As COP27 goes full-steam ahead in Egypt this week, countries are taking a long hard look at their emissions targets. So many media articles this week highlight the level of skepticism among thought leaders in halting the rise to 1.5 °C above pre-industrial levels. Yet while the energy sector often takes centre stage, the transport sector clocks in at 24% of total emissions (OECD Regions and Cities at a Glace 2022) and has seen the largest increase in emissions, doubling in the period from 1970-2018. What can we do to help cities run off fumes?
Cars per capita
Even though technology has progressed and vehicle energy efficiency has improved, these positive trends are cancelled out by the fact that people are buying more cars and driving them more than ever before. As a result, fuel consumption and related emissions have been driven up – a combination that doesn’t fare well for reaching our emissions targets.
But now for the good news… In Europe, the number of private vehicles per capita decreased in most regions during the last two decades, especially in capital regions. London for example has seen a 12% decline in private per capita vehicle ownership since 2000.
In the opposite lane, in many regions of Mexico, Chile and the United States, private vehicle ownership has increased significantly. The regions of Morelos and Tlaxcala in Mexico saw a fourfold increase in the number of private vehicles between 2001-20.
Other places haven’t hit peak car quite yet either. The mountainous Aosta Valley region (northwestern Italy) recorded almost 1,800 vehicles per 1,000 inhabitants. This is the highest number of private vehicles per capita across OECD regions. But it’s not like this everywhere in Italy – this is more than three times the number of vehicles per capita in the coastal region of Liguria (also north-western Italy). There are large regional disparities too in vehicles per capita in the United States, Canada and Greece.
More potholes & pitfalls
It’s sad to say that the downsides don’t stop there. Vehicle exhaust fumes not only affect the environment as greenhouse gas emissions, but they also contribute to the release of PM2.5 into the air and increased general air pollution. PM2.5 are microparticles in the air that can affect your health when levels are high. A tell-tale sign that PM2.5 levels might be elevated is when the air outside looks hazy.
These emissions can also have direct cognitive effects, with impacts on learning and productivity. One study examined outcomes for students in Florida who attended the same elementary school and split up for high school. The primary difference was that one high school was “downwind” of a highway. They found that those who studied downwind of the high school experienced decreases in test scores, more behavioural incidents and more absences, relative to when those who attended the upwind school. Another study even found that air pollution, in particular PM2.5, reduced the speech quality of Canadian Members of Parliament.
How are cities and regions taking action?
The need for cleaner air is clear – so how are places running off fumes?
Paris – The Climate Air Energy Plan aims to phase out diesel-run vehicles by 2024 and gasoline-powered vehicles by 2030. The French capital has also lowered the speed limit for drivers on most streets in a bid to curb the number of cars in the city, reduce noise and fight climate change.
California – State regulators voted to ban the sale of gas-powered cars by 2035, an important move given that California is the largest auto market in the US.
Mexico – At the Major Economies Forum on Energy and Climate (MEF) in June 2022, President Andrés Manuel López Obrador announced the goal of producing 50% zero-emission vehicles by 2030.
The Clean Cities group helps hold cities accountable by ranking cities on where they are in reaching zero-emission mobility by 2030. Currently, the list puts Oslo, Norway, Amsterdam, Netherlands and Helsinki at the top of the list.
Electric boogie
In most OECD countries, capital regions are leading the adoption of electric or hybrid vehicles. Electric cars can help reduce carbon emissions. They have much lower emissions than fuel-powered cars and many regions are moving towards generating electricity from low carbon sources. This can likely be explained by the shorter distances that inhabitants need to travel to their destinations, as well as the greater availability of charging stations.
In the regions of Oslo and Viken in Norway, almost 30% of private vehicles are either electric or hybrid as of 2020, an increase of 20pp in only four years. Brussels Capital Region, Greater London, Budapest and Stockholm recorded a share of around 7% in the same year.

The seven cities of Barcelona, Berlin, Budapest, Rome, Turku, Florence, and Murcia are part of the USER-CHI project, which focuses on charging infrastructure for electric vehicles. These cities will test solutions for efficient electric vehicle charging. Technologies include a digital planning tool that determines the best location for charging stations, a wireless charging solution for electric cars, and solar-powered charging hubs for e-bikes and scooters.
Transportation transformations
Electric vehicles can be part of the solution, but further initiatives must be pursued to reduce the number of privately-owned vehicles.
Increased investment in public transport to create greener, more accessible and more efficient transportation in cities can further reduce car use in cities. Further, greater emphasis and improved infrastructure for bicycles and electric scooters can incentivise alternative forms of mobility.
So while it is clear that some cities are chugging along in the right direction, most must do more to clear the fumes – for the health of their citizens and the climate.
Read more on the OECD work on Regions and Cities here.
Nina Trouvé is working at the OECD Centre for Entrepreneurship, SMEs, Regions and Cities. She is specialising in communications engagement and impact. She is currently an undergraduate student at Brown University, pursuing degrees in Economics and International & Public Affairs focussing on public policy and development. She is interested in pursuing matters in international development, gender equality and environmental equity.