The research presented in this thesis is funded by the European Union and addresses the relationship between people and automated decision support in the context of Traffic Management. Given that automation might not always be 100% reliable, the first research question to be addressed is what effect does automation reliability have on human decision making? User trials contribute to addressing the question of, how can user interfaces be designed to cope with the effects of different levels of automation reliability. The thesis is developed around the concept of Content (the users' information requirements), Format (the paradigm of interaction and communication protocols) and Form (how information is presented to the users). Results demonstrate that, even in the absence of explicit feedback, users are sensitive to automation reliability and can adapt their information search and decision making strategies accordingly. The user's decision on whether or not to seek further information cannot be attributed only to information availability or accessing costs, but the visual appearance of the user interface can have a higher influence on user behaviour. These observations and conclusions led to the refinement of the Content/Format/Form concept to a broader sociotechnical design framework.