Transport has powerful impacts on health. Well-designed transport policies and infrastructure investment priorities can lead to far-reaching reductions in traffic-related health risks from air and noise pollution and injury. Cycling and walking, on their own or as part of a public transport journey, can greatly enhance physical activity levels and help prevent a range of chronic diseases including heart disease, some cancers and type 2 diabetes. The transport sector is also a major source of GHG emissions, and thus an important focus of climate change mitigation. To optimize the social and economic benefits that can be derived from mitigation, transport mitigation strategies need to be examined in light of expected health impacts – both co-benefits and potential risks. Additionally, strategies may be examined in light of their potential to achieve greater health equity by improving the access of diverse groups to social, educational and economic opportunities. In light of this need, WHO undertook a review of potential health co-benefits (and risks where relevant) of transport mitigation strategies.