Without an internal combustion engine under the hood, electric vehicles mean we’ll have quieter roads, right?
Not really, according to a noise expert.
In a response to a question on this subject, Erica D. Walker, assistant professor of epidemiology at Brown University in Rhode Island observed that sounds would be different with EVs on roads — but not necessarily quieter.
There’s a difference between sounds and noise — the latter generally being a way to define unwanted sound. So what one might consider a sound, someone may consider noise.
So, the question more or less becomes: Will EVs produce more noise?
The amount of noise from ICE vehicles depends on vehicle speed. At about 50 km/h, a gas-powered vehicle will produce sound levels between 33 and 69 decibels — the range between a quiet library and a loud dishwasher, according to Walker.
At about 110 km/h, sound levels can get up to 89 decibels —equivalent to two people shouting their conversation at each other.
A 1981 U.S. Environmental Protection Agency estimate showed about half the U.S. population is exposed to traffic noise every year that was loud enough to be harmful to their health.
EVs, on the other hand, are quieter at low speeds as they don’t have the same noise or vibration.
However, the U.S. National Highway Traffic Safety Administration requires EVs and hybrids to produce sounds ranging from 43 to 64 decibels when they are moving at less than 30 km/h. This is to ensure pedestrians will hear these vehicles coming. The type of warning sounds it left to the manufacturer.
“At high speeds, there may not be much difference between gas-powered cars and EVs or hybrids,” Walker noted. “That’s because other factors like tire and wind noise become louder as cars move faster.”
Infrastructure is another factor. Lower-income neighbourhoods with poorly maintained roads are more likely to hear an EV making its way down the road.
“Cracks, depressions and holes in roads can increase sound levels as cars travel across them,” Walker said.