Impression difference to vehicle interior sound between active and passive driving situation

Abstract

In near future, autonomous vehicles are expected to be more popular due to the technology development. This transition from active to passive driving condition may change the driver’s impression to vehicle interior sound. And the interior sound improvement for autonomous vehicles should be done according to the difference. In this study, we investigated whether driver’s impression to interior sound changes or not according to the driving situation through subjective evaluation test using a driving simulator. In the test, an original driving simulator was prepared to reproduce identical sounds and conditions at both active and passive driving conditions. As the presented sounds, sound pressure level (SPL) decreased or increased sound at low, mid, or high frequency bands were reproduced with the original sound. Participants drove the simulator under various driving conditions including acceleration and deceleration and evaluated discomfort about the sound. As the result, low or high frequency SPL decreased sounds were evaluated to be more discomfort at passive condition than that at active condition. Especially this tendency became significant at the acceleration and deceleration condition. From these results, high or low frequency noise reduction was found to be important in the future autonomous vehicle development.