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Introduction
Josh Everett – SMEC AustraliaWorked on modelling in Canberra for 11 years
Used TransCAD, then EMME, now back to TransCAD
Presentation StructureCSTM
Updates to the CSTM
Calibration/Validation of the CSTM
Hopefully time for questions
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4-step strategic transport model
824 Zones
28,000 Links – 6 categories
102 Bus Routes (87 AM, 90 PM) plus school buses
Four land use types: Population, Employment, Retail Space, Enrolments
Based on generalised cost function
CSTM Structure
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CSTM – The Four Steps
Trip GenerationFixed generation rates for each of six purposes based on population
Home Based trips are modified by socio-economic factors
Trip DistributionTrip totals apportioned by land use
Three different gravity models – Work, Education, Other
Mode ChoiceMulti-level binomial structure for Work, Education, Other
Includes Car, Bus, Bicycle and Park & Ride
Traffic AssignmentEquilibrium assignment with link-based delay
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TransCAD is a native GIS program
More intuitive user interface than EMME
Object oriented coding environment
Includes all procedures as functions instead of terminal script
Uses different database structure, 2-way links
CSTM converted to TransCAD 7 model
Retains model structure and flow
Utilises built-in TransCAD functions where necessary
Update: TransCAD
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Input Data Update
Converted road network to TransCAD format
Reviewed and updated 2011 and 2016 road networks
Updated 2016 public transport network with actual –imported directly from GTFS
Included actual bus stop locations from GTFS
Updated future road networks with latest capital works projections, including 2041
Included “Town Centre Roads” with lower speed and capacity to approximate friction and congestion
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Previous CSTM used 2-hour trip rates modified to 1-hour using 65% assumption
Updated using trip generation rates calculated from Household Travel Survey
New 1-hour rates are 74% of 2-hour rates
Updated directional distribution for 1-hour
Trip Generation Update
Trip Purpose
Updated 2011 AM(One hour)
2011 PM(One hour)
Rate Proportion Rate ProportionHBW 0.112 24.5% 0.089 24.7%HBE 0.092 20.2% 0.013 3.6%Other 0.253 55.3% 0.258 71.7%HBS 0.006 1.4% 0.045 12.4%HBO 0.124 27.1% 0.114 31.8%NHBEB 0.005 1.2% 0.006 1.6%NHBO 0.117 25.6% 0.093 25.8%
All 0.457 100% 0.359 100%
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Model uses inverse exponential distribution:
𝑃𝑖𝑗 =1
𝑒𝑝𝑐𝑘= 𝑒−𝑝𝑐𝑘
Calibrated to survey data using iterative minimisation of RMSE
HBW used Census Journey-to-Work data (24 hour)
HBE used ACT Government school enrolments (missing private schools, CIT, university)
Other used Household Travel Survey
Generated K-factor matrices to better fit data
Trip Distribution Update
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Trip
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Trip Generalised Cost
Calibrated Gravity Curves
HBW
HBE
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OTH PM
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Gravity Curve Coefficient
Exponential Gravity Curve Calibration
HBW HBE OTH AM OTH PM
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Previously updated mode choice to include bicycles and Park & Ride
Modified generalised cost component weights to match NGTSM
Updated fares, including different fares by purpose, and removed the distance-based fare structure
Updated parking costs by travel purpose
Updated bicycle coefficients
Currently working on future PT network
Mode Choice Update
Total Person
Trips
Motorised
Person Trips
Bicycle
Person Trips
Car Person
Trips
Park & Ride
Person Trips
Enhanced
Transit Trips
Bus Person
Trips
Additional Bus
Person Trips
Additional Car
Person Trips
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No major changes to assignment
Conical function for link delay with interrupted/uninterrupted capacity modifiers
Uses TransCAD’s built-in PT assignment, including Park & Ride
Tighter convergence threshold to meet validation criteria (from 2% to 0.1%)
Assignment Update
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PM Peak Model
New PM peak model for all yearsCalculated new trip generation rates based on Household Travel SurveyPM peak has 79% of AM Peak trips, lower than expectedMain reduction in trips due to educationNew PM public transport networkWork and Education gravity coefficients same as AM, Other uses different coefficientPark & Ride disabledRoad network almost the same, except for school zones
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Developed new validation criteria in association with EPSDD based on VicRoads, RMS and UK DfT standards
Assignment convergence checks that assignment equilibrium has been reached
Feedback convergence checks that sufficient model iterations have been used
Screenline volumes are total volumes across district screenlines
Link volumes are individual volumes at district screenlines
Public transport OD matches model trip matrix to ticket data
Validation Criteria
Stage Source Criteria Threshold
Assignment Convergence
VicRoads/UK DfT
RGAP, and < 1%
RAAD, or < 1%
AAD, or < 1 veh/h
%Diff < 5% > 95%
Feedback Convergence
VicRoads
%RMSE, or < 1%
Max GEH < 2
ScreenlineVolumes
%Diff ±50𝑉−0.3953
Link Volumes
VicRoads/RMS NSW
R² > 0.9
%RMSE < 30%
VicRoads
Slope 0.9 – 1.1
GEH < 5* 50%
GEH < 10* 80%
Public Transport OD
-R² > 0.9
Slope 0.9 – 1.1
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Screenline Validation
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PM Screenline Validation
Difference Minimum Maximum
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AM Screenline Validation
Difference Minimum Maximum
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Criterion TargetOriginal
2011 AM
Updated2011 AM
2011 PM
R² 0.9 0.83 0.93 0.89Slope 0.9-1.1 0.94 0.95 0.97%RMSE < 30% 43% 28% 32%GEH < 5 50% 33% 50% 51%GEH < 10 80% 64% 73% 70%Average GEH
- 9.2 6.7 7.1
Linkflow Validation
y = 0.948xR² = 0.9255
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Observed Volume
AM Peak Comparison of Car Volumes on Screenline Links
y = 0.9679xR² = 0.8869
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Observed Volume
PM Peak Comparison of Car Volumes on Screenline Links
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Gathered OD data from MyWay ticketing
Used trips that have mid-point between 8:00-9:00AM
Joined transfers into a single OD trip
Compared model and ticket data at a district level
PT OD Validation
y = 0.9763xR² = 0.9934
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Observed Trips
AM Peak Public Transport Trips by District
y = 0.9979xR² = 0.9896
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Observed Trips
PM Peak Public Transport Trips by District
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Future Upgrades
Native TransCAD functions
Travel DataHousehold Travel Survey
Traffic count program
Input DataSeparated land use – Education, Retail, Employment
Intersection delay
Future Travel BehaviourLight Rail
Autonomous vehicles