交通工程学课件chp2traffic student

ursWhatarethecomponentsoftransportationsystem?transportationsystem?RoadCars,trucks,buses,RoadsandTrafficControl 2-1CharacteristicsofRoadUsers,Vehicles,2-1CharacteristicsofRoadUsers,Vehicles,andRoadsandResponsibilitiesand（职责与要求Professionalethics（职业道德Drivingcapabilities（驾驶能力DrivingProcess（驾驶过程Eyesandears(informationBrain(informationHandsandfeetPhysiologicalandPsychologicalVisual 80%ofthedivers‘informobtainedbytheireyesVision（视力）StaticviandDynamicvisualacuColorvision（色感VisualFieldsofVision（视野PhysiologicalandPsychologicalPerceptiontime（知觉时间）includesthedetection,identification,anddecisionelementsinvolvedinrespondingtoaReactiontime（反应时间）isthetimeittakestoinitiatethephysicalresponse.Perception-reactiontime（PRT，知觉-反应时间）：2.5s(AASHTO， 标准，绿皮书AASHTO:AmericanAssociationofStateHighwayandTransportationAnimportantcauseofroadcrashes（事故Estimatessuggestthatfatigueisafactorinupto30%offatal（ ）crashesand15%ofseriousinjury（重伤）crashesinAustralia.FactorscausingLackofqualityTimeofday：1am-6am,2pm-LengthofPurposesofTrip（目的Work,school, ,business,NeedsofPassengers（需求Safe,rapid,comfortable,convenient,GeometricDesign:Curves（曲线）,unevenroadsurface（不平整路面）,slopes（坡度）Space（空间NegativeImpactonSociety（社会影响CharacteristicsofPedLevelofService（服务水平）VsPedFlow:P16,Table2-5(Fruin,1980s)Walkingspeed（速度）vsdensity（密度）:Figure2-2(Polus,1979)FactorsAffectingPedTable2-6:Age,gender,trippurpose,education（教育）,mood（心境）,streetview,trafficstate,livingarea(urbanvs.rural)行速度较快，生活性出09~25m人，儿童个人空间要较快速度高；乡村人生节奏慢，步行速度慢Dimensions:Length,height,overhangsatthefrontandrear（前悬、后悬,andwheelbase（轴距Usedforroadandhighwaydesign:Minimumturningradii（最小转弯半径）Affectfacilityuse:U-turnsfromleftturnbays(prohibitedorallowed)SelectionofDesignPassengerCar→Parkinglots/→umspeed（最高速度Accelerationtime（加速时间 umgradeability(orgradeability)（最umgradevvvaxvt1at2xvKinematicsofVehicles（车辆动力学UniformAccelerationModel（匀加速模型dv Acc.~Speed~timeDistance~timeDistance~Uniformxv2 0 20 0Brakingdistance（制动距离Vinitialvehiclespeed（初始速度, coefficientoffriction（附着系数）betweentiresandroadwayigrade（坡度）expressedasadecimal,“+”forupgrades,“-”fordowngrades.Stabilityof））CharacteristicsofShortdistance:5–6km(20DynamicDecreasedBrakingCharacteristicsofBicycle ）:HighflowTidalflow（潮汐性Discreteness（离散性）:LowflowLackofcontrol（P19：Theratioofthelengthofthetotalroadnetworktothelandarea.Generally,levelofserviceoftheroadnetworkincreaseswithroaddensitySurface（路面）subgrade（路基）,bridgesandculverts（桥涵）,etc.Crosssection（横断面）,horizontal（平曲线），andverticalalignment（纵曲线RuralRoadPatterns（公路网布局P20,Table2-10forcharacte图 特点与性放射形路网一般用于中心城市与郊区、周围城镇间的交通联系，对于发挥大城市的经济、政治、科技、文化、信息中心作用，促进中心城市对周围地区的辐射和影响有重要作用，不足之处是周围城镇之间联系三角形路网一般用于规模相当的重要城镇间的直达交通联系这种布局形式通达性好效率高但设量大平行的几条干线分别联系着一系列城镇，而处于两条线上的城镇之间缺少便捷道路连接，是一种不完善的路网布局树叉形的路网一般是公路网中的最后一级是从干线公分叉出去的支线公路，将乡镇，自然村寨与市、县联接起来UrbanRoadPatterns（城市道路网布局SanRing(RadialandCircular)（放射环形London,Beijing,图 特点和性布局严整、简洁，有利于建筑布置，方向性好，网上交通分布均匀，交叉通组织容易，但非直线系数大，通达性差，过境交通不易分流，对大城市进一步扩展不利建筑物沿交通轴线两侧铺开，公共交通布置在主要交通干道范围内，横向靠步行或非机动车，有利于公共交通布线和组织，但容易造成纵向主干道交通压力过大，不易形成市中心交通干线以市中心为形心向外辐射，城市沿对外交通干线两侧发展，形成“指状”城市，这种布局具有带形布局的优点，同时缩短了到市中心的距离。缺点是中心区交通压力过大，边缘区相互间交通联系不便，过境交通无法分流这种布局具有通达性好、非直线系数小、有利于城市扩展和过境交通分流等优点，一般用于大城市，但不宜将过多的放射线引向市中心，以免造成市中心交通过分集中,Theactualnumberofvehiclespassingapointduringagiventimeinterval(usuallyonehourorlonger).FlowRate（交通流率Thenumberofvehiclespassingapointduringatimeintervallessthanonehour(usually15min.),butexpressedasanequivalenthourlyvolume.AADT#vehsobservedina#daysinayearWADTWADT17QADTAverageDailyTraffic（平均日交ADT1nQMADTMonthlyADT（月平均日交通量MADT1nQnisthenumberofdaysinaWADTWeeklyADT（周平均日交通量MonthlyVariation（月变化Seasonalfluctuationsintrafficdemandreflectthesocialandeconomicactivityoftheareabeinservedbthehihwa.MonthlyTrafficVolumeMonthlyTrafficVolumeVariationsfortheSameandUrbanSegments(Muranyi,1963)MonthlyK-factor（月变系数-P23,Equation2-Example2-K月>1.0ifMADTislowerthanK月<1.0ifMADTishigherthanWeeklyVariationorDailyVariationbyDayoftheWeek（周变化、日变化）Kfactor（日变系数Equation2-9SampleData（抽样数据Example2-13PHV-PeakHourVolume（ Basedoncountswithinpeakhour,lessthanonehourinlength.（小时内某一时段的交通量扩大为小时的交通量）100015x60minutes=4000vehiclesper1PHFPeakHour Ratiooftotalhourlyvolumetothe um15-minuteflowrate V=theHourlyvolume,inV15=thevolumeduringthepeak15minutesofthepeakhour,inveh/15minPHF=V/PeakHourFlowExample2-3PeakPeakhour:5:15-6:15PMPeakhourvolume:3189Peakflowrate:938x4=3752.Kfactor（方向分布系数DeterminationofDHV（设计小时交通量30thhighesthourlyvolumeinayearDHV/AADTisstable,typicallybetween0.11-0.15inourcountry.Equation2-DDHVDesignDirectionalHourlyEquation2-15，2-2-1,2-2-1,2-SpotSpeed（地点车速）Thespeedtakenatafixedroadsidepoint.OverallJourney)Speed（行程车速）Thespeedincludesstopsatwhichamotoristcanmaintainwhentryingtotravelatthehighestsafespeed.RunningSpeed（行驶车速）TheoverallspeedexclusiveofstopsTheaveragespeedmaintainedoveraparticularcoursewhilethevehicleismovingandisfoundbydividingthelengthofthecoursebythetimedurationthevehiclewasinmotion.OperatingSpeed（运行车速）:Theoverallspeedexclusiveofstops.Thehighestoverallspeedatwhichadrivercantravelonagivenhighwayunderfavorableweatherconditionsandunderprevailingtrafficconditionswithoutatanytimeexceedingthesafespeedasdeterminedbythedesignspeedonasection-by-sectionbasis.(AASHTOspeedatwhichthevolumeis DesignSpeed（设计车速）Theumsafespeedthatcanbemaintainedoveraspecifiedsectionofhighwaywhenconditionsaresofavorablethatthedesignfeaturesofthe ern.(AASHTOGreenBook)））StatisticsStatisticsofAverage(Mean)Speed（平均车速Equation2-17：Usingdatafromaspotspeedstudy,theaverageiscalculatedbysummingallthemeasuredspeedsanddividingbythesamplesize,n.PercentileSpeed（百分比车速50thpercentilespeedorMedianSpeed（中位车速Thespeedbelowwhich85percentofmotoristsFrequentlyusedtosetspeedlimits(限速Thespeedbelowwhich15percentofmotoristsTMSTMSandTMS-TimeMeanSpeed（时间平均车速Averagespeedofallvehiclespassingapointorshortsegmentofhighwayoversomespecifiedtimeinterval.Equation2-Arithmeticmean（算术平均值VtnnSMS-SpaceMeanSpeed（区间平均车Averagespeedofallvehiclesoccupyingagivensectionofahighwayoversomespecifiedtimeinterval.Equation2-HarmonicMean（调和平均值V111 tRelationshipRelationshipbtw.TMSandV=Vs 2tVtV2sVσtisthestandarddeviation（标准差）orMeanSquareErrorMSE，均方差）ofSMS.σsisthestandarddeviationorMSEofDerivationof DoitbyExample2-Driver:drivingabilities,gender,age,yearsofdrivingexperience,etc.Roadway:alignment,slope,numberoflanes,pavementtype,visibility,etc.Trafficconditions:trafficvolume,mixedtrafficflow,overtaking,trafficmanagement,FunctionalClassificationofRoadsandHighways:5levels way,ClassIHihway,ClassIIHihway,ClassIIIHighway,andClassIVHighwayUnclassifiedHighway（等外公路ClassificationClassificationofUrbanFunctionalClassificationofRoadsandHighways（道路UrbanRoads:4Expressway（快速路）MajorArterial（主干道）,MinorArterialorCollectorRoad（次干道）,LocalRoad（支路）DefinitionDefinitionofThenumberofvehiclesoccupyingagivenlengthoflaneorroadwayaveragedovertimevehiclesperkilometer(vpkm)orvehiclesperkilometerperlane(vpkmpl)