Emission Factors for Transport

Please refer to the guidance notes (either in PDF or within the spreadsheet 'Notes' page) for more information about the datasets provided below.

Publication YearTitleEmission factorNotes
2025Fleet Weighted Road Transport Emission Factor 2023Fleet Weighted Road Transport Emission Factor 2023

These datasets contain fleet weighted road transport emission factors by vehicle type, for hot exhaust, cold start exhaust, evaporative emissions and tyre and brake wear from the 2023 NAEI.

Guidance Note 2023
2025Primary NO2 Emission factors for road transport 2025Primary NO2 Emission factors for road transport 2025 Primary NO2 Emission Factors for Road Vehicles: 2025 version Guidance Note
2025Vehicle fleet composition projections (Base 2023)Vehicle fleet composition projections (Base 2023)

The Base 2025 fleet composition projections data provided in this spreadsheet are consistent with those used in the 2023 NAEI (Base 2025) road transport emission projections for the UK, excluding London. 

 
2013Alternative vehicle technology emission factorsAlternative vehicle technology emission factors  

 

For previous versions of the above data, please see the Data Archive page.


Published: 23 January, 2024

Last updated: 6 November, 2025