G round is the regulation of the European Parliament and of the Council No. 540/2014. Since July 1, 2019, an acoustic warning signal (Acoustic Vehicle Alerting Systems, AVAS for short) must be installed in new types of hybrid electric and purely electric vehicles to fuel cell cars to protect pedestrians. In the USA, a similar obligation will apply from 2020. Exactly two years later, the rule set out in Article 8 will apply to all new hybrid and electric vehicles. Which in turn does not mean that it only has to be done then.
The regulation in Annex VIII not only regulates the point in time from which vehicles must be equipped with the AVAS. System requirements are also listed. For example, the AVAS must automatically generate a continuous acoustic signal in the speed range between starting up and a speed of around 20 kilometers per hour and when reversing. Why only up to 20 km /h? Because at higher speeds the rolling noise of the tires drowns out the actual engine sound even in modern combustion vehicles.
Interesting: Originally, an easily accessible switch was required that enables activation or deactivation. This 'pause function' has now been canceled by the UNECE and declared inadmissible. Important: The AVAS must be activated automatically when the vehicle is restarted. At the same time, the volume can react to the speed.
Manufacturers give first examples of their noises
The noise itself must be comparable to that of a vehicle of the same class equipped with a combustion engine , is it [called. But it shouldn't sound exactly like a gasoline or diesel engine. Which also shatters the dream of every Fiat 500 driver of a city car with a full V8 sound. It shouldn't be pieces of music either.
Just like the designs of the car bodies, the designs of the AVAS sounds should also differ from manufacturer to manufacturer. 'After all, at the moment a BMW sounds different from a Mercedes or a Porsche - that should also be the case with electric cars,' explains Hugo Fastl, professor at the chair for human-machine communication at the Technical University of Munich (TUM). In the future, it will be easier to recognize a vehicle by its sound.
This is what matters in sound design
The big question now is: “How is such a sound made developed at all? ”The basic rule is that it will take place in the medium frequency range. BecauseOn the one hand, too high frequencies can no longer be perceived by older people. And on the other hand: 'Very low frequencies are difficult to radiate,' says Fastl. “To do this, the speakers on the car have to be very large.” In addition to the frequency, the tone color plays an important role. 'It's like in music: you can also play the first bars of a Mozart symphony on your smartphone so that everyone can recognize the melody,' says Fastl. “That doesn't sound so great, though. If it's played by a chamber orchestra with ten musicians, that's better. And a full orchestra with 50 people can play it as the composer imagined. ”Understandably, this task is not performed by an orchestra at TUM, but by a computer.
Above all, sports car owners will spend hours talking about another point can entertain: the roughness of a sound. It is determined by how quickly the volume of the sound changes. 'If there is roughness in a noise, it is perceived as sporty,' explains Fastl. 'You can hardly sell a Ferrari without roughness.'
Directed sound would be a calm solution
This is an idea that is being tested not only in the automotive industry, but also currently at train stations, airports and wherever many people need to be informed in large rooms of directed sound. The fact that more and more cars are coming onto the market with automatic pedestrian detection could give this technology the “directed” thrust it needs. In dangerous situations, vehicles would specifically target the person concerned, while nobody else would hear anything. This procedure would also make permanent sounding unnecessary.
Of course, the AVAS topic not only affects Europe, but also causes a sensation in the USA, for example. 'When there will be more quiet electric and hybrid cars on the road in the future, it will be important that pedestrians not only see these vehicles, but can also reliably hear them,' says US Secretary of Transportation Anthony Foxx. According to the National Highway Traffic Safety Administration (NHTSA), 2,400 pedestrian accidents per year could be prevented with the help of AVAS technology. According to estimates by the NHTSA, automakers incur around $ 39 million more annually. If the safety effect and the saved accident costs are calculated on the other hand, AVAS should in turn bring benefits of up to 300 million dollars per year. In the USA, unlike in Europe, the AVAS should be activated instead of up to 20 to 30 km /h.