Dynamic Traffic Dynamic Traffic Assignment and Assignment and Applications in the Twin Applications in the Twin Cities AreaCities Area

Steve WilsonSteve Wilson SRF Consulting GroupSRF Consulting Group

Duluth, MinnesotaDuluth, Minnesota

August, 2008August, 2008

OutlineOutline

Background/FHWA SupportBackground/FHWA Support 35W Bridge Project35W Bridge Project Test ApplicationsTest Applications FHWA DTA Ongoing DevelopmentFHWA DTA Ongoing Development

What is Dynamic What is Dynamic Traffic Assignment Traffic Assignment (DTA)?(DTA)? Mesoscopic traffic assignment Mesoscopic traffic assignment

modelmodel– More responsive to operational More responsive to operational

factors (queuing) than traditional factors (queuing) than traditional travel demand modelstravel demand models

– More responsive to system level More responsive to system level factors (route-changing) than factors (route-changing) than traditional operations modelstraditional operations models

Travel Demand Model Travel Demand Model Assignment Assignment LimitationsLimitations Trips are instantaneously on all Trips are instantaneously on all

links between origin to links between origin to destination (not time-dependent)destination (not time-dependent)

Congestion delay does not Congestion delay does not adequately reflect bottlenecks adequately reflect bottlenecks (upstream or downstream) (upstream or downstream)

DTA Models DTA Models AvailabilityAvailability Federal Highways DTAFederal Highways DTA Commercial VendorsCommercial Vendors

– CITILABSCITILABS– TRANSCADTRANSCAD– PTV PTV – EMME/2 EMME/2 – OthersOthers

FHWA DTA (TrEPS) FHWA DTA (TrEPS) ProgramProgram

Started in 1995Started in 1995 Two parallel tracks (Real-time ITS and Two parallel tracks (Real-time ITS and

Operational Planning) Operational Planning) Linking planning and operationsLinking planning and operations

– Concept of “Concept of “Operational PlanningOperational Planning”” Fill in the traffic analysis tool gapFill in the traffic analysis tool gap

– Macroscopic (static, regional) Macroscopic (static, regional) – Mesoscopic (dynamic, regional) Mesoscopic (dynamic, regional) – Microscopic (dynamic, corridor)Microscopic (dynamic, corridor)

Integration with TDM and microscopic Integration with TDM and microscopic model model

Program ActivitiesProgram Activities

DTA concept education and outreachDTA concept education and outreach

– Webinars (online) – several per yearWebinars (online) – several per year

– Short seminar (0.5-1 day) – on demandShort seminar (0.5-1 day) – on demand

– Workshops (2.5 day) – 2 to 3 per yearWorkshops (2.5 day) – 2 to 3 per yearMn/DOT (September 2008)Mn/DOT (September 2008)

Program ActivitiesProgram Activities

Technical support to state agenciesTechnical support to state agencies– MPO/DOT – FHWA division – Resource MPO/DOT – FHWA division – Resource

center – FHWA HQ or TFHRCcenter – FHWA HQ or TFHRC– Educational SupportEducational Support

Training for DTA conceptsTraining for DTA concepts

– Modeling SupportModeling Support Assist in initial modeling and dataset Assist in initial modeling and dataset

buildupbuildup Can be extended to consultants for a Can be extended to consultants for a

federally funded projectfederally funded project Matching-fund may be needed if more Matching-fund may be needed if more

involvement is requestedinvolvement is requested

M&O StatusM&O Status (updated May 2008) (updated May 2008)

State Users

Workshops held

Future Workshops(TBD)

Initial Development of Initial Development of Twin Cities FHWA DTA Twin Cities FHWA DTA ModelModel

I-35W Bridge I-35W Bridge CollapseCollapse

FHWA ResponseFHWA Response Pace of StudyPace of Study

MnDOT Model MnDOT Model DevelopmentDevelopment Importing of regional TDF model Importing of regional TDF model

networknetwork Importing of regional TDF model Importing of regional TDF model

trip tablestrip tables Network cleaningNetwork cleaning Simplified traffic control Simplified traffic control

assumptionsassumptions

MnDOT Model MnDOT Model DevelopmentDevelopment Calibration/adjustment of O-D Calibration/adjustment of O-D

matricesmatrices Testing of routing/improvement Testing of routing/improvement

scenariosscenarios

Initial Development of Initial Development of Twin Cities FHWA DTA Twin Cities FHWA DTA ModelModel

I-35W Bridge I-35W Bridge CollapseCollapse

FHWA ResponseFHWA Response Pace of StudyPace of Study

I-35W UPA ProjectI-35W UPA Project

UPA Program UPA Program CompetitionCompetition

Innovative, multi-Innovative, multi-modal, pricedmodal, priced

Open by end of Open by end of 20092009

I-35W UPA ProjectI-35W UPA Project

Priced dynamic shoulder lane segment

Addition of a HOT lane in Crosstown reconstruction project

Conversion of existing HOV lane to HOT lane

Also: BRT advanced implementation, park-ride, ITS

Why Dynamic Traffic Why Dynamic Traffic Assignment?Assignment? AvailabilityAvailability Better MOEs for comparison of Better MOEs for comparison of

AlternativesAlternatives High-level operational evaluationHigh-level operational evaluation HOT lane capabilitiesHOT lane capabilities

Why Why NotNot Dynamic Dynamic Traffic Assignment?Traffic Assignment? Availability/readinessAvailability/readiness

Memory/CPU resourcesMemory/CPU resources

Learning curveLearning curve

Traffic engineers’ comfort zoneTraffic engineers’ comfort zone

AnalysisAnalysis(Top 20 O-D pairs impacted by (Top 20 O-D pairs impacted by bridge collapse)bridge collapse)

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Twin Cities FHWA DTA Twin Cities FHWA DTA ModelModel

Travel time into Travel time into Downtown areaDowntown area

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FHWA DTA Model FHWA DTA Model (Subarea)(Subarea)

Learning CurveLearning Curve

““CORSIM-like”CORSIM-like”

Wiki help systemWiki help system

Model Integration w/ TDF Model Integration w/ TDF softwaressoftwares

FHWA DTA HOT Lane FHWA DTA HOT Lane OptionsOptions Distance-basedDistance-based

Link-basedLink-based

Zone-based (coming soon)Zone-based (coming soon)

FHWA DTA HOT Lane FHWA DTA HOT Lane Options FlexibilityOptions Flexibility

Multiple User Class Multiple User Class FlexibilityFlexibility

Flexible Traffic Flow Flexible Traffic Flow ModelModel

Exportable Tabular Exportable Tabular OutputOutput

Graphic OutputGraphic Output

Time Stream Time Stream ComparisonsComparisons

FHWA DTA TestsFHWA DTA Tests(with subarea model)(with subarea model)

Sensitivity to geometric changesSensitivity to geometric changes– Through lane addThrough lane add– Auxiliary lane addAuxiliary lane add– Bottleneck queuingBottleneck queuing

Stadium event departureStadium event departure Peak-segment ramp O-D volumesPeak-segment ramp O-D volumes

Best Candidate DTA Best Candidate DTA UsesUses Evacuation Planning Work zones Systems Planning Value pricing/HOT Lanes Benefit-Cost Analysis Travel demand model feedback

Lessons LearnedLessons Learned

New DTA model not short-term New DTA model not short-term responseresponse

Integration with planning/simulation Integration with planning/simulation modelsmodels

Role of DTA in project development Role of DTA in project development processprocess

FHWA DTA V2.0 FHWA DTA V2.0 Modeling FeaturesModeling Features Lane-group based Anisotropic Mesoscopic Lane-group based Anisotropic Mesoscopic

Simulation (AMS) models Simulation (AMS) models Relative gap gradient based assignment Relative gap gradient based assignment

algorithmalgorithm Epoch implementation for 24-hour to multi-Epoch implementation for 24-hour to multi-

day assignmentday assignment Destination and origin-based time-dependent Destination and origin-based time-dependent

least-cost path algorithms for various least-cost path algorithms for various applicationsapplications

Vertical integration with TDM and VISSIMVertical integration with TDM and VISSIM

2008 Projects and 2008 Projects and Applications OutlookApplications Outlook

In progressIn progress– Military Deployment Transportation Improvement in Military Deployment Transportation Improvement in

Guam (PB, FHWA)Guam (PB, FHWA)– Interstate highway corridor improvement (TTI, TxDOT, Interstate highway corridor improvement (TTI, TxDOT,

ELPMPO)ELPMPO)– Value Pricing (ORNL, FHWA; SRF, Mn/DOT, TTI, TxDOT)Value Pricing (ORNL, FHWA; SRF, Mn/DOT, TTI, TxDOT)– Evacuation operational planning (UA, ADOT; LSU, LDOT; Evacuation operational planning (UA, ADOT; LSU, LDOT;

Noblis, FHWA; U of Toronto)Noblis, FHWA; U of Toronto)– Integrated Corridor Management modeling (CS, FHWA)Integrated Corridor Management modeling (CS, FHWA)– Bay area regional modeling (CS, MTC)Bay area regional modeling (CS, MTC)– Florida turnpike system traffic and evacuation analysis Florida turnpike system traffic and evacuation analysis

(FDOT Turnpike)(FDOT Turnpike)– Commercial development traffic improvement (PAG)Commercial development traffic improvement (PAG)

Future Outreach Future Outreach ActivitiesActivities ArizonaArizona

– Workshop (July 29-31, jointly funded by Workshop (July 29-31, jointly funded by MAG and FHWA)MAG and FHWA)

MinnesotaMinnesota– Mn/DOT workshop (September 09)Mn/DOT workshop (September 09)

CaliforniaCalifornia– CalTrans and CA MPOs (August 11-13, CalTrans and CA MPOs (August 11-13,

2008)2008) 2-3 Kick-the-Tire webinars (FY 09)2-3 Kick-the-Tire webinars (FY 09) 2-3 Training workshops (FY 09)2-3 Training workshops (FY 09)

FHWA DTA V2.0 FHWA DTA V2.0 Modeling FeaturesModeling Features Suite of supporting tools to facilitate model Suite of supporting tools to facilitate model

use:use:– Pre-processingPre-processing

Network cleaningNetwork cleaning Demand integrationDemand integration

– Post-processingPost-processing Time-space diagramsTime-space diagrams Time-varying link statistics reportsTime-varying link statistics reports Cumulative arrival curvesCumulative arrival curves Impacted vehicle analysisImpacted vehicle analysis Vehicle path analysisVehicle path analysis

AcknowledgementsAcknowledgements

FHWAFHWA– Jim McCarthyJim McCarthy– Chung TranChung Tran

Mn/DOT Planning DivisionMn/DOT Planning Division– Brian IsaacsonBrian Isaacson– Mark FilipiMark Filipi– Tony FischerTony Fischer

DynusT LabsDynusT Labs– Yi-Chang Chiu, University of ArizonaYi-Chang Chiu, University of Arizona

Questions?Questions?

Steve WilsonSteve Wilson

swilson@srfconsulting.comswilson@srfconsulting.com