“Decarbonising the transport system is fundamental to any transition to net zero,” said Mathilde Mesnard, Deputy Director at OECD Environment, as she opened the webinar. Mariana Mirabile, Economist at OECD Environment, highlighted that “decarbonising the transport system requires triggering behavioural change in favour of walking, cycling and public transport—going beyond efforts to electrify vehicles.”
Catalonia has been a pioneer in recognising this need, introducing a Mobility Law in 2003 that refocused priorities from private vehicles to sustainable transport. Yet, as Mesnard noted, transport remains the region’s highest-emitting sector, accounting for 32% of greenhouse gas emissions in 2022.
Mirabile explained that decades of car-centric policies have reinforced car dependency in OECD regions, creating an “attractiveness gap” in which the most polluting option—private vehicles—is also the most convenient. She also pointed out that “no single policy can transform a complex system”, meaning reversing this gap would require co-ordinated policies and governance changes.
Figure 1: The iceberg structure: Policies that react or anticipate and policies that transform
Source: Transforming Catalonia’s Mobility System for Net Zero, Mariana Mirabile, OECD Green Talks LIVE, 11 February 2025.
A systems approach can help policymakers reverse the “attractiveness gap” across transport modes and trigger behavioural changes in favour of sustainable options at scale. “Transport decisions aren’t purely personal preferences; they are largely determined by how systems are designed,” said Mirabile.
Furthermore, a systems approach focuses on understanding how complex systems—such as the mobility system—function in order to identify the policies with the highest potential to trigger transformative change. It also challenges the ideas that have shaped today’s transport model, as the same ideas are unlikely to lead to radically different systems.
Using a systems approach, the OECD report categorises policies into two types. The first are reactive or anticipatory policies, which aim to reduce the harm of the transport choices fostered by the current mobility system. The second type includes transformative policies, which seek to redesign the underlying structure of transport systems to enable large-scale shifts in transport choices. “Transformative policies should be prioritised,” emphasised Walid Oueslati, Head of the Climate, Biodiversity, and Water Division at the OECD, who also highlighted that “mindset shifts are at the root of change.”
Some of the policies discussed during the webinar included:
- Road space reallocation (e.g. pedestrianisation, high-quality cycling network, exclusive bus lanes) was identified as the action with the highest transformative potential.
- Expanding low-emission zones can be transformative in intent but is more effective when combined with road space reallocation and improved connectivity between active and shared transport.
- Investing in public transport is critical, particularly when paired with space reallocation, micromobility solutions and integrated information and payment systems.
- Electric vehicle subsidies do not transform the system away from car dependency but are still necessary to get to net zero. There is potential to rethink these subsidies and redirect them to support smaller vehicles and micromobility solutions.
- Public transport fare reductions can increase ridership but their long-term impact on transport systems is uncertain, as they may strain funding and reduce service quality over time.
Tatiana Fernández, Head of Transformative Innovation at the Generalitat de Catalunya, emphasised that without a systems approach, policies will continue to react to symptoms rather than trigger structural changes. “This is not enough,” she warned.
Fernández also argued that achieving transformation requires more than policy—it demands a cultural shift in how mobility is perceived and prioritised. “The key question is whether we optimise the system we have now or build the one we need for the future,” said Fernández. “There are no silver bullets for that; we need to engage people locally, develop new evidence and indicators, and change narratives.”
Catalonia’s Smart Specialisation Strategy is based on this idea and is organised around shared agendas. “Shared agendas bring together stakeholders committed to a common vision,” Fernández explained. These “coalitions of the willing” align efforts across sectors, fostering collective transformative action by identifying, experimenting with, and scaling existing solutions that have the potential to bring about systemic change.
Oueslati concurred on the importance of political will and stakeholder engagement. “Governments, researchers, businesses and civil society must work together as a coalition of the willing to drive this transition.” Public acceptability was another key factor identified for successful policy implementation. Better communication—particularly highlighting the health benefits of sustainable mobility—can help increase support for transformative climate policies. Citing survey evidence, Mirabile highlighted a perception gap between the actual level of public support for transformative policies (such as road space reallocation) and policymakers’ perceptions of that support.
As Catalonia’s experience shows, transforming the mobility system is complex and requires the engagement and co-ordination of numerous actors in the territory. Yet, this transformation has the potential to deliver immense benefits for people, the economy and the planet.
OECD Green Talks LIVE
This webinar—and the report on which it was based—are part of a programme of work at the OECD Environment Directorate aimed at supporting countries, regions and cities develop transformative net-zero strategies via a systems approach. The report is the third in a series of publications building evidence on system-level changes needed to reach net zero, and its content is also available via a policy highlights, and 2’ videos. Learn more about the OECD’s work on transformational change for net zero on its website.
The webinar replay is available to watch on the OECD website, and is part of the OECD Green Talks LIVE series. It brings experts together to discuss pressing environmental issues.
