Development of a measurement scale to assess Automated Driving System HMIs

While the introduction of Automated Driving Systems (ADS) is intended to make driving safer and more comfortable, it may also make the interaction between user and vehicle more complex and prone to confusion. This in turn may create unintended safety risks. It is therefore important to be able to assess to what extent ADS provide their users with clear and unambiguous information concerning system state and concerning allowed or expected actions from the side of the user. In this project, TNO has developed a questionnaire to measure whether the information provided by an ADS to its user is experienced as clear and unambiguous. The questionnaire consists of nine items, which were shown to discriminate between good and bad Human Machine Interface (HMI) designs in terms of user perception and comprehension.