2010 Nissan Leaf EV - Click above for high-res image gallery
While advocates have long heralded a reduction in noise pollution (in addition to lowered air pollution) as an advantage of electric vehicles, not everyone is convinced that silent cars are a good thing.
We use our senses to navigate through life and when one or more of them are diminished, we rely on the others. Such is the case for blind people who must use their hearing to make up for some visual deficit (see archived posts on the topic here and here). Every automaker working on electrified vehicles is aware of this and researching what sorts of sounds those vehicles should make for safety reasons.
For instance, Nissan engineer Toshiyuki Tabata has spent his career making cars quieter, but is now working on the LEAF to have it create sound. No final decision has been made, but reports tell us that Nissan is currently leaning toward making the LEAF sound like the whining, flying cars in the film Blade Runner.