International non-binding policies for sustainable land passenger transport in Europe: A scoping review

In addition to binding policies, a multitude of non-binding policies can be found in the transport sector. Non-binding policies often provide visions, guidelines, recommendations, and even agreements and targets, which can influence the policy agenda and its implementation. To date, few studies have focused on non-binding policies in the transport sector. This article presents a scoping review of non-binding policies on land passenger transport in Europe, based on the PRISMA-ScR methodology. We analysed 5826 documents from 49 policy databases maintained by public international institutions and identified more than 500 non-binding policies on sustainable land transport in Europe published between 2015 and 2024. We then applied Latent Dirichlet Allocation (LDA), a topic modelling approach, to identify the key topics addressed in these non-binding policies. The analysis indicates that non-binding policies represent a widely used and established instrument in transport policy with different levels of formality. They tend to increase in number between 2015 and 2024 with a peak in 2021. Non-binding policies are produced by a variety of institutions with the majority being issued by the European Union, rail transport organisations, the United Nations and networks of cities and regions. Position papers are the most common type of non-binding policies followed by resolutions and opinions. Key themes in non-binding policies on sustainable land passenger transport address modes and services, land use and infrastructure, access and safety, funding and development, transport externalities, governance and research. A range of transport issues are addressed in these non-binding policies, and it is conceivable that some of these issues may enter the binding policy sphere in the future. This article helps to illustrate the growing role of non-binding policies in the changing transport policy landscape and highlights the capacity to shape future binding policies, particularly regarding inclusivity and intersectoral planning.