For years now, U.S. regulators have been working on a rule, known as the “quiet car rule”, that will force electric vehicle manufacturers to include a device in their EVs to emit a sound at up to 19 mph to protect pedestrians.

It was supposed to be implemented in EV models coming as soon as next year, but now automakers have one more year to adapt to the new rule.

The new rule is controversial in the EV community. While most admit that quiet cars can be a problem at low-speeds, especially for the visually impaired, people also fear that adding a sound will remove an important benefit of electric vehicles.

While limiting pollution from fuel emissions is the main benefit of all-electric vehicles, EVs also limit noise pollution, especially in urban environments.

At higher speeds, tire noises are greater than engine noise and therefore, there’s not much of a difference between electric cars and gas-powered cars. But at lower speeds, EVs can be hard to hear coming.

A ruling on this issue has been in the works since 2013, when the NHTSA estimated that the odds of an electric or hybrid vehicle being involved in a crash with a pedestrian are 19% higher compared with a louder gas-powered vehicle. The original proposal estimated that the rule could reduce pedestrian and bicyclist injuries by 2,800 instances every year, but it has now been revised to 2,400.

A decision has been pushed on several occasions and a 2016 ruling said that automakers don’t have to install the device in their EVs for another 3 years.

The U.S. Department of Transportation (DOT) reviewed the rule under the new administration and confirmed this week that automakers can wait until 2020 to implement the new noise devices.

Solutions

Automakers will have to install at least one external speaker on electric and hybrid vehicles to emit a constant sound “to be recognizable as a motor vehicle in operation” at low speeds.

Tesla has apparently been considering an alternative – though it’s not clear if it would work under the new rule.

During a Q&A session back in 2013, CEO Elon Musk answered a question from a Tesla owner worried about children playing in her neighborhood and not hearing her Model S coming at low-speed:

“There is this question of having the Model S make a noise. Obviously, the challenge is to avoid noise pollution at the same time.”

Musk continued by saying “we are in discussion with” but he was interrupted by someone in the crowd and he trailed off about the fact that there are two schools of thought on the issue.

He added:

“I think the sensible and ideal thing long-term is to have proximity sensors that direct a pleasant sound in the direction of where somebody is walking – so therefore, it’s the least amount of noise, and it’s not annoying, and it’s only going to where it needs to go. That’s what I think is the right long-term solution.”

The CEO continued and said that “it will take a bit of work to get there, but hopefully, that’s where things will end up.”

That was back in 2013 and Tesla did indeed continue working on the problem since in 2016, Model S schematics with a device for “pedestrian noise” leaked:

Now the actual noise is only one part of the problem. As Musk mentioned in his explanation, you need to detect the pedestrians in order to send the noise toward them.

Tesla’s Enhanced Autopilot sensor suite and 360-degree camera coverage enables pedestrian detection.

A combination of the “speaker pedestrian noise” and the new sensor suite could be all Tesla needs to implement the system described by Musk.

The goal would be to optimize security and reduce noise pollution at the same, but again, it’s not clear if the system would be allowed under the new rule.

In the meantime, enjoy your current quiet electric vehicles.

FTC: We use income earning auto affiliate links. More.

Subscribe to Electrek on YouTube for exclusive videos and subscribe to the podcast.