Forthcoming changes: electric vehicle mileage share updates
Updated 16 April 2026
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This publication is available at https://www.gov.uk/government/publications/tag-forthcoming-changes/forthcoming-changes-electric-vehicle-mileage-share-updates
Description: Update to forecasted vehicle kilometres driven by fuel type and vehicle fuel efficiencies.
Unit: TAG data book, A1.3.9 and A1.3.10
Change announced: April 2026
Expected release date: May 2026
Description
This update incorporates new evidence into 2 tables in the TAG data book:
- table A1.3.9: forecast vehicle kilometres (vkm) by fuel type
- table A1.3.10: forecast fuel efficiency for different vehicle types
These changes ensure that transport appraisals continue to use up-to-date data and modelling. The updates reflect the latest outputs from modelling undertaken by the Office for Zero Emission Vehicles (OZEV) and include:
- new historic data
- updated modelling for the Zero Emission Vehicle (ZEV) mandate, reflective of 2025 amendments
- new evidence on the utility rate of plugin hybrid electric vehicles (PHEVs)
All data book updates will become definitive in May 2026.
Overview
The forecasts provided in this update are consistent with the assumptions used in the government’s energy and emissions projections (EEP).1 This captures firm and funded government policy and includes the impact of the Zero Emission Vehicles mandate regulation, which requires an increasing proportion of new car and van sales to be zero‑emission, reaching 80% and 70% respectively by 2030.
Detail
Vehicle kilometres by fuel type (table A1.3.9)
The updated modelling shows a slight reduction in the amount of distance driven using electricity for both cars and light goods vehicles (LGVs) over the appraisal period. This reduction is primarily the result of the amendments to the Vehicle Emissions Trading Schemes (VETS) Order 2023 (PDF, 900KB).
This amendment extends the flexibilities available to vehicle manufacturers under the ZEV mandate, such as borrowing credits from future years, trading credits and using carbon compliance surpluses. This mean that manufacturers are expected to rely more on PHEVs in the near term to meet their obligations under the mandate. The revised forecasts therefore show a slightly lower share of vkm powered by electricity across the appraisal period, with greater impacts in the short-term.
Another important factor is the availability of new data on how PHEVs are used. The evidence indicates that PHEVs complete a smaller proportion of their journeys in electric mode than previously assumed. This change reduces the amount of electric driving attributed to PHEVs within the model and contributes further to the short term dip in electric vkm.
Together, these effects mean that the share of vkm driven using electricity is expected to be around four percentage points lower for cars and just over 4 percentage points lower for LGVs in 2030 compared with the previous published forecast. Although these differences are noticeable in the short term, the new and old projections gradually converge so that by 2050 the gap has narrowed to less than 2 percentage points. The resulting increase in petrol and diesel vkm is small in scale and does not significantly alter long-term trends.
Updates to table A1.3.9
Table: proportion of cars, LGV and other vehicle kilometres using petrol, diesel or electricity
| Petrol (car) | Diesel (car) | Electric (car) | Petrol (LGV) | Diesel (LGV) | Electric (LGV) | |
|---|---|---|---|---|---|---|
| 2015 | 50.1% | 49.7% | 0.1% | 2.2% | 97.6% | 0.1% |
| 2016 | 48.8% | 51.0% | 0.2% | 2.0% | 97.8% | 0.2% |
| 2017 | 48.4% | 51.3% | 0.3% | 2.0% | 97.8% | 0.2% |
| 2018 | 49.0% | 50.6% | 0.4% | 2.1% | 97.7% | 0.2% |
| 2019 | 50.2% | 49.2% | 0.6% | 2.1% | 97.5% | 0.3% |
| 2020 | 51.3% | 47.6% | 1.1% | 2.2% | 97.3% | 0.5% |
| 2021 | 52.5% | 45.5% | 2.0% | 2.2% | 96.9% | 0.9% |
| 2022 | 53.7% | 43.2% | 3.2% | 2.3% | 96.2% | 1.5% |
| 2023 | 55.1% | 40.3% | 4.6% | 2.4% | 95.5% | 2.1% |
| 2024 | 56.3% | 37.4% | 6.2% | 2.7% | 94.8% | 2.6% |
| 2025 | 56.8% | 34.7% | 8.5% | 2.8% | 93.6% | 3.6% |
| 2026 | 57.0% | 31.8% | 11.1% | 2.9% | 92.3% | 4.8% |
| 2027 | 57.0% | 28.9% | 14.0% | 3.0% | 90.0% | 6.9% |
| 2028 | 56.0% | 25.9% | 18.1% | 3.1% | 86.6% | 10.3% |
| 2029 | 54.2% | 22.9% | 23.0% | 3.2% | 81.9% | 14.9% |
| 2030 | 50.7% | 19.8% | 29.6% | 3.0% | 76.0% | 21.0% |
| 2031 | 47.3% | 17.0% | 35.7% | 2.8% | 70.5% | 26.6% |
| 2032 | 44.2% | 14.5% | 41.3% | 2.7% | 65.7% | 31.6% |
| 2033 | 41.2% | 12.4% | 46.5% | 2.6% | 61.4% | 36.1% |
| 2034 | 38.3% | 10.5% | 51.1% | 2.4% | 57.5% | 40.0% |
| 2035 | 35.7% | 9.0% | 55.3% | 2.3% | 54.1% | 43.5% |
| 2036 | 33.3% | 7.7% | 59.0% | 2.2% | 51.1% | 46.7% |
| 2037 | 31.0% | 6.6% | 62.4% | 2.1% | 48.4% | 49.4% |
| 2038 | 28.8% | 5.7% | 65.4% | 2.0% | 46.1% | 51.9% |
| 2039 | 26.8% | 5.0% | 68.1% | 2.0% | 44.0% | 54.0% |
| 2040 | 24.9% | 4.5% | 70.6% | 1.9% | 42.2% | 55.9% |
| 2041 | 23.2% | 4.1% | 72.7% | 1.8% | 40.7% | 57.5% |
| 2042 | 21.7% | 3.7% | 74.6% | 1.7% | 39.4% | 58.9% |
| 2043 | 20.4% | 3.4% | 76.2% | 1.7% | 38.3% | 60.1% |
| 2044 | 19.3% | 3.2% | 77.5% | 1.6% | 37.3% | 61.0% |
| 2045 | 18.4% | 3.0% | 78.6% | 1.6% | 36.6% | 61.9% |
| 2046 | 17.8% | 2.8% | 79.4% | 1.5% | 36.0% | 62.5% |
| 2047 | 17.2% | 2.7% | 80.1% | 1.5% | 35.4% | 63.0% |
| 2048 | 16.8% | 2.6% | 80.6% | 1.5% | 35.0% | 63.5% |
| 2049 | 16.5% | 2.5% | 81.0% | 1.5% | 34.6% | 63.9% |
| 2050 | 16.3% | 2.4% | 81.3% | 1.5% | 34.3% | 64.2% |
Fuel efficiency forecasts (table A1.3.10)
The updated fuel efficiency projections include adjustments that reflect additional years of real-world data and revised modelling assumptions in relation to the ZEV mandate.
For petrol cars, the new forecasts show a slight improvement in fuel efficiency over the appraisal period. This change is modest but nonetheless improves the accuracy of the forecasts. The outlook for diesel cars has changed in the opposite direction. Newer diesel vehicles have generally become larger and heavier, which reduces their fuel efficiency. As these less efficient models become a greater share of the fleet over time, the average efficiency of diesel cars declines compared to earlier projections. This shift is more apparent from the 2040s onwards.
Updated estimates for petrol LGVs indicate that they are improving in efficiency from a 2015 baseline, but at a slower rate than was anticipated in previous forecasts. This revision reflects updated evidence on the outturn fuel efficiency of these vehicles. However, the overall impact on appraisal is expected to be small, since petrol models make up a relatively small proportion of the LGV fleet. Forecasted efficiencies for diesel LGVs exhibit only minimal compared to previous forecasts.
There are minor updates to the forecasted efficiency of electric cars and vans.
Updates to table A1.3.10a
Table: forecast assumed vehicle fuel efficiency improvements to 2050, change in vehicle efficiency per annum
| Petrol (car) | Diesel (car) | Electric (car) | Petrol (LGV) | Diesel (LGV) | Electric (LGV) | ||
|---|---|---|---|---|---|---|---|
| 2015 | 2016 | -1.37% | -0.57% | 0.02% | 0.07% | -0.62% | 0.11% |
| 2016 | 2017 | -1.18% | -0.38% | 0.01% | -1.60% | -1.18% | 0.00% |
| 2017 | 2018 | -1.02% | -0.05% | 0.00% | -2.97% | -0.71% | 0.20% |
| 2018 | 2019 | -0.82% | 0.15% | -0.01% | -1.01% | -0.53% | -0.04% |
| 2019 | 2020 | -0.82% | 0.08% | -0.01% | -1.89% | -0.21% | 0.17% |
| 2020 | 2021 | -0.82% | -0.07% | -4.04% | -1.22% | -0.77% | 0.14% |
| 2021 | 2022 | 1.20% | -0.02% | -4.14% | -2.45% | -0.27% | -0.48% |
| 2022 | 2023 | -0.75% | 0.07% | -2.25% | 1.34% | -0.37% | -0.47% |
| 2023 | 2024 | -0.76% | 0.11% | -1.79% | -0.85% | -0.57% | -0.26% |
| 2024 | 2025 | -0.75% | 0.17% | -1.98% | -0.80% | -0.50% | 0.31% |
| 2025 | 2026 | -0.64% | 0.21% | -1.77% | -0.70% | -0.45% | -0.50% |
| 2026 | 2027 | -0.55% | 0.26% | -1.55% | -2.24% | -0.37% | -0.41% |
| 2027 | 2028 | -0.42% | 0.25% | -1.68% | -0.36% | -0.27% | -0.53% |
| 2028 | 2029 | -0.36% | 0.24% | -1.65% | -0.30% | -0.19% | -0.35% |
| 2029 | 2030 | -0.31% | 0.24% | -1.75% | 0.39% | 0.23% | 0.51% |
| 2030 | 2031 | -0.17% | 0.30% | -1.22% | 2.63% | 0.19% | 1.12% |
| 2031 | 2032 | -0.30% | 0.29% | -0.95% | 0.24% | 0.34% | 1.58% |
| 2032 | 2033 | -0.18% | 0.45% | -0.80% | -0.39% | 0.05% | 1.78% |
| 2033 | 2034 | -0.18% | 0.47% | -0.71% | -2.08% | 0.33% | 1.70% |
| 2034 | 2035 | -0.14% | 0.58% | -0.65% | 4.01% | 0.24% | 1.43% |
| 2035 | 2036 | -0.10% | 0.72% | -0.61% | -0.33% | 0.15% | 1.11% |
| 2036 | 2037 | -0.08% | 0.67% | -0.60% | -0.05% | -0.03% | 0.82% |
| 2037 | 2038 | -0.06% | 0.78% | -0.59% | -3.74% | -0.28% | 0.59% |
| 2038 | 2039 | -0.06% | 1.04% | -0.59% | 1.60% | 0.46% | 0.40% |
| 2039 | 2040 | -0.05% | 0.97% | -0.59% | 0.29% | 0.26% | 0.25% |
| 2040 | 2041 | -0.22% | 0.70% | -0.58% | -2.63% | 0.54% | 0.18% |
| 2041 | 2042 | -0.08% | 0.04% | -0.58% | 0.18% | -0.32% | 0.12% |
| 2042 | 2043 | 0.04% | 1.14% | -0.57% | 0.44% | 0.77% | 0.07% |
| 2043 | 2044 | -0.05% | 1.17% | -0.55% | 5.22% | 0.03% | 0.02% |
| 2044 | 2045 | -0.02% | 0.45% | -0.55% | -1.99% | -0.16% | -0.04% |
| 2045 | 2046 | 0.02% | 0.00% | -0.55% | -0.04% | -0.08% | -0.07% |
| 2046 | 2047 | 0.02% | 0.00% | -0.54% | 0.22% | 0.18% | -0.14% |
| 2047 | 2048 | 0.01% | 0.00% | -0.53% | 0.21% | 0.17% | -0.18% |
| 2048 | 2049 | 0.01% | 0.00% | -0.52% | 0.20% | 0.16% | -0.23% |
| 2049 | 2050 | 0.01% | 0.00% | -0.52% | 0.20% | 0.16% | -0.27% |
Updates to table A1.3.10b
Table: forecast assumed vehicle fuel efficiency improvements to 2050, cumulative change in vehicle efficiency (factor from 2015)
| Petrol (car) | Diesel (car) | Electric (car) | Petrol (LGV) | Diesel (LGV) | Electric (LGV) | |
|---|---|---|---|---|---|---|
| 2015 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| 2016 | 0.99 | 0.99 | 1.00 | 1.00 | 0.99 | 1.00 |
| 2017 | 0.97 | 0.99 | 1.00 | 0.98 | 0.98 | 1.00 |
| 2018 | 0.96 | 0.99 | 1.00 | 0.96 | 0.98 | 1.00 |
| 2019 | 0.96 | 0.99 | 1.00 | 0.95 | 0.97 | 1.00 |
| 2020 | 0.95 | 0.99 | 1.00 | 0.93 | 0.97 | 1.00 |
| 2021 | 0.94 | 0.99 | 0.96 | 0.92 | 0.96 | 1.01 |
| 2022 | 0.95 | 0.99 | 0.92 | 0.89 | 0.96 | 1.00 |
| 2023 | 0.95 | 0.99 | 0.90 | 0.91 | 0.95 | 1.00 |
| 2024 | 0.94 | 0.99 | 0.88 | 0.90 | 0.95 | 0.99 |
| 2025 | 0.93 | 0.99 | 0.87 | 0.89 | 0.94 | 1.00 |
| 2026 | 0.93 | 1.00 | 0.85 | 0.88 | 0.94 | 0.99 |
| 2027 | 0.92 | 1.00 | 0.84 | 0.87 | 0.94 | 0.99 |
| 2028 | 0.92 | 1.00 | 0.82 | 0.86 | 0.93 | 0.98 |
| 2029 | 0.91 | 1.00 | 0.81 | 0.86 | 0.93 | 0.98 |
| 2030 | 0.91 | 1.01 | 0.80 | 0.86 | 0.93 | 0.98 |
| 2031 | 0.91 | 1.01 | 0.79 | 0.89 | 0.94 | 1.00 |
| 2032 | 0.91 | 1.01 | 0.78 | 0.89 | 0.94 | 1.01 |
| 2033 | 0.90 | 1.02 | 0.77 | 0.88 | 0.94 | 1.03 |
| 2034 | 0.90 | 1.02 | 0.77 | 0.87 | 0.94 | 1.05 |
| 2035 | 0.90 | 1.03 | 0.76 | 0.90 | 0.95 | 1.06 |
| 2036 | 0.90 | 1.04 | 0.76 | 0.90 | 0.95 | 1.07 |
| 2037 | 0.90 | 1.04 | 0.75 | 0.90 | 0.95 | 1.08 |
| 2038 | 0.90 | 1.05 | 0.75 | 0.86 | 0.94 | 1.09 |
| 2039 | 0.90 | 1.06 | 0.74 | 0.88 | 0.95 | 1.09 |
| 2040 | 0.90 | 1.07 | 0.74 | 0.88 | 0.95 | 1.10 |
| 2041 | 0.90 | 1.08 | 0.73 | 0.86 | 0.96 | 1.10 |
| 2042 | 0.90 | 1.08 | 0.73 | 0.86 | 0.95 | 1.10 |
| 2043 | 0.90 | 1.09 | 0.73 | 0.86 | 0.96 | 1.10 |
| 2044 | 0.90 | 1.10 | 0.72 | 0.91 | 0.96 | 1.10 |
| 2045 | 0.90 | 1.11 | 0.72 | 0.89 | 0.96 | 1.10 |
| 2046 | 0.90 | 1.11 | 0.71 | 0.89 | 0.96 | 1.10 |
| 2047 | 0.90 | 1.11 | 0.71 | 0.89 | 0.96 | 1.10 |
| 2048 | 0.90 | 1.11 | 0.71 | 0.89 | 0.96 | 1.09 |
| 2049 | 0.90 | 1.11 | 0.70 | 0.89 | 0.96 | 1.09 |
| 2050 | 0.90 | 1.11 | 0.70 | 0.90 | 0.96 | 1.09 |
Summary
The updates to tables A1.3.9 and A1.3.10 make small but important adjustments to forecasts of vehicle kilometres and fuel efficiency of the car and LGV fleets.
The revised modelling shows a temporary reduction in the share of electric powered travel for cars and light goods vehicles, reflecting updated assumptions about how manufacturers will comply with the Zero Emission Vehicle (ZEV) mandate and new evidence that plugin hybrid electric vehicles use their electric mode less frequently than previously estimated. These differences lessen over time, with long term projections returning close to earlier trends.
Fuel efficiency forecasts have also been refined: petrol cars show slight improvements, diesel cars are projected to become less efficient as newer models tend to be larger and heavier, and changes for light goods vehicles remain modest, with slower efficiency gains for petrol models and minimal adjustments for diesel models.
Key points:
- short-term reduction in electric vehicle kilometres for cars and LGVs due to updated modelling of the ZEV mandate and evidence on PHEVs
- petrol-car efficiency improves slightly; diesel-car efficiency declines in later years
- LGV efficiency changes remain small, with slower improvement for petrol models and little change for diesel models
Contact
For further information on this guidance update, please contact:
Transport Appraisal and Strategic Modelling (TASM) division
Department for Transport
Zone 1/3 Great Minster House
33 Horseferry Road
London
SW1P 4DR
Email: tasm@dft.gov.uk