Detection of traffic sound for driving safety: Effects of car body sound insulation

Abstract

Hearing is an important physiological function that humans rely on to sense the surrounding situations. It is well understood that acoustic cues are critical for pedestrians, bicycle and motorcycle riders to identify traffic, thus to avoid potential risks in a timely manner. Similarly, efficient and accurate perception of external acoustic warning signals (e.g., car horn and siren sounds) in the traffic environment are also important for driving safety. As modern vehicles are made more and more sound proofing, mainly for the sake of riding comfort, it is increasingly difficult for drivers to hear external sounds, which can impair the driver's hearing perception and detection of potential danger posed by nearby traffic through natural hearing. Currently, there is a lack of research in the literature regarding the relationship between the sound perception capability by drivers and driving safety. Therefore, this study focuses on investigating how well the acoustic warning signals in the surrounding traffic environment can be perceived by the driver under various conditions and its potential influences on driving safety. To correlate the effectiveness of drivers detecting the external traffic sound to the sound isolation level of the car body, the sound insulation performance of two selected passenger car models and the subjective sound localization accuracy through vehicle structures are measured. It is found that the existence of the car body, more specifically the car body sound insulation effect, noticeably degrades the sound localization accuracy of drivers. In addition, the perceived sound source direction is found to shift toward the side of the car body with lower sound insulation performance.