The objective of the study is to facilitate the development of a uniform methodological framework to assess policy measures promoting sustainable energy use in the sector. In order to do so, we (i) give on overview of the transport sector of the Danube Region and the potential policy measures to promote sustainable energy; (ii) expound the methodological issues of policy assessment in the transport sector, with special focus on modelling tools, and (iii) present an illustrative assessment for the external effects of two above mentioned policy approach.