TRL - Creating the future of transport


TRL holds the most extensive vehicle emissions database in the UK and provides this information to the Department for Transport, Defra, local authorities and consultancies. This database has been used as the foundation for UK urban emission inventories and as input into the road transport component of the Defra National Atmospheric Emissions Inventory.


TRL has been central to the provision of these emission factors through involvement in a range of ongoing national and international projects.

TRL recently completed the co-ordination of the 5FP project ARTEMIS (Assessment and Reliability of Transport Emission Models and Inventory Systems). This has resulted in the development of a harmonised emission model for road, rail, air and ship transport to provide consistent emission estimates at the national, international and regional levels. Various outputs from this and associated projects have been used to revise the UK emission factors. In addition to the provision of the traditional average-speed-based emission factors, the ARTEMIS project successfully supported the development of instantaneous emission models, which TRL has subsequently been using in conjunction with micro-simulation traffic models. These types of modelling tools are ideally suited to the assessment of changes in driving styles, in addition to simple changes in average speeds.

TRL assists local authorities, central government, planners, developers and others to understand and improve air quality and minimise transport emissions. We provide a wide range of research and consultancy services, including emissions testing and modelling, the development of Air Quality Action Plans and research on driving characteristics and associated fuel consumption. TRL can also provide advice and guidance to organisations on vehicle choice and the effectiveness of a range of traffic management initiatives including clear zones, low-emission zones, congestion charging, urban traffic management, and controlled and managed motorways.

Our key capabilities in this area include:

  • regulated and unregulated pollutants
  • fuel consumption, CO2 and carbon emissions
  • vehicle emission measurement
  • assessment of alternative fuels and powertrains
  • vehicle emission modelling
  • emissions inventories
  • development and provision of emission factors
  • roadside vehicle emission testing
  • development of driving cycles
  • research into driving characteristics
  • emission reduction strategies
  • policy assessment
  • advice, guidance and training.


For further information about our work on climate change and emissions, please see the Energy & Climate Change section of this website.


The Air Quality Archive provides data and reports for the following projects: 

  • UK road transport emission data
  • the Highways Agency Roadside Air Pollution Monitoring Network
  • revision of the Design Manual for Roads and Bridges (DMRB) Vol. 11.3.1
  • Transport for London - Victoria Monitoring Facility.


Click here for more information on Emissions

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