Yet what happens when the Brabus engineers get their hands on an electric vehicle for the first time? Which is what they did with the Tesla Roadster, the first electric sports car suitable for mass production from the USA. Unusually, improving performance is initially not important with this car. Brabus simply improved the Tesla’s handling and spruced up its appearance a little and added (this being the actual innovation) the “space sound generator”, which provides suitable acoustic accompaniment to the violent acceleration from zero to a hundred in about four seconds. So it’s goodbye to the sound of a “fully-laden tumble dryer”, as one critic lamented, and hello to a choice between the sonorous sound of a V8, a husky six-cylinder powerhouse or even a space racer with cheeping fantasy sounds. And as the manufacturer affirms, “the intensity of the sound adapts to the output of the electric engine”.

It will probably only become apparent how the sound generator contributes to road safety along the lines of “pedestrians, hear the signs”, or indeed noise pollution, in a few years, when considerably more electric cars are on the streets. Both in the USA and Europe, experts are warning of the dangers of the “quiet cars”: “We have been trying to make cars quiet for 30 years,” stated Robert Strassburger, Vice President of Vehicle Safety at the Alliance of Automobile Manufacturers in an interview for the Washington Post, “but we never thought that someday they could be too quiet.” Yet a study by the National Highway Traffic Safety Administration (NHTSA) from 2009 found that precisely that could be the case. After analyzing accidents involving around 8,000 hybrid electric cars and around 600,000 vehicles with combustion engines, the NHTSA study concluded that in certain situations and at low speed, the accident risk of vehicles running on electricity, which are silent, is up to 50% higher.

• Part 1: Better a loudspeaker than a sneaker
• Part 2: Minimum volume for cars?
• Part 3: Ring tones for electric cars