NCSU Research Shows Consumers Prefer Engine Noise For Hybrids

Researchers from North Carolina State University have released the results of a study they conducted on the consumer acceptability of different types of noise that can be added to hybrid vehicles. Most hybrids, when operating in electric mode, do not create enough noise to be heard by pedestrians and cyclists. The National Federation For The Blind has expressed concern that hybrid and electric vehicles pose a real danger to visually impaired pedestrians.

The researchers considered six different types of noise and three variations within each type, and asked 24 subjects to rate each noise type's overall acceptability. Noises were classified as engine, horn, hum, siren, whistle and white. According to the results, study subjects overwhelmingly preferred engine, hum and white noises over horn, siren and whistle noises, noting that the preferred noises were similar in character to the operational noises that conventional vehicles make now.

The researchers suggested that while automakers are constantly challenged to make their vehicles quieter, the addition of noise could contain a relative component that could adjust the sound the car makes based upon the ambient noise in the car's surroundings.

Several manufacturing and regulatory groups are researching the issue of electric vehicle noise as it relates to pedestrian and cyclist safety. Both the National Highway Traffic Safety Administration and the Society of Automotive Engineers are studying the issue of noise in vehicles with alternative propulsion systems, and Congress is currently considering whether to require the Secretary of Transportation to conduct additional research, make recommendations and oversee the implementation of regulations on minimum noise standards for vehicles on the road.