hile present transport systems provide numerous benefits, the negative societal impacts are enormous. In particular, the global transportation sector is responsible for almost one-quarter of greenhouse gas (GHG) emissions (mostly CO 2), with about 72% thereof from road transport 1. Despite decades of progress for alternative and low-carbon fuels and technologies, most developed countries remain locked-in to the dominance of privately owned, fossil fuel-powered vehicles 2,3. Transport emissions are expected to grow further in scenarios produced by the International Energy Agency (IEA), even if currently announced policies are implemented (Fig. 1) 4-6. This Perspective summarizes available evidence for which policy mixes can be highly effective in reducing GHG emissions within road transport in the long-term while pointing out directions for further policy and research development. Clearly the transportation sector needs to carry its weight in meeting deep decarbonization goals. Compared to 2019, both the 1.5 °C and 2.0 °C Paris Agreement scenarios require global GHG reductions of about 30-40% by 2030, 60-80% by 2050 and likely close to 100% (or zero net emissions) thereafter 5,7. GHG mitigation ambitions are higher in Organisation for Economic Cooperation and Development (OECD) countries because they are the source of most historical emissions and are thought to have more flexibility for large-scale investment in low-carbon technologies 8. Because expected mitigation costs are lower in road transport than in aviation or shipping 9-11 , we start with the assumption that road transport should at least proportionally fulfil the ambition of the total mitigation targets noted above. That said, emissions from aviation and shipping are growing more quickly and require additional GHG mitigation policies 2. We focus on national and regional policymaking. Cities are important in the transition towards more sustainable transport, but their scope for governmental climate change action tends to be smaller than on the national level 12. While we identify insights with global relevance, most of the available literature analyses developed countries, mainly in Europe and North Americapointing to a clear research need to better understand climate policy design for developing countries. Further, our analysis focuses more on passenger travel which is responsible for most GHG emissions in transport, though we call for more attention to road freight.