It used to be that auto companies wanted to make cars as quiet as possible. Now they're working to make them louder. And all in the name of safety.
Nissan added a digital humming noise to its Leaf electric vehicle to warn people with hearing or vision impairments that the car was coming. Now Toyota is following suit with the Prius.
In Japan, Toyota is offering to hook up a speaker in the engine compartment of the popular hybrid to broadcast a synthesized sound so pedestrians can hear the car approach when it's in the electric-only mode. Listening to a video of the device in operation brought to mind a chorus of cicadas.
The option is being offered only in Japan, but Toyota is studying it for the United States. The dealer-installed option costs about $150.