UKERC Transport Evidence Compendium

Why this report matters

The UK transport sector is one of the greatest challenges to achieving net zero. While other sectors have reduced emissions since 1990, transport emissions have barely changed, still accounting for 36% of UK carbon emissions. Decarbonising transport requires urgent, systemic changes across passenger mobility, freight, the supporting infrastructures and wider society. The UKERC Transport Evidence Compendium synthesises 20 years of UKERC research into an integrated, policy-relevant resource to inform national and local decision-makers. It provides robust evidence on how transport systems can transition to clean, low-carbon futures – supporting better health, improved equity and economic opportunity alongside climate goals.

What the report covers

The compendium focuses on five key themes aligned with government structures: personal mobility; freight transport; low carbon futures and pathways; social and behavioural change; and public health. It brings together interdisciplinary evidence from engineering, economics, social sciences and environmental research to show why whole-system approaches are vital.

Ten key takeaways

1. Energy demand reduction is central: Increasing car size, slower-than-expected electric vehicle adoption, suboptimal speeds and soaring air travel demand offset gains from cleaner technologies. Without cutting transport energy demand, it will be virtually impossible – or prohibitively expensive – to meet the UK’s net zero targets.
2. Reducing total car travel in the short to medium term has become essential: Achieving a 20-50% cut in car mileage by 2030 is necessary. This requires a mix of road user charging, parking levies, road space reallocation and substantial investment in public transport and active travel infrastructures.
3. EVs alone are not enough: Combined social and technological changes offer earlier reductions, higher cumulative savings and lower system costs than electrification alone. Policies must combine vehicle electrification with measures to restrict the sales of large, inefficient cars and promote smaller, lighter models alongside improving urban planning and addressing the role of advertising.
4. Electrified transport can enhance grid flexibility and reduce infrastructure strain when supported by smart demand management and targeted policy interventions at local and national levels. Frequent plug-in behaviour by EV owners maximises the financial and carbon-saving potential of V2G systems while enhancing grid storage capacity for low-carbon energy systems. Attention must also be paid to equitable access to EV infrastructure.
5. Active travel offers major benefits in towns and cities: Walking and cycling can substantially cut CO₂ emissions and improve public health, but only when supported by measures to restrict car use.
6. Need to tackle long-distance, single occupancy car trips: Improving, prioritising and investing in efficient alternatives such as fast and reliable rail, express coach services, e-bikes for medium distances and supporting “destination shifting” to bring activities closer to home are needed alongside pricing structure that penalises high carbon, inefficient transport.
7. International aviation is a major barrier to net zero: Air travel contributes disproportionately to emissions. Demand management measures, such as frequent flyer levies, route and speed optimisation and no airport expansions, are needed alongside technological innovation.
8. Urban freight needs reform: Electrifying van fleets, optimising load factors, and using e-cargo bikes and urban consolidation centres could cut last-mile freight emissions by up to a third.
9. Public and shared transport are critical to net zero futures: But their success hinges on targeted investment, effective systemic integration and coordination, supportive measures and prioritisation, and car restraint policies.
10. Health and economic co-benefits are huge: Diesel cars and vans cost society £6 billion annually in health impacts alone. Reducing transport emissions will save the NHS billions annually. Transitioning to cleaner modes will reduce premature deaths, chronic diseases and health inequalities.

Conclusion

The UKERC Transport Evidence Compendium provides policymakers with a comprehensive, systems-wide assessment of the challenges and solutions for decarbonising transport. It shows that achieving net zero requires action far beyond simply electrifying vehicles: we must also reshape mobility demand, urban design, freight logistics and societal behaviours. The evidence points to the need for strong leadership, coordinated governance and policies that prioritise equity and systemic change alongside accelerated technology development and deployment.