Development of Nissan Approaching Vehicle Sound for Pedestrians: How to solve the trade off between Quietness and Pedestrian safty of the Electric vehicles? 2011-39-7231
Electric Vehicles are very quiet at low speeds therefore people (especially the visually impaired) have difficulty recognizing that these vehicles are approaching. To address this concern, Approaching Vehicle Sound for Pedestrians system development has been discussed worldwide. In Japan, USA, Europe and China, government regulation is currently under study. As a solution to meet this concern, Nissan has developed the VSP (Approaching Vehicle Sound for Pedestrians) system for implementation on Nissan's first mass production Electric Vehicle. Nissan VSP emits a futuristic sound to satisfy 3 key stakeholders' concerns; for pedestrians to provide detectability, for drivers and neighborhoods to maintain a quiet environment. The sound emitted during forward motion has a “twin peaks and one dip” frequency signature, with modulation (or rhythmic structure) to accommodate human-beings ear frequency sensitivity, hearing loss due to aging and ambient noise conditions. Additionally, special emphasis is placed on the forward sound emitted when the vehicle is “taking-off'(starting forward motion)” to notify pedestrians that the vehicle is about to move, in response to real world feedback gathered in surveys with visually impaired in Japan and USA. The system also includes a reverse motion or “backing up” sound that has an easy to recognize cadenced(or rhythmic structure) characteristic.