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In 2010 Nissan launched the Approaching Vehicle Sound for Pedestrian (VSP) system on a production Electric Vehicle (EV), including a digital sound generator and speaker that automatically emits a sound during reverse and low speed forward movement. The system is intended to provide auditory cues for pedestrians to help compensate for the quiet condition of EVs and Hybrid Electric Vehicles (HEVs). In the future such systems will be mandatory on EVs and HEVs, as President Obama signed a bill in 2010 requiring NHTSA to start the rule making process. The development of the VSP system started in 2007, involving meetings with representatives from the visually impaired community to understand their concerns. A final VSP sound with a “twin peaks” spectral profile was developed to accommodate the hearing sensitivities of young adults with normal hearing and aging pedestrians with high Hz hearing loss.

Vehicles with electric powertrains emit less noise than internal combustion engine vehicles. These quiet cars have raised concerns about pedestrian safety, especially among the visually impaired community. The primary concern is related to when electric vehicles are travelling at low speeds where tire noise and aerodynamic noise is minimal. In these situations, the EV might not provide an adequate auditory cue for visually impaired pedestrians who need auditory information for navigation and decision making. A system called Approaching Vehicle Sound for Pedestrians (VSP) has been developed for the 2011 Nissan Leaf EV to help address the potential quiet car concern. This system emits a digitally generated signal from an onboard speaker to provide auditory cues to pedestrians during low speed forward movement and reverse. The auditory cues are designed to help achieve the same detectablity performance as internal combustion engine sound.