Dynamic Traffic Assignment and Applications in the Twin Cities Area

1. Dynamic Traffic Assignment and Applications in the Twin Cities Area Steve Wilson SRF Consulting Group Duluth, Minnesota August, 2008

2. Outline • Background/FHWA Support • 35W Bridge Project • Test Applications • FHWA DTA Ongoing Development

3. What is Dynamic Traffic Assignment (DTA)? • Mesoscopic traffic assignment model • More responsive to operational factors (queuing) than traditional travel demand models • More responsive to system level factors (route-changing) than traditional operations models

4. Travel Demand Model Assignment Limitations • Trips are instantaneously on all links between origin to destination (not time-dependent) • Congestion delay does not adequately reflect bottlenecks (upstream or downstream)

5. DTA Models Availability • Federal Highways DTA • Commercial Vendors • CITILABS • TRANSCAD • PTV • EMME/2 • Others

6. FHWA DTA (TrEPS) Program • Started in 1995 • Two parallel tracks (Real-time ITS and Operational Planning) • Linking planning and operations • Concept of “Operational Planning” • Fill in the traffic analysis tool gap • Macroscopic (static, regional) • Mesoscopic (dynamic, regional) • Microscopic (dynamic, corridor) • Integration with TDM and microscopic model

7. Program Activities • DTA concept education and outreach • Webinars (online) – several per year • Short seminar (0.5-1 day) – on demand • Workshops (2.5 day) – 2 to 3 per year Mn/DOT (September 2008)

8. Program Activities • Technical support to state agencies • MPO/DOT – FHWA division – Resource center – FHWA HQ or TFHRC • Educational Support • Training for DTA concepts • Modeling Support • Assist in initial modeling and dataset buildup • Can be extended to consultants for a federally funded project • Matching-fund may be needed if more involvement is requested

9. M&O Status (updated May 2008) State Users Workshops held Future Workshops (TBD)

10. Initial Development of Twin Cities FHWA DTA Model • I-35W Bridge Collapse • FHWA Response • Pace of Study

11. MnDOT Model Development • Importing of regional TDF model network • Importing of regional TDF model trip tables • Network cleaning • Simplified traffic control assumptions

12. MnDOT Model Development • Calibration/adjustment of O-D matrices • Testing of routing/improvement scenarios

13. Initial Development of Twin Cities FHWA DTA Model • I-35W Bridge Collapse • FHWA Response • Pace of Study

14. I-35W UPA Project • UPA Program Competition • Innovative, multi-modal, priced • Open by end of 2009

15. I-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

16. Why Dynamic Traffic Assignment? • Availability • Better MOEs for comparison of Alternatives • High-level operational evaluation • HOT lane capabilities

17. Why Not Dynamic Traffic Assignment? • Availability/readiness • Memory/CPU resources • Learning curve • Traffic engineers’ comfort zone

18. Analysis(Top 20 O-D pairs impacted by bridge collapse)

19. Twin Cities FHWA DTA Model

20. Travel time into Downtown area

21. FHWA DTA Model (Subarea)

22. Learning Curve • “CORSIM-like” • Wiki help system • Model Integration w/ TDF softwares

23. FHWA DTA HOT Lane Options • Distance-based • Link-based • Zone-based (coming soon)

24. FHWA DTA HOT Lane Options Flexibility

25. Multiple User Class Flexibility

26. Flexible Traffic Flow Model

27. Exportable Tabular Output

28. Graphic Output

29. Time Stream Comparisons

30. FHWA DTA Tests(with subarea model) • Sensitivity to geometric changes • Through lane add • Auxiliary lane add • Bottleneck queuing • Stadium event departure • Peak-segment ramp O-D volumes

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

32. Lessons Learned • New DTA model not short-term response • Integration with planning/simulation models • Role of DTA in project development process

33. FHWA DTA V2.0 Modeling Features • Lane-group based Anisotropic Mesoscopic Simulation (AMS) models • Relative gap gradient based assignment algorithm • Epoch implementation for 24-hour to multi-day assignment • Destination and origin-based time-dependent least-cost path algorithms for various applications • Vertical integration with TDM and VISSIM

34. 2008 Projects and Applications Outlook • In progress • Military Deployment Transportation Improvement in Guam (PB, FHWA) • Interstate highway corridor improvement (TTI, TxDOT, ELPMPO) • Value Pricing (ORNL, FHWA; SRF, Mn/DOT, TTI, TxDOT) • Evacuation operational planning (UA, ADOT; LSU, LDOT; Noblis, FHWA; U of Toronto) • Integrated Corridor Management modeling (CS, FHWA) • Bay area regional modeling (CS, MTC) • Florida turnpike system traffic and evacuation analysis (FDOT Turnpike) • Commercial development traffic improvement (PAG)

35. Future Outreach Activities • Arizona • Workshop (July 29-31, jointly funded by MAG and FHWA) • Minnesota • Mn/DOT workshop (September 09) • California • CalTrans and CA MPOs (August 11-13, 2008) • 2-3 Kick-the-Tire webinars (FY 09) • 2-3 Training workshops (FY 09)

36. FHWA DTA V2.0 Modeling Features • Suite of supporting tools to facilitate model use: • Pre-processing • Network cleaning • Demand integration • Post-processing • Time-space diagrams • Time-varying link statistics reports • Cumulative arrival curves • Impacted vehicle analysis • Vehicle path analysis

37. Acknowledgements • FHWA • Jim McCarthy • Chung Tran • Mn/DOT Planning Division • Brian Isaacson • Mark Filipi • Tony Fischer • DynusT Labs • Yi-Chang Chiu, University of Arizona

38. Questions? Steve Wilson swilson@srfconsulting.com