The Nissan Leaf is the first of the new batch of electric vehicles to reveal its new sound meant that alerts pedestrians to its presence. However, while advocates for the blind are pleased with the sound, the National Federation for the Blind is not happy that Nissan has added a switch that allows drivers to turn the noise off.
As the reasoning goes, the main point of creating artificial sounds is to alert pedestrians that rely on hearing to know if a car is approaching. If drivers can turn the system off, the whole effort becomes pointless. Nissan, though, says it added the switch to balance the needs of drivers and pedestrians while also claiming the sound is not really audible inside the car. Like the disable switches for stability control systems, the noise is only turned off for the current drive cycle. Each time the car is turned off, the noise is re-enabled. We see the value in turning off such sound signatures in limited circumstances (teens creeping up their parents' driveway after curfew, whirring in late to a drive-in movie, etc.), but can understand the NFB's concern all the same.
This early in the roll-out of electric vehicles, with new legal standards are still evolving, and the National Federation for the Blind plans to continue pursuing legislation that would make permanent sound systems mandatory in all hybrid and electric vehicles.