The US Department of Transport (DoT) recently decreed that all hybrid and electric vehicles must make a noise to protect pedestrians, especially folks who are blind or have limited vision. Rather than just saying, "okay, we're adding a noise to our EVs, you guys," Nissan made a big production about releasing its "song," even giving it a name. "'Canto' has been developed to help with pedestrian safety, as well as to provide ... a sound that is energizing and confident," the company said in a press release.
The sound changes tone and pitch when the vehicle speeds up and slows down, and is activated at speeds of around 12 to 19 mph. In the US, the standard is 30 km/h (19 mph), a rule the DoT said "will help prevent about 2,400 pedestrian injuries each year once all hybrids [sold in the US] are properly equipped." Nissan says its own sound is also made to "enrich the aural environment of a typical city street" and be clearly audible, but not disturbing to city residents or vehicle occupants.
Nissan says that "Canto" comes from Latin and means "I sing," adding that the sound is still subject to change. To me, the harmonic tone (below) sounds like a cross between an orchestra warming up and THX's "the audience is listening" theater sound trailer. If you're crossing the street when one of its future vehicles shows up (the EV above is the Leaf Nismo concept), it's certain to make your activities feel more dramatic, anyway.