An Acoustic Vehicle Alert System (AVAS) is designed to alert pedestrians to the presence of electric vehicles.
AVAS has been mandatory in Europe on all new types of electric and hybrid vehicles since 1 July 2019. The regulation will also apply to every quiet electric and hybrid vehicle registered from July 2021.
Put simply, the systems add exterior noise to quiet vehicles to improve road safety in towns and cities.
Sounds generators produce a specified level of noise when they are reversing or running at speeds below 20km/h (12 mph). This is particularly important for pedestrians with visual impairments, but also for other vulnerable road users such as cyclists and children.
For manufacturers, it’s an opportunity to experiment with different sounds. Although the acoustic alert must comply to legislation and sound pleasant for the outside world, manufacturers can use something that suits the brand profile.
Rudi Halbmeir is a sound designer at Audi. He said: “It’s funny, it used to be my job to make the cars as quiet as possible. Now I have to make it louder with artificial sounds.”
Fellow sound designer Stephan Gsell added: “The noise should not just meet the legal requirements; it should also be pleasant to listen to and just be a nice sound overall. If you drive Audi, you should hear Audi.”
Interestingly, thanks to varying level requirements, an electric Audi will sound exactly the same in Europe and China, but the US version will sound different. In the US, AVAS is required at speeds of up to 31km/h (19mph).
AVAS is nothing new. Since its launch, the Renault Zoe has been equipped with a ZE Voice system, which is active at speeds from 1mph to 18mph. The frequency of the noise changes as the speed increases. You even get a choice of sounds, so you can create your own sci-fi symphony.
Engines and spaceships
Other brands, such as Nissan, Jaguar and Mitsubishi, were also ahead of the curve in terms of meeting AVAS legislation. The sound of the Jaguar I-Pace was tested by members of Guide Dogs for the Blind.
A spokesperson for the charity said: “Guide Dogs campaigned hard to make it compulsory for quiet vehicles to have sound generating systems built in and turned on, including when the vehicle is stationary at a pedestrian crossing.”
Other companies, like Siemens and Harman, have been working on sound generators for many years. Harman started developing a suite of active noise management solutions in 2009. The external Electronic Sound Synthesis (eESS) system projects a specific sound from speakers at the front and rear of the vehicle.
HALOsonic offers customisable in-cabin sound management solutions. This allows a manufacturer to select a signature that fits the brand, whether it’s a sporty engine note or a sound that resembles a spaceship.
One thing’s for certain: thanks to AVAS, electric cars might be quiet, but they’ll never be silent.