基于HCM的匝道通行能力研究(英文版).pptx

FREEWAYMERGEANDDIVERGESEGMENTS,(firstpart)HarbinInstituteofTechnologyApril.12,2016,汇报人：XXXXXX我只知道一件事，就是我一无所知苏格拉底,匝道的用途好的开始是成功的一半,匝道主要出现于高速路上，有时也出现在集散道路上。出现匝道控制的道路：多车道公路，双车道公路，城市主干道等,（1）连接两个道路设施的专用道路（2）在主线限制干扰时，为车辆提供以较高的速度实现分合流位移操作的结构（3）高速路上所有的分合流均在匝道连接上发生,集散公路（CollectorandDistributorRoad）,（1）城市附近的公路，干线公路（arterialhighway）的支路。各级公路都可设集散公路。（2）高速公路的集散公路是为了减少进出高速公路的车流交织和进出口数量在高速公路的一侧或两侧修建的与高速公路平行而又分离供车辆进出的专用车道。（3）集散公路能够有效提高存在交织运行的互通式立体交叉口的通行能力。,匝道组成与连接的形式,组成：匝道本身与匝道的两端接口,匝道连接方式：匝道高速公路连接（高速，多车道，集散道路）匝道城市道路连接Whenarampconnectiontoasurfacefacility(suchasamultilanehighway)oraCDroadwayisdesignedforhighspeedmergingordivergingwithoutcontrol,itmaybeclassifiedasarampfreewayjunctionforthepurposeofanalysis.,匝道的分类,（1）对于ramp-freeway连接：入口匝道（on-ramp）与出口匝道（off-ramp）（2）对于主要道路设施连接：主要合流连接（Majormergejunction）与主要分流连接（Majordivergejunction）（3）右侧匝道（righthandramps）和左侧匝道（4）单车道与双车道匝道（5）匝道上下游的附近匝道会对分析结果产生影响定义的明确对于获得可靠的结果来说必不可少,匝道连接的运行条件分析,一般情况：单车道右侧匝道分合流混乱原因：高换车道率特殊情况：双车道右侧匝道，左侧匝道模仿一般，稍作修改，即可适用,匝道的分析范围（空间与时间）,不独立，相互影响定义匝道影响区域，方便预测运行特性出入口匝道的影响区域（1英尺=0.3048m）高峰小时中的高峰15分钟,匝道连接的服务水平指标人是衡量一切的尺度？,稳定流（LOS：AE）根据影响区域的密度确定不稳定流（LOS：F）需求流量大于上游或者下游路段通行能力(1英里=1.609km),高速路所需数据问题太复杂，生命太短暂,1.FFS:5575mi/h;2.Numberofmainlinefreewaylanes:25;3.Terrain:level,rolling,ormountainous;orpercentgradeandlength;4.Heavyvehiclepresence:percenttrucksandbuses,percentrecreationalvehicles(RVs);5.Demandflowrateimmediatelyupstreamoftherampfreewayjunction;6.Peakhourfactor:upto1.00;and7.Driverpopulationfactor:0.851.00.最重要的是FFS（若无实测数据，适用模型进行预测）坡长的测量从匝道连接交叉点处开始,匝道高速路连接所需数据,1.Typeoframp:onramp,offramp,majormerge,majordiverge;2.Sideofjunction:righthand,lefthand;3.Numberoflanesonramproadway:1lane,2lanes;4.Numberoframplanesatrampfreewayjunction:1lane,2lanes;5.Lengthofacceleration/decelerationlane(s);12.Foradjacentupstreamordownstreamramps:a.Upstreamordownstreamdistancetothemerge/divergeunderstudy,b.Demandflowrateontheupstreamordownstreamramp,andc.Peakhourfactorandheavyvehiclepercentagesfortheupstreamordownstreamramp.,方法论未考虑的情形,Speciallanes,suchashighoccupancyvehicle(HOV)lanes,asrampentrylanes;Rampmetering;orIntelligenttransportationsystemfeatures.,输出结果与操作流程,1.Specifyinginputvariablesandconvertingdemandvolumestodemandflowratesinpassengercarsperhourunderequivalentbaseconditions;2.EstimatingtheflowremaininginLanes1and2ofthefreewayimmediatelyupstreamofthemergeordivergeinfluencearea;3.Estimatingthecapacityofthemergeordivergeareaandcomparingthecapacitywiththeconverteddemandflowrates;4.Forstableoperations(i.e.,demandislessthanorequaltocapacity),estimatingthedensitywithintherampinfluenceareaanddeterminingtheexpectedLOS;and5.Whendesired,estimatingtheaveragespeedofvehicleswithintherampinfluencearea.,Input：几何参数与需求变量Output：LOSandCapacityEstimation:densityandspeedintherampinfluencearea,变量总结,vF=flowrateonfreewayimmediatelyupstreamoftherampinfluenceareaunderstudy(pc/h),v12=flowrateinfreewayLanes1and2immediatelyupstreamoftherampinfluencearea(pc/h),vFO=flowrateonthefreewayimmediatelydownstreamofthemergeordivergearea(pc/h),vR=flowrateontheonramporofframp(pc/h),vR12=sumoftheflowratesinLanes1and2andtherampflowrate(onrampsonly)(pc/h),DR=densityintherampinfluencearea(pc/mi/ln),andSR=averagespeedintherampinfluencearea(mi/h).,Step1:SpecifyInputsandConvertDemandVolumestoDemandFlowRates,（1）如前所述，在分析之前本方法所涉及的几何参数与交通变量均需明确（2）所有主线到达车流，匝道上的和附近上下游匝道上的车流均需要从小时流量转换成高峰小时流率,vi=demandflowrateformovementi(pc/h),Vi=demandvolumeformovementi(veh/h),PHF=peakhourfactor,fHV=adjustmentfactorforheavyvehiclepresence,andfp=adjustmentfactorfordriverpopulation,Step2:EstimatetheApproachingFlowRateinLanes1and2oftheFreewayImmediatelyUpstreamoftheRampInfluenceArea,（1）到达匝道影响区域中机动车车道分布的影响因素,TotalfreewayflowapproachingtherampinfluenceareavF(pc/h),TotalonorofframpflowvR(pc/h),TotallengthoftheaccelerationlaneLAordecelerationlaneLD(ft),andFFSoftherampatthejunctionpointSFR(mi/h).对于所研究匝道上游几百英尺范围内的驶入匝道，会使得第一二车道中的机动车辆增加对于所研究匝道下游几百英尺范围内的驶出匝道，会使得欲驶出主线中的车辆在第一二车道增加,Step2:EstimatetheApproachingFlowRateinLanes1and2oftheFreewayImmediatelyUpstreamoftheRampInfluenceArea,（2）不同的车道数，临近匝道对于第一二车道中车辆分布的影响,双向四车道，不考虑双向六车道，重点考虑双向八车道，数据不足，无法考虑,（3）临近匝道距离足够近时，需要考虑的因素FlowrateontheadjacentupstreamrampVu(pc/h),DistancebetweenthesubjectrampjunctionandtheadjacentupstreamrampjunctionLUP(ft),FlowrateontheadjacentdownstreamrampvD(pc/h),andDistancebetweenthesubjectrampjunctionandtheadjacentdownstreamrampjunctionLDOWN(ft).（如何测量）,Step2:EstimatetheApproachingFlowRateinLanes1and2oftheFreewayImmediatelyUpstreamoftheRampInfluenceArea,（1）EstimatingFlowinLanes1and2forOn-Ramps,v12=flowrateinLanes1and2(pc/h),vF=totalflowrateonfreewayimmediatelyupstreamoftheonramp(merge)influencearea(pc/h),andPFM=proportionoffreewayvehiclesremaininginLanes1and2immediatelyupstreamoftheonrampinfluencearea.,Step2:EstimatetheApproachingFlowRateinLanes1and2oftheFreewayImmediatelyUpstreamoftheRampInfluenceArea,（2）第一二车道中车辆分布比例的确定,Step2:EstimatetheApproachingFlowRateinLanes1and2oftheFreewayImmediatelyUpstreamoftheRampInfluenceArea,（3）对于双向六车道Pfm公式的说明,对于孤立匝道和未发现临近匝道对研究匝道有影响的匝道，使用13-3当临近匝道距离足够近的时候（多近为足够近？）对于临近上游有驶出匝道，使用13-4对于临近下游有驶出匝道，使用13-5,Step2:EstimatetheApproachingFlowRateinLanes1and2oftheFreewayImmediatelyUpstreamoftheRampInfluenceArea,EstimatingFlowinLanes1and2forOff-Ramps,对于驶出匝道，一二车道中将包含所有的使出匝道的车辆与部分通过主线的车辆,V12=flowrateinLanes1and2ofthefreewayimmediatelyupstreamofthedecelerationlane(pc/h),vR=flowrateontheofframp(pc/h),andPFD=proportionofdivergingtrafficremaininginLanes1and2immediatelyupstreamofthedecelerationlane.,Step2:EstimatetheApproachingFlowRateinLanes1and2oftheFreewayImmediatelyUpstreamoftheRampInfluenceArea,（2）off-ramp第一二车道中车辆分布比例PFD的确定,Step2:EstimatetheApproachingFlowRateinLanes1and2oftheFreewayImmediatelyUpstreamoftheRampInfluenceArea,（3）对于双向六车道Pfm公式的说明,对于孤立匝道和未发现临近匝道对研究匝道有影响的匝道，使用13-9当临近匝道距离足够近的时候（多近为足够近？）对于临近上游有驶入匝道，使用13-10对于临近下游有驶出匝道，使用13-11,Step2:EstimatetheApproachingFlowRateinLanes1and2oftheFreewayImmediatelyUpstreamoftheRampInfluenceArea,特殊情况,对于上游驶入与下游驶出的研究匝道将该情况分为两种情形，分别进行计算，最后取比例较大的那一个,对于驶入与驶出匝道来说，以上的计算方程只应用于右侧单车道匝道，对于左侧的或者双车道连接匝道，一般都应用三个公式中的第一个公式,Step2:EstimatetheApproachingFlowRateinLanes1and2oftheFreewayImmediatelyUpstreamoftheRampInfluenceArea,对于车道分布预测的合理性进行检验,前面对于驶入与驶出匝道的车道分布公式均是通过大量的数据进行回归分析得出的。但是基于回归分析很可能得出不合理或者无法预料的预测结果，于是需要对于预测结果进行检验，下面提出两条对于车道1和车道2的流量的限制条件,1.Theaverageflowperlaneintheouterlanesofthefreeway(lanesotherthan1and2)shouldnotbehigherthan2,700pc/h/ln.2.Theaverageflowperlaneinouterlanesshouldnotbehigherthan1.5timestheaverageflowinLanes1and2.,两个限制条件中的任何一个被破坏，均需要矫正，这就需要下面的方法进行修改。,Step2:EstimatetheApproachingFlowRateinLanes1and2oftheFreewayImmediatelyUpstreamoftheRampInfluenceArea,对于双向六车道分布进行检验（只有一条外侧车道）,v3=flowrateinLane3ofthefreeway(pc/h/ln),vF=flowrateonfreewayimmediatelyupstreamoftherampinfluencearea(pc/h),andv12=flowrateinLanes1and2immediatelyupstreamoftherampinfluencearea(pc/h).,Step2:EstimatetheApproachingFlowRateinLanes1and2oftheFreewayImmediatelyUpstreamoftheRampInfluenceArea,对于双向八车道分布进行检验（有两条外侧车道）,v3=flowrateinLane3ofthefreeway(pc/h/ln),vF=flowrateonfreewayimmediatelyupstreamoftherampinfluencearea(pc/h),andv12=flowrateinLanes1and2immediatelyupstreamoftherampinfluencearea(pc/h).,Step3:EstimatetheCapacityoftheRampFreewayJunctionandComparewithDemandFlowRates,三个重要的核查点：1.Thecapacityofthefreewayimmediatelydownstreamofanonramporimmediatelyupstreamofanofframp,2.Thecapacityoftheramproadway,and3.Themaximumflowrateenteringtherampinfluencearea.,Step3:EstimatetheCapacityoftheRampFreewayJunctionandComparewithDemandFlowRates,对于高速路段，进入分合流区域，匝道路段进行饱和度检验，若成功，则向下计算密度，否则LOS为F,Step4:EstimateDensityintheRampInfluenceAreaandDeterminethePrevailingLOS,DensityinOn-Ramp(Merge)InfluenceAreas：,DensityinOff-Ramp(Diverge)InfluenceAreas：,LOSinrampinfluenceareasisdirectlyrelatedtotheestimateddensitywithinthearea,asgivenbyEquation1321orEquation1322.Exhibit132,shownpreviously,containsthecriteriaforthisdetermination.,Step5:EstimateSpeedsintheVicinityofRampFreewayJunctions,所需要估计的两种平均速度：（是否单独计算outerlane的车速）Averagespeedofvehicleswithintherampinfluencearea(mi/h),andAveragespeedofvehiclesacrossalllanes(includingouterlanes)withinthe1,500ftlengthoftherampinfluencearea(mi/h).,Step5:EstimateSpeedsintheVicinityofRampFreewayJunctions,Flowratesinouterlanescanbehigherthanthevaluecitedforbasicfreewaysegments.Thebasicfreewaysegmentvaluesrepresentaveragesacrossallfreewaylanes,notflowratesinasinglelaneorasubsetoflanes.Themethodologyhereinallowsflowsinouterlanestobeashighas2,700pc/h/ln.Theequationsforaveragespeedinouterlaneswerebasedonadatabasethatincludedaverageouterlaneflowsashighas2,988pc/h/lnwhilestillmaintainingstableflow.Valuesover2,700pc/h/ln,however,areunusualandcannotbeexpectedinthemajorityofsituations.,Outerlane的流率可以比基本路段的高对于分流区，允许Outerlane的速度比FFS的高但是对于分合流区所有车辆的速度要控制在FFS之内。,匝道的特殊情形：双车道入口匝道,与单车道入口匝道相比：密度，通行能力Forfourlanefreeways:PFM=1.000;Forsixlanefreeways:PFM=0.555;andForeightlanefreeways:PFM=0.209.,匝道的特殊情形：双车道出口匝道,与单车道入口匝道相比：密度，通行能力Forfourlanefreeways:PFD=1.000;Forsixlanefreeways:PFD=0.450;andForeightlanefreeways:PFD=0.260,匝道的特殊情形：左侧匝道,至今没有可靠的方法进行分析，将左手匝道当作右手匝道进行计算，使用一个矫正参数乘以计算值为左侧匝道值,匝道的特殊情形：双向十车道公路,降维的思想：从总的到达车流中减去第五车道的流量后，将五车道视为四车道进行分析,匝道的特殊情形：主要合流区,检查上游汇入道路与合流后道路下游路段的饱和度，LOS无法确定,匝道的特殊情形：主要分流区,分别检查上游汇入道路与分流后道路下游路段的饱和度，LOS无法确定,匝道的特殊情形：匝道的重叠影响区域分析,Wheneveraseriesoframpsonafreewayisanalyzed,the1,500ftrampinfluenceareascouldoverlap.Insuchcases,theoperationintheoverlappingregionisdeterminedbytherampinfluenceareahavingthehighestdensity.,案例：