This study provides an overview of the energy use and greenhouse gas emissions of corporate fleets as well as the potential fuel and cost savings of a broad range of practical measures. The study covers both passenger and freight fleets and is relevant for both fleet managers and policy makers. It concludes that the entire corporate fleet emits almost half of the total road transport emissions in the EU and consumes nearly 200 billion euro worth of fuel each year. The report contains a comprehensive and practical overview of options for fleet owners for reducing their fuel consumption and fleet costs such as influencing vehicle technology, driving style and mobility choices. This in turn can simultaneously contribute to reducing global oil consumption with positive effects for energy security, climate change and air quality.