An electric car could be so silent that it may not alert pedestrians that it is incoming or cruising down the street. As for Daimler’s e-Smart city car, its sound engineers addressed the issue by creating artificial noise similar to those heard from conventional engines. Sound engineer Christoph Meier, head of powertrain acoustics at Daimler, and his team invented a “sonorous purring” -- pitched higher than conventional vehicles – for the e-Smart city car, and a huskier noise for the Mercedes-Benz SLS AMG Coupe Electric Drive to signify its power.
“People expect some exterior noise from a vehicle, because we all grew up with the ‘vroom vroom’ of combustion engines,” Meier remarked. Daimler, however, is not the only carmaker adding fake noise to electric cars to address safety as well as make their offerings stand out.
Renault SA also provided its Zoe hatchback with three noise choices and Nissan Motor Co. has endowed its Leaf EV with artificial sound. Carmakers will have to prepare for an expected move by regulators to require them to install warning noises on their vehicles as early as 2014. Artificial motor noise could save lives while protecting investments in electric cars.
Since electric vehicles are almost soundless while cruising at low speeds, they could be a possible silent threat for cyclists and pedestrians who are more reactive when hearing sounds of vehicle engines.
Accidents caused by soundless EVs could affect demand, which is still struggling despite recent gains. “If a silent electric vehicle knocks over an elderly person or a child, it’s not worth the risk,” said Neil King, an analyst with Euromonitor told Bloomberg. “It happens often enough in urban areas that people are stepping into the road without looking. You can’t get around that.” [source: Bloomberg]