Factors that Influence the Performance of Approaching Vehicle Sound for Pedestrian (VSP) Systems 2012-01-0991
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. Testing in a hearing research laboratory and real world testing with the visually impaired confirmed that the VSP sound achieves similar detectability performance as that of an internal combustion engine sound in key pedestrian listening tasks.
This paper will discuss the results of the next phase of research intended to further evaluate the usefulness of the “twin peaks” VSP sound to pedestrians. Factors such as pedestrian age and direction of vehicle approach were studied to understand the influence on sound cognition. In addition, the correlation between vehicle sound pressure level (SPL) and pedestrian crash incident rates was studied to confirm the appropriate SPL setting for VSP. Finally, the paper will explain the driver acceptance level of the VSP sound based on results of a customer ownership survey.