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1、13.4交织区域的分析Weavingareashavebeenthesubjectofagreatdealofresearchsincethelate1960s,yetmanyfeaturesofcurrentproceduresrelyheavilyonjudgment.Thisisprimarilyduetothegreatdifficultyinandcostofcollectingcomprehensivedataonweavingoperations.Weavingareascoversignificantlengthsandgenerallyrequirev
2、ideotapingfromelevatedvantagepointsortime-linkedseparateobservationofentryandexitterminalsandvisualmatchingofvehicles.Further,therearealargenumberofvariablesaffectingweavingoperations,and,therefore,alargenumberofsitesreflectingthesevariableswouldneedtobeobserved.自20世纪60年代后期就对交织区域问题进行了大量的
3、研究,然而，许多现行规程的特点主要还是依赖于判断。这主要是由于在交织运作方面的全面的数据收集存在极大的困难和成本。交织区域主要涉及重要的交织路段长度和一般需要从较高的有利位置进行录像﹐或进出口路端的时间分离观察及车辆匹配的视界。此外,存在大量的影响交织运作的潜在变量,并且，因此,许多的位置体现出这些变量需要能被观察到。Thefirstresearchstudyleadinguptothethirdedition1985HCMfocusedonweavingareas[3].Thisunfortunate,asbasicsectionmodelswouldberevise
4、dlater,causingjudgmentalmodificationinweavingmodelsforconsistency.Itreliedon48setsofdatacollectedbythethenBureauofPublicRoadsinthelate1960sandanadditional12setscollectedspecificallyforthestudy.Themethodologythatresultedwascomplexanditerative.Itwaslatermodifiedaspartofastudyofallfreeway-r
5、elatedmethodologies[4]inthelate1970s.In1980,asetofinterimanalysisprocedureswaspublishedbyTRB[5],whichincludedthemodifiedweavinganalysisprocedure.Italsocontainedanindependentlydevelopedmethodologythatproducedoftensubstantiallydifferentresults.Thelattermethodologywasdocumentedinasubsequent
6、study[6].Toresolvethedifferencesbetweenthesetwomethodologies,anotherstudywasconductedintheearly1980s,usinganewdatabaseconsistingof10sites[7].Thisstudyproducedyetathirdmethodology,substantiallydifferentfromthefirsttwo.Asthepublicationdateofthe1985HCMapproached,thethreemethodologieswerejud
7、gmentallymerged,usingtheten1980ssitesforgeneralvalidationpurposes[8].Anumberofstudiesthroughoutthe1980sand1990scontinuedtoexaminethevariousweavingapproaches,withnocommonconsensusemerging[9-12].第一个主要集中于交织区域的研究是在1985年HCM的第三版之前[3]。这是不幸的,因为随后基本部分规程就被修改了，为了导致在交织规程审判的一致性。它项研究主要
