page_title: Electric vehicle warning sounds
section_title: Nissan
hierarchical_section_title: Electric vehicle warning sounds / Specific systems / Nissan
caption_attribution_description: English: Nissan Leaf control panel showing the warning sound switch. The middle button on the bottom can turn OFF the artificial digital sound the car makes (a faint whirrr) when the Leaf is traveling under 20 MPH to alert pedestrians, the blind, and others of its presence.
context_page_description: Electric vehicle warning sounds are sounds designed to alert pedestrians to the presence of electric drive vehicles such as hybrid electric vehicles, plug-in hybrid electric vehicles, and all-electric vehicles travelling at low speeds. Warning sound devices were deemed necessary by some government regulators because vehicles operating in all-electric mode produce less noise than traditional combustion engine vehicles and can make it more difficult for pedestrians and cyclists to be aware of their presence. Warning sounds may be driver triggered or automatic at low speeds; in type, they vary from clearly artificial to those that mimic engine sounds and those of tires moving over gravel.
  Japan issued guidelines for such warning devices in January 2010 and the U.S. approved legislation in December 2010. The U.S. National Highway Traffic Safety Administration issued its final ruling in February 2018, and requires the device to emit warning sounds at speeds less than 18.6 mph with compliance by September 2020, but 50% of "quiet" vehicles must have the warning sounds by September 2019.
context_section_description: Vehicle Sound for Pedestrians or VSP is a Nissan-developed warning sound system in electric vehicles. The Nissan Leaf was the first car manufactured by Nissan to include VSP, and the electric car includes one sound for forward motion and another for reverse. The VSP was also used in the Nissan Fuga hybrid launched in 2011. The system developed makes a noise easy to hear for pedestrians to be aware of the vehicle approaching, but the warning sounds do not distract the car occupants inside. Nissan explained that during the development of the sound they studied behavioural research of the visually impaired and worked with cognitive and acoustic psychologists, including the National Federation of the Blind, the Detroit Institute of Ophthalmology, experts from the Vanderbilt University Medical Center and a Hollywood sound design studio.
  Nissan's Vehicle Sound for Pedestrians is a sine-wave sound system that sweeps from 2.5 kHz at the high end to a low of 600 Hz, a range that is easily audible across age groups. Depending on the speed and whether the Leaf is accelerating or decelerating, the sound system will make sweeping, high-low sounds. For example, when the Leaf is started the sound will be louder, and when the car is in reverse, the system will generate an intermittent sound. The sound system ceases operation when the Nissan Leaf reaches 30 km/h (18.6 mph) and engages again as the car slows to under 25 kilometres per hour (16 mph). For the 2011 Leaf, the driver could turn off sounds temporarily through a switch inside the vehicle, but the system automatically reset to "On" at the next ignition cycle. The system is controlled through a computer and synthesizer in the dash panel, and the sound is delivered through a speaker in the front driver's side wheel well.  Nissan said that there were six or seven finalist sounds, and that sound testing included driving cars emitting various sounds past testers standing on street corners, who indicated when they first heard the approaching car. Nissan removed the ability to disable the pedestrian alert between model year 2011 and 2012 in anticipation of the U.S. ruling to be issued by the National Highway Traffic Safety Administration.
  The Leaf's electric warning sound had to be removed for cars delivered in the U.K., as the country's law mandates that any hazard warning sound must be capable of being disabled between 11:00 pm and 6:00 am, and the Leaf's audible warning system does not allow for such temporary deactivation. For the 2014 UK model of the car, the VSP system is enabled by default, though a button on the dash permits drivers to disable the system until the next time the car is switched on.
caption: 2011 Nissan Leaf equipped with warning sound pause switch.
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