Highly automated cars (Level 4 or 5) allow their users to become passengers instead of drivers and this means that the interaction between the car and their users will change. This opens up possibilities of creating new, innovative ways of interaction that could help, guide and support car users in their new role. The SIIC project has investigated if and how sound can be used for user interaction in highly automated cars. Our general hypotheses have been that sound-based interaction, “auditory displays'', can fulfil a number of purposes identified as crucial for the user experience in highly automated cars; it can increase trust, reduce motion sickness, enhance users’ mental model of the automation and enhance their general comfort and wellbeing. Our main approach has been to design auditory displays based on a continuous sonification approach that is more proactive and subtle in comparison to the traditional chimes used in cars today. Furthermore, it has also been the aim to merge ideas from the computer game industry with research and methods from the car industry to be able to innovate this novel research area.