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时间:2019-02-05
《相关信号交叉口饱和流率动态提取方法》由会员上传分享,免费在线阅读,更多相关内容在工程资料-天天文库。
1、第13卷第1期交通运输工程学报Vol.13No.12013年2月JournalofTrafficandTransportationEngineeringFeb.2013文章编号:16711637(2013)01009806信号交叉口饱和流率动态提取方法杨东援,罗江邻,刘罛,段征宇(同济大学道路与交通工程教育部重点实验室,上海201804)摘要:提出了利用感应线圈检测器动态提取饱和流率的方法,前后车辆离开线圈的时间差为车头时距,计算第4辆至最后一辆处于饱和状态车辆的平均饱和车头时距,运用指数平滑法处理历史饱和车头时距与当前周期饱和车
2、头时距。确定了车型及饱和车头时距判断阈值,当线圈占用时间大于小型车平均占用线圈时间2倍时,判断为大型车,小型车的饱和车头时距判断阈值为历史平均值加1s,大型车的饱和车头时距判断阈值为历史平均值加5s。用VISSIM软件进行仿真,验证提取方法的有效性。仿真结果表明:动态提取方法能减少饱和车头时距突变的影响,当前周期车头时距骤减31.3%,饱和流率仅增加5.6%,5个周期的饱和流率分别为1782、1682、1600、1690、1773veh·h-1,而-1。与传统方法相比,该方法能满足动态提取的需求,实施HCM模型的计算结果为1680veh
3、·h成本低。关键词:信号交叉口;饱和流率;动态提取;饱和车头时距;阈值中图分类号:U491.51文献标志码:A犇狔狀犪犿犻犮犲狓狋狉犪犮狋犻狅狀犿犲狋犺狅犱狅犳狊犪狋狌狉犪狋犻狅狀犳犾狅狑狉犪狋犲犪狋狊犻犵狀犪犾犻狕犲犱犻狀狋犲狉狊犲犮狋犻狅狀YANGDongyuan,LUOJianglin,LIUChong,DUANZhengyu(KeyLaboratoryofRoadandTrafficEngineeringofMinistryofEducation,TongjiUniversity,Shanghai201804,China)
4、犃犫狊狋狉犪犮狋:Thedynamicextractionmethodofsaturationflowratebyusinginductioncoildetectorwasproposed.Takingthetimedifferenceofthefrontvehicleandthefollowingvehiclewhendepartingfromaninductioncoildetectorasheadway,theaveragesaturationheadwayfromthefourthvehicletothelastvehiclei
5、nsaturationstatewascalculated.Theaveragesaturationheadwaysofhistoryandcurrentcycleweredealtwithexponentialsmoothingmethod.Thresholdsforjudgingvehicletypeandsaturationheadwayweredetermined.Whentheoccupationtimeofavehiclewasmorethantwiceoftheaverageoccupationtimeofsmallveh
6、icle,thevehiclewasjudgedaslargevehicle.Thethresholdofsaturationheadwayforsmallvehiclewashistoricalaveragesaturationheadwayadding1s,andthatoflargevehiclewashistoricalaveragesaturationheadwayadding5s.ThevalidityoftheproposedmethodwastestifiedbyusingsoftwareVISSIM.Simulatio
7、nresultindicatesthatthedynamicextractionmethodcanreducethesuddenchangeinfluenceofsaturationheadway.Whenthesaturationheadwaysuddenlydecreasesby31.3%incurrentcycle,thesaturationflowrateonlyincreasesby5.6%,andthesaturationflow-1ratesin5cyclesare1782,1682,1600,1690,1773veh·h
8、respectively,nevertheless,the-1rateofHCMmodelis1680veh·h.Comparedwiththetraditionalmethods,themethodmee
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