Turn signal sounds, originally mechanical ticks produced by relay devices, are now electronically generated in vehicles to provide auditory feedback to drivers that indicates the operational status of the turn signal. This shift allows for greater flexibility in sound design, yet the impact of acoustic features on drivers’ subjective impressions remains insufficiently understood. This study investigates the perceptual impact of acoustic characteristics of turn signal sounds, focusing on impressions such as a sense of caution, a feeling of being rushed, and drowsiness. Several typical turn signal sounds were selected, and their BPM (beats per minute) and pitch were modified to generate multiple acoustic variations. In a subjective listening experiment, 33 participants rated each sound using 5-point scales based on impression measures including a sense of caution, a feeling of being rushed, and drowsiness. Results showed that turn signal sounds with original BPM and unaltered pitch were generally perceived as more pleasant and suitable. Furthermore, increased BPM and pitch enhanced the sense of caution and the feeling of being rushed, while reductions in these parameters tended to induce drowsiness. These results suggest practical implications for the design of vehicle auditory interfaces aimed at enhancing driver safety and comfort.
Miyajima et al. (2025) studied this question.