Do Electric Cars Make Noise? EV Sounds Compared to Gas Cars

While EVs tend to be quiet, that presents challenges.

Electric vehicle driving through a tunnel

Emanuel M Schwermer/Getty Images

Electric vehicles (EVs) are quiet. Electrons moving from a battery to a motor make no noise. Without an internal combustion engine, there is never the sound of valves knocking, gears grinding, fans whirring, or engines sputtering.

The only sound an EV emits when idling is the quiet hum of the electric motor, and when moving the whir of tires and wind. This can be a boon in urban environments, where road traffic is the main contributor to noise pollution. But it can also be a drawback, as quieter cars can pose dangers to the blind or visually impaired.

Noise Pollution

When we think of pollution from vehicles, we might initially think of the dangers of air pollution, but noise pollution also can have a number of negative health consequences. Today, 54% of the world's population lives in cities, and in addition to the impacts on humans, noise pollution is one of the greatest threats to wildlife.

Traffic noise suppresses frogs' immune systems. It decreases the ability of birds to communicate with each other and to detect predator threats. And it reduces terrestrial wildlife's ability to forage, care for their young, and reproduce. It is no wonder that during coronavirus lockdowns around the world in 2020, noise levels in urban environments were reduced by 35% to 68%—one of the contributing factors allowing wildlife to rebound in greater numbers, even if only temporarily. With EVs, those reductions could be permanent.

Reducing the Noise

While city planners have made various efforts to mitigate urban noise pollution, such as redesigning building layouts, road networks, green spaces, or street configurations, only in the past two decades has a solution come from the primary sources themselves: quieter vehicles. At speeds up to 30 mph, EVs (and hybrids when driven in electric mode) are far quieter than vehicles with internal combustion engines. An electric motor is nearly silent, meaning “rolling noise” from tires and wind are the main source of any sounds an EV makes.

Even creeping along at fewer than 10 mph, the traffic flow of internal combustion engine vehicles emits roughly 56 decibels, according to one study—more than the World Health Organization's recommendation that daytime noise levels remain below 50 decibels—while EVs are virtually silent.

When moving at higher speeds, however, tire and wind noise are a greater percentage of total traffic noise than engine noise is, reducing the difference between EVs and gas-powered cars. Still, in the pursuit of energy efficiency to increase EV driving range, many EV manufacturers emphasize aerodynamics to reduce the drag coefficient. This reduces wind noise, so that even at higher speeds, EVs were on average 2 decibels quieter than gas-powered cars.

Too Little Interior Noise?

Ironically, the absence of the masking effect of engine noise (and vibration) has led to complaints about road and wind noise among EV drivers.

In an EV, subtler noises such as minor creaks and squeaks that were once drowned out by engine noise can be audible. The rotation of magnets in an electric motor can also emit high-frequency whining noises during operation, especially noticeable during low-speed driving, prompting design refinements of the motor and attempts to muffle internal noises.

One study predicts that acoustic and thermal insulation materials for EVs will grow by 21% annually over the next decade. The challenge, however, is one of weight. In an internal combustion engine vehicle, sound-deadening materials are often added to the vehicle with little consideration of the effect on gas mileage. Adding extra weight to an EV, however, reduces the battery range in a vehicle that is already on average heavier than a comparable gas-powered car.

Dangerously Quiet?

Visually impaired person crossing a street

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Concerns about the quiet nature of EVs have prompted concerns about pedestrian safety, especially among advocates for the blind and visually impaired. A study by Vision Australia and Monash University reported that 35% of people who are blind or visually impaired had either a collision or near-collision with a hybrid or electric vehicle.

Since 2019, the U.S. National Highway Traffic Safety Administration (NHTSA) has required new EVs to automatically make noise when they are traveling slower than 18.6 miles per hour “to ensure that blind, visually impaired, and other pedestrians are able to detect and recognize nearby hybrid and electric vehicles.” Beyond 18.6 mph, road noise emitted by EVs is nearly the same as that of gasoline cars.

In Europe and Australia, electric vehicles must be equipped with an Acoustic Vehicle Alert System (AVAS) that emits noise at speeds lower than 20 kilometers (12 miles) per hour. The AVAS noise in some EVs is external only, so those inside the car may not even hear it.

The threat to pedestrian safety doesn't just affect the blind or visually impaired, however, since inattentive sighted walkers texting in crosswalks may fail to look up from their phones without noticeable vehicle noise. While data is limited, studies suggest a link between pedestrians being distracted by mobile phone use while crossing streets and a rise in pedestrian-vehicle collisions.

Artificial Noise

Creating artificial noises to conform to AVAS requirements leaves car manufacturers with the opportunity to create brand sound signatures. BMW, for example, is working with a Hollywood composer to create a specific sound for its EVs. Volvo, by contrast, has opted to merely increase the expected road noise of a vehicle rather than create its own custom sound. While the sounds need to be within volume standards set by the governing regulations, what could emerge is a medley of different sounds from different vehicle makes on the road. Whether that's a good thing or a bad thing remains to be seen.

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