But that doesn’t mean it would be quieter.
People can have different feelings about the same sound. As the founder of the Community Noise Lab at Brown University’s School of Public Health, I am particularly interested in how we, as humans, decide what a sound is and what is a noise — which is what we call unwanted sounds. We perceive the sounds we experience daily in many ways, from quiet to loud. And they can make us feel happy, angry, or many things in between.
These feelings can affect our health by relaxing or stressing us. Studies also show chronic noise exposure can affect sleep and hearing and contribute to health problems like heart disease.
How loud are cars?
We know that gasoline-powered cars make a lot of noise, especially on highways where they can travel at high speeds. In 1981, the U.S. Environmental Protection Agency estimated that nearly 100 million people nationwide were exposed to traffic noise every year that was loud enough to harm their health. At the time, this was about 50% of the U.S. population.
Many factors influence how loud a car is on the road, including its design, how fast it travels, and physical road conditions. On average, cars moving at around 30 mph on local roads will produce sound levels ranging from 33 to 69 decibels. That’s the range between a quiet library and a loud dishwasher.
This video compares the decibel levels produced by loud, moderate and quiet dishwashers.
For cars traveling at typical speeds on the interstate, around 70 mph, sound levels range up to 89 decibels. That’s equivalent to two people shouting their conversation at each other.
Electric and hybrid gas/electric cars emit very low sounds at low speeds because they don’t have internal combustion engines producing noise and vibrations. To ensure that pedestrians will hear electric and hybrid vehicles coming, the National Highway Traffic Safety Administration requires these vehicles to emit sounds ranging from 43 to 64 decibels when they are moving at less than 18.6 mph. Each manufacturer uses its own warning sounds.
At high speeds, there may not be much difference between gas-powered cars and EVs or hybrids. That’s because other factors like tire and wind noise become louder as cars move faster.
Urban noise is a serious health threat worldwide, and the main source is motor vehicles.
Quieter streets for everyone
Infrastructure also contributes to street noise. Cracks, depressions, and holes in roads can increase sound levels as cars travel.
Another way to reduce traffic noise would be to build more bike lanes and paths in less-wealthy communities, which often lack them, and encourage people to substitute this cheaper, healthier, cleaner, and quieter mode of transportation when they can.
Electric vehicles are still out of reach for many people because most models cost more than gas-powered cars. So, in reality, the benefits of switching to electric-powered vehicles — such as lower fuel costs, cleaner air, and somewhat quieter streets — are going mainly to people who live in wealthier communities and can afford EVs.
That inequitable distribution of benefits is what the EPA calls an environmental injustice: a situation in which everyone doesn’t have the same degree of protection from environmental and health hazards. To share those benefits more equally, electric vehicles will have to become as affordable as gas-powered versions.
Many people think of noise as a nuisance that’s less urgent than other, more pressing environmental issues like air and water pollution. As a result, governments fail to plan for noise, measure it, mitigate it, or regulate it in any meaningful way.
Noise is a significant environmental stressor that negatively affects everyone’s health and well-being, especially those most vulnerable. At Community Noise Lab, we aim to shed light on the public health implications of noise, argue for more holistic measurements of sound, and study noise with other environmental pollutants like water and air pollution, working alongside vulnerable communities across the United States.