1.7 - conversion of models from trips to cube voyager

Conversion of Main Roads Western Australia Transport Models from TRIPS to Cube Voyager

Shaun Tabone

November 28, 2011

Project Summary

- The need to convert:• Issues with TRIPS

TRIPS no longer developed or supported by CitilabsTRIPS has a lower level of precisionMRWA used several custom programs written in Fortran. Issues with transparency and long-term maintenance

• Cube benefitsConstantly being developed and improved by CitilabsVoyager scripting allows for greater flexibility and customisationBetter integration with GIS and geodatabasesCube Scenario manager allows for multiple scenario tests to be set up quickly

Converting MRWA TRIPS models to Cube Voyager

6 December 2011

Project Summary

- Main Roads Western Australia models• Regional Operations Model (ROM)• Peak Period Model (PPM)• Mandurah – Dunsborough Model (MDM)• State Wide Model (SWM)

- Custom Software (coded in Fortran)• MRDLOAD – daily assignment model• BCRATIO – calculation of BCRs for input networks• MODCAR – car availability model


6 December 2011

Regional Operations Model

- Four-step model• Covers the Perth Metro area• 5 model years (2006, ‘11, ‘16,

‘21, ‘31)• 18 trip purposes, 1160 zones

- Uses the custom programs MRDLOAD, BCRATIO and MODCAR

- A live model, used on a regular basis on request from clients

6 December 2011Converting MRWA TRIPS models to Cube Voyager

Peak Period Model

- One hour AM and PM peak period assignment model• 5 model years (2006, ‘11, ‘16,

‘21, ‘31)• 18 trip purposes, 1160 zones

- Demand and network from the ROM

- Junction coding for:• All signalised junctions• All roundabouts• Priority junctions with turn

bans


Mandurah – Dunsborough Model

- Four-step model• Covers the area immediately

south of the ROM• 5 model years (2001, ‘06, ‘11,

‘21, ‘31)• 2 user-classes assigned

using a stochastic method

- Sub-areas models for Busselton and Bunbury inside regional model

- A live model, used on a regular basis on request from clients


State Wide Model

- Four-step model• Covers whole of WA• 5 model years (2001, ‘06, ‘11,

‘21, ‘31)• Four trip purposes• AADT Demand assigned

using All-or-nothing or a stochastic method based on trip purpose


Some of the challenges along the way…

Project Challenges and OutcomesMRDLOAD

Challenges• Coded in Fortran• Dial stochastic assignment … but Cube Voyager doesn’t have this

feature• Approximation for intersection capacity and delay based on link

attributes• Fast run times approx 30sec

Outcomes• Intersection capacity/delay calculations converted to Voyager

scripting• Incremental assignment methodology shown to most closely

replicate MRDLOAD path building • Run time only 2.5 minutes


6 December 2011

Project Challenges and OutcomesMRDLOAD


6 December 2011

• Close match of VHT and VKT at global and link level (<1% difference)

• Difference plots reveal almost no difference in assigned link times

• Used in concert with BCRATIO, the resulting BCRs are within +/-1%

Project Challenges and OutcomesRegional Operations Model

Challenges• Use of not just MRDLOAD, but also MODCAR and BCRATIO

custom programs• Simplistic folder structure and automated file naming for many files

made indentifying key input and output files difficult• 18 trip purposes

Outcomes• Scenario Manager set up with initial Keys• Folder structure revised to better differentiate between Input,

Output and intermediate files • Sensible file names allocated to key Input and Output files• BCRATIO and MODCAR converted to Voyager• Only minor differences in final output demand tables (<0.5%).


6 December 2011

Project Challenges and OutcomesRegional Operations Model


6 December 2011

- Expanded folder structure allows for better differentiation between Input, Output and intermediate files

Project Challenges and OutcomesPeak Period Model

Challenges• MRWA junction coding included:

headers for all junctionsUsed fractional lanes to simulate shared lanes

• Checks of the assigned network revealed some turns having very high delays

• Cube default conversion of junction coding did not adequately deal with these issues

Outcomes• Scenario Manager + Keys + Folder structure + file naming (as per

ROM)• MATRIX Record processing used to convert junction code. Able

to successfully maintain headers, correctly interpret shared lanes, and mandate minimum capacities


6 December 2011

Project Challenges and OutcomesPeak Period Model


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Turn Delay (min)

Voyager TRIPS

- Converted Voyager model yields: • More smaller delays

(<10sec); and• fewer larger delays (>30sec)

Project Challenges and OutcomesMandurah – Dunsborough and State Wide Models

Challenges• MDM is a two tier model with two sub-regional models sitting

inside a larger regional area model• In both models, some user classes used dial stochastic processes

for path-building. In the MDM this was treated inconsistently between the two sub-regional models

Outcomes• Scenario Manager + Keys + Folder structure + file naming (as per

ROM)• Dial path building used to provide a reasonable spread of trips• Consistent sub-regional model process adopted


6 December 2011

Project Challenges and OutcomesMandurah – Dunsborough and State Wide Models

Dial Paths TRIPS MDM

6 December 2011

- Stochastic spread of paths not as extensive

- However, some of the Dial paths aren’t realistic

- Burrell path building shown to provide a reasonable spread of trips


Burrell Paths Converted Voyager MDM

Project Challenges and OutcomesConclusions

MRWA models now all sit inside Cube Voyager

MRWA staff have been running both old and new models in parallel to gain experience, and compare outputs

The conversion process highlighted a number of potential improvements to the MRWA models, some of these are only possible with the move to Voyager, for example the building of Cube Avenue models


6 December 2011

Thank You

[email protected]

1.7 - conversion of models from trips to cube voyager

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