Left Turn (DLT) Median U Turn (MUT) Crossing U Turn .Develop Alternative Intersection Guides Displaced

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  • DevelopAlternativeIntersectionGuides

    DisplacedLeftTurn(DLT)MedianUTurn(MUT)RestrictedCrossingUTurn(RCUT)August2014

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  • PresentationOutline

    Introduction ProjectBackground,Objectives,andTeam OverviewofAlternativeIntersections OverviewofDisplacedLeftTurn OverviewofMedianUTurnandRestrictedCrossingUTurn

    AdditionalResources

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  • Introduction

    TodaysPresenters JeffShaw,FHWA PeteJenior,Kittelson&Associates,Inc. HermanusSteyn,Kittelson&Associates,Inc.(DLTauthor) Dr.JoeHummer,WayneStateUniversity(RCUTauthor) JonathanReid,ParsonsBrinkerhoff(MUTauthor)

    WebinarOverview

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  • PresentationOutline

    Introduction ProjectBackground,Objectives,andTeam OverviewofAlternativeIntersections OverviewofDisplacedLeftTurn OverviewofMedianUTurnandRestrictedCrossingUTurn

    AdditionalResources

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  • ProjectBackground

    PastAlternativeIntersections/Interchanges:InformationalReport(AIIR) PublishedbyFHWAin2010 Providedasummaryoftherangeofintersectionformsprofessionalscouldconsider

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  • ProjectBackground

    EveryDayCounts(EDC)Initiative Designedtoidentifyanddeployinnovationaimedatreducingthetimeittakestodeliverhighwayprojects,enhancesafetyandprotecttheenvironment.

    Forthisproject Assistingeffortstobringrenewedfocustoalternativeintersections

    createeasytouseguidesandsupplementarywebinarmaterials

    FosterawiderimplementationoftheseEDCintersectionandinterchangedesignsbystatehighwayandlocalroadagencies,

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  • ProjectObjectives

    Developmaterialsthatwillaidhighwayplannersanddesigners

    Facilitatethedeploymentoffour(4)AlternativeIntersectiondesigns: DivergingDiamondInterchange(DDI) DisplacedLeftTurnIntersection(DLT) RestrictedCrossingUTurnIntersections(RCUT) MedianUTurnIntersection(MUT)

    Replacethe2010AIIRinformationwithcurrentresearchandfindings

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  • ProjectObjectives

    GuideOutline consistentforallGuides Chapter1 Introduction Chapter2 PolicyandPlanning Chapter3 MultimodalConsiderations Chapter4 Safety Chapter5 OperationalCharacteristics Chapter6 OperationalAnalysis Chapter7 GeometricDesign Chapter8 Signal,Signing,MarkingandLighting Chapter9 ConstructionandMaintenance Appendices

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  • ProjectObjectives

    FocusoftheGuides Policyandplanningconsiderations Multimodalconsiderations Publicoutreachmaterialsandresources Currentsafetyresearchandoperationalpractices

    Whilestillproviding Geometricdesignguidance Signals,signingandpavementmarkingdetails Constructionconsiderations

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  • ProjectTeam

    OverallProjectManagement FederalHighwayAdministration VirginiaTechTransportationInstitute Kittelson&Associates,Inc.(BrianRay,PrincipalInvestigator)

    DivergingDiamondInterchange Dr.BastianSchroeder ChrisCunningham

    DisplacedLeftTurnIntersection HermanusSteyn,Kittelson&Associates,Inc.

    MedianUTurnIntersection JonathanReid,ParsonsBrinckerhoff

    RestrictedCrossingUTurnIntersection Dr.JoeHummer,WayneStateUniversity

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  • PresentationOutline

    Introduction ProjectBackground,ObjectivesandTeam OverviewofAlternativeIntersections OverviewofDisplacedLeftTurnIntersection OverviewofMedianUTurnandRestrictedCrossingUTurnIntersections

    AdditionalResources

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  • OverviewofAlternativeIntersections

    Providepotentialtoimprovesafetyandreducedelayatalowercostthantraditionalsolutions

    Oftenunfamiliartotransportationpractitionersduetolimitedexistingapplications

    Requirespecificplanningandpolicyconsiderationsforallusers

    Createtheneedforpublicinvolvementanddrivereducation

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  • PlanningConsiderations

    Alternativeintersectionevaluationsmayvarydependingonthestageoftheprojectdevelopmentprocess

    Planningleveldesignevaluationsmaynotrequireadetailedlevelofanalysis

    Evaluationsshouldbecomprehensiveenoughtoanswerkeyprojectquestionsforeachuniqueprojectcontext

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  • PedestrianandBicycleAccommodation

    Pedestriansmayberequiredtocrossmultiplelaneswithpotentialmultistagecrossings

    Somemaneuversthroughintersectionarecounterintuitiveforpedestriansandbicycles

    Bicyclistsareaccommodatedontheroadoroffstreetinsharedusepaths

    Evaluatetradeoffstoaddressvarioususerneeds

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  • StakeholderOutreach Theimplementationmayrequireextensivepublicoutreachandeducationalmeetingstofamiliarizethepublicwiththeunusualgeometry. Outreachshouldbedirectedatallusers

    Source: Utah Department of Transportation

    Source: North Carolina Department of Transportation

    Source: Utah Department of Transportation

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  • TypesofAlternativeIntersections

    DisplacedLeftTurnIntersection ContinuousFlowIntersection(CFI) CrossoverDisplacedLeftTurnIntersection

    MedianUTurnIntersection MedianUturnCrossover BoulevardTurnaround MichiganLoon ThrUTurnIntersection

    RestrictedCrossingUTurnIntersection SuperstreetIntersection JturnIntersection SynchronizedStreetIntersection

    DivergingDiamondInterchange DoubleCrossoverDiamond(DCD)

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  • PresentationOutline

    Introduction ProjectBackground,ObjectivesandTeam OverviewofAlternativeIntersections OverviewofDisplacedLeftTurnIntersection OverviewofMedianUTurnandRestrictedCrossingUTurnIntersections

    AdditionalResources

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  • Poll

    ArethereDisplacedLeftTurnintersectionsinyourstate?

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  • DisplacedLeftTurnIntersection

    OverviewofIntersectionType MultimodalConsiderations SafetyConsiderations Operations GeometricDesign Signing,StripingandLighting Construction

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  • Overview:DisplacedLeftTurnIntersection

    Anyintersectionformrelocatingoneormoreleftturnmovementsonanapproachtotheothersideoftheopposingtrafficflow. Allowsleftturnmovementstoproceedsimultaneouslywiththethroughmovements

    Eliminatestheleftturnphaseforthisapproach Reducesthenumberoftrafficsignalphasesandconflictpoints(locationswhereuserpathscross)

    Canresultinimprovementsintrafficoperationsandsafetyperformance

    Greentimecanbereallocatedtofacilitatepedestriancrossings

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  • Overview:DisplacedLeftTurnIntersection

    FourleggedDLTwithdisplacedleftsonamajorstreet

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  • Overview:DisplacedLeftTurnIntersection

    RangeofConfigurations FourleggedDLTintersectionwithfourdisplacedlefts

    Withchannelizedrightturns Withoutchannelizedrightturns

    FourleggedDLTintersectionwithmajorstreetdisplacedleftsandchannelizedrightturns

    Withchannelizedrightturns Withoutchannelizedrightturns

    ThreeleggedDLTintersectionwithmajorstreetdisplacedleft ThreeleggedDLTintersectionwithminorstreetdisplacedleft

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  • With/WithoutChannelizedRightTurns

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  • MultimodalConsiderations/CompleteStreets

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    Designelements Widthofroadway

    Crossingdistanceforpedestrians Exposureofbicyclistsinconflictzones

    Busstoplocationsrelativetonaturalwalkingpaths Uniquemovements Largevehicles

  • Pedestrians

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    Designandoperationalchallenges

  • Bicycles:OnStreetBicyclists

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  • Bicycles:OffStreetBicyclists

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  • Bicycles:BicycleLeftTurn

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    On-Street Left: Bicycle Box

    Off-Street Left: Share with Pedestrians

  • Transit:BusPullout

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    PotentialQueueJumpforLeft/ThroughBuses

  • Transit:InTravelLanesBusStops

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    Queuingbehindstoppedbuses

  • SafetyPrinciples

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    ThereislimiteddocumentationaboutthesafetyperformanceofDLTintersections

    Conflictsarecorrelatedwithcollisionsandareoftenusedasasurrogatemeasure

    DLTIntersectionConflictanalysisisshownbelow

    PartialDLT:30conflictpoints14crossing,16merging/diverging

    Conventional:32conflictpoints16crossing,16merging/diverging

  • SafetyConcerns

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    Driverunfamiliarity Counterintuitivedesignfeatures Useappropriatedesignandsigningtopreventwrongwaymovement

    DesirableUndesirable

  • OperationalPrinciples

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    DLTsusuallyimplementedtomaximizethroughput OperationalBenefit

    allowingleftturnstomoveconcurrentlywiththroughtraffic

  • SignalPhasing DLTcanhaveupto5

    signalizedintersections 1isthemainintersection 2through5arethe

    crossoverintersections

    DLTintersectionstypicallyhaveshortercyclelengthsthansimilarlysizedtraditionalintersections Duetothereduced

    numberofphases andtheneedtoreduce

    queuelengthsbetweenthecloselyspacedintersections

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  • SystemwideConsiderations

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    Canbeimplementedasacorridorwidetreatment

    Fewersignalphasesallowforlongergreenbands,improvingsignalcoordination

    Bangerter Highwaywith8DLTintersectionsandoneDDI

    DLT

    DDI

  • OperationalAnalysisandTools

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    PlanninglevelTools Criticallaneanalysis

    CapX HCMAnalysisMethods

    HCS,Synchro,Vistro Limitations

    Closelyspacedintersections

    Modelingunusualgeometry;e.g.,displacedleftturns

    Microsimulation

  • GeometricDesign

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  • GeometricDesignParameterandPrinciples

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    MainIntersection Uniquedisplacedleftturnsconfiguration

    Accommodatingpedestrians(refugeislands) Appropriateturningpaths

  • GeometricDesignParametersandPrinciples

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    CrossoverIntersectionGeometry

  • GeometricDesignParametersandPrinciples

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    CrossoverIntersection Therearetwowaystoaccommodatethegeometrywheretherightturnbypasslanejoinsthecrossroadthroughlanes:

    SignalizedrightturnAddlanewithadownstream

    lanemerge

  • OperationalEffectsofGeometricDesign

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    CrossoverIntersection Trafficoperationsestablishesinitialcl