Monday, August 08, 2022

Electric Cars and the Sound of Silence

 

Electric vehicles (EV's for short) are not so common where I live that they are even an every-day encounter, although being within 30 miles of the Austin Tesla plant, we do see Teslas fairly often on the highways.  But a problem that had never occurred to me about electric cars is currently being intensively studied by most car makers, and the result will affect how cityscapes sound in the future.

 

If an electric car moves faster than 20 MPH or so, its tires make enough road noise so that it's not that much quieter than most modern internal-combustion-engine (ICE) vehicles.  But at speeds lower than that, but fast enough to cause injuries in collisions with pedestrians, you simply can't hear them.  The electric motors are nearly silent.  And for visually-impaired and blind people who rely on the sounds of ICE vehicles to navigate, this can be a real problem.

 

As reported by John Seabrook in a recent New Yorker article, way back in 2003 a friend came by National Federation of the Blind activist Deborah Kerr Stein's house driving a new Toyota Prius, which in its battery mode was so quiet that Stein couldn't hear it at all even as it passed within a few feet of her.  She thought at the time "We've got a real problem."

 

After numbers of experiments with different electric vehicles and investigations into pedestrian accidents involving electric vehicles, it turned out that not only blind people, but sighted pedestrians also had problems noticing electric cars because they were so much quieter at low speeds than ICE vehicles.  Statistics reported in 2011 showed that hybrids and EVs showed a 35% greater chance of being involved in collisions with pedestrians and a 50% greater chance of collisions with bicyclists. 

 

This evidence was used to persuade Congress to pass and President Obama to sign the Pedestrian Safety Enhancement Act in 2012, which called for a "sound or set of sounds for all vehicles of the same make and model."  The National Highway Traffic Safety Administration (NHTSA) took six years after that to devise technical specifications saying how loud and in what frequency ranges these sounds must be, and now the various car manufacturers who either sell or think about selling EVs must comply.

 

Seabrook interviewed numerous sound designers and engineers at GM, Renault, Ford, and other makers, and many of those interviewed were looking forward to contributing to an entirely new aspect of automotive history:  artificial characteristic sounds. 

 

For most of the time that people have lived with ICE vehicles, we have unconsciously learned to associate certain kinds of sounds with certain vehicles.  Seabrook even unearthed an acoustic engineer who could tell the make and model of a car just by the sound of its engine idling.  To me, most cars with their engines running just sound like cars, but the one exception that comes to mind is the exhaust noise made by the old-style VW Beetle produced from the 1950s to the 1990s or so.  It had a characteristic high note that made the sound unmistakeable for anything else.  But for the most part, automakers regarded sounds made by the car as something to be minimized, and many smaller vehicles going above 30 MPH or so don't make much more sound than an electric vehicle does.

 

But now we're going to have to get used to the different sounds devised by car makers to characterize their individual EVs.  Presumably, the EVs on the road now meet these requirements, but Tesla, the current leader in numbers on the road, has had run-ins with the Feds regarding some acoustic options that were installed for a time.  After a 2020 software update, Tesla drivers could play goat bleats, ice-cream truck music, and various less presentable noises through the external speakers installed in every Tesla.  The NHTSA clamped down on it and thereby earned the title "fun police" from Elon Musk, but Teslas are presumably still compliant with the Pedestrian Safety Enhancement Act.

 

This set of developments presents a relatively rare case in which a potential engineering problem was noticed and headed off before the number of potential problem vehicles got too large to deal with conveniently. This benign outcome was enabled by an alert "mediating institution"—the National Federation of the Blind—which was accustomed to dealing with governments and helping to draft legislation.  And it has the side benefit of making EVs safer for everybody else too, as many accommodations for the disabled tend to do. 

 

The mediating institution in this case is a privately owned and operated organization, and the profession of engineering has many such entities dealing with largely technical matters:  setting standards, organizing new protocols for new technologies, and so on.  Those who would want all such operations conducted by government agencies need to consider the fact that one of the strengths of American society is its proliferation of vigorous, competent, and useful mediating institutions.  Government power was involved in this case, and many times that is an appropriate outcome, but it was not government by itself that dealt with the problem, but government prompted by the private mediating institution that got the job done. 

 

Fortunately, the issue at hand was not subject to much political pulling and hauling, as neither Republicans nor Democrats wanted to look like they were opposed to helping blind people.  So while a new technology presented a new potential problem to a certain group of people, they noticed it soon enough to deal with it in a way that is not overly burdensome on car makers, and has actually led to a considerable amount of creativity on the part of sound designers.

 

I have not had the opportunity to listen to an EV at low speed to find out if I can hear it coming if I 'm looking the other way, but if I can, I'll have the National Federation for the Blind, the Pedestrian Safety Enhancement Act, and the sound designers working for whatever car company made the car to thank.  And so will you.

 

Sources:  John Seabrook's article "On Alert" appeared on pp. 24-29 of the Aug. 8, 2022 issue of The New Yorker.

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