christchurch (nz) transportation models update - a moving feast
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Christchurch
Largest city in South Island Third largest city in NZ Population, 425k Transport:
International Airport Large Port (inland ports) Flat terrain – cycle-friendly Bus system (central focus) Car travel dominates (>80%)
4 Stage Model (land use ---> travel) Uses:
Infrastructure/PT system assessments Demands for lower tiered models
Owned by regional/local Govt agencies Calibrated to 2006 4 Stage Models checked every 5 years Validation check planned after 2011 (Census)
Christchurch Transportation Model (CTM)
But then…..
Earthquakes, 2010-2011 Half roads suffered some damage CBD
Closed, businesses forced to relocate Over 1000 buildings (1/3) demolished
Residential Significant damage in east
Census delayed to 2013 Rebuild still ongoing
The Project
Check the CTM predictions for 2013 against observedHow is the model performing?Model inputs:
Land use from 2013 Census Transport network – roads & intersections Transport network – bus system
Normally straight-forward but……
The Challenge
Massive shift in land use distribution
Roadworks still prevalent in 2013
2015 hub-and-spoke buses on 2013 network
Had to work with data available
Lots of traffic counts –> lots of processing
Software update => results change
Bus Network Bus exchange
Temporary 2013 New 2015
Bus routes: Through routes 2013 Hub-and-spoke 2015
Change in road directions
Traffic Counts
Link counts required on screenlines Significant amount of data available But ….
Not processed (raw files, not geo-referenced) Processing/mapping significant (and tedious) task Inconsistent formats – more manual intervention Directional discrepancies
Traffic Counts – Lessons
Never underestimate data processing required
Model useful tool to check counts
Significant gaps in screenlines… …but no point counting in some areas (road
works/red zones) Solution:
Include factored old counts to complete the screenlines
Traffic Counts – Mind the Gap
Model Performance – Counts
Total Vehicles GEH Criteria AM IP PM ON Daily
% Screenlines with GEH<5 > 60% 59% 55% 64% 82% 86%<7.5 > 75% 73% 82% 77% 91% 91%<10 > 90% 73% 91% 77% 100% 95%
% Links with GEH
<5 >= 65% 52% 66% 49% 82% 68%<7.5 >= 75% 72% 80% 66% 96% 87%<10 >= 85% 83% 92% 79% 97% 94%<12 >= 95% 92% 97% 88% 100% 97%
RMSE 30% 32% 30% 40% 47% 29%