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The UK’s Transport Decarbonisation Plan: Everything you need to know
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Transport is the UK’s highest-emitting sector, and tackling its emissions is essential if the country is to meet its net zero ambitions. That’s why, in 2021, the UK Government launched its Transport Decarbonisation Plan – a roadmap for slashing carbon emissions across everything from road vehicles and rail to aviation and shipping.
But what does the Plan actually say? Who’s responsible for delivering it? And how has it been received so far?
In this article, we’ll unpack the key details of the UK’s Transport Decarbonisation Plan – looking at what it means for different parts of the transport industry, and what progress has (or hasn’t) been made since it was first introduced.
What is the UK Transport Decarbonisation Plan?
“ The Transport Decarbonisation Plan is the UK Government’s strategy for cutting carbon emissions from the transport sector, which is responsible for around 30% of the UK’s total greenhouse gas (GHG) emissions, making it the country’s highest-emitting sector. ”
The UK government published the Plan in July 2021, setting out a vision for a net zero transport system by 2050. It outlines how the government aims to work with local authorities, industry, and the public to reduce dependence on fossil fuels, scale up cleaner technologies, and encourage more sustainable ways of getting around.
It covers all modes of transport, from cars and buses to trains, planes, and shipping, and combines policy proposals, regulatory changes, and funding plans designed to make low-carbon transport the norm.
The UK's Net Zero Target and the role of the Transport Decarbonisation Plan
“ In 2019, the UK became the first major economy to legislate a commitment to achieve net zero GHG emissions by 2050. This ambitious goal requires balancing the amount of emissions emitted with the amount removed from the atmosphere, effectively reducing the UK's contribution to global warming to zero. ”
To navigate this path, the government introduced the Net Zero Strategy: Build Back Greener in October 2021. This comprehensive strategy outlines policies and proposals for decarbonising all sectors of the UK economy – including the energy system, industry, and transportation – to meet the 2050 target.
Within this overarching framework, the Transport Decarbonisation Plan (TDP), published in July 2021, serves as a sector-specific roadmap. Recognising that transport is the largest contributor to the UK's GHG emissions, the TDP details the government's approach to reducing emissions linked to the sector. Its objectives include:
- Reducing emissions across all transport modes.
- Cutting costs for businesses and consumers through cleaner technologies.
- Improving air quality to enhance public health.
- Tackling congestion to create more efficient transport networks.
By implementing the Transport Decarbonisation Plan, the UK aims to transform its transportation sector, making it more sustainable and playing a pivotal role in achieving the nation's decarbonisation ambitions.
Key commitments in the UK's Transport Decarbonisation Plan
“ Reaching net zero by 2050 won’t be possible without a radical shift in how the UK approaches transport. The sector has long been one of the hardest to decarbonise, partly because it cuts across so many areas of daily life, from how we commute and travel to how goods move around the country. ”
That’s why the TDP sets out a wide-ranging set of actions to modernise the system and support cleaner, more reliable alternatives. It covers every major mode of transport and ties specific commitments to clear deadlines, backed (at least in theory) by investment and regulation.
Below is a quick overview of the key commitments, which we’ll unpack in more detail below:
| Mode of Transport | Key Commitment |
|---|---|
| Passenger vehicles | Ban on new petrol/diesel cars and vans by 2030; hybrids allowed until 2035 |
| Buses and HGVs | Ban on new diesel HGVs and buses: those between 3.5 and 26 tonnes by 2035, and over 26 tonnes by 2040 |
| Rail | Remove all diesel-only trains by 2040; invest in battery and hydrogen tech |
| Aviation | Net zero domestic aviation by 2040; full aviation alignment with the 2050 decarbonisation targets |
| Public transport & active travel | Half of all urban journeys walked or cycled by 2030; £2bn+ investment |
| Maritime | Phase-out of non-zero emission vessels; push for stronger global IMO targets |
Now let’s look at what each of these actually means in practice:
Passenger vehicles
The biggest headline is the ban on new petrol and diesel cars and vans from 2030, with new hybrids allowed until 2035 (but only if they can travel a “significant distance” in electric mode). After that, only zero emission cars, such as fully electric or hydrogen vehicles, can be sold.
This isn’t new – the ban was announced before the Plan – but the Transport Decarbonisation Plan adds a clearer regulatory framework. The government has pledged to introduce new rules for carmakers around fuel efficiency and EV sales, to give the industry more certainty and help scale up investment in zero emission vehicles. The second-hand car market won’t be affected, so petrol and diesel vehicles will still be available for use in the foreseeable future.
Buses and heavy goods vehicles (HGVs)
For larger vehicles, the Plan sets out a timeline for ending the sale of new fossil fuel models:
- Diesel buses and HGVs between 3.5 and 26 tonnes to be phased out by 2035
- Heavier HGVs to follow by 2040
These targets are ambitious, and the next step will be formal consultations and regulations to support rollout. Clean HGV technology and zero emission buses are still developing, but the government argues that early action can create new jobs and industrial opportunities in the UK.
Rail and freight
The UK first committed to ending the use of diesel-only trains back in 2018, with a 2040 deadline – a goal reaffirmed in the Plan. But with over half the rail network still dependent on diesel, the challenge is far from over.
In the meantime, the government has pledged investment in alternatives like battery-electric and hydrogen trains, which can help reduce emissions on non-electrified lines. It has also now published a Rail Environment Policy Statement, setting out priorities for improving air quality, reducing waste, protecting biodiversity, and supporting wider sustainability goals across the rail sector.
The Transport Decarbonisation Plan also outlines a longer-term vision for a net zero rail network by 2050 – though this is yet to be confirmed as a formal target.
Aviation
Aviation is often the elephant in the room when it comes to decarbonising transport, it’s a fast-growing sector with limited low-carbon options. Globally, it accounts for around 2.5% of CO₂ emissions, but in wealthy countries like the UK, that figure is higher at 7% of the country's annual emissions.
Rather than dodging the issue, the Transport Decarbonisation Plan commits UK aviation to net zero by 2050, with a specific target of 2040 for domestic flights currently under consultation. This will be supported by the Jet Zero Strategy, which focuses on sustainable aviation fuels (SAFs), new aircraft technology, and more efficient flight paths.
Public transport and active travel
One criticism of the UK’s approach to decarbonising transport has been its emphasis on electric vehicles at the expense of investing in public and active transport options that reduce car dependency altogether. The Plan attempts to respond to this by putting more focus on walking, cycling, and public transport.
It includes a £2 billion investment to support walking and cycling infrastructure, with a goal for 50% of all journeys in towns and cities to be walked or cycled by 2030. A further £12 billion is set aside to help local authorities decarbonise public transport and improve air quality in urban areas.
Maritime and shipping
Shipping is often overlooked in transport decarbonisation strategies, but the Transport Decarbonisation Plan includes key commitments for this sector too.
The Plan sets out the government’s intention to consult on a phase-out date for new non-zero emission domestic vessels, alongside policies to support the use of low-carbon fuels, investment in port electrification, and the development of clean maritime technologies.
On the international stage, the UK also pledged to press for stronger global action on shipping emissions through the International Maritime Organization (IMO), including more ambitious global targets.
What progress has been made towards the TDP?
Since the release of the UK's Transport Decarbonisation Plan in 2021, there have been notable developments in the nation's journey toward reducing transport emissions. Here's an overview of the progress made up to March 2025:
Overall UK emissions trends
In 2024, the UK's GHG emissions decreased by approximately 4%, reaching 371 million tonnes of CO₂ equivalent (MtCO₂e), down from 385 MtCO₂e in 2023. This marks a 54% reduction compared to 1990 levels. However, the decline is largely attributed to decreased gas and coal usage in electricity generation and industry sectors, including the closure of the last coal-fired power station and an expansion in renewable energy sources.
Transport emissions
“ The transport sector remains the largest contributor to the UK's greenhouse gas emissions. In 2024, domestic transport emissions fell by 2% (2 MtCO₂e), primarily due to reduced diesel consumption in road transport. Despite this reduction, transport accounted for 30% of the UK's total emissions. ”
Electric vehicle (EV) adoption
The UK has seen significant growth in electric vehicle adoption. In 2024, nearly 382,000 new electric cars were sold, representing a 21.4% increase from the previous year and accounting for 19.6% of all new car sales. This surge positioned the UK as Europe's largest market for electric car sales, overtaking Germany. However, challenges remain in meeting the government's ambitious targets, which aim for 80% of new car sales to be zero-emission by 2030 and 100% by 2035. Factors such as high electricity prices and public perception continue to influence the pace of EV adoption.
Policy developments and challenges
The UK government has implemented various policies to support transport decarbonisation, including the expansion of the Ultra-Low Emission Zone (ULEZ) in London. In its first year, the expanded ULEZ led to a 14% reduction in nitrogen dioxide emissions in outer London boroughs and a 13% decrease citywide. Despite initial opposition, the initiative has contributed to improved air quality across the city.
However, concerns have been raised regarding the adequacy of current policies to meet long-term emission reduction targets. The Climate Change Committee's 2024 report highlighted a slowdown in policy implementation and called for accelerated action to achieve the UK's decarbonisation ambitions.
“ While the UK has made progress in reducing transport emissions since the introduction of the TDP, significant challenges remain. Continued policy support, infrastructure development, and public engagement are essential to meet the ambitious targets set for 2030 and beyond. ”
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Challenges to the success of the Transport Decarbonisation Plan
While the Transport Decarbonisation Plan was welcomed as a step in the right direction, progress hasn’t been smooth, and there are growing concerns that the UK won’t meet its transport targets without faster, more decisive action.
Below is a breakdown of some of the biggest challenges the UK now faces in trying to deliver the plan:
| Challenge | What’s the issue? | Why it matters |
|---|---|---|
| Too much focus on electric cars | The TDP puts a lot of weight behind EV adoption – but puts far less emphasis on reducing overall car use. | Without more investment in public transport and active travel, we risk just swapping petrol traffic for electric. |
| Lack of electric vehicle charging infrastructure | The UK still doesn’t have enough public charging points to keep pace with growing EV demand. | Without a reliable, accessible charging network, drivers may hesitate to switch to electric vehicles. |
| Rail electrification falling behind | The target is to remove diesel-only trains by 2040, but only around 38% of the UK rail network is electrified as of 2025. | Hydrogen and battery trains can help, but large-scale progress relies on electrification, and right now, it's slow. |
| Lack of ambition on public transport | Funding for walking and cycling is welcome, but clean buses, trains, and trams haven’t had the same kind of push or policy clarity. | Without a more appealing public transport offer, cutting car use will be difficult, especially outside big cities. |
| Aviation left largely untouched | The government committed to decarbonising the sector, but didn’t limit airport expansion or passenger growth. | Aviation remains one of the hardest sectors to decarbonise – and it’s growing fast. |
| Big bets on future tech | A lot of the plan hinges on technologies that aren’t widely available yet – from hydrogen HGVs to zero-emissions shipping and aviation. | If these don’t scale fast enough, the UK risks missing its targets or relying heavily on offsets. |
| Political uncertainty | Mixed signals from political leaders – including some who’ve questioned the 2050 net zero target – have created doubt around long-term commitment. | Without cross-party backing, long-term transport policies could be watered down or delayed. |
“ While the Transport Decarbonisation Plan laid the groundwork for cutting emissions across the UK’s transport sector, progress so far has been patchy. With deadlines looming and some of the biggest shifts still ahead, the next few years will be crucial. Without more investment, stronger policy signals, and a clearer focus on reducing demand for travel, not just cleaning it up, the UK risks falling short of its net zero transport goals. ”
Looking forward
The UK's Transport Decarbonisation Plan has set ambitious goals to achieve net-zero emissions by 2050. As we look ahead, several key developments and initiatives are shaping the future of transport decarbonisation:
Maritime Decarbonisation Strategy
In March 2025, the UK government unveiled a comprehensive strategy to achieve an emissions-free shipping fleet by 2050. The plan includes interim targets of a 30% reduction in greenhouse gas emissions by 2030 and an 80% reduction by 2040, relative to 2008 levels. This initiative focuses on developing alternative fuels and establishing charging infrastructure in harbors to facilitate the transition to cleaner maritime operations.
Lower Thames Crossing approval
The approval of the £9 billion Lower Thames Crossing, a new road tunnel connecting Essex and Kent, has sparked debate. While supporters argue it will alleviate congestion and boost the economy, critics contend it may increase carbon emissions and traffic. This development underscores the ongoing challenge of balancing infrastructure expansion with environmental commitments.
Green refueling infrastructure
Private sector investments are accelerating the establishment of green refueling hubs. Aegis Energy, for example, has secured £100 million to develop facilities offering biofuel, electric charging, and potentially hydrogen refueling for commercial vehicles. The first five hubs are slated for completion by 2027, with plans for 30 operational sites by the end of the decade, helping to scale up access to green transport technology across the UK.
Industry challenges
The transport sector continues to face challenges, including industry pushback on climate policies. European airlines have lobbied for the relaxation of carbon pricing regulations and delays in sustainable aviation fuel mandates, citing economic concerns. Balancing environmental objectives with economic realities remains a critical aspect of the decarbonisation journey.
“ While the TDP has set a clear direction for reducing transport emissions, achieving its ambitious goals requires continuous effort, collaboration, and adaptation to emerging challenges and opportunities. The coming years will be pivotal in translating plans into tangible outcomes on the path to net-zero transport. ”
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Sources:
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- UK Government, Net Zero Strategy, https://www.gov.uk/government/publications/net-zero-strategy
- Greenly, Net Zero Strategy: What Is It and How Can You Implement It?, https://greenly.earth/en-gb/blog/ecology-news/net-zero-strategy-what-is-it-and-how-can-you-implement-it
- Greenly, Carbon Emissions: What You Need to Know, https://greenly.earth/en-gb/blog/ecology-news/carbon-emissions-what-you-need-to-know
- Greenly, Electric Cars: Are They Really Ecological?, https://greenly.earth/en-gb/blog/industries/electric-cars-are-they-really-ecological
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- Our World in Data, Global Aviation Emissions, https://ourworldindata.org/global-aviation-emissions#:~:text=Flying%20is%20one%20of%20the,of%20the%20world's%20carbon%20emissions
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- UK Government, Jet Zero Strategy, https://assets.publishing.service.gov.uk/media/62e931d48fa8f5033896888a/jet-zero-strategy.pdf
- Greenly, Could Aviation Be Decarbonised and Become Sustainable?, https://greenly.earth/en-gb/blog/industries/could-aviation-be-decarbonised-and-become-sustainable
- UK Government, The Second Cycling and Walking Investment Strategy (CWIS2), https://www.gov.uk/government/publications/the-second-cycling-and-walking-investment-strategy/the-second-cycling-and-walking-investment-strategy-cwis2#:~:text=It's%20one%20of%20the%20best,walked%20or%20cycled%20by%202030
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- Greenly, Are Low Emission Zones Like ULEZ Successful?, https://greenly.earth/en-gb/blog/ecology-news/are-low-emission-zones-like-ulez-successful
- The Times, Expanded ULEZ Cuts Emissions, Nitrogen Dioxide, https://www.thetimes.com/uk/environment/article/expanded-ulez-cuts-emissions-nitrogen-dioxide-d5tz22fdr?utm_source=chatgpt.com®ion=global
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- Transport + Energy, New Maritime Decarbonisation Strategy Announced, https://transportandenergy.com/2025/03/26/new-maritime-decarbonisation-strategy-announced/?utm_source=chatgpt.com
- The Guardian, Lower Thames Crossing Tunnel Plan Approved, https://www.theguardian.com/uk-news/2025/mar/25/lower-thames-crossing-plan-essex-kent-approved-tunnel?utm_source=chatgpt.com
- The Times, Start-Up Wins £100m Backing to Roll Out Green Refuelling Sites, https://www.thetimes.com/business-money/companies/article/start-up-wins-100m-backing-to-roll-out-green-refuelling-sites-w8hfr03kv?utm_source=chatgpt.com®ion=global
- Financial Times, FT Article on UK Climate Transport Policy, https://www.ft.com/content/f5e59ab2-349b-42e5-ba3f-473f92684449?utm_source=chatgpt.com