Future Tense

Gridlock Is Coming Back. Noise Doesn’t Have To.

How cities could sound when commutes, and cars, are the norm once again.

Horrific backed-up traffic on a winding highway.
Shhhhhhhh… hroe/istock/Getty Images Plus

What does a city sound like? Asked that question, do you think of the dull roar of traffic, the staccato yelp of a horn, the wobbling screech of an alarm? In other words, do you think of cars? Automobiles are such a fixture of the urban landscape that it’s easy to overlook just how much they dominate the soundscape, too.

But that changed when the coronavirus pandemic arrived a year ago. As workplaces went virtual and shopping shifted online, traffic largely vanished. The relative quietude delighted many urban residents—and not just humans. A study of Bay Area sparrows found that their birdsongs grew richer as the automotive din subsided.

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That tranquility proved to be fleeting. (And you might have missed it, spiked as that early-pandemic moment was with uncertainty and fear.) Traffic has made a steady recovery as far back as last summer, and it is poised to grow further as workplaces reopen. Even after a tough year, the acoustic part of the early lockdown is one aspect of the pandemic we should remember warmly: Our neighborhoods weren’t just more enjoyable without cars constantly rumbling by. The reduced noise made them healthier, too.

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Although no one likes being startled awake by a blaring car horn, auditory intrusions also come from a variety of other urban sources, such as helicopters, firetrucks, and jackhammers. But helicopters eventually fly away, firetrucks pass, and construction crews go home. Meanwhile traffic’s cacophony is endless if you live along a major thoroughfare. No other urban sound can be so unrelenting. And while there isn’t much we can do about the annoyance of a siren—it’s loud for a reason—there are a number of tools available to reduce the clamor of cars.

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Prolonged exposure to noise is deeply harmful to human health. A study of London residents found that those subjected to sustained, high levels of traffic noise were more likely to die, especially from strokes, and another from Sweden found increased risk of heart attacks. According to the World Health Organization, excessive noise can “cause cardiovascular and psychophysiological effects, reduce performance and provoke annoyance responses and changes in social behavior.”

Traffic noise can be damaging even if it goes unnoticed. Loud nocturnal sounds interrupt sleep, disrupting circadian rhythms and leading to hypertension. “Noise leads people to toss and turn more,” says Tara McAlexander, a professor of epidemiology and statistics at Drexel University. “So even when people say they’re not bothered, there is something still happening below the surface.”

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Although people may not fully appreciate the health risks, most still try to avoid living near busy roads. “Noise is a part of the lack of quality of life in these environments, though the health impact is not directly tangible” says Anne Moudon, a professor emerita at the University of Washington’s department of urban design and planning. Low-income, minority communities have a disproportionate share of major thoroughfares, making the decisions to route so many urban interstates through them during the 1950s and 1960s seem even more inequitable.

Looking to the future, one might hope that the growing popularity of electric vehicles could allow urban streets to grow quieter as drivers trade in their rumbling gas guzzlers. Bad news: Most traffic noise—75 to 90 percent, according to California’s transportation department—is caused not by internal combustion engines but by tires rubbing against asphalt.

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All of that being the case, can cities do something about the noise—especially as workplaces begin to reopen to commuters?

Moudin points to slower streets as one potentially promising solution. “Noise grows logarithmically with speed,” she says, “so slowing automobiles—whether electric or otherwise—is very important.” Conveniently, a push for reducing urban speed limits is already underway, spurred by cities’ Vision Zero campaigns to reduce traffic fatalities. Washington, D.C.,  and Boulder, Colorado, are among cities that have set the default urban speed limit to 20 mph (the slogan is “20 is plenty”). Another option is using “quiet pavement” with asphalt calibrated to soften sounds.

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But adjusting speed limits and asphalt mix won’t stop a driver leaning on his horn to get a neighbor’s attention or a motorcycle owner whose favorite sound is his own revving engine. Such activities may not be as dangerous to health as the ongoing roar of traffic, but they’re still annoying—and they violate an implicit social contract by allowing the interests of a single person to trump those of a majority preferring peace and quiet. An intuitive policy solution is to impose a fine, such as New York City’s $350 penalty for unnecessary honking. Israel has taken a more aggressive approach, banning car alarms outright. But enforcing automobile noise violations can be tricky; the driver may be long gone by the time police respond to a complaint.

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Technology could offer a solution. In recent years muscle car owners have converged on the London borough of Kensington and Chelsea to show off their souped-up engines (some have even flew in custom vehicles from the Middle East). Facing increasingly disgruntled residents, last October the borough council installed two “noise cameras” which automatically photograph the license plates of vehicles exceeding the legal limit of 80 decibels. Violators receive a fine of £100 in the mail. “Residents are thrilled,” says Borough Councillor Johnny Thalassites, who has championed the program. “For the first time in many years they’re sleeping a bit better.”

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Thalassites says that the borough’s noise cameras have attracted inquiries from officials in France, Canada, and Australia—but not yet the United States. Could fresh memories of the pandemic’s quiet streets prompt American cities to take a stand against excessive automobile noise? One would hope so—after all, they’re starting to address the scourge of leaf blowers. Why not car alarms, which in addition to being punishingly loud are also useless?

Still, there are worse things than suffering the jolt of a car alarm. In lost sleep, higher blood pressure, and many other maladies, those living next to traffic’s constant din pay a far higher price for the intrusive ubiquity of urban car noise.

Future Tense is a partnership of Slate, New America, and Arizona State University that examines emerging technologies, public policy, and society.

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