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Acoustic alerts for EVs – sounds good?

Acoustic alerts for EVs – sounds good?

As urban spaces become increasingly more populated, noise pollution is becoming a growing disturbance. And sometimes, something designed with another goal in mind, can provide an unexpected solution to a separate problem. This is the case with electric vehicles. There are, of course, environmental advantages to going electric, but perhaps equally as important, is the promise of quieter streets and traffic. This would drastically improve the overall quality of urban life. But an often overlooked consequence, is that silence can not only be peaceful but also dangerous when it comes to traffic.

Have you ever crossed the streets with earphones in? Did you look more closely for upcoming cars? Most people rely a lot more on their ears in traffic than they are aware of. While our ears might not be the only sense we use, they do play an important role in identifying dangers – and this is only taking able-bodied people into consideration. For people with visual impairments, acoustics are even more crucial to be able to move confidently. 

A new directive from the European Union is addressing this exact problem. How can we keep traffic safe for pedestrians with EVs on the streets? Their answer is AVAS. The Acoustic Vehicle Alerting System is mandatory for all new electric car models, meaning all e-cars that enter the market for the first time, as of summer 2019. From 2021 on, all newly registered EVs will have to have the alerting system on board. This goes for all electric vehicles with four wheels or more, so cars, buses, trucks and the like. E-cars that are already on the streets, however, don’t have to retrofit any acoustic alerts for now.

The noise-emitting device is meant to protect the visually impaired, older people and children in traffic, by requiring EVs to make an artificial sound whilst driving. The noise that will have to be emitted when driving at a speed of up to 20 kmh (12 mph) is meant to aid those who depend on it – and arguably everyone else. At higher speeds, tyre sounds and wind resistance are said to be enough of an auditive cue. In the US, a similar directive asks for e-cars to make a sound up until 30 kmh (18.6 mph). Some initiatives even demand a noise at all speeds.

While the volume of the AVAS is also predefined to be at least 56 decibels and at most 75 decibels (the latter is about the average volume of a standard car), the sound itself is not legally specified, as long as it has a rise and fall in pitch indicating acceleration and deceleration. This means, that car brands can and are coming up with their very own distinctive sound designs. This has of course already been the case for combustion engines. The rumble of a powerful engine is not by accident, but rather purposefully constructed to sound so. But with actual mechanical noises out of the picture, the possibilities are growing exponentially. The acoustic backdrop of cities might therefore become a lot more varied in the future. Let’s hear what’s to come!

Expert
Giuseppe Sacchi
Senior Product Manager