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Electric vehicle warning sounds

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 when travelling at speeds less than 18.6 mph (30 km/h) with compliance by September 2020, but 50% of “quiet” vehicles must have the warning sounds by September 2019. In April 2014, the European Parliament approved legislation that requires the mandatory use of an Acoustic Vehicle Alerting System  (AVAS). Manufacturers must install an AVAS system in four-wheeled electric and hybrid electric vehicles that are approved from July 1, 2019, and to all new quiet electric and hybrid vehicles registered from July 2021. The vehicle must make a continuous noise level of at least 56 dBA (within 2 meters) if the car is going 20 km/h (12 mph) or slower, and a maximum of 75 dBA.

Electric vehicle warning sounds01

Several automakers have developed electric warning sound devices, and since December 2011 advanced technology cars available in the market with manually activated electric warning sounds include the Nissan Leaf, Chevrolet Volt, Honda FCX Clarity, Nissan Fuga Hybrid/Infiniti M35, Hyundai Sonata Hybrid, and the Toyota Prius (Japan only). Models equipped with automatically activated systems include the 2014 BMW i3 (option not available in the US), 2012 model year Toyota Camry Hybrid, 2012 Lexus CT200h, all EV versions of the Honda Fit, and all Prius family cars recently introduced in the United States, including the standard 2012 model year Prius, the Toyota Prius v, Prius c and the Toyota Prius Plug-in Hybrid. The 2013 Smart electric drive, optionally, comes with automatically activated sounds in the U.S. and Japan and manually activated in Europe.

Enhanced Vehicle Acoustics (EVA), a company based in Silicon Valley, California and founded by two Stanford students with the help of seed money from the National Federation of the Blind, developed an after market technology called “Vehicular Operations Sound Emitting Systems” (VOSES). The device makes hybrid electric vehicles sound more like conventional internal combustion engine cars when the vehicle goes into the silent electric mode (EV mode), but at a fraction of the sound level of most vehicles. At speeds higher than between 20 miles per hour (32 km/h) to 25 miles per hour (40 km/h) the sound system shuts off. The system also shuts off when the hybrid combustion engine is active.

VOSES uses miniature, all-weather audio speakers that are placed on the hybrid’s wheel wells and emit specific sounds based on the direction the car is moving in order to minimize noise pollution and to maximize acoustic information for pedestrians. If the car is moving forward, the sounds are only projected in the forward direction; and if the car is turning left or right, the sound changes on the left or right appropriately. The company argues that “chirps, beeps and alarms are more distracting than useful”, and that the best sounds for alerting pedestrians are car-like, such as “the soft purr of an engine or the slow roll of tires across pavement.” One of the EVA’s external sound systems was designed specifically for the Toyota Prius.

Post time: Sep-11-2023