EVALUATION OF ANNOYANCE AND SUITABILITY OF A BACK-UP WARNING SOUND FOR ELECTRIC VEHICLES

This paper describes the evaluation of the annoyance and suitability of a back-up warning sound for electric vehicles (EV). Three back-up signals used for the evaluation were categorized into three types: broadband, tonal and multi-tone. The reversing sound for a Nissan Leaf (EV-first mass production) will also be included as a benchmark for the other three sound signals. The sample sound was generated based on the human hearing threshold in several individual related areas; age-related, normal and working noise exposure frequency range. Each sound was evaluated in turn by the respondents in a nearby neighborhood, college, town area and rural area in terms of level of annoyance and its suitability as an EV back-up sound to alert pedestrians as they run quietly on the road, which can cause a hazard. Every tested sound perception result is based on the place where the respondents live. An appropriate sound for a quiet vehicle can help pedestrians to detect it and at the same time maintain acceptable environmental sound levels.