alexsingleton
August 29, 2013

# Open Geocomputation: CO2 Emissions and the Pupil School Commute

RGS Conference 2013 - 29th August, London.

August 29, 2013

## Transcript

1. ### Alex Singleton Department of Geography and Planning ! www.alex-singleton.com Open

Geocomputation: CO2 Emissions and the Pupil School Commute http://www.flickr.com/photos/epsos/5591761716/sizes/o/in/ photostream/
2. ### Overview • Rates of active transport (e.g. cycling or walking)

to school are in decline • Pupil-school commute is estimated to contribute around 658k tonnes of CO2 / year • Transport adopted for the pupil-school commute has obvious implications for CO2 emissions
3. ### Traditional Estimation Technique • Euclidean Distance • Euclidean distance •

Average emissions values for mode of transport 183.2 vehicle CO2 g/km (DEFRA 2011) ! SL – trip – 1.2km ! 1.2 * 183.2 = 219.84 CO2 g / journey ! Daily commute - 219.84 * 2 = 439.68 OpenStreetMap
4. ### Problems • No account for real world geography – Straight

lines will typically underestimate true distances • No sensitivity to different vehicle types – What about train / bus etc? • Geocomputation provides a solution…
5. ### Challenges • Estimate transport network level routes for pupil journeys

• Account for variable CO2 emissions between different vehicle types • Individual level for a national population?
6. ### Model • d distance • p pupil • i pupil

home postcode • j school postcode • e CO2 g/km • t transport mode • g location k p = 2 d i p j p t p ( )e t p g p ( )w t p ( ) ( ) Distance CO2g/km Weight
7. ### Pupil Data • Department for Education – Pupil Level Annual

School Census (PLASC) • Postcode level • 2007 – 2012 – “usual” travel mode • 7,373,505 pupil records after exclusions (e.g. no postcode etc) – multiple years (2011) • Mostly state school pupils
8. ### Vehicle Data • Department for Transport – LSOA average CO

2 g/km for those vehicles registered within these zones – Driver Vehicle Licensing Agency (DVLA) • European legislation directive 91/441/EC – Cars registered after March 2001 • Caveat – Possible underestimation? » 162.9 CO 2 g/km differs from the DEFRA national estimate of 183.2 CO 2 g/km (DEFRA 2011). » Might be specific car types for school run?
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11. ### Data Processing OpenStreetMap railway=light_rail railway=subway PostGIS Road / Path Light

Rail / Tube Routino .osm XML files Meridian2 Railway Lots of Cleaning! 1) Single lines 2) Nodes join 3) Nodes at stations Postcode Directory
12. ### Software Infrastructure PostGIS PgRouting Iterative process for each pupil Routino

1) Query pupil (origin, destination, mode) Rail / Light Rail 2) Mode Choice? Road Pupil (distance, mode) 3) Car based? Yes Return LSOA Avg. CO2 g/km No Use type averages Pupil (distance, mode, CO2 g/km) 4) Implement the model

14. ### 0.00 0.25 0.50 0.75 0.00 0.25 0.50 0.75 0.00 0.25

0.50 0.75 0.00 0.25 0.50 0.75 0.00 0.25 0.50 0.75 0.00 0.25 0.50 0.75 0.00 0.25 0.50 0.75 0.00 0.25 0.50 0.75 0.00 0.25 0.50 0.75 0.00 0.25 0.50 0.75 0.00 0.25 0.50 0.75 0.00 0.25 0.50 0.75 0.00 0.25 0.50 0.75 1 2 3 4 5 6 7 8 9 10 11 12 13 0−0.5km 0.5−1km 1−1.5km 1.5−2km 2−2.5km 2.5−3km 3−3.5km 3.5−4km 4−4.5km 4.5−5km 5−5.5km 5.5−6km 6−6.5km 6.5−7km 7−7.5km 7.5−8km 8−8.5km 8.5−9km 9−9.5km 9.5−10km Distance Percentage Mode BUS CAR NON School Year • Over time increase in distance of non • Year 6-7 – large jump in distance non – Bus more prevalent
15. ### Model Output • Versus a simple model (straight line, vehicle

national averages)
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19. ### Next Steps • Estimating Bus Routes – Walk to bus

stop – route to school? • Multimodal journeys • Data issues – E.g. confusion in London (tube, rail, light rail) • Scaling issues – This all takes a very long time! • Temporal changes – Policy evaluation