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San Francisco’s Dynamic Traffic Assignment Model

San Francisco’s Dynamic Traffic Assignment Model. Background. SFCTA DTA Model Peer Review Panel Meeting July 25 th , 2012. Outline. Project Background Modeling tool suite SF-CHAMP 4.3.0 Fury Previous DTA work. SF-CHAMP.

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San Francisco’s Dynamic Traffic Assignment Model

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  1. San Francisco’s Dynamic Traffic Assignment Model Background SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY SFCTA DTA Model Peer Review Panel Meeting July 25th, 2012

  2. Outline • Project Background • Modeling tool suite • SF-CHAMP 4.3.0 Fury • Previous DTA work SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY

  3. SF-CHAMP • Simulates the travel pattern of every Bay Area Resident based on: • Demographics • Land use • Transportation Network SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY

  4. = Tour = Trip Number indicates trip order 4 2 1 7 6 5 3 SF-CHAMP HOME-BASED TOUR DESTINATION A tour is an entire chain of trips: from your primary origin, to all of your destinations, and then back again. SECONDARY HOME-BASED TOUR HOME Primary destinations vs.Intermediate stops PRIMARY TOUR: Home-based Work INTERMEDIATE STOP ON WAY TO WORK WORK Consequences of choices: Do you have a car available? Did you leave the car at home? Do you have a complicated day? WORK-BASED SUB-TOUR WORK-BASED DESTINATION SF-CHAMP Model Basics

  5. SF-CHAMP Data • Most models BATS 1996 • New estimations (BATS 2000): • Mode choice • Auto Availability • New calibration (ACS) • Workplace Location Choice • Auto Availability • Tour mode choice • New validation • 2010 APCs and Ridership • Recent Traffic Counts SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY

  6. CHAMP SEQUENCING – PART 1 • Workplace location • Vehicle Availability: • Accessibility of home • Accessibility of work • Accessibility between home and work • Tours Generated • Accessibility of home • Accessibility of work • Accessibility between home and work • Initially Schedule Tours • Primary destinations for non-work tours • Initial tour schedule • Accessibility SF-CHAMP Model Basics

  7. CHAMP SEQUENCING – PART 2 • Tour scheduling • Accessibility by time of day for chosen destination • Tour mode • Accessibility to destinations for that time of day by mode • Choose intermediate stops along tours (tours become trips) • Trip mode choice • Cost • Travel Time • Assign trips by mode to specific transit lines and highway paths • Cost • Travel Time SF-CHAMP Model Basics

  8. SF-CHAMP – in Flow Chart Form SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY

  9. Spatial Detail – Analysis Zones Trips are aggregated into “zones” 981 zones in San Francisco 1,275 in other Bay Area counties SF-CHAMP Model Basics

  10. Spatial Detail - Transit Every transit stop Every transit line Every street SF-CHAMP Model Basics

  11. SF-CHAMP – Roadway validation SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY

  12. SF-CHAMP – Roadway validation SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY

  13. SF-CHAMP – Roadway validation SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY

  14. SF-CHAMP – Roadway validation Estimated/Observed Estimated/Observed %RMSE SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY

  15. SF-CHAMP – Transit validation SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY

  16. An additional tool in the toolbox - DTA Regional static user equilibrium activity-based model SF-CHAMP Time-dependent user equilibrium with realistic, but simplified vehicle simulation Dynamic Traffic Assignment Highly realistic simulation of vehicle behavior and interactions Traffic Microsimulation SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY

  17. Northwest quadrant DTA network 200 Internal Zones 60 External Zones 3,000 Nodes 7,000 Links 240 Signals 83 Transit Lines SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY

  18. How have we used DTA? • Presidio Parkway Construction • Where do vehicles re-route when intra-SF ramps are taken away on Doyle Drive? SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY

  19. How have we used DTA? • Geary Bus Rapid Transit • Where do vehicles re-route when we take a lane away from Geary? • How do diversions affect other streets? SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY

  20. SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY

  21. Geary BRT DTA – Diversions (draft) SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY

  22. Issues that arose from current DTA use • DTA represents ideal world network LOS knowledge • Drastic shifts away from main-line roadways when their capacity reduced • Hides potential congestion on Geary • Subarea reliant on demand from external stations • Validation of individual turn movements important • “Surgical Adjustments” still required • Reliant on centroid-connector placement • Conflicting validation data SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY

  23. San Francisco’s Dynamic Traffic Assignment Model Model Development Process SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY SFCTA DTA Model Peer Review Panel Meeting July 25th, 2012

  24. Outline - Model Development Process • Objectives for now versus the future • Overall Approach • DTA Package Selection • Project Tasks and Schedule SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY

  25. DTA Model Development Objectives (for now) • Have a working DTA model with results that make sense for the PM Peak period in San Francisco • Have seamless process from SF-CHAMP to DTA results: • Little human intervention • Reduce human error • Use SF-CHAMP demand directly • Behaviorally consistent • Allow SF-CHAMP to take advantage of all fixes • Test having SF-CHAMP use DTA as it’s network model SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY

  26. Left for “the Future” • Rigorous validation for specific subareas • Reconfiguring centroid loadings to be at parking • Trip chaining and tours • Loading miiples from SF-CHAMP with their individual characteristics • Influence of non-motorized travel on traffic flow • 24 hour model; bigger subarea? • Assigning people to transit trips • The future is now (FAST-TrIPs) SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY

  27. DTA Model Development Approach • Write code when possible for repeated human tasks : • Data format conversion • Network manipulation and validation for DTA • Output validation and visualization • Develop in an open source environment • Don’t re-write code that exists in our DTA package • Make a counts database that interacts with our network (CountDracula) SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY

  28. DTA Model Development Approach • Use as much ‘real’ data as possible • Signal timings • Stop signs • Transit • Traffic flow parameters • Fix all issues “at the source” if possible • Network geometry • Turn prohibitions • Demand (SF-CHAMP) SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY

  29. DTA Package Selection • Evaluated alternatives that we knew about • Selected Dynameq because: • Mature UI • Developer responsive with development pathway • Detailed network representation: • Lane-based delay • Transit vehicles and schedules explicit • Was able to run • Results made sense when we tested it SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY

  30. Tasks and Schedule 2011 2012 A S O N D J F M A M J J A S O Project Management Model Development Demand Preparation Network Preparation Data Preparation Model Calibration Tools Development Demand Conversion Network Conversion Signal Conversion Transit Conversion Summary Application/Integration Integration Memo Applications Evaluation/Reporting Peer Review Webinar SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY

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