Press release

UK efforts to cut transport emissions could fail unless congestion also tackled, says think tank


8 December, 2021

Switching to electric vehicles will cut carbon emissions, but reducing traffic is also needed to make sure the UK hits its 2030 climate target, and will bring wider benefits, finds a new Green Alliance report.

Transport accounts for nearly a third of UK carbon emissions and cars alone are responsible for 40 per cent of that, making them the single highest emitting sub-sector of the economy, but sales of electric vehicles are still a low percentage of total sales.

To be sure the UK can hit its emission reduction targets, analysis published by the think tank Green Alliance today recommends that the government should also introduce more measures to help drivers switch to walking, cycling and public transport. [1]

This requires greater national investment in public transport over the next decade, as well as more support for local authorities to improve facilities for active travel and to make neighbourhoods more walkable.

The report highlights the additional economic benefits of traffic reduction. Shifting just 1.7 per cent of car journeys to active travel would provide the UK with up to £2.5 billion per year in health benefits. [2] And reducing congestion would provide an economic boost, as the cost of congestion was estimated to be almost £8 billion in 2018. [3]

Green Alliance’s study analysed fast, medium, and slow electric vehicle sales trajectories in the period up to the UK’s 2030 ban on the sale of new petrol and diesel cars. The fast scenario is based on the Climate Change Committee’s recommended rate of uptake to meet climate targets, the medium trajectory was calculated by Green Alliance and aligns with government’s prediction of average sales rates, and the slow trajectory is the Department for Transport’s own worst case scenario, of only 50 per cent of vehicles sold in 2030 being purely electric. [4]

The study found that, even under the medium sales trajectory, which the government thinks is most likely, the average annual mileage per car would have to fall by around 1,700 miles if emissions targets are to be met. Under the slow sales trajectory, the annual average mileage per car would need to be cut by almost 30 per cent, or 2,300 miles a year fewer, to keep emissions on track.

To encourage a rise in uptake, the government has announced it will introduce a zero emission vehicle (ZEV) mandate, placing EV sales targets on car companies from 2024. [5] However it has not yet chosen the levels for these targets.

Green Alliance recommends the government takes decisive action now to set ambitious ZEV mandate targets but also take steps to manage future traffic levels. This would provide insurance in the event that electric vehicle sales do not follow the fastest uptake trajectory over the next decade.

Helena Bennett, senior policy adviser at Green Alliance, said:
“Switching to electric vehicles is the top priority for cutting emissions from cars, but it can’t be the only tool used to make transport greener. Better and more affordable public transport, safe cycle routes and walkable places must be a centrepiece of the government’s transport strategy.”



Notes to editors

[1] Not going the extra mile, December 2021

[2] Ricardo-AEA, 2013, Review of the impacts of carbon budget measures on human health and the environment

[3], press release, 12 February 2019, ‘Congestion costs UK nearly £8 billion in 2018’

[4] The Climate Change Committee, Sixth carbon budget: surface transport, December 2021
The Climate Change Committee (CCC), the UK government’s independent climate adviser, recommends that 97 per cent of new cars sold in 2030 should be battery electric vehicles (EVs) if the UK is to be on track to meet its goal of net zero carbon emissions by 2050.

[5] Net Zero Strategy: Build Back Greener, HM Government, October 2021, Policy paper overview: Net Zero Strategy: Build Back Greener – GOV.UK ( To encourage the rollout of EVs rise in uptake, the government has announced it will introduce a zero emission vehicle (ZEV) mandate, placing EV sales targets on car companies from 2024. Ambitious targets in the ZEV mandate would help speed up the EV transition.


Helena Bennett

Senior policy adviser

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