlocationDetectspresenceMeasuresspeedApplicationsPermanentCountStationsIntersectionDetectionFreewaymonitoringOtherCountingDevicesTimeofVolumeStudy24-hrStudyAconsecutive24-hrstudybetweennoonofMondayandnoonofFriday16-hrStudy6amto10pm12-hrStudy7amto7pmPeakHourStudy7amto9am,4pmto6pmWeekend12pm(or6pm)ofFridayto12pm(or6am)ofMondayIntersectionVolumeStudyTimeofStudy:PeakhourManualMethodAtleastoneobserverforeachentrance(leg)Threeobserversforhightrafficentrancestocountthrough,leftturn,andrightturnvehicles.RoadNetworkVolumeStudyTypesofVolumeCountStationsControlStation（控制性觀測站）ToobtainADTMonthly(7daystoamonth)orquarterly(7consecutivedays/quarter)countsTemporaryStation（臨時觀測站）Toobtainsample(coverage)countsAtpointsofsignificantchangealongthetrafficvolumerouteprofile,onfreewayrampsandconnectors,onroadswhichintersecthighwaysandatothernecessarylocationsRequiredfactoringtoAADTtosevermostneeds3-2SpeedStudy（車速調(diào)查）TypesandPurposesofSpeedStudySpotSpeedStudy（地點車速調(diào)查）Spotspeedstudiesareconductedtoestimatethedistributionofspeedsofvehiclesinastreamoftrafficataparticularlocationonahighway.Usedfor:Establishtheeffectivenessofneworexistingspeedlimitsand/orenforcementpracticesEstablishtrendstoassesstheeffectivenessofnationalpolicyonspeedlimitsandenforcementSpecificdesignapplications(likesightdistance)Specificcontrolapplications(yellow/allredtiming–thesizeofdilemmazonedependsonspeed)Investigationofhigh-accidentlocationsatwhichspeedissuspectedtobeacausativefactorTypesandPurposesofSpeedStudySpaceSpeedStudy（區(qū)間車速調(diào)查）EvaluateroadwayLevelofServiceUsedtoimprovealignmentdesignParameterfordeterminingefficiencyoftrafficoperationsUsedintrafficassignment(transportationplanning)UsedtodeveloptrafficmanagementmeasuresandsignaltimingEvaluatetheeffectivenessofmeasuresTrafficflowparameterSpotSpeedStudyMeasurespeedatspecificlocationsRecordspeedofindividualvehiclesastheypassTimeMeanSpeed(TMS)Location:generallyonstraightsegmentwithoutanydisturbance（無干擾）TimetoConductStudyGenerallyattimeswhentrafficflowratesarelessthan750-1000vphplforfreewaysOnehourbetween9:00–11:30,14:30–16:00,19:00–21:00SpotSpeedStudySampleSize（樣本大?。㎜arger

than50(or100)InappropriateMeasureofSpotSpeedsAlwayspickthefirstvehicleoftheplatoon,whichtendstohavelowerspeedTendtomeasurespeedsofacertaintypeofvehicle(e.g.,trucks)TendtomeasurehighspeedvehiclesSpotSpeedStudyMethodsofcollectingManualAutomaticRadarLaserPiezo-electricImageprocessingRunningSpeedorSpaceSpeedStudyRunningSpeed（行駛速度）TheoverallspeedexclusiveofstopsSpace

Speed（區(qū)間速度）IncludestopsOveralltravelspeedMethodsofCollectingLicenseplate（牌照法）Floatingcar(refertovolumestudy)（流動車法）Carfollowing(platoon）（跟車法）LicensePlate道路名稱__________起點__________終點__________調(diào)查日期__________調(diào)查員__________天氣__________

序號車輛類型起點時間T1終點時間T2行程時間ΔT=T2-T1區(qū)間車速V=L/ΔT1

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CarFollowingMethod道路名稱__________起終點__________調(diào)查日期__________調(diào)查員__________天氣__________路段編號觀測時間減速次數(shù)以及原因中途停車最終斷面時間行人自行車會車轉(zhuǎn)向車公交停靠其他原因停止時間起動時間1

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Example3-13-3DensityStudy（交通密度調(diào)查）DensityThenumberofvehiclespresentonagivenlengthoflaneorroadway.(單位長度車道上，某一瞬時所存在的車輛數(shù))Highdensitiesindicatethatindividualvehiclesareveryclosetogether,whilelowdensitiesimplygreaterdistancesbetweenvehicles.Headway,spacing,gap,andclearanceareallvariousmeasuresfordescribingthespacebetweenvehicles.DensityStudyMethods:input-output（出入量法）,photography（攝影）DensityStudyTechniqueInput-outputMethod（出入量法）Attimet0,thenumberofvehiclesisE(t0).Attimet,thenumberofvehiclespassingAandBareQA(t)andQB(t).Then,attimet,E(t)=QA(t)-QB(t)+E(t0)Thedensityis:K(t)=E(t1)/LABInput-outputMethodApproachtoobtainE(t0)LicenseplatePhotographTestcar(測試車法)ThetestcarstartsfrompointAatt0,andarriveatpointBatt1.Thenumberofvehiclespassedbyandpassingthetestcarareaandb.ThenumberofvehiclespassingpointBisq.

E(t0)=q+a-bInput-outputMethodTechniqueFreewayssegmentswithoutmerging(合流)ordiverging(分流)Thesegmentislongerthan800m,withtraveltimelongerthan5minutes.NeedtorecordthenumberofvehiclespassingthestartandendofthesegmentsNeedtorecordthenumberofvehiclesovertakingandovertakenbythetestcar.Pros

andConsoftheInput-outputTechniquePros（優(yōu)點）SimpleintermsofmethodandmeasuringdevicesCanbeusedforvarioustrafficconditionsAccurateandeffectiveCons（缺點）Theerrorofcountingthenumberofvehiclespassingthestart(A)andend(B)pointsincreaseswithtime.(moreobservations).Photography(abovetheGround)Method（地面上攝影觀察法）

K:Density

L:Lengthofthesegment

n:thenumberofphotosduringtimeperiodT

Ki:thenumberofvehiclesinthei-thphoto.Lusuallyfallsbetween50and100m.Multiplecamerasrequiredforlongsegments.AerialPhotography（航空攝影）Photostakenfromfixed-wingaircrafts,helicopters,balloons,…Usethesameequationasthepreviousmethodtocalculatedensity.ProsandConsPros:mostaccurateCons:expensive;notsuitablefortunnelsandbridges.Occupancy（占有率）DensityisdifficulttomeasureOccupancyisoftenmeasuredbydetectorsDefinedastheproportionoftimeadetectoris“occupied”(時間占有率)Alsotermed“l(fā)aneoccupancy”TimeofOccupancyLVLDtoPulsesTimevi==lengthofvehicle+lengthofsensortimeofoccupancyLV+LDtomsecLD:lengthofthedetectorzoneSpaceofOccupancyTheproportionofspaceoccupiedbyvehicles(空間占有率）補充：RelationshipbetweenDensityandOccupancyLv:AveragevehiclelengthLD:lengthofthedetectorzoneMeasurefromaspecificdetectorinalaneUnit:vehiclesperkmperlane補充：ImageProcessingTechnology（視頻檢測技術(shù)）InserttheimageprocessingvideoNeedtoconvertfileformatParametersDetected:

Speed,occupancy,classification,gap,volumeHomeworkAssignment復習思考題3-2習題3-13-4DelayStudy（行車延誤調(diào)查）TypesandDefinitionsofTrafficDelayDelay

Delaysareoftenusedtomeasuretheperformanceoftrafficflowatintersections.FixedDelay（固定延誤）Thetimelostcausedbytrafficcontroldevicesandenvironmentrather

thanvehicles.StoppedTimeDelay（停車延誤）Thetimeavehicleisstoppedwhilewaitingtopassthroughtheintersection.TypesandDefinitionsofTrafficDelayTravel-timeDelay（行駛延誤）Thedifferencebetweenthedriver’sdesiredtotaltimetotraversetheintersectionandtheactualtimerequiredtotraverseit.Time-in-queueDelay（排隊延誤）Thetotaltimefromavehiclejoininganintersectionqueuetoitsdischargeacrossthestop-lineorcurb-line.TypesandDefinitionsofTrafficDelayApproachDelay（引道延誤）Notonlyincludesstoppedtime,butalsoincludesthetimelostwhenavehicledeceleratesfromitsambientspeedtoastop,aswellaswhileacceleratingfromthestopbacktoitsambientspeed.FactorsAffectingTrafficDelayDriverVehicleRoadwayPercentageofTurningVehiclesVolume-Capacity(V/C)RatioLevelofServiceTrafficControlEnvironmentApplicationsofDelayDataEvaluatetheDegreeofTrafficCongestionGrasptheTrendofDelayAnalysisLevelofServiceBasisforRoadwayRehabilitation（改建）TransportationPlanningEconomicAnalysisBefore-afterStudyTrafficManagementDelay

StudyTechniquesCar-followingMethod（跟車法）Conductedalongwithtraveltimestudytoobtaininformationontraveltime,runningspeed,overallspeed,anddelay.Usuallyusedtoconducttraveltimeanddelaystudiesforpublictransportation.SheetforrecordingTravelTimeandDelayDelay

StudyTechniquesInput-outputMethod（輸入-輸出法）Usedfordelaystudyofbottlenecks（瓶頸路段）Recordtheamountofvehiclesenteringandexitingthebottlenecksegmentevery5minor15min.時間到達離去阻塞情況到達累計離去累計4:00-4:1580808080無阻塞4:16-4:3010018090170阻塞開始4:31-4:4512030090260阻塞4:46-5:009039090350阻塞5:00-5:157046090440阻塞消散5:16-5:307053090530阻塞結(jié)束Table3-8:Developmentanddissolutionoftrafficqueue.Trafficdelayofthe300thvehicle?Capacity=360vhe/hrTotalDelay=AreaIntersectionDelayStudyLocationswithtrafficcongestionTime:peakoroff-peakhourSampleSizeAtleast30/50vehiclesUseEquation3-16or3-17todeterminethepreliminarysamplesize.Needstobeconfirmedaftercollectingdata.IntersectionDelayStudyPointSamplingMethod（點樣本法）Manualcountmethod(proposedbyUniv.ofBerkeley,1954)Toobtainqueuetime（排隊時間）onintersectionapproaches（引道）3

to4observersandastopwatchOneobservernotifiesotherevery15seconds(mayuseotherintervalslike20s)ThesecondonecountsthenumberofstoppedvehiclesThethirdonecountsstop-and-govehiclesandthosewithoutstopping交叉口________引道________車道________調(diào)查日期________天氣________觀測員________觀測時間在下列時間內(nèi)停在引道內(nèi)的車輛數(shù)引道交通量+0s+15s+30s+45s停駛車數(shù)非停駛車數(shù)

合計

EquationsTotalDelayAveragedelayforstoppedvehiclesAveragedelayforallvehiclesPercentageofstoppedvehiclesAllowableerrorExample3-2開始時間停過的車輛數(shù)引道交通量015s30s45s停止車輛數(shù)不停止車輛數(shù)17：00027911617：01400361417：0291614618017：031491317017：045002417小計192230335637ProsandConsofPointSamplingMethodProsAnindividualerrordoesnotaffectresultssignificantlyDoesnotrelyontrafficsignalComprehensiveresultsdescribingdelayatintersectionsConsNotappropriatewhenthepercentageofstoppedvehiclesisveryhigh(e.g.,nearly100%)Forapproacheswithmulti-lanes,needmoreobserversForsinglelaneapproach,notabletodistinguishdelayfordifferenttypesofmovements(TH,LT,RT)Hasresultonaveragedelay,whilenoinformationonthedistributionofdelay.3-5CapacityStudy（通行能力調(diào)查）CapacityStudyRoadwaySegmentHeadwayStudyHeadwayofplatoonsHeadwayfordifferentvehicletypesPassengercarequivalence（換算成當量小車）IntersectionGapStudyLeftturningvehiclesCapacityStudyIntersectionSaturationFlowRate（飽和流率）Assumethatanintersection’sapproachsignalweretostaygreenforanentirehour,andthetrafficwasasdenseascouldreasonablybeexpected.Thenumberofvehiclesthatwouldpassthroughtheintersectionduringthathouristhesaturationflowrate.SaturationFlow（飽和流量）Themaximumnumberofvehiclespassingtheapproachoraconflictpointduringagreeninterval.（在一次綠燈時間內(nèi)，進口道或沖突點上連續(xù)車隊能通過停車線或沖突點的最大流量）CapacityStudySaturationheadway（飽和車頭時距）Example3-4(車頭時距方法）SaturationHeadway3-6Origin-Destination(OD)Study（起訖點調(diào)查）DefinitionsTrip（出行）BasicunitoftravelbehaviorTripinvolvesmovementfromasingleorigintoasingledestination.Describedintermsoforigins,destinations,purposes,timesofoccurrence,travelmodes,androutes.Eachtriphasasingleoriginandasingledestination;hascertainpurpose(s);usesoneormoretrafficmodes.DefinitionsTrip（出行）Residenttrip（居民出行）Eachtripmustbemadeviahighwaysorurbanroads.Traveltimeshouldbelongerthan5min.Tripswithbicyclingshouldbelongerthan400m.Tripstakenbywalkingorbicyclingusethestartpointastheoriginandthefurthermostpointasthedestination.DefinitionsTripEnds（出行端點）OriginanddestinationThenumberofnodesistwicethenumberoftripsInternalTrip（境內(nèi)出行）TripsmadewithinthestudyareaExternal(Through)Trip（過境出行）TripspassingthroughthestudyareaDefinitionsInter-zonalTrip（區(qū)間出行）OriginanddestinationindifferentzonesIntra-zonalTrip（區(qū)內(nèi)出行）OriginanddestinationwithinthesamezoneCentroid（小區(qū)形心）CenteroftripsinazoneExpectationLine（期望線）LineconnectingcentroidsWidthofthelinerepresentingtheamountoftripsDefinitionsMajorDirectionalExpectationLine（綜合期望線、主流傾向線）Themergeofclosedexpectationlinesforbetterpresentation（seefigureinnextslide)CordonLine（調(diào)查區(qū)域境界線）AnimaginaryboundaryaroundastudyareaofinterestEstablishedtodefineaCBDorothermajoractivitycenterDefinitionsScreenLine（分隔核查線）Someformofnaturalorman-madebarrieracrosswhichtherearealimitednumberofcrossingpointsDefinitionsTripProduction（出行產(chǎn)生）Home-basedtrips:Movementassociatedwiththehomeendofatripiscalledtripproduction,whetherthetripisleavingorcomingtothehome.Non-home-basedtrips:theoriginofatripTripAttraction（出行吸引）Home-basedtrips:thehomeendofatripNon-home-basedtrips:thedestinationofatripTripDistribution（出行分布,O-D交通量）AmatrixthatdisplaysthenumberoftripsgoingfromeachorigintoeachdestinationDefinitionsODTablePurposesofODStudy(Survey)ODstudiesareconductedtounderstandthepatternofthemovementofpersonsandgoodsinaparticularareaofinterestduringaparticularperiodoftime.ODstudiesaretypicallyconductedinordertocollectdataasabasisfortraveldemandmodeling.Oncedemandmodelsarecreated:analysisoftravelcharacteristics,e.g.,traveltime,delay,pollutiontheimpactofmodificationorclosure(duetoanincidentorroadwork)ofexistingroutesthedesignandevaluationoftheeffectivenessofnewroutesontheexistingtransportationnetworkusedtomakelongrangetravelforecaststoidentifypotentialfutureproblemsinthetransportationnetworkandevaluatealternativesolutionsTypesofOD

StudyPersonTrip（個人出行）ResidentialtripsSurveyincludestrippurposes,travelmodes,timesofoccurrence,tripdistance,OandD,andfacilities(landuse)VehicleTravel（車輛出行）VehiclesincludetrucksandbusesSurveyincludestypesofvehicles,load,purposes,numberoftrips,startingandarrivingtime,OandD,etc.GoodsMovement（貨物流通出行）Dispatchcenter,parkinglocation,storage,etc.Typesofgoods,carloadings（運入運出量）,etc.ODDataCollectionMethodsHomeInterviewSurvey（家訪調(diào)查，個人出行）RoadsideInterviewSurvey（路邊詢問調(diào)查）PaperSurvey（發(fā)表調(diào)查，車輛出行）PostcardMailback（明信片法）WorkTripSurvey（工作出行調(diào)查）LicensePlate（車輛牌照調(diào)查）ODDataCollectionMethodsBusStationorOn-boardSurvey（ontransitvehicles)（公交站點調(diào)查）FillingSurveyForms(bythosepurchasingIC