Urgency impression and driving behavior evaluation for warning sounds inside car cabin

Warning sound design is particularly important for in-vehicle information display, among the increasing demand and complexity of information design to support safe driving. The information presented to drivers is extensive and increasingly complex. For the warning that enables drivers to correctly understand the meaning and avoid confusion, it is crucial to design sounds correspond to the criticality and urgency of the situation. In this study, the authors conducted a driving simulator experiment simulating a frontal collision to examine how different types of warning sounds affect driving behavior and urgency impression. The participants were asked to follow the front vehicle, that randomly change the speed, to keep 40-m distance. When the distance got shorter, warning sounds were presented via loudspeaker. In the experiment, three different warning sound that varies the urgency impression were compared. The results showed that the driving behaviors, such as throttle release time (TRT) and brake reaction time (BRT), were differed by the types of warning sounds elicited different driving behaviors. In some cases, the warning sound promoted safer driving such as faster throttle release and the avoidance of sudden braking.