This paper is based on parts of Deliverable 2 of the European Project OPTIC (Optimal Policies for Transport in Combination, see DLR and KIT, 2010). It focuses on the development of an inventory of tools and methods for the early detection of unintended effects. Additionally, it deals with the question of when and where integrating assessment approaches is recommendable along the policymaking process. The inventory of tools and methods is done for mainly qualitative approaches (denominated as structurally open methods) and mainly quantitative approaches (denominated as structurally closed methods, more precisely EU models TRANSTOOLS and TREMOVE). A methodology is presented using examples that illustrate step by step the consideration of either structurally open or structurally closed methods focusing on the detection and the assessment of unintended effects. On the basis of these examples, recommendations are given when and where the consideration of different assessment approaches is most promising regarding the initially set policy objectives
