Transportation is an essential part of city life. However the extensive use of private cars in urban transport systems leads not only to a decrease in public health and quality of life but also drives global warming through the emission of GHG. The growth rate of CO 2 emissions caused by transportation is among the highest across all energy sectors. In order to mitigate climate change, it is therefore crucial to reverse this trend and change urban transport systems towards more climate compatibility. Thus, this thesis investigates if and how mobility demand and climate protection can be combined in urban transport systems.To answer these questions, the thesis discusses characteristics of climate-friendly transportation based on findings from academic literature. Moreover, policy instruments to transform urban transportation towards climate compatibility as well as possible obstacles and constraints in this regard are investigated. More precisely, socio-technical/infrastructural, technological, financial, legal, institutional/organisational, political, habitual, and cultural constraints are described and the significance of pragmatic, moral, and cognitive legitimacy is ascertained with regard to public and political acceptance of policies.Drawing on these theoretical assumptions, the case of Berlin is analysed in more detail. Based on policy documents, statistical data, expert interviews, and a public hearing in the Senate of Berlin, it is investigated how the city plans to make its transport system more climate-friendly and what the actual state of climate compatibility within the transport sector is at the moment. As a result, it could be observed that policies for climate-friendly transport are in place and mostly implemented but that the amount of CO 2 emissions caused by the transport system and especially by road traffic has more or less stagnated since the 1990s. Several reasons for this development could be ascertained: The transformation towards climate compatibility is, on the one hand, constrained bylegal, infrastructural, institutional, political, habitual, and cultural factors as well as by the lack of personnel within the city administration, and, on the other hand, hampered by the perceived inacceptability of car-restrictive policies.The conclusion from this thesis is therefore that it is thereotically possible to combine mobility demand and climate protection in urban transport systems and it is furthermore imperative in order to mitigate climate change and its dreaded impacts. In practical terms, however, cities face several intertwined and often very distinct obstacles and constraints that can only be overcome by long-term, dedicated, and citizen-oriented policy planning and implementation.