In-car sound analysis and driving speed estimation using sounds with different frequencies as cues

Correct estimation of driving speed plays important roles on road safety. In-car sound is an auxiliary cue often neglected. This study attempted to explore human speed perception through in-car sound and find useful sound elements by separating sounds into different frequencies. 41 eligible male drivers were recruited. The four conditions in the present experiment included normal sound, no sound, high-cut sound (above 600 Hz) and low-cut sound (below 600 Hz). The results showed a serious underestimation at high speeds. Quiet cabin leads to speed underestimation. However, weakening intensity of frequencies below 600 Hz which descended as speed increased (against overall pattern) helped improve estimation performance especially at higher speeds which is most underestimated with normal sound.Relevance to industryThis study can contribute to soundproofing design in vehicle industry by suggesting that specific sound frequencies be preserved while irrelevant ones are weakened. In this way driving safety and vehicle quietness could be achieved at the same time.

► In-car noise analysis by its volume and frequency.
► Drivers' speed estimation performance with in-car noise.
► Low frequency noise helps speed estimation performance.
► Designers should keep certain low frequency noise and volume in terms of safety.