Please refer to the guidance notes (either in PDF or within the spreadsheet 'Notes' page) for more information about the datasets provided below.
| Publication Year | Title | Emission factor | Notes |
| 2025 | Fleet Weighted Road Transport Emission Factor 2023 | Fleet Weighted Road Transport Emission Factor 2023 (XLSX 57.27 KB)
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 (PDF 616.KB) |
| 2025 | Primary NO2 Emission factors for road transport 2025 | Primary NO2 Emission factors for road transport 2025 (XLSX 70.41 KB) | Primary NO2 Emission Factors for Road Vehicles: 2025 version Guidance Note |
| 2025 | Vehicle fleet composition projections (Base 2023) | Vehicle fleet composition projections (Base 2023) (XLSX 418.82 KB)
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. | |
| 2013 | Alternative vehicle technology emission factors | Alternative vehicle technology emission factors (PDF 543.02 KB) |
For previous versions of the above data, please see the Data Archive page.