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SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY San Francisco’s Dynamic Traffic Assignment Model Background SFCTA DTA Model Peer Review Panel Meeting July 25 th, 2012
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SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY2 Outline Project Background Modeling tool suite SF-CHAMP 4.3.0 Fury Previous DTA work
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SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY3 SF-CHAMP Simulates the travel pattern of every Bay Area Resident based on: Demographics Land use Transportation Network
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SF-CHAMP Model Basics4 SF-CHAMP HOME WORK INTERMEDIATE STOP ON WAY TO WORK WORK-BASED DESTINATION HOME-BASED TOUR DESTINATION 1 7 6 5 4 3 2 = Tour = Trip Number indicates trip order PRIMARY TOUR: Home-based Work WORK-BASED SUB-TOUR SECONDARY HOME-BASED TOUR Primary destinations vs. Intermediate stops Consequences of choices: Do you have a car available? Did you leave the car at home? Do you have a complicated day? A tour is an entire chain of trips: from your primary origin, to all of your destinations, and then back again.
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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 AUTHORITY5
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SF-CHAMP Model Basics6 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
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SF-CHAMP Model Basics7 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
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SF-CHAMP – in Flow Chart Form SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY8
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SF-CHAMP Model Basics9 Trips are aggregated into “zones” 981 zones in San Francisco 1,275 in other Bay Area counties Spatial Detail – Analysis Zones
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SF-CHAMP Model Basics10 Spatial Detail - Transit Every transit stop Every transit line Every street
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SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY11 SF-CHAMP – Roadway validation
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SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY12
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SF-CHAMP – Roadway validation SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY13
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SF-CHAMP – Roadway validation SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY14 Time of Day Area TypeEAAMMDPMEV24HR 0/1/21.3300.9691.0411.0351.0091.030 31.2891.0511.1691.0501.1631.128 4/51.2811.1041.2351.0841.2891.191 All Locations1.3031.0351.1351.0541.1241.105 Time of Day Volume ClassificationEAAMMDPMEV24HR <40k1.3851.0851.1781.0841.1201.135 40-80k1.3091.0921.2001.0151.1811.140 >=80k1.2880.9821.0791.0821.0881.073 All Locations1.3031.0351.1351.0541.1241.105 Time of Day Volume ClassificationEAAMMDPMEV24HR <40k0.2180.0900.1160.0770.1430.107 40-80k0.0970.0500.0670.0450.0830.057 >=80k0.1290.0480.0470.0690.0670.050 All Locations0.0800.0320.0360.0370.0470.035 Estimated/Observed %RMSE
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SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY15 SF-CHAMP – Transit validation
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An additional tool in the toolbox - DTA SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY16 SF-CHAMP Dynamic Traffic Assignment Traffic Microsimulation Time-dependent user equilibrium with realistic, but simplified vehicle simulation Regional static user equilibrium activity-based model Highly realistic simulation of vehicle behavior and interactions
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Northwest quadrant DTA network SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY17 200 Internal Zones 60 External Zones 3,000 Nodes 7,000 Links 240 Signals 83 Transit Lines
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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 AUTHORITY18
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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 AUTHORITY19
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SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY20
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Geary BRT DTA – Diversions (draft) SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY21
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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 AUTHORITY22
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SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY San Francisco’s Dynamic Traffic Assignment Model Model Development Process SFCTA DTA Model Peer Review Panel Meeting July 25 th, 2012
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SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY24 Outline - Model Development Process Objectives for now versus the future Overall Approach DTA Package Selection Project Tasks and Schedule
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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 AUTHORITY25
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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 AUTHORITY26
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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 AUTHORITY27
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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 AUTHORITY28
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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 AUTHORITY29
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SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY 30 Tasks and Schedule Project Management Model Development Tools Development Application/Integration Evaluation/Reporting 2011 2012 A S O N D J F M A M J J A S O Demand Preparation Network Preparation Data Preparation Model Calibration Network Conversion Demand Conversion Signal Conversion Transit Conversion Summary Integration Memo Applications Peer Review Webinar
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