Julie Ballantyne

1. Christchurch (NZ) Transport Model
Update – A Moving Feast
Julie Ballantyne

2. 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%)

3.  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)

4. 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

5. The Project
Check the CTM predictions for 2013 against observed
How is the model performing?
Model inputs:
 Land use from 2013 Census
 Transport network – roads & intersections
 Transport network – bus system
Normally straight-forward but……

6. 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

7. Change to the Landscape - Residential
Waimakariri
Selwyn

8. Change to the Landscape - Residential
River corridor
Hill suburbs

9. Change to the Landscape - Business

10. Change to the Landscape - Business
CBD

11. Road Network

12. Road Network – Road Works

13. Road Network – Road Works

14. Road Network - Closures

15. Bus Network
 Bus exchange
 Temporary 2013
 New 2015
 Bus routes:
 Through routes 2013
 Hub-and-spoke 2015
 Change in road directions

16. Network - 2006

17. Network - 2013

18. Network - 2015

19. 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

20. Traffic Counts – Lessons
 Never underestimate data processing required
 Model useful tool to check counts

21.  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

22. Traffic Counts

23. Validation - Targets

24. Validation Data
 Vehicle travel times
 PT Boardings (2015)
 Census Journey-to-Work
 Traffic counts

25. Model Performance – Travel Times

26. Model Performance – Travel Times
AM IP PM

27. Model Performance – PT Boardings
AM – Corridor
by Destination

28. 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%

29. Model Performance – Counts

30. Model Performance - JTW

31. Model Performance - JTW
Census JTW Model HBW

32. Summary
 Significant changes in Christchurch
 Variation in counts – model used to identify
outliers
 The model:
 CTM outputs checked using 2013/15 observed
 CTM performing well
 Next challenge:
 Ongoing monitoring of changing land use patterns