BMW AG is weighing whether to add artificial sounds to its electric vehicles to make them safer to pedestrians. German rivals Audi and Mercedes-Benz say that they already have started developing brand-specific sounds while Nissan and Infiniti have revealed the solutions they will use to ensure that their EVs don't pose a danger to people when traveling at low speeds.
BMW spokesman Tobias Hahn said the BMW and Mini prototype electric cars currently are not equipped with active sound systems that add artificial noise at low speeds.
"However we have been looking into possible technical solutions for a while and we would be able to add such a feature to our vehicles should this turn out to be a real problem,” he said in an e-mail reply to questions. “We are also cooperating with organizations for the visibly impaired in Germany."
BMW's Mini E EV prototype is undergoing field trials in Europe, China and the United States. The luxury automaker will begin trials of its ActiveE EV prototype, based on its 1-series coupe, in 2011.
BMW will launch its first EV production model in 2013.
Mercedes parent Daimler AG wants on-board components and modules in its alternative-powertrain cars tuned so that they deliver a naturally produced sound that warns pedestrians but does not mimic the noise created by an internal combustion engine.
Audi's acoustics experts are working to create a futuristic engine note for the brand's EV.
Nissan' Motor Co.'s Leaf EV compact hatchback emits a noise that can be described as a cross between a small jet plane and a monorail. The sound was developed with input from the U.S.-based National Federation for the Blind and the Detroit Institute of Ophthalmology, which Nissan said helped configure the final specifications.
The M35h gasoline-electric hybrid from Nissan luxury brand Infiniti has a system that links an in-car sound synthesizer with a speaker built into the front bumper. The system works from start-up -- when the sound is the loudest -- to 30 kilometers per hour (about 19 mph) by emitting a range of high and low sounds at different volume levels.
Above roughly 25kph (16 mph), road, wind and tire noises are louder than engine noises.