If all of the vehicles in the world were to convert to electric, would it be quieter? – Joseph, age 10, Chatham, New Jersey

If everyone everywhere received a free electric vehicle at the same time – and owners were required to travel at really slow speeds across well-maintained roads – the world would sound different.

But that doesn’t mean it would be quieter.

People can have different feelings about the same sound. As the founder of Community Noise Lab at Brown University’s School of Public Health, I am particularly interested in how we, as humans, decide what is a sound and what is a noise – which is what we call unwanted sounds. We perceive the sounds that we experience in our daily lives 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 that chronic exposure to noise can affect your 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 be harmful to 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. https://www.youtube.com/embed/20aeY67N5tk?wmode=transparent&start=0 This video compares the decibel levels produced by loud, moderate and quiet dishwashers.