Chapter 32. Additional Efficient Warning Sounds of Electric and Hybrid Vehicles

Electric or hybrid vehicles are very silent, which represents a major advantage for the reduction of noise annoyance in urban areas. But, this makes them dangerous for pedestrians, especially vulnerable ones as visually impaired people. Current solutions consist of using warning sound so that the exterior noise of an electric vehicle is as high as for a conventional one. This may cancel the benefit of electric vehicles for the reduction of sound annoyance. The eVADER project (funded by the European Commission) aims at proposing a prototype car which combines a high safety and a low noise level. A part of the work program consisted of perceptual studies. The goal of these studies was to evaluate the influence of various timbre parameters on the detectability and the unpleasantness of a warning sound. Results show that it is possible to make an electric vehicle easily detected while keeping its sound level much lower than the one of a conventional car.