The Effectiveness of Alert Sounds for Electric Vehicles Based on Pedestrians’ Perception

One of the largest problems with electric vehicles is that they often go unnoticed by pedestrians due to the absence of noticeable noise generated by electric motors, which is a potential cause of accidents and collisions. Surprisingly, this positive property in terms of reducing the noise pollution is in fact becoming a road safety problem. In addition, with the promotion of electric traction vehicles due to new environmental policies and the current proliferation of personal mobility vehicles, this problem could even be increased in the coming years. Therefore, the future global road regulation has included aspects on noise and warning sounds that electric vehicles must emit in the years to come. However, despite the requirements, no specific signal type or many other features have been established. Only the emission levels have been set (56–75 dB). Consequently, within the framework of this problem, this article evaluates the acoustic characteristics of the sound that should be emitted by electric vehicles so that pedestrians can easily detect them and the optimal sound pressure level they should emit to not unnecessarily raise noise pollution levels, concluding that the emission limits established are excessive in certain scenarios and that optimal warning sounds must be focused on electronically imitating combustion engine noises.