Beyond a direct impact on land use (LU) patterns, European Commission (EC) policies often have substantial impacts on various domains. To uphold and improve the quality of legislation, a thorough ex ante impact assessment of EC policies should therefore evaluate policy proposals on all three domains of sustainability: economy, environment, and society (Organisation for Economic Co-operation and Development [OECD], 2010). However, straightforward impact assessment of EC policies is often not possible because various policy domains are inherently intertwined. For example, a trade policy can have a direct impact on the agricultural sector, and new transport infrastructures can influence economic growth, while both policies, together and individually, may affect LU. To make the impact assessment challenge even greater, various policies may either propagate or compensate impacts, thus causing nonlinear interactions. Such complex dynamics can be grasped only by an elaborate impact assessment effort. In 2002 the EC introduced an Impact Assessment (IA) procedure to provide “evidence for political decision-makers on the advantages and disadvantages of possible policy options by assessing their potential impacts” (EC, 2002a). This procedure has to be applied to all Commission initiatives that aim to quantify economic, social, and environmental impact. More recently, the EC has also published guidelines for Territorial Impact Assessment, which should be carried out when policies target specific territories, or when policies may produce uneven impacts throughout the territory (EC, 2013a).