On Adding Sound to Quiet Vehicles

Alternative energy vehicles such as hybrids and electric tend to run quieter than many hydrocarbon fueled vehicles. Their relative quietness could negatively affect pedestrian and driver safety because of reduced sound cues compared to louder vehicles. The present study examined preferences for sounds that might provide an acceptable auditory cue to quiet vehicles. Participants heard and then rated 18 sounds (3 variations in six categories). Each sound was displayed in conjunction with a video of a moving hybrid vehicle. The sounds of an engine, white noise, and hum sound in that order were most preferred as added sound to a quiet vehicle. Implications for adding sounds to facilitate pedestrians’ detection of moving vehicles and for aiding drivers ’ awareness of speed are discussed