Environmental considerations aside, probably one of the most appealing things about driving an electric vehicle is that as soon as you press the 'gas' pedal, the instant torque leading to peppy acceleration is accompanied by... near silence. The fact that you can join the flow of traffic without a cacophony of sound is a surprisingly pleasant experience. A selling point, no doubt.
Understandably, such silent operation is seen as a potential risk to the blind, who may not be able to hear an approaching EV, and back in 2010, the National Federation of the Blind backed the Pedestrian Safety Enhancement Act of 2010 - which was signed into law on Jan 4, 2011.
The bill can be read here, but one specific requirement is that new electric or hybrid vehicles are "to provide an alert sound conforming to the requirements of the motor vehicle safety standard." The bill itself didn't stipulate what type of sound, how loud, or at what speeds it must be made, but the National Highway Transportation Safety Administration (NHTSA) was charged to come up with the requirements, and in January of this year, made its recommendations.
Among those recommendations, EVs would have to emit a sound when traveling below 18 mph, while above this speed it would not be necessary due to tire-on-road noise becoming the dominant sound of an approaching vehicle. The law requires noise generators to be phased in, starting in September 2014, and in the lead up to this deadline, some groups have expressed concern.
One such group is the Alliance of Automobile Manufacturers, representing most of the major car companies. While the alliance supports the federal rule in principle, and promotes a partnership with the National Federation of the Blind, they nonetheless released official comments on March 15, 2013 opposing the the NHTSA recommendations. They stated, "If implemented as proposed, it would result in alert sounds that are louder than necessary, create driver and occupant annoyance, and cost more than necessary for the intended purpose."
In short, adding cost and driver annoyance to EVs will probably make them less appealing to buy - and that is problematic in a auto market segment which is only just starting to gain traction. But are cost and annoyance good enough reasons to oppose the NHTSA?
There are others concerned about the issue of noise pollution. NoiseOff, who weighed in on this issue back in 2008, before the bill was signed into law, is an organization, "founded as a means to present the issue of noise pollution to third parties and provide a voice for people who are adversely affected by noise pollution." Their position is that EVs' inherent silence makes urban life more livable, especially for those living near busy roadways, thoroughfares and intersections, who have to live with vehicle noise at all hours of the day.
One of their key concerns was stated on their website. "While the United States Congress recognized the deleterious effects of noise pollution, no federal agency is mandated with monitoring its health and environmental consequences, including the Environmental Protection Agency (EPA) where its Office of Noise Abatement and Control (ONAC) was essentially defunded. As a result, the problem of elevated traffic noise caused by artificial vehicle sound is unregulated with no protections afforded to the public."
It's a fair point. Noise pollution is a problem in urban environments, so it's reasonable to highlight concerns over noise pollution, especially if no authority is in charge of effectively regulating it.
Still, the NHTSA estimated in its January 2013 recommendations that, "if this proposal were implemented, there would be 2,800 fewer pedestrian and pedal cyclist injuries over the life of each model year of hybrid cars, trucks and vans and low speed vehicles, as compared to vehicles without sound."
My take on this is that a synthesized noise needn't be offensive if done correctly. The plug-in Fisker Karma, for example, generates a sound at low speeds that doesn't intrude into the cabin, and is subdued enough that it doesn't contribute any greater level of noise than its own range-extending combustion engine. The NHTSA website offers audio file samples of proposed vehicle sounds - check them out. I've listened to many of them, and they don't appear overtly intrusive either. What would not be good is for a "ring-tone" approach, where consumers could choose any sound they liked - it would seem sensible that a clear association between a certain sound and an oncoming vehicle would need to be established.
However, one final thought. I wonder whether this law is more important in terms of establishing safety as compared with what perhaps should be considered a more urgent matter; ensuring drivers are not distracted by texting, making phone calls and playing with "infotainment" systems. These distractions, I would suggest, pose greater risks to both the blind and able-sighted, than does silent operation of an EV below 18 mph.
Image credit : Oregon DOT
Phil Covington holds an MBA in Sustainable Management from Presidio Graduate School. In the past, he spent 16 years in the freight transportation and logistics industry. Today, Phil's writing focuses on transportation, forestry, technology and matters of sustainability in business.