Purpose – The purpose of this paper is to illustrate and discuss how stakeholder assessment of scenarios can be used to trigger a structured and, therefore, more efficient debate amongst stakeholders about future options for achieving a more eco-efficient transport system in Europe. Particularly, it wants to explore the extent to which a distinction between the desirability and the feasibility of a potential future development can render such debates more rational and transparent. Design/methodology/approach – The paper is based on a project on eco-efficient transport for the Science and Technology Option Assessment panel of the European Parliament (STOA). Key elements of the methods used in the STOA project were easily understandable scenarios and a survey of the main assumptions underlying the scenarios. Both the scenarios and the survey were used in a stakeholder workshop to assess the desirability and the feasibility of approaches towards establishing a more eco-efficient transport system. Findings – The methodological approach proved helpful for collecting a large amount of valuable information in a relative short time. In particular, the distinction between desirability and feasibility was useful in mapping out the patterns of opinion amongst stakeholders and for understanding where there is common ground, where there are differences and what the reasons behind these differences are. It helped in identifying promising pathways towards more eco-efficient transport futures and in getting a better understanding of barriers and of the ways to overcome them. Practical implications – The approach served as the basis for having a well-structured, rational and, thus, efficient debate. In practice, this factor is relevant because stakeholder involvement is crucial when it comes to transitions of socio-technical systems, such as the transport system. Keeping stakeholders motivated to take part in such participatory processes is only possible, however, if they perceive that these processes are well-structured and, therefore, efficient. Originality/value – In contrast to many other scenario-based approaches, the scenarios in this project were understood as an input to the discussion and not as the result of a process. Furthermore, not only the results but also the underlying assumptions of the scenarios were explicitly made a topic for assessment. The differentiation between desirability and feasibility was used as a guiding dimension for the assessment. [ABSTRACT FROM AUTHOR]