Advantages of Directive Acoustic Sources for Audible Alert Systems in EV

The rapid growth of Electric Vehicles (EV’s) and Hybrid Electric Vehicles (HEV’s) has increased the concern that the relative silence of these type of vehicles will result in an increased risk to pedestrian safety. A practical solution to this problem is to add artificial sounds to EV's to aid their detection by pedestrians and other vulnerable road users.

Acoustic warning systems for EV’s should increase pedestrian safety and simultaneously produce a small impact on environmental noise levels. This paper shows the main advantage of using a directive acoustic source implemented as a beamforming loudspeaker array in an EV to increase pedestrian safety and control the effect on noise pollution. An example of such a system has been implemented in a Nissan Leaf vehicle and its performance in realistic situations has been assessed. The experimental results show that this type of approach is very effective to increase close-to-accident pedestrian safety near EV’s and simultaneously reduce noise pollution with respect to conventional acoustic warning devices.