Under a new rule issued by the U.S. National Highway Traffic Safety Administration, electric cars will be required to produce noise when traveling at slower speeds. The rule is designed to ensure pedestrians—especially those who are blind or visually impaired—are aware that an electric car is nearby.

With electric cars becoming more prevalent, our roads are getting quieter. But that silence causes about 2,400 pedestrian injuries a year because people don’t realize an electric vehicle is nearby, like when they’re walking through a parking lot or neighborhood.

It’s unclear what noise the NHTSA requires these vehicles to make, but it must “provide adequate audible warning to pedestrians.” So, if you’re traveling below speeds of 19 miles per hour or less, your vehicle will be required to make a noise.

While the reasoning behind the requirement is sound, it doesn’t make sense for these vehicles to make noise in all situations. If you’re stuck in a traffic jam, for example, you’ll have no choice but to listen to the noise so long as you’re going under 20 mph. Hopefully, it’s not an obnoxious beeping.

Will it be a beep? Or perhaps a boop?

“With more, quieter hybrid and electrical cars on the road, the ability for all pedestrians to hear as well as see the cars becomes an important factor of reducing the risk of possible crashes and improving safety,” explained U.S. Transportation Secretary Anthony Foxx.

Some EVs and hybrids already feature some type of noise. The Kia Soul EV for example whirs at a high pitch at low speeds.

Manufacturers have until Sept. 1, 2019, to equip their vehicles with a mechanism that makes noise.