Fostering sustainable mobility is regarded as a major goal for the future development of cities. The advanced traveller information systems (ATISs), such as multi-modal route planners are envisioned as tools for enhancing more environment-friendly mobility behaviour. The authors' recent study that comprises methods of action research and Delphi forecasting, not only evaluates the actual effectiveness, but also the future expectations with regards to ATIS. Therefore the trans-disciplinary research project 'ITSworks' examined users' and experts' perspectives by working within the example of a multi-modal route planner called 'AnachB' set-up for the city area of Vienna (Austria). Within a 'Test-setting' 38 users tested the systems for several weeks, whereas 31 international experts discussed the potential of ATISs for promoting sustainable mobility in general.