Background Īs a result of increased sales of full electric vehicle and hybrid electric vehicles in several countries, some members of the blind community have raised concerns about the noise reduction when those vehicles operate in all-electric mode, as blind people or the visually impaired consider the noise of combustion engines a helpful aid while crossing streets and think quiet hybrids could pose an unexpected hazard. and Japan and manually activated in Europe. The 2013 Smart electric drive, optionally, comes with automatically activated sounds in the U.S. 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. 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). 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. 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. In April 2014, the European Parliament approved legislation that requires the mandatory use of an Acoustic Vehicle Alerting System ( AVAS). 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. Japan issued guidelines for such warning devices in January 2010 and the U.S. Warning sounds may be driver triggered (as in a horn but less urgent) or automatic at low speeds in type, they vary from clearly artificial (beeps, chimes) to those that mimic engine sounds and those of tires moving over gravel. 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 (especially those with visual impairments) to be aware of their presence. The chart below shows different types of power tools and their noise levels.The 2011 Nissan Leaf was the first electric car equipped with Nissan's Vehicle Sound for Pedestrians called 'Canto'.Įlectric vehicle warning sounds are sounds designed to alert pedestrians to the presence of electric drive vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs) travelling at low speeds. Duration is typically measured over a workday and accumulated through many years. The noise level is therefore expressed in decibels (dB) on the "A" scale, or dB(A).ĭuration of exposure is equally important. Most workplace noises include a wide band of frequencies and are measured through the "A" filter in sound-level meters. Sounds must also be specified in terms of frequency or pitch. Hearing protection should be used for any level over 85 dB and double protection for any level over 105 dB. In other words, sound intensity doubles every 3 dB. But 93 dB is still twice as much noise as 90 dB. A sound 1,000 times more powerful than near total silence is 30 dB.įor example, a backhoe and a compressor each producing 90 dB have a combined output of 93 dB, not 180. A sound 100 times more powerful than near total silence is 20 dB. On the decibel scale, the smallest audible sound (near total silence) is 0 dB. This means that noise levels can't be added directly like other numbers. The decibel scale is not linear but logarithmic. Decibel (dB) is the unit used to measure a sound's strength.
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