The European Commission (EC) has defined the objective to reduce carbon emission in transport by at least 60% compared to the year 1990. Until 2020 the increase of CO2 emissions shall be limited to 8% [1]. Therefore the EC is funding research projects which are dealing with eco-assistant/information systems such as the within the EU co-funded 7th Framework eCoMove project (Cooperative Mobility Systems and Services for Energy Efficiency) eCoMove. Based on in-vehicle but also cooperative systems such as dynamic eco-navigation, dynamic eco-guidance or other systems that support eco driving, which addressing route choice, velocity profile and traffic control information enable the driver to a more eco-friendly driving style which shall result in reduced fuel consumption. . In order to reach the envisaged goal it is very important that the systems are accepted by the driver and that driver comply with the system’s recommendations. Different methods, such as field trials, driving simulator studies and microscopic network simulations have been applied to verify and validate different applications with the main goal to assess the impacts of eco driving support systems on potential reduction of fuel consumption and carbon emission. The current paper provides an overview of the methodology used to validate the implemented tools and the findings of the conducted studies.