Designing Alert Systems in Takeover Transitions: The Effects of Display Information and Modality

In conditionally automated driving, in-vehicle alert systems can provide drivers with information to assist their takeovers from automated driving. This study investigated how display modality and information influenced drivers’ acceptance of the in-vehicle alert systems under different event criticality situations. We conducted an online video study with a 3 (information type) × 3 (display modality) × 2 (event criticality) mixed design involving 60 participants. The results showed that considering drivers’ perceived usefulness and ease of use, presenting why only information was not sufficient for takeovers as compared to what will only information and why + what will information. Participants reported higher ease of use in the combination of speech and augmented reality condition when compared to the speech only condition. High event criticality led to drivers’ lower perceived usefulness and more negative opinions of the displays. The findings have implications for the design of in-vehicle alert systems during takeover transitions.