Presentation by Ricardo-AEA's Transport Practice Director, Sujith Kollamthodi. Presented at the Transport Research Board 92nd Annual Meeting, Wednesday 16 January, Washington DC

1. European approaches to transport data collection
and analysis for strategic policy and impact
evaluation
TRB 92nd Annual Meeting
Session 824: Transport data program development: International best
practices – Part 2
16th January 2013
Sujith Kollamthodi
Practice Director – Sustainable Transport
Ricardo-AEA Limited

2. Overview
• Ricardo-AEA is responsible for annually
compiling the UK’s National Atmospheric
Emissions Inventory
• Key part of this is the road transportation
emissions inventory
• Complexity of the road transportation
sector means that multiple data sources
are required to provide accurate
estimates
• New techniques and data sources are
enabling us to make significant
improvements to these inventories

3. Basic methodology
Emissions from each = Emission Factor X Activity
vehicle type
(Tonnes per year) (grams/km or g/kg fuel (vkm traveled or kg fuel
consumed)
1.4
1.2
NOx (g/km)
1.0
0.8
Emission factor 0.6
determinants: 0.4
0.2
•pollutant type Emission 0.0
•vehicle type factors 0 50 100 150
•vehicle size (engine •hot exhaust Speed (kph)
size/weight) •cold start
•vehicle age •evaporative
•retrofit technology EMISSIONS
•fuel type
•fuel quality • tonnes/yr (UK)
•fuel volatility
Activity data • 1x1 km maps
•speed
•km traveled/yr
•temperature
•fuel
•degradation
consumption/yr
•trip length

4. Road transport inventory – coverage
and level of disaggregation
Pollutants
• CO2, CH4, N2O, Fuel consumption
• NOx, PM10, PM2.5, CO, VOCs, benzene, 1,3-
butadiene, SO2, NH3, primary NO2, PAHs…
Vehicle types
• Petrol and diesel cars
• Petrol and diesel vans
• Rigid and artic HGVs
• Buses and coaches
• Motorcycles
Road types
• Urban
• Rural
• Motorway

5. Activity data
Annual vehicle km data
• Department for Transport (DfT) traffic census: for Great Britain, with
disaggregation for England, Scotland, Wales
Vehicle Speed data
• DfT traffic census
Vehicle sales and fleet composition data (DfT Licensing Statistics)
• % diesel cars
• % by age (to derive fleet composition by emissions standard)
• Technology, retrofits
Fuel consumption data from UK official fuel sales statistics
• Gasoline, diesel, LPG , natural gas
• Bottom-up estimates reconciled with top-down fuel sales data

6. Road traffic by vehicle type and road
class
Road traffic by vehicle type and road class in Great Britain 2011 (Billion vehicle kilometers)
Cars and Motor- Buses & Goods All motor
taxis cycles coaches Light vans vehicles vehicles
Motorways 2 75.0 0.4 0.4 12.5 11.2 99.5
Rural 'A' roads:
Trunk 3 44.3 0.4 0.3 7.9 5.2 58.1
Principal 66.2 0.8 0.6 11.4 4.1 83.1
All rural 'A' roads 110.5 1.1 0.9 19.3 9.3 141.2
1
Urban 'A' roads:
Trunk 3 4.3 - - 0.7 0.3 5.4
Principal 60.5 0.8 1.1 9.2 2.3 73.9
All urban 'A' roads 64.7 0.8 1.2 9.9 2.6 79.3
4
All major roads 250.3 2.4 2.5 41.7 23.0 319.9
Minor roads:
Minor rural roads 52.8 0.8 0.5 10.8 1.4 66.3
Minor urban roads 1 84.3 1.5 1.7 14.0 1.2 102.7
All minor roads 137.1 2.3 2.1 24.9 2.6 169.0
ALL ROADS 387.4 4.6 4.7 66.6 25.6 488.9
Information required by 31st August each year: all years back to 1990
on a consistent basis

7. Mapping fuel use and emissions
Emissions mapped using
• OS UK Road Network Links
• DfT traffic census count-point data
• Speed data from automatic traffic counters
OS Road
Network
• VKM traveled statistics
DfT Traffic Links
Flows &
VKM
Implied UK-average emission factors for
Average
Emission
Factors by
many different road types
Road Type
• 1x1 km emission maps
• Local Authority Fuel Use Statistics
to support provision of sub-national
energy trends
• Local Authority CO2 end user
emissions

8. Scoping Study on use of Automatic
Number Plate Recognition (ANPR)
data
Current situation
• Vehicle fleet composition estimates based on
licensing data, vehicle survival functions,
mileage-with-age profiles
• No regional or road-type variations, except
assumption that higher mileage for diesel cars
on rural roads/motorways than on urban roads
NAEI analysis of ANPR data
• Variation in petrol/diesel car mix by region and
road type
• Variation in age distribution for cars, vans and
heavy duty trucks by region and road type

9. Scoping Study on use of Automatic
Number Plate Recognition (ANPR)
data
ANPR data: Proportion of car fleet on urban roads
comprising diesel cars in different regions of the UK:
2007-2010 East of England
40% East Midlands
London
35% North East
North West
30% South East
South West
West Midlands
25%
Yorkshire/Humber
Scotland
20%
2006 2007 2008 2009 2010 Wales

10. Benefits of using ANPR data
Improved
emissions for
both AQ and
GHG
inventories
Country-specific
Improved fleet
inventories for GHG
composition emissions from road
data transport
Improvements to the
UK’s National
Transport Model and
Improvements to Local road scheme
Authority Air Quality assessment tools
Review and Assessments,
Air Quality Action Plans
and Local Authority CO2
inventories

11. Summary
• UK road transportation emissions inventory
relies on a huge amount of traffic and vehicle
data supplied by the UK Department for
Transport
• Continuous improvement of the methodologies
used means that the current approach has a
high level of accuracy
• ANPR data can help further improve
transportation inventories by providing better
resolution at the regional and local level

12. Sujith Kollamthodi
Practice Director – Sustainable Transport
Ricardo-AEA Limited
The Gemini Building
Fermi Avenue
Harwell
Oxfordshire
OX11 0QR
United Kingdom
Tel: +44 (0)870 190 6513
E: sujith.kollamthodi@ricardo-aea.com
W: http://www.ricardo-aea.com
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