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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


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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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


TransLink Mandate - Integration of:

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Public

Transport

Intelligent Transportation Systems

Vehicle Emissions Testing

Regional

Cycling

Transportation Demand Management

Roads &

Bridges


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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Rapid Transit Projects in the Region

Not pictured: BRT projects


Current SkyTrain Capacity Issues

Picture: Broadway Station (SkyTrain), inbound boarding, AM peak.

SkyTrain capacity: major subject for application of this model7


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


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


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




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The 24-Hour Dynamic Assignment

30-minute time-dynamic passenger volumes 2011, colour-coded by v/c-ratio


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)


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


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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of

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Time of day

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


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Calibration of Time-Dynamics: Model versus Counts

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Start time, 60-minute interval

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


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Lougheed Station, Suburban


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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


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Bus boardings in Surrey (Outlying Suburban Community)

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APC boarding 2007


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Bus boardings in Richmond, a suburban community


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


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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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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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


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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


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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Thank You

Ian FisherTransLink

[email protected]

www.translink.bc.ca

Wolfgang ScherrPTV

[email protected]

www.ptvamerica.com

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