Design of an in-car user interface requires knowledge from the field of Human Factors as well as from usability the-ory. In this project, a user interface for an automatic parallel parking system has been developed. The main research question has been which display modality to choose, as current literature does not give a clear-cut answer to whether to use auditory or visual displays for in-car information systems. We also wanted to investigate how much information is needed in order to complete an automatic parallel parking. Results from three user evaluations with different prototypes indicate that audiovisual presentation is best suited for the task, and that feedback messages could be kept short. However, further research is needed since a real-life traffic situation differs from that in a sealed-off environment as the one used in this project.