Investigation into the Detection of a Quiet Vehicle by the Blind Community and the Application of an External Noise Emitting System

The blind community is concerned that vehicles are becoming too quiet and unsafe for pedestrians¹. With vehicle manufacturers successfully working to develop quieter vehicles and the emergence of a new class of quiet hybrid and electric vehicles, this concern from the blind community will continue to increase. The basis of this concern is that a blind person uses acoustic cues to determine the location and speed of vehicles to avoid dangerous situations.

To begin understanding this concern a jury study at the National Federation of the Blind California conference was performed. A combustion engine vehicle was converted to an electric vehicle and speakers were attached at each corner. Blind volunteers from the conference participated in the study where the vehicle was driven past them three times under different conditions. The subject raised their hand when they heard the vehicle and the distances from the subject were noted. The results of this study indicate that the loss of normal combustion engine noises may significantly affect the ability of blind individuals to distinguish approaching vehicles and that a substitute engine noise appears to be viable option for reversing this risk.

An investigation was then performed to begin to address two of the basic implementation issues with an external noise emitting system for electric vehicles. The first investigation is of the speed range where a system would be most applicable and the second is of the placement and orientation of the speakers on the vehicle. This is done by evaluating an internal combustion engine vehicle as a benchmark for what is currently acceptable.