The quietness of electric vehicles is a definite asset, especially in busy cities where the streets are littered with sound pollution from idling cars. At low speeds, however, this asset can be a safety hazard for pedestrians and cyclists. Above 35mph, the sound of car tires and wind resistance is enough to alert people, but below 35mph, people have a difficult time recognizing that there is an oncoming vehicle. This is especially concerning for the blind and visually-impaired who rely on the sounds of traffic to navigate the streets. In 2009, the National Highway Traffic Safety Administration found that, when traveling at speeds lower than 35mph, hybrid and electric vehicles are 37% more likely to hit pedestrians and 66% more likely to collide with cyclists than the traditional noisy, internal combustion engine cars. These statistics are stark and have encouraged action. The Pedestrian Safety Enhancement Act of 2010 requires the Department of Transportation to study and establish a sound standard for EV’s.
In the meantime, to address this problem, Delta Senselab did a report addressing the external warning sounds for hybrid and electric vehicles. SenseLab compared a set of experimental sounds. The sounds were rated on audibility, suitability, and annoyance (the sounds can be heard here). Senselab concluded that, “optimal warning sounds and good sound systems will make it possible to generate sufficient warning sounds with much less noise pollution than from vehicles with internal combustion engines.” Think of SenseLab’s report as a proposed soundtrack for electric vehicles–a soundtrack that could make EV’s much safer on the road.