Scania : The sound of the future Scania

What should the electrically powered truck of the future sound like? That was the question when Interactive Institute Swedish ICT and Scania carried out two sound surveys to find sounds that work for both pedestrians and drivers.

Electric vehicles are not completely silent, but they don't provide the same engine sound as a combustion engine. Instead other sounds can become more prominent in the cabin, such as the sound of the wheels against the road.

Taking the driver's pulse

So, to test the sound inside the cabin, professional drivers were exposed to different sounds while driving in Scania's driver simulator. The drivers got to hear three different engine sounds: two artificially-designed sounds and one sound that represents what an electric vehicle sounds like today while speeding up and braking.

'The engine sound helps the driver understand if the vehicle is running as it should and if the vehicle's got power in certain situations. That kind of sound is what we are trying to recreate for electric vehicles,' says Johan Fagerlönn, scientist at Interactive Institute Swedish ICT.

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Johan Fagerlönn, scientist at Interactive Institute Swedish ICT.

During the test the driver's pulse is being measured to see if some sounds are perceived as more stressful or annoying, thereby increasing their pulse, and if the sound changes the driver's behaviour. Afterwards, the drivers themselves get to evaluate the sounds, saying what they thought about the sound itself and if it managed to provide them with the required information on which to respond.

Increasing traffic safety

The external sound of an electric vehicle is also an important factor. By 2019, all new electric vehicles in the European Union need to have a sufficiently high sound to warn passers-by that they are near. The external sound was tested at Scania by the Interactive Institute in a big project that involves several partners, including the Swedish Energy Agency, Trafikverket and Luleå University of Technology.

'In this project we are also researching how external sound affects people's opinion of electric vehicles. For example, we look at whether an added sound makes you not want to be around it, so that perhaps it puts you off buying the vehicle, or perhaps it's a sound that manages to increases traffic safety by making people aware that there is a vehicle around,' says Fagerlönn.

The test will result in recommendations for the industry that companies can use as a starting point when manufacturing electric vehicles, and thereafter customise it to make it their own.