www.ptvamerica.com south coast british columbia transportation authority regional application of...
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www.ptvamerica.com
South Coast British Columbia Transportation Authority
www.translink.bc.ca
Regional Application of 24-Hour Dynamic Transit Assignment
12th TRB Transportation Planning Application Conference, Houston TX, May 2009
Wolfgang Scherr, PTVIan Fisher, TransLink
Regional Application of 24-Hour Dynamic Transit Assignment
Overview
> Transit planning in Metro Vancouver and current capacity issues
> Dynamic transit assignment – the method
> Model development
> Application in service planning and operations planning
> Conclusions and future directions
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Regional Application of 24-Hour Dynamic Transit Assignment
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Metro Vancouver
21 cities
2.2 million residents, 3.2 million by 2040
> 294 million transit boardings (unlinked) in 2007
> 78 annual transit rides (linked) per resident
Major gateway for sea, air and rail freight
> No urban freeways/motorways
> Prior to 1999 no regional transportation agency
Regional Application of 24-Hour Dynamic Transit Assignment
TransLink Mandate - Integration of:
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Public
Transport
Intelligent Transportation Systems
Vehicle Emissions Testing
Regional
Cycling
Transportation Demand Management
Roads &
Bridges
Regional Application of 24-Hour Dynamic Transit Assignment
Intermodal Transit Network
> ALRT (SkyTrain)
> Commuter rail (West Coast Express)
> Passenger ferry (SeaBus)
> Bus (includes trolleybus)
> B-Line (frequent, limited stop)
> Community shuttle (minibus)
> BRT and LRT (planned)
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Regional Application of 24-Hour Dynamic Transit Assignment
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Rapid Transit Projects in the Region
Not pictured: BRT projects
Regional Application of 24-Hour Dynamic Transit Assignment
Current SkyTrain Capacity Issues
Picture: Broadway Station (SkyTrain), inbound boarding, AM peak.
SkyTrain capacity: major subject for application of this model7
Regional Application of 24-Hour Dynamic Transit Assignment
Overview of the Regional Transit Model (RTM)
24-hour operations model (supply), average weekday
24-hour passenger model (demand)
> Dynamic assignment
> Fixed OD matrices, 800 zones, interface to regional four-stage model
Platform: VISUM
Applications
> Operations planning: routes and patterns, fleet requirements, schedule development
> Operations analysis for new rapid transit corridors
> Service planning: transit area plans, bus network planning
> Visualizations and animations that are comprehensible to lay people
History:
> Phase A (2006): rail-only model
> Phase B (2008): regional model of all modes 8
Regional Application of 24-Hour Dynamic Transit Assignment
The Dynamic Assignment Method
VISUM’s “Timetable-based assignment”
> Schedule-based method (as opposed to headway-based)
> Path-builder uses operations schedule data
> The supply model based on individual vehicle runs
> Assumption: deterministic flow of vehicles and trains according to schedule
> Multiple paths and multiple connections are built using branch&bound
> Naturally a time-dynamic method:
> Travel conditions vary during the day
> Availability of paths varies during the day
> Travel time of paths varies during the day
> Path choice:
> Box-Cox transformed LOGIT
> Impedance = IVT + OVT + NT + Delta(early, late) + {correction for similarity of connections}
> Vancouver RTM: capacity constraints not included9
Regional Application of 24-Hour Dynamic Transit Assignment
bus run 2
bus run 3
bus run 1
Schedule-Based Assignment - Schematic
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space
origin destinationtransfer
train run 1
train run 2
train run 3
train run 4
train run 5
bus-only connection
bus-only connection
intermodal connection
intermodal connection
intermodal connection
Regional Application of 24-Hour Dynamic Transit Assignment
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The 24-Hour Dynamic Assignment
30-minute time-dynamic passenger volumes 2011, colour-coded by v/c-ratio
Regional Application of 24-Hour Dynamic Transit Assignment
Model Development – Supply Side
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Integration of existing operations data
Network topology
> Nodes and links (NAVTEQ street network)
> Stops, stations (resolution as in APC/AVL)
Schedule
> Data: lines/routes/patterns, run times, runs with departure and arrival times
> Existing schedule: imported
> Future schedule: edited
Fleet model
> Vehicle types, capacities, consists
> Procedure for block building (vehicle rotations)
Regional Application of 24-Hour Dynamic Transit Assignment
Model Development – Demand Side
Counts
> Station boarding counts – good 24-hour coverage for SkyTrain
> Link loading counts: ferry, commuter rail, specific SkyTrain links
> Automated Passenger Count System (APC)
> All bus lines except community shuttles
> Mainly used: total route boardings in hourly increments over 24-hours
> APC evaluation tool was still being calibrated itself during our model calibration
OD matrices
> Four segments : AM, Midday, PM, Evening
> Existing demand: derived with matrix calibration and matrix crafting methods
> Future demand:
> Link to regional four stage model
> Future OD demand = existing OD demand + delta forecast
Departure time distributions
> Derived from counts
> Adjusted to meet real-world time distributions all over the region13
Regional Application of 24-Hour Dynamic Transit Assignment
Model Development: Departure Time Distribution
> Morning peak of demand: dependent on distance from centre
> Afternoon peak: no significant difference observed between markets 14
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11 - inside of core area 21 - between near suburbs and core31 - between distant suburbs and core 41 - between distant and near suburbsAM Peak PM Peak
Regional Application of 24-Hour Dynamic Transit Assignment
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Calibration of Time-Dynamics: Model versus Counts
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SkyTrain boarding 2006 survey
VISUM model boarding 2007
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Waterfront Station, CBD
Rail stations: centre versus sub-urban
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SkyTrain boarding 2006 survey
VISUM model boarding 2007
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Lougheed Station, Suburban
Regional Application of 24-Hour Dynamic Transit Assignment
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Calibration of Time-Dynamics: Model versus Counts
Suburban bus lines (aggregated APC data for several routes)
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APC boarding 2007
VISUM model boarding 2007
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Bus boardings in Surrey (Outlying Suburban Community)
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Start time, 60-minute interval
APC boarding 2007
VISUM model boarding 2007
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Bus boardings in Richmond, a suburban community
Regional Application of 24-Hour Dynamic Transit Assignment
Applications (1): Operations Scenarios SkyTrain
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Study
> Develop and analyze multiple scenarios to operate SkyTrain with existing fleet
Result
> The present operations are optimal with regard to capacity
Analysis
> Use of aggregated and time-disagregated performance measures
Regional Application of 24-Hour Dynamic Transit Assignment
Other Applications (2)
Other SkyTrain Studies:
> Future maximal capacity for the critical segment BW-WF
> Fleet strategy: it is desirable to add 3-car units to the fleet (now only 2-car units)
> Operations concepts for future extensions of the SkyTrain system (UBC Line, Evergreen Line)
Bus service planning:
> Bus network planning in the context of a new rail line
> The Canada Line (ALRT) will open in 8/2009
> Bus realignments, bus schedules, bus fleet usage
System Analysis:
> 2011 short-term forecast: interaction of the existing SkyTrain Lines with the new Canada Line
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Regional Application of 24-Hour Dynamic Transit Assignment
Conclusions (1)
Transit supply varies over time
> The use of dynamic tools seems natural in transit planning.
A lesson learned
> It is good to start with a sub-network and later expand to entire region
> Early applications allow:
> Planners to learn the tool, the data
> Stakeholders to give feedback and formulate requirements for the final model
Benefits of 24-hour dynamic transit assignment:
> Better understanding how demand builds up at congested spots
> Analysis of peak and off-peak operations
> Visualizations of time-dynamic supply and demand
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Regional Application of 24-Hour Dynamic Transit Assignment
One Benefit of Dynamic Assignment: Visualization
DA can help to visualize and explain truths about congestion:
> Congestion is of short duration - in a 24-hour perspective
> It is challenging to provide capacity as flexibly as demand varies
> The demand peak has shifted and the rules of operations have to adjust20
Regional Application of 24-Hour Dynamic Transit Assignment
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Future Perspectives
Next studies:
> Contribute operations analysis to three major strategic studies:
> Expo Line Upgrade study
> UBC Line rapid transit study
> Strategic Network Review
> Analysis of BRT projects
> Area transit plans
Future model improvements:
> Calibration of in-station transfer volumes (recent surveys)
> Adding capacity constraints to the assignment model
> Holding passengers in stations if departing train over capacity
> Diverting passengers to alternative paths
> Changing time of departure (peak spreading)
> Research on time-of-day distribution of demand
Regional Application of 24-Hour Dynamic Transit Assignment
Acknowledgements
Peter Klitz, TransLink
Graeme Masterton, TransLink
Cherry Xiong, PTV
Kean Lew , PTV
Anett Ehlert , PTV
Fang Yuan , PTV
Juergen Beyer , PTV
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Regional Application of 24-Hour Dynamic Transit Assignment
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Thank You
Ian FisherTransLink
www.translink.bc.ca
Wolfgang ScherrPTV
www.ptvamerica.com
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