The Carbon Border Adjustment Mechanism (CBAM)
14 min
Level
In this article, we break down what the EU CBAM is, how it works, and what businesses need to do to comply.
ESG / CSR
Industries
MEASURE
ACT
COMFORM
Train Vs Car: What are their Carbon Footprints?
Level
“ Tackling climate change is a collective effort, and for most of us, that means trying to make more sustainable choices in our everyday lives. But even the simplest decisions – like whether to travel by train or by car – aren’t always as straightforward as they seem. ”
Most people assume that taking the train is better for the environment. It makes sense: trains can carry far more people than a single car, and they often seem like the more efficient option. But when you start looking at the details – how many people are in the car, what type of fuel is being used, or where the electricity is coming from – the answer gets a lot more complicated.
In this article, we’ll take a closer look at the carbon footprint of both cars and trains, and explore what really makes one greener than the other.
What this article covers
- How transport contributes to global emissions
- Whether trains are always the more sustainable choice
- How electric cars compare to trains on carbon emissions
- Why car manufacturing emissions matter
- The importance of electricity sources in different countries
- How transport infrastructure affects the environment
- The key factors that influence which option is better for the climate
Why transportation choice matters
“ Transportation is one of the largest sources of greenhouse gas emissions globally. It accounts for roughly one-fifth of all carbon dioxide (CO₂) emissions worldwide, or 24% when focusing specifically on energy-related CO₂ emissions. ”
The main reason for this is that around 90% of the world’s transport energy still comes from fossil fuels such as petrol and diesel. Transport is also responsible for a major share of global oil use, accounting for around 57% of total oil demand. Burning these fuels releases large amounts of carbon dioxide into the atmosphere, where it traps heat and contributes to global warming.
Because the transport sector plays such a significant role in climate change, reducing emissions from this area is essential if we’re to meet global climate targets. But while efforts to decarbonize transport are underway – from electrification and cleaner fuels to policy changes – it’s a long-term process that won’t happen overnight.
“ That’s why individual choices still matter. Whether we drive or take the train, our decisions have a direct impact on emissions. But which option is actually better for the environment? ”
Is taking the train the greener option?
It’s widely assumed that taking the train is much better for the environment than traveling by car. The logic is simple: trains can carry hundreds of passengers at once, while most car journeys involve just one or two people. But does this assumption hold up under closer scrutiny?
According to the Intergovernmental Panel on Climate Change (IPCC), road transport accounts for approximately 70% of global transport-related carbon emissions, while rail is responsible for just 1%. These figures make it clear that, in absolute terms, road travel produces significantly more emissions than rail.
However, this high-level view doesn’t tell the whole story. To make a fair comparison, we need to look at emissions per passenger kilometer. And when we do, the picture becomes more complex, especially when considering factors like the type of car, fuel source, number of passengers, and how the train is powered.
Train vs Car - it’s in the detail
The carbon footprint of travelling by car or train depends on several key factors – and the results can vary significantly depending on the situation. The biggest drivers of emissions are:
- Energy type (petrol, diesel, electric)
- Number of passengers sharing the journey
- Train class (economy, business or first-class)
- Distance travelled
- How the electricity is generated, in the case of electric vehicles or trains
For example, here’s how average car emissions compare based on fuel type and passenger count:
| Car Type | 1 passenger | 2 passengers | 4 passengers |
|---|---|---|---|
| Petrol car | 192g CO2e | 96g CO2e | 48g CO2e |
| Diesel car | 171g CO2e | 85.5g CO2e | 42.75g CO2e |
| Electric car (EV) | 53g CO2e | 26.5g CO2e | 13.25g CO2e |
Note: figures are average emissions per passenger kilometer traveled. Source.
When compared with rail, the differences become clearer. Some of the most energy-efficient train services – such as the Eurostar, which is transitioning to renewable electricity – emit as little as 6g CO₂e per passenger kilometer. On the other hand, traditional national rail services, which often still run on diesel, produce an average of 41g CO₂e per passenger kilometer.
Train emissions can also vary by ticket class. Business and first-class carriages tend to carry fewer passengers, which means emissions per seat can be significantly higher than in economy class.
So, what do these numbers tell us?
In most cases, taking the train will result in fewer emissions than driving a petrol or diesel car, especially if you’re traveling alone. But the equation shifts when we factor in electric vehicles and car sharing.
Based on lifecycle analysis from the International Council on Clean Transportation (ICCT), a typical mid-sized electric car charged on the average European grid emits around 47 g CO₂e per kilometer. When shared between three to four passengers, this drops to approximately 12–16 g CO₂e per passenger kilometer, making a fully occupied EV comparable to, or potentially better than, many train journeys in terms of carbon footprint.
“ That’s why it’s important to consider the full picture: energy source, occupancy, distance, and infrastructure all play a role. While trains are often the greener choice, they’re not always the automatic winner. ”
Which has better green technology - trains or cars?
Electric cars are accelerating fast
Electric vehicles (EVs) are becoming a common sight on roads around the world. In many countries, petrol and diesel cars are being phased out. For example, in the UK, the sale of new petrol and diesel cars will be banned by 2030, and all new cars and vans will need to be 100% zero emission by 2035.
This shift is being fuelled by:
- Strong consumer demand for cleaner alternatives
- Tighter emissions regulations
- Rapid improvements in EV technology and affordability
Trains are going electric too – but more slowly
Rail networks are also becoming greener. Electric trains are now widespread across Europe and other regions, and some countries are trialing hydrogen or battery-powered trains as low-emission alternatives to diesel.
But progress is slower – and one key reason is lifespan.
Cars are replaced quickly – trains are not
- The average age of a car on US roads is 12.8 years
- Newer, cleaner models enter the market regularly
- This fast turnover helps the industry adopt new technology quickly
Trains, by contrast, are built to last. Rolling stock often stays in service for 30 to 40 years. While this makes rail durable and cost-effective, it also means that technological upgrades happen far less frequently.
So which is greener?
While EVs are catching up fast, trains still tend to be more efficient per passenger kilometer – especially when powered by renewable electricity.
But in terms of technological progress, the car industry is moving more quickly, thanks to:
- Shorter product lifecycles
- Market competition
- More frequent upgrades
Both sectors are heading in the right direction, just at very different speeds.
Car renewal - a double edged sword
A fast turnover means faster innovation
The short lifespan of most cars is a major advantage when it comes to sustainability.
Cleaner models, faster
Newer, lower-emission vehicles can replace older, more polluting ones more quickly.
Rapid innovation
Short lifecycles support fast development in EV technology and efficiency.
Phasing out fossil fuels
Quicker turnover makes it easier to eliminate petrol and diesel models from the road.
This is part of the reason why EVs have seen such fast growth in recent years.
But manufacturing comes at a cost
Each time a new car is built, emissions are generated – regardless of whether it runs on petrol or electricity.
That’s because the production process includes:
- Extracting and refining raw materials
- Transporting those materials and components
- Assembling the vehicle in an energy-intensive factory
Bigger cars = bigger footprints
The carbon footprint of a newly manufactured vehicle depends heavily on its size and type:
Small petrol car
A Citroën C1 produces around 6 tonnes of CO₂e during manufacture.
Large SUV
A Land Rover Discovery produces around 35 tonnes of CO₂e.
Electric vehicle
EVs can generate up to 80% more emissions than petrol cars, mainly due to battery production.
EVs catch up – if you keep them
Although EVs start out with higher manufacturing emissions, they catch up fast.
On average, an electric car overtakes a petrol car in terms of total carbon footprint after just 21,700 km of driving.
After that point, the gap only widens, meaning the longer you keep an EV, the greater the climate benefit.
Close
The hidden footprint of transport infrastructure
When comparing the sustainability of trains and cars, it’s easy to focus solely on tailpipe emissions or electricity use. But there are other environmental impacts that often get overlooked and these can significantly shift the balance.
Railways, roads, stations, tunnels and bridges all require vast amounts of materials and energy to build — and to maintain over time. These lifecycle emissions aren’t reflected in emissions-per-kilometer stats, but they do contribute to the total environmental footprint of transport.
One study found that rail infrastructure can generate up to 141% more emissions than the operational emissions from passenger rail. This highlights the hidden cost of building and maintaining extensive rail networks.
Beyond emissions, new transport infrastructure can also have a lasting impact on ecosystems. Whether it's a new high-speed rail line or a motorway expansion, construction often involves:
- Deforestation or loss of green spaces
- Fragmentation of habitats and wildlife corridors
- Soil sealing, erosion, and loss of biodiversity
Both rail and road projects come with trade-offs. While trains are often more efficient in operation, their infrastructure can be just as disruptive to the environment.
Not all sustainability gains are visible
A full comparison between cars and trains needs to go beyond what we see on the road or tracks. Materials used, land cleared, and long-term infrastructure maintenance all play a role in determining which mode of transport is more sustainable over its lifecycle.
What’s powering the electricity?
“ Electric vehicles and trains are undoubtedly cleaner than their fossil-fuelled counterparts, but that’s only part of the story. The environmental impact also depends on how that electricity is produced. ”
Not all electricity is created equal
While electric motors produce zero tailpipe emissions, the source of the electricity they run on can vary dramatically. Many energy providers still rely heavily on fossil fuels such as gas, oil, or even coal. Others offer electricity from renewable sources like wind, solar, and hydro.
This choice, whether made by a household, a business, or a national rail network, directly affects the carbon footprint of each kilometer traveled.
Country-specific energy mixes matter
The emissions linked to electric transport also depend on the national energy mix. For example:
UK energy mix
Gas: 38.9%
Renewables: 44.4%
Nuclear: 14.8%
Renewables: 44.4%
Nuclear: 14.8%
The UK still relies heavily on fossil fuels, but has made notable progress in renewable energy adoption.
France energy mix
Nuclear: 70%
Hydro + wind + solar: 26%
Fossil fuels: 4%
Hydro + wind + solar: 26%
Fossil fuels: 4%
France has one of the lowest-carbon energy mixes in Europe, thanks to its strong reliance on nuclear and renewables.
US energy mix
Fossil fuels: 60.0%
Nuclear: 18.6%
Renewables: 21.4%
Nuclear: 18.6%
Renewables: 21.4%
The US still leans heavily on gas and coal, though renewables and nuclear are gaining ground in certain regions.
This means that an electric train or car used in France typically has a much lower carbon footprint than the same vehicle operating in the US, or even in the UK.
It’s not just about use – it’s also about manufacture
The electricity mix also affects the manufacturing emissions of vehicles. Electric cars or trains built in countries with greener grids start off with a smaller embedded carbon footprint, reinforcing the case for shifting to clean energy across the board.
Trains vs cars in the US
In the US, car dependency remains dominant, with limited intercity rail options and chronic underinvestment in rail infrastructure. However, EV uptake continues to accelerate, even as recent policy rollbacks threaten to slow progress on transport decarbonisation.
🚆
Train ridership
Amtrak recorded 32.8 million riders in FY 2024 – its highest ever. While demand is rising, federal rail funding remains under pressure, with key infrastructure grants paused or frozen under Trump’s 2025 budget plan.
🚗
EV infrastructure
Over 4 million EVs are now on US roads. Sales hit 7.6% of all new vehicles in 2023, but progress is at risk: the $5B NEVI charging rollout was halted in early 2025, with only partial funding recently released after legal challenges.
📜
Climate policy
The US had pledged to cut transport emissions by 50% by 2030. But many Biden-era climate programmes – including EV incentives and public transit grants – are now being rolled back or defunded by the Trump administration.
So, which is greener?
Trains typically come out ahead when it comes to carbon emissions – especially for solo travel and longer distances. But as we've seen, the answer isn’t always so black and white. With the rise of electric vehicles, car sharing, and greener energy mixes, there are cases where driving can be just as sustainable – or even more so.
And the picture gets even more complicated when you factor in manufacturing emissions, infrastructure impacts, and how fast green tech is advancing in the automotive sector. Some experts even argue that in the near future, cars may outperform trains on environmental grounds – particularly in countries with clean electricity grids.
So what’s the smartest choice? It depends on your specific journey and your setup. Here’s a quick checklist to help guide your decision:
✅ The final verdict: train or car?
Trains typically have the lowest carbon footprint – especially for solo travellers or longer distances. But as we’ve seen, driving (especially in an electric or shared car) can sometimes be just as sustainable, depending on the context.
Here’s a quick decision guide:
✅ Take the train if:
- You’re travelling solo
- The train is electric (not diesel)
- You’re in a country with a clean energy mix (e.g. France)
- There’s a fast and convenient rail connection
- You’re only going one way and want to avoid the hassle of driving
🚗 Consider driving if:
- You’re travelling with two or more people
- You’re using a fully electric or hybrid vehicle
- Your EV is charged using renewable energy
- The train route is slow, indirect, or unavailable
- You plan to keep the car long-term or it’s second-hand
Close
What about Greenly?
At Greenly, we help companies understand and reduce the environmental impact of their activities – whether it’s transport, infrastructure, or energy use.
Here’s how we can support your sustainability journey:
💡 What about Greenly?
| How Greenly helps | What it means for you |
|---|---|
|
📊 Measure your carbon footprint
|
We help businesses track their emissions across Scope 1, 2, and 3 – from energy use to purchased goods and beyond. |
|
🔍 Identify reduction opportunities
|
Our platform highlights the biggest drivers of your emissions and shows you where to take action first. |
|
📄 Simplify reporting and compliance
|
Whether you need to meet CSRD, SECR, or GHG Protocol requirements, our tools and expert support make climate reporting seamless. |
|
♻️ Go deeper with Life Cycle Assessments
|
We analyze the full environmental impact of your products or services – from raw materials to end of life. |
|
🌍 Build a more sustainable strategy
|
From setting science-based targets to engaging your suppliers, we support long-term, meaningful change. |
Want to turn sustainability into action? Get in touch to see how Greenly can help.
Sources:
- Greenly, Electric cars – are they really ecological?
https://greenly.earth/en-gb/blog/industries/electric-cars-are-they-really-ecological - Greenly, What is the Intergovernmental Panel on Climate Change (IPCC)?
https://greenly.earth/en-gb/blog/ecology-news/what-is-the-intergovernmental-panel-on-climate-change-ipcc - Greenly, Fossil fuels: pros, cons and alternatives
https://greenly.earth/en-gb/blog/ecology-news/fossil-fuels-pros-cons-and-alternatives - Greenly, Climate change in 2022 – where do we stand?
https://greenly.earth/en-gb/blog/ecology-news/climate-change-in-2022-where-do-we-stand - The Guardian, What’s the carbon footprint of a new car?
https://www.theguardian.com/environment/green-living-blog/2010/sep/23/carbon-footprint-new-car - Brussels Blog, Carbon footprint of car manufacturing (PDF)
https://brusselsblog.co.uk/PDF/CarFootprintM.pdf - The Guardian, Do electric cars really produce fewer carbon emissions than petrol or diesel vehicles?
https://www.theguardian.com/business/2023/dec/23/do-electric-cars-really-produce-fewer-carbon-emissions-than-petrol-or-diesel-vehicles - Reuters, When do electric vehicles become cleaner than gasoline cars?
https://www.reuters.com/business/autos-transportation/when-do-electric-vehicles-become-cleaner-than-gasoline-cars-2021-06-29 - European Union Agency for Railways, Environmental benefits of rail (PDF)
https://www.era.europa.eu/system/files/2024-07/20242052_PDF_TR0924239ENN_002.pdf - UK Government, Energy Trends – June 2025 (PDF)
https://assets.publishing.service.gov.uk/media/685bda130433072fce0e0fe1/Energy_Trends_June_2025.pdf - Low Carbon Power, Energy mix in France
https://lowcarbonpower.org/region/France - UK Office of Rail and Road, Passenger rail usage statistics
https://dataportal.orr.gov.uk/statistics/usage/passenger-rail-usage - S&P Global, EV sales reach record high in UK (2024)
https://www.spglobal.com/commodity-insights/en/news-research/latest-news/metals/010625-uk-data-ev-sales-reach-record-high-of-381970-units-in-2024
More Articles
View all
Decarbonization: what it is and why it matters
1 min
Level
What is decarbonization and why is it urgent? Learn practical steps companies can take to support the global move toward net zero emissions.
What is the EU Taxonomy?
1 min
Level
Discover the EU Taxonomy: what it is, how it defines sustainable activities, and its impact on businesses and financial markets.
Top 10 Carbon Management Software
1 min
Level
In this article, we’ll explore five of the leading carbon management software platforms available today. Whether you're looking to measure your carbon footprint, create actionable decarbonisation plans, or meet regulatory requirements, these tools can help you build a more sustainable future.