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A Multiclass Dynamic Traffic Assignment Model for Special Events Management

A Multiclass Dynamic Traffic Assignment Model for Special Events Management. 12 th TRB National Transportation Planning Applications Conference May 17-21, 2009 Houston, Texas. Fang Yuan, Ph.D., P.E. Karen Giese, P.E. Kean Lew, P.Eng. Outline. Model Background Dynamic Assignment

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A Multiclass Dynamic Traffic Assignment Model for Special Events Management

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  1. A Multiclass Dynamic Traffic Assignment Model for Special Events Management 12th TRB National Transportation Planning Applications Conference May 17-21, 2009 Houston, Texas Fang Yuan, Ph.D., P.E. Karen Giese, P.E. Kean Lew, P.Eng

  2. Outline • Model Background • Dynamic Assignment • Pedestrian-Vehicle Interactions • Output

  3. Geographic Context

  4. Geographic Context

  5. Geographic Context

  6. Geographic Context

  7. Model Context • City of Vancouver hosts many large special events, including 2010 Winter Olympic and Paralympic Games • Existing City analysis tools limited: • Planning for events in isolation • No future projection of impacts • The City sought to develop a special event planning tool that would: • Capture the travel patterns of pedestrians and vehicles during special events (including interactions between them) • Allow for the testing of alternative transportation networks and event demand profiles / schedules • Facilitate scenario development with limited input detail

  8. Model Context (cont’d) • Existing pedestrian models generally fell into two categories: • Planning Models with limited consideration of pedestrian activity • Microsimulation Models with explicit pedestrian behavior modeling at an operational level, but limited route choice capabilities or vehicle modeling and high input burden • Solution: • Development of the Downtown Vancouver Transportation and Emergency Management System (DVTEMS)

  9. DVTEMS Model Features • Planning-level travel demand model • Focus on pedestrian route choice • Feature dynamic assignment • Based on the VISUM platform • Custom pedestrian-vehicle interactions • Communication through visual platform • Quantitative analysis

  10. DVTEMS Model Application • Identification of Bottlenecks/Network Deficiencies • Pedestrian Management Strategies • Event Road Closure Plans • Special Event Impacts • Construction Road Closure Alternatives • Emergency Management Planning

  11. DVTEMS Model Scope • Study Area: Stadium District • Model Extents: Downtown Peninsula • 24-hour Weekday (Friday) and Saturday 15-minute time intervals Pedestrians and Vehicles Calibrated Base (2007) and 2010

  12. Dynamic Assignment • Key Benefits (vs. Static Assignment) • Account for Special Event Temporal Characteristics • Account for Capacity Constraints and Changes • Model Proper Interaction of Real Flows • Model Impacts of Short-Term Measures • Present Congestion Phenomena

  13. VISUM Dynamic User Equilibrium (DUE) • Model and solution by G. Gentile & L. Meschni of Univ. of Rome • Multi mode, multi user dynamic traffic assignment • Accept time-varying input attributes (e.g. capacity, mode) • Can handle spillback and departure time choice • Coarse time discretization (DVTEMS: 24-hr period in 15-min interval) • Macroscopic flow model (simplifed kinematic wave theory) • Parabolic/trapeodial fundamental diagram (instead of VDF)

  14. VISUM Dynamic User Equilibrium (DUE) Vehicles Flow Diagram

  15. VISUM Dynamic User Equilibrium (DUE) Pedestrian Flow Diagram

  16. Modeling Pedestrian-Vehicle Interactions • No Interactions • Pedestrians use only sidewalk and cross roads at intersections • Two separate assignments • Controlled Interactions • Assign some roads (lanes) to pedestrians (e.g. special events): ped capacity = sidewalk capacity + road capacity assigned to pedestrians • Perform pedestrian assignment with defined pedestrian capacity • Update car turn capacity according to pedestrian flows at intersections • Perform car assignment with updated link and turn capacities

  17. Modeling Pedestrian-Vehicle Interactions • Random Interactions • Pedestrians may randomly and discontinuously take car capacity • Set predefined pedestrian capacity • Perform pedestrian assignment with pedestrian capacity • Update car turn capacity according to pedestrian flows at intersections • Reduce further car link capacity according to pedestrian flows on links • Perform car assignment with updated link and turn capacities

  18. Custom Interactions in DVTEMS • Two-way Pedestrian Capacity • Allows Pedestrians to Utilize Both Sidewalks Along Street • Vehicle-Pedestrian Interaction at Intersections • Uses Actual Crosswalk Flows from Assignment • Pedestrian Inundation • Pedestrians Encroach on Vehicle Space • Vehicle Capacity Decreased • User-defined Parameters

  19. Two-Way Sidewalk Capacity Vehicle capacity = f (link width in one direction) Ped capacity = f (link width in both directions AND ped volume)

  20. Two-Way Sidewalk Capacity Iteration 1: Ped Capacity EB = Ped Capacity WB = f (link width in BOTH directions) Initial Pedestrian Assignment: bi-directional flow for each link

  21. Two-Way Sidewalk Capacity Iteration 2 and Onward: Ped Capacity EB = (Ped Vol EB / Total Ped Vol) * Total Ped Capacity Ped Capacity WB = (Ped Vol WB / Total Ped Vol) * Total Ped Capacity Continue Pedestrian Assignment Iterations until Convergence

  22. Vehicle-Pedestrian Interaction at Intersections Run Pedestrian Assignment to Obtain Flows for Each Crosswalk Update Vehicle Turn Capacity = f (Ped Volumes) Run Vehicle Assignment with Updated Vehicle Turn Capacity

  23. Pedestrian Inundation • Pedestrian Encroachment on Vehicle Lane(s) • Parameters to be User-Defined (On or Off): • Inundation Allowed (Global Setting) • Pedestrian Link Density Threshold for Inundation (Global Setting) • On-Street Parking Allowed (Link Setting) • Pedestrian Allowed On Road (Link Setting)

  24. Pedestrian Inundation Link Density < Inundation Threshold Link Density > Inundation Threshold Link Density > Inundation Threshold

  25. Pedestrian Inundation • Link Density > Inundation Threshold Run Pedestrian Assignment to Obtain Flows and Capacity Required from Vehicle Network Adjust Vehicle Link Capacity Run Vehicle Assignment with Updated Vehicle Link Capacity

  26. DVTEMS Model Output • Volume by Time Interval and Mode • Pedestrian Density by Time Interval • Pedestrian Level of Service by Time Interval • Inundation Occurrence (Link Density > threshold and parameters allow for inundation) • Travel Times To/From Stadium by Mode

  27. Event 1 Start: 19:00 Pre-Event 2 Start: 18:50 Event 2 Start: 21:00 Example Scenario Results: Volumes, Density, LOS Over Time 20:30 20:00 19:15 19:30 19:45 19:00 18:15 20:15 18:45 18:00 17:15 17:30 17:45 17:00 18:30

  28. Event 1 End: 21:30 Event 2 End: 23:00 Example Scenario Results: Volumes, Density, LOS Over Time 21:00 21:45 21:30 21:15 22:00 22:45 22:30 22:15 23:00 23:15 23:30 23:45

  29. Example Scenario Results: Link Closure 19:15

  30. DVTEMS Future Expandability • Geographic and Temporal Expansion • Refined Pedestrian Route Choice through Real Data • Addition of New Scenarios

  31. www.ptvamerica.com Questions and Discussion Thank you for your attention. Special thanks to: University of Rome City of Vancouver Presentation Dedicated to Kean Lew, P.Eng.

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