Electric vehicle warning sounds
Encyclopedia
Electric vehicle warning sounds are a series of sounds designed to alert pedestrians to the presence of electric drive vehicles such as hybrid electric vehicle
Hybrid electric vehicle
A hybrid electric vehicle is a type of hybrid vehicle and electric vehicle which combines a conventional internal combustion engine propulsion system with an electric propulsion system. The presence of the electric powertrain is intended to achieve either better fuel economy than a conventional...

s (HEVs), plug-in hybrid electric vehicle
Plug-in hybrid electric vehicle
A plug-in hybrid electric vehicle , plug-in hybrid vehicle , or plug-in hybrid is a hybrid vehicle which utilizes rechargeable batteries, or another energy storage device, that can be restored to full charge by connecting a plug to an external electric power source...

s (PHEVs), and all-electric vehicles (EVs) travelling at low speeds. Their purpose is because vehicles operating in all-electric mode produce less noise than traditional combustion engine
Internal combustion engine
The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...

 vehicles and can make it more difficult for pedestrians, the blind, and others, to be aware of their presence.

Japan issued guidelines for such warning devices in January 2010 and the U.S. approved legislation on December 2010. Several automakers have developed electric warning sound devices, and as of December 2010 advanced technology cars available in the market with manually activated electric warning sounds include the Nissan Leaf
Nissan Leaf
Nissan introduced its first battery electric vehicle, the Nissan Altra at the Los Angeles International Auto Show on 29 December 1997. The Altra EV was produced between 1998 and 2002, only about 200 vehicles were ever produced, and it was mainly used as a fleet vehicle for companies such as...

, Chevrolet Volt
Chevrolet Volt
The Chevrolet Volt is a plug-in hybrid electric vehicle manufactured by General Motors. The Volt has been on sale in the U.S. market since mid-December 2010, and is the most fuel-efficient compact car sold in the United States, as rated by the United States Environmental Protection Agency...

, Nissan Fuga Hybrid/Infiniti M35, and the Toyota Prius
Toyota Prius
The Toyota Prius is a full hybrid electric mid-size hatchback, formerly a compact sedan developed and manufactured by the Toyota Motor Corporation...

 (Japan only). Models equipped with automatically activated systems include all Prii family cars to be introduced in the United States, including the standard 2012 model year Prius, the Toyota Prius v
Toyota Prius v
The Toyota Prius v, also named Prius α in Japan, and Prius + in Europe, is a full hybrid gasoline-electric compact MPV/station wagon produced by Toyota Motor Corporation introduced in Japan in May 2011 and in the U.S. in October 2011. It is scheduled to be released in the European market by mid 2012...

, and the Toyota Prius Plug-in Hybrid
Toyota Prius Plug-in Hybrid
The Toyota Prius Plug-in Hybrid is a mid-size plug-in hybrid electric vehicle to be produced by Toyota Motor Corporation and scheduled to be released to the market beginning in January 2012...

.

Background

As a result of increased sales of hybrid electric vehicle
Hybrid electric vehicle
A hybrid electric vehicle is a type of hybrid vehicle and electric vehicle which combines a conventional internal combustion engine propulsion system with an electric propulsion system. The presence of the electric powertrain is intended to achieve either better fuel economy than a conventional...

s in several countries, there have been 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 feel quiet hybrids could pose an unexpected hazard.

This problem is not exclusive to electric vehicles. In 2007 research at the Technical University Munich showed that ordinary vehicles in background noise are often detected too late for safe accident avoidance. The researchers measured the distances of 35 approaching vehicles to a pedestrian in the moment when they just got audible in a stationary background noise. These distances were then compared to the stopping distances of the respective cars and an algorithm was proposed to estimate them based on auditory masking
Auditory masking
Auditory masking occurs when the perception of one sound is affected by the presence of another sound.- Simultaneous masking :Simultaneous masking is when a sound is made inaudible by a "masker", a noise or unwanted sound of the same duration as the original sound.-Critical bandwidth:If two sounds...

.

Research conducted at the University of California, Riverside
University of California, Riverside
The University of California, Riverside, commonly known as UCR or UC Riverside, is a public research university and one of the ten general campuses of the University of California system. UCR is consistently ranked as one of the most ethnically and economically diverse universities in the United...

 in 2008 found that hybrid cars are so quiet when operating in electric mode (EV mode) that they may pose a risk to the blind, small children, the elderly, runners, cyclists, and other pedestrians, as they may have only one or two seconds, depending on the context, to audibly detect the location of approaching hybrid cars when the vehicles operate at very slow speeds. This research project was funded by the National Federation of the Blind.

The experiment consisted of making audio recordings of a Toyota Prius
Toyota Prius
The Toyota Prius is a full hybrid electric mid-size hatchback, formerly a compact sedan developed and manufactured by the Toyota Motor Corporation...

 and combustion engine
Internal combustion engine
The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...

 Honda Accord
Honda Accord
The Honda Accord is a series of compact, mid-size and full-size automobiles manufactured by Honda since 1976, and sold in a majority of automotive markets throughout the world....

 approaching from two directions at 5 miles per hour (8 km/h) to assure that the hybrid car operated only with its electric motor. Then test subjects in a laboratory listened to the recordings and indicated when they could hear from which direction the cars approached. Subjects could locate the hum of the internal combustion engine
Internal combustion engine
The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...

 car at 36 feet (11 m) away, but could not identify the hybrid running in electric mode until it came within 11 feet (3.4 m), leaving just less than two seconds to react before the vehicle reached their position. In a second trial, the background sounds of two quietly idling combustion engine cars were added to the recordings to simulate the noise of a parking lot. Under this condition, the hybrid needed to be 74 percent closer than the conventional car before the subjects could hear from which direction the cars approached. Subjects could correctly judge the approach of the combustion car when it was about 28 feet (8.5 m) feet away. This result means that under closer to normal environmental noise, a pedestrian would not be able to correctly determine the hybrid's approach until it was one second away.

A separate 2008 study from Western Michigan University
Western Michigan University
Western Michigan University is a public university located in Kalamazoo, Michigan, United States. The university was established in 1903 by Dwight B. Waldo, and as of the Fall 2010 semester, its enrollment is 25,045....

 found that hybrids and conventional vehicles are equally safe when travelling more than about 20 miles per hour (32.2 km/h), because tire and wind noise generate most of the audible cues at those speeds. Hybrid cars were also tested safe when leaving a stoplight and it was found that under this condition they do not pose a risk to pedestrians. All Prius
Toyota Prius
The Toyota Prius is a full hybrid electric mid-size hatchback, formerly a compact sedan developed and manufactured by the Toyota Motor Corporation...

 models used in the study engaged their internal combustion engines when accelerating from a standstill and produced enough noise to be detected.

A 2009 study conducted by the U.S. National Highway Traffic Safety Administration
National Highway Traffic Safety Administration
The National Highway Traffic Safety Administration is an agency of the Executive Branch of the U.S. government, part of the Department of Transportation...

 found that crashes involving pedestrians and bicyclists have higher incidence rates for hybrid electric vehicle
Hybrid electric vehicle
A hybrid electric vehicle is a type of hybrid vehicle and electric vehicle which combines a conventional internal combustion engine propulsion system with an electric propulsion system. The presence of the electric powertrain is intended to achieve either better fuel economy than a conventional...

s than internal combustion engine
Internal combustion engine
The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...

 (ICE) vehicles in certain vehicle maneuvers. These accidents commonly occurred in zones with low speed limits, during daytime and in clear weather. The study found that a HEV was two times more likely to be involved in a pedestrian crash than was a conventional ICE vehicle when a vehicle is slowing or stopping, backing up, or entering or leaving a parking space. Vehicle maneuvers were grouped in one category considering those maneuvers that might have occurred at very low speeds where the difference between the sound levels produced by the hybrid versus ICE
Internal combustion engine
The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...

 vehicle is the greatest. Also the study found that the incidence rate of pedestrian crashes in scenarios when vehicles make a turn was significantly higher for HEVs when compared to ICE vehicles. Similarly, The NHTSA study also concluded that the incidence rate of bicyclist crashes involving HEVs for the same kind of maneuvers was significantly higher when compared to conventional vehicles.

In September 2010, Volvo Cars
Volvo Cars
Volvo Car Corporation, or Volvo Personvagnar AB, is a Swedish automobile manufacturer founded in 1927, in Gothenburg, Sweden. It is owned by Zhejiang Geely Holding Group. Volvo was originally formed as a subsidiary company to the ball bearing maker SKF. When Volvo AB was introduced on the Swedish...

 and Vattenfall
Vattenfall
Vattenfall is a Swedish power company. The name Vattenfall is Swedish for waterfall, and is an abbreviation of its original name, Royal Waterfall Board...

, a Swedish energy company, issued a report regarding the results of the first phase of the Volvo V70 Plug-in Hybrid demonstration program. Among other findings, before the trial drivers participating in the field testing were concerned about being a danger to pedestrians and cyclists due to the quietness of the electric-drive vehicle. After the test several of them change their opinion and said that this issue was less of a problem than expected. Nevertheless, some test drivers said they experienced incidents of not being noticed while others said they had taken extra care in their driving with regard to this issue.

Regulations

Since 2009 the Japanese government, the U.S. Congress and the European Commission
European Commission
The European Commission is the executive body of the European Union. The body is responsible for proposing legislation, implementing decisions, upholding the Union's treaties and the general day-to-day running of the Union....

 are exploring legislation to establish a minimum level of sound for plug-in electric
Plug-in electric vehicle
A plug-in electric vehicle is any motor vehicle that can be recharged from any external source of electricity, such as wall sockets, and the electricity stored in the rechargeable battery packs drives or contributes to drive the wheels...

 and hybrid electric vehicles when operating in electric mode, so that blind people and other pedestrians and cyclists can hear them coming and detect from which direction they are approaching. Tests have shown that vehicles operating in electric mode can be particularly hard to hear below32 km/h (19.9 mph).

Japan

Beginning in July 2009 the Japanese government began assessing possible countermeasures through the Committee for the Consideration of Countermeasures Regarding Quiet Hybrid and Other Vehicles, and in January 2010 the Ministry of Land, Infrastructure, Transport and Tourism issued guidelines for hybrid and other near-silent vehicles.

United States

The Pedestrian Safety Enhancement Act of 2010 was approved by the U.S. Senate by unanimous consent on December 9, 2010 and passed by the House of Representatives by 379 to 30 on December 16, 2010. The act does not stipulate a specific speed for the simulated noise but requires the U.S. Department of Transportation to study and establish a motor vehicle safety standard that would set requirements for an alert sound that allows blind and other pedestrians to reasonably detect a nearby electric
Electric car
An electric car is an automobile which is propelled by electric motor, using electrical energy stored in batteries or another energy storage device. Electric cars were popular in the late-19th century and early 20th century, until advances in internal combustion engine technology and mass...

 or hybrid vehicle
Hybrid electric vehicle
A hybrid electric vehicle is a type of hybrid vehicle and electric vehicle which combines a conventional internal combustion engine propulsion system with an electric propulsion system. The presence of the electric powertrain is intended to achieve either better fuel economy than a conventional...

, and the ruling must be finalized within eighteen months. The bill was signed into law by President Barack Obama
Barack Obama
Barack Hussein Obama II is the 44th and current President of the United States. He is the first African American to hold the office. Obama previously served as a United States Senator from Illinois, from January 2005 until he resigned following his victory in the 2008 presidential election.Born in...

 on January 4, 2011.

Enhanced Vehicle Acoustics

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
After-market (general)
After-market refers to any market where the customers who purchase one product or service are likely to purchase a related, follow-on product....

 technology called "Vehicular Operations Sound Emitting Systems" (VOSES). The device makes hybrid electric vehicle
Hybrid electric vehicle
A hybrid electric vehicle is a type of hybrid vehicle and electric vehicle which combines a conventional internal combustion engine propulsion system with an electric propulsion system. The presence of the electric powertrain is intended to achieve either better fuel economy than a conventional...

s sound more like conventional internal combustion engine
Internal combustion engine
The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the 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 (32.2 km/h) to 25 miles per hour (40.2 km/h) the sound system shuts off. The system also shuts off when the hybrid combustion engine kicks in.

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
Noise pollution
Noise pollution is excessive, displeasing human, animal or machine-created environmental noise that disrupts the activity or balance of human or animal life...

 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 carlike, 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
Toyota Prius
The Toyota Prius is a full hybrid electric mid-size hatchback, formerly a compact sedan developed and manufactured by the Toyota Motor Corporation...

.

ECTunes

ECTunes is developing a system that utilizes directional sound equipment to emit noise when and where it is needed. According to the company, its technology sends audible signals only in the direction of travel, thus allowing the vehicle to be heard by those who may be in the car's path, without disturbing others with unwelcome noise. Energi Horsens, a Danish firm, has provided a significant investment to help ECTunes fully develop its technology.

The ECTunes system, and most others so far disclosed, use a control box, with software, digital amplifiers and weather-friendly external speakers. ECTunes' system connects to the car, and reads speed and acceleration, shutting down when the car reaches approximately 20 miles per hour (8.9 m/s), at which point the tires and wind are making noise of their own. The company is testing its sounds in a Citroën C1
Citroën C1
The Citroën C1 is a city car produced by the French manufacturer Citroën since 2005.The C1 was developed as part of the B-Zero project by PSA Peugeot Citroën in a joint-venture with Toyota. The Peugeot 107 is identical to the C1 other than the front bumper and front and rear lights, while the...

 electric car
Electric car
An electric car is an automobile which is propelled by electric motor, using electrical energy stored in batteries or another energy storage device. Electric cars were popular in the late-19th century and early 20th century, until advances in internal combustion engine technology and mass...

 and a Mega Van, at the University of Warwick
University of Warwick
The University of Warwick is a public research university located in Coventry, United Kingdom...

 in the U.K.

Fisker Automotive

Fisker Automotive
Fisker Automotive
Fisker Automotive is an American automaker based in Anaheim, California. The company's first product, the Fisker Karma is among the world's first true electric vehicles with extended range...

 is in the last stages of developing a sound-generator to be incorporated in its Fisker Karma
Fisker Karma
The Fisker Karma is a plug-in hybrid luxury sports sedan produced by Fisker Automotive and manufactured at Valmet Automotive in Finland. The United States Environmental Protection Agency rated the Karma's combined city/highway fuel economy at equivalent in all-electric mode, and at in...

 luxury plug-in hybrid electric vehicle
Plug-in hybrid electric vehicle
A plug-in hybrid electric vehicle , plug-in hybrid vehicle , or plug-in hybrid is a hybrid vehicle which utilizes rechargeable batteries, or another energy storage device, that can be restored to full charge by connecting a plug to an external electric power source...

, scheduled to begin sales in February 2011. According to the carmaker, the sound is designed to both alert pedestrians and enhance the driver experience, and the warning noise will be emitted automatically. The Fisker Karma will emit a sound through a pair of external speakers embedded in the bumper. According to a company spokeman the sound is a mix between a "Formula One car and a starship".

The developing process took between nine months to a year, and three sound companies sent in synthesized WAV
WAV
Waveform Audio File Format , is a Microsoft and IBM audio file format standard for storing an audio bitstream on PCs...

 file samples that were evaluated by Fisker employees and executives. The prospective sounds were studied in an audio chamber to allow engineers to evaluate the sounds without other noise interfering. After testing the candidate sounds in different locations relative to the vehicle, Fisker will fine-tune the final sound with its own equipment.

Ford

The 2012 Ford Focus Electric
Ford Focus Electric
The Ford Focus Electric is a 5-door hatchback electric car being produced by Ford Motor Company. The Focus electric will be Ford's first full production, all-electric passenger vehicle. The initial U.S. market roll-out is scheduled to be limited to 19 regional markets, beginning with California and...

 will include warning sounds for pedestrians. Ford Motor Company
Ford Motor Company
Ford Motor Company is an American multinational automaker based in Dearborn, Michigan, a suburb of Detroit. The automaker was founded by Henry Ford and incorporated on June 16, 1903. In addition to the Ford and Lincoln brands, Ford also owns a small stake in Mazda in Japan and Aston Martin in the UK...

 developed four alternative sounds, and in June 2011 involved the electric car fans by asking them to pick their favorite from the four potential warning sounds through the Focus Electric Facebook
Facebook
Facebook is a social networking service and website launched in February 2004, operated and privately owned by Facebook, Inc. , Facebook has more than 800 million active users. Users must register before using the site, after which they may create a personal profile, add other users as...

 page.

General Motors

General Motors
General Motors
General Motors Company , commonly known as GM, formerly incorporated as General Motors Corporation, is an American multinational automotive corporation headquartered in Detroit, Michigan and the world's second-largest automaker in 2010...

' first commercially available plug-in hybrid electric vehicle
Plug-in hybrid electric vehicle
A plug-in hybrid electric vehicle , plug-in hybrid vehicle , or plug-in hybrid is a hybrid vehicle which utilizes rechargeable batteries, or another energy storage device, that can be restored to full charge by connecting a plug to an external electric power source...

, the Chevrolet Volt
Chevrolet Volt
The Chevrolet Volt is a plug-in hybrid electric vehicle manufactured by General Motors. The Volt has been on sale in the U.S. market since mid-December 2010, and is the most fuel-efficient compact car sold in the United States, as rated by the United States Environmental Protection Agency...

, introduced in December 2010, includes warning sounds for pedestrians. GM's system is called Pedestrian-Friendly Alert System and it is manually activated by the driver, but future generations probably will include an active system.
The automaker conducted a test with a group of the visually challenged at Milford Proving Grounds in order to evaluate the audible warning systems on the Volt when a pedestrian is in the car's proximity. The system uses the car's horn to emit a series of warning chirps, like a low tone of a horn, enough to provide an alert but not to startle. According to GM engineers, the biggest challenge is "developing an active system that can distinguish a pedestrian from another vehicle"; otherwise, the sound will go off frequently, producing noise pollution
Noise pollution
Noise pollution is excessive, displeasing human, animal or machine-created environmental noise that disrupts the activity or balance of human or animal life...

 instead.

Hyundai

Hyundai
Hyundai
Hyundai ) is a global conglomerate company, part of the Korean chaebol, that was founded in South Korea by one of the most famous businessmen in Korean history: Chung Ju-yung...

 developed a warning noise for called the Virtual Engine Sound System (VESS). The system, which was introduced in September 2010 on its test fleet of BlueOn
Hyundai BlueOn
The Hyundai BlueOn is a subcompact 5-door hatchback electric car to be produced by Hyundai Motor Company. According to the manufacturer, the Blue-on all-electric range is and has a top speed of over...

 electric hatchbacks, provides synthetic audio feedback mimicking the sound of an idling internal combustion engine
Internal combustion engine
The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...

.

The 2011 Hyundai Sonata Hybrid is the first mass production
Mass production
Mass production is the production of large amounts of standardized products, including and especially on assembly lines...

 car manufactured by Hyundai to include the warning sound system. In 2010 the carmaker decided to have a button on the Sonata Hybrid's instrument panel to turn the VESS on and off, but after the enactment of the Pedestrian Safety Enhancement Act of 2010, signed into law by President Obama in early 2011, and learning that the U.S. National Highway Traffic Safety Administration
National Highway Traffic Safety Administration
The National Highway Traffic Safety Administration is an agency of the Executive Branch of the U.S. government, part of the Department of Transportation...

 would not allow such switches to avoid the noise device to be turned off, Hyundai decided not to install the button, and the first Sonata Hybrids destined for the U.S. market had to be altered to remove the switch.

Lotus Engineering

Lotus Engineering, a consultancy group of British sports carmaker Lotus Cars
Lotus Cars
Lotus Cars is a British manufacturer of sports and racing cars based at the former site of RAF Hethel, a World War II airfield in Norfolk. The company designs and builds race and production automobiles of light weight and fine handling characteristics...

, partnered in 2009 with Harman Becker, a producer of audio systems, to develop and commercialize a synthetic automotive audio systems. Lotus has worked on a number of hybrid
Hybrid vehicle
A hybrid vehicle is a vehicle that uses two or more distinct power sources to move the vehicle. The term most commonly refers to hybrid electric vehicles , which combine an internal combustion engine and one or more electric motors.-Power:...

 and electric vehicles and its engineers thought they would be safer if these vehicles made a noise while moving around the factory. Originally developed to cancel out intrusive noises
Active noise control
Active noise control is a method for reducing unwanted sound.- Explanation :...

 inside a car, the noise canceling system was adapted so that it could also simulate engine sounds that change with speed and use of the throttle, providing audible "feedback" to drivers of vehicles with a silent engine. At the same time, and through the addition of external speakers, the sound system allows pedestrians to hear the noise too, but optionally there can be a different sound within the car from the one that is emitted for the outside. Lotus used a Toyota Prius
Toyota Prius
The Toyota Prius is a full hybrid electric mid-size hatchback, formerly a compact sedan developed and manufactured by the Toyota Motor Corporation...

 to demonstrate the device but did not reveal if it intended to bring this technology to market.

Lotus' synthetic sound system was incorporated in the Lotus Evora
Lotus Evora
The Lotus Evora is a sports car produced by British car manufacturer Lotus. The car, which was developed under the project name Project Eagle, was launched as the Evora on 22 July 2008 at the British International Motor Show.- Development :...

 414E Hybrid, a concept
Concept car
A concept vehicle or show vehicle is a car made to showcase new styling and or new technology. They are often shown at motor shows to gauge customer reaction to new and radical designs which may or may not have a chance of being produced....

 plug-in hybrid unveiled at the 2010 Geneva Motor Show. The system, called HALOsonic Internal and External Electronic Sound Synthesis, is a suite of noise solutions that uses patented technologies from Lotus and Harman International
Harman International Industries
Harman International Industries is an American-based international audio and infotainment equipment company. The company designs, manufactures and markets audio and infotainment products for the car, the home, theatres and venues, as well as electronics for audio professionals...

. The audio system generates engine sounds inside the vehicle through the audio system. The system also generates the external sound through speakers mounted at the front and rear to provide a warning to increase pedestrian safety. The system comes with four driver-selectable engine sounds, two of which have been designed to have characteristics of a multi-cylinder conventional V6 and V12 engine.

Nissan

Vehicle Sound for Pedestrians or VSP is a Nissan-developed warning sound system in electric vehicles
Battery electric vehicle
A battery electric vehicle, or BEV, is a type of electric vehicle that uses chemical energy stored in rechargeable battery packs. BEVs use electric motors and motor controllers instead of, or in addition to, internal combustion engines for propulsion.A battery-only electric vehicle or...

. The Nissan Leaf
Nissan Leaf
Nissan introduced its first battery electric vehicle, the Nissan Altra at the Los Angeles International Auto Show on 29 December 1997. The Altra EV was produced between 1998 and 2002, only about 200 vehicles were ever produced, and it was mainly used as a fleet vehicle for companies such as...

 was the first car manufactured by Nissan to include VSP, and the electric car
Electric car
An electric car is an automobile which is propelled by electric motor, using electrical energy stored in batteries or another energy storage device. Electric cars were popular in the late-19th century and early 20th century, until advances in internal combustion engine technology and mass...

 includes one sound for forward motion and another for reverse. VSP will also be used in the upcoming Nissan Fuga hybrid, due in 2011. The system developed makes a noise easy to hear for those outside 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 behavioral 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
Vanderbilt University Medical Center
The Vanderbilt University Medical Center is a collection of several hospitals and clinics, as well as the schools of medicine and nursing associated with Vanderbilt University in Nashville, Tennessee.It comprises the following units:...

 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
Hertz
The hertz is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon. One of its most common uses is the description of the sine wave, particularly those used in radio and audio applications....

, 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 kilometres per hour (19 mph) and engages again as the car slows to under 25 kilometres per hour (16 mph). The driver can turn off sounds temporarily through a switch inside the vehicle, but the system automatically resets 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.

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.

RocketAudio Traffic

RocketAudio Traffic is developing a sound system based on modern synthesizer technology. It can simulate any petrol based motorsound that is prerecorded and designed with its tools. The software is platform independent and is currently running on lightweight ARM based systems (dimension 70mmx70mmx15mm, power consumption 2 watts max) and PC for evaluation purposes. Its authentical motorsound, its flexibility in integration (CANBus / Sensors via ADC) and simple generation of new sound events are its main advantages. Currently its tested on electric carts and scooters. Videos with sound examples are availlable on their website.
Since the system is fully programmable it can switch sounds, do starting and stopping sounds, fade out when reaching a certain speed, produce a softer motorsound for interiors and produce more sounds for special events like driver notification on closing the door for example. The goal of this flexibility is to asure compatibility with customer needs and future changes in legislation. RocketAudio Traffic GmbH is a german company which formed in 2011.

Toyota

Toyota Motor Company teamed up with Fujitsu Ten
Fujitsu Ten
is a Japanese company developing and manufacturing car audio, video, navigation and control systems. The headquarters is located in Kobe, Hyōgo Prefecture, Japan...

 to develop an automatic warning system for hybrids and electric vehicles to alert pedestrians when the car is propelled by its electric motor. The companies also studied the development of a system that would change the alarm's tune and volume with the assistance of an obstacle-detection radar.

On August 2010 Toyota began sales of an onboard device designed to automatically emit a synthesized sound of an electric motor when the Prius
Toyota Prius
The Toyota Prius is a full hybrid electric mid-size hatchback, formerly a compact sedan developed and manufactured by the Toyota Motor Corporation...

 is operating as an electric vehicle at speeds up to approximately 25 kilometres per hour (15.5 mph). The device will be available in Japan through authorized Toyota dealers and Toyota genuine parts & accessories distributors for retrofitting on the third-generation Prius at a price of (~) including the consumption tax. The alert sound rises and falls in pitch according to the vehicle's speed, thus helping indicate the vehicle's proximity and movement to nearby pedestrians. Toyota is planning to use other versions of the device for use in gasoline-electric hybrids
Hybrid electric vehicle
A hybrid electric vehicle is a type of hybrid vehicle and electric vehicle which combines a conventional internal combustion engine propulsion system with an electric propulsion system. The presence of the electric powertrain is intended to achieve either better fuel economy than a conventional...

, plug-in hybrids, electric vehicle
Electric vehicle
An electric vehicle , also referred to as an electric drive vehicle, uses one or more electric motors or traction motors for propulsion...

s as well as fuel-cell hybrid vehicles planned for mass production
Mass production
Mass production is the production of large amounts of standardized products, including and especially on assembly lines...

. The device meets the 2010 government regulations issued for hybrid and other near-silent vehicles.

Toyota's Vehicle Proximity Notification System (VPNS) will be introduced in the United States in all 2012 model year
Model year
The model year of a product is a number used worldwide, but with a high level of prominence in North America, to describe approximately when a product was produced, and indicates the coinciding base specification of that product....

 Prii family vehicles, including the Prius v, Prius Plug-in Hybrid and the standard Prius. The system is being introduced to comply with the Pedestrian Safety Enhancement Act of 2010.

Other carmakers

Tesla Motors
Tesla Motors
Tesla Motors, Inc. is a Silicon Valley-based company that designs, manufactures and sells electric cars and electric vehicle powertrain components. It was the only automaker building and selling a zero-emission sports car, the Tesla Roadster, in serial production...

 and Think Global, both manufactures of electric car
Electric car
An electric car is an automobile which is propelled by electric motor, using electrical energy stored in batteries or another energy storage device. Electric cars were popular in the late-19th century and early 20th century, until advances in internal combustion engine technology and mass...

s already in the market, are assessing this safety issue. Ford Motor Company
Ford Motor Company
Ford Motor Company is an American multinational automaker based in Dearborn, Michigan, a suburb of Detroit. The automaker was founded by Henry Ford and incorporated on June 16, 1903. In addition to the Ford and Lincoln brands, Ford also owns a small stake in Mazda in Japan and Aston Martin in the UK...

 is developing a system for emitting external sounds to future hybrids and electrics, including its Focus BEV
Ford Focus BEV
The third generation of Ford Focus debuted at the 2010 North American International Auto Show as the 2011 year model. The car shown was a 5-door hatchback, also debuting a new 2.0L direct injection I4 engine...

, scheduled for 2011, and a next-generation hybrid and plug-in hybrid vehicle planned for 2012. Nancy Gioia, Ford's Director for Global Electrification commented that "car companies should consider standardizing tones from future hybrids and electrics to avoid a cacophony of confusion on the streets."

Criticism and controversy

After Nissan's new sounds were publicized, the U.S. National Federation of the Blind issued a statement saying that "while it was pleased that the alert existed, it was unhappy that the driver was able to turn it off." The NFB approves the Nissan Leaf's forward motion sound, but it said the forward noise should also be used for reversing because the "intermittent sound is not as effective as a continuous sound" and that the car should emit warning sounds when it is idling, not only when it's moving slowly. Nevertheless, their main complaint is that they don’t think the driver should be able to switch the sound off.

Several anti-noise and electric car
Electric car
An electric car is an automobile which is propelled by electric motor, using electrical energy stored in batteries or another energy storage device. Electric cars were popular in the late-19th century and early 20th century, until advances in internal combustion engine technology and mass...

 advocates have opposed the introduction of artificial sounds as warning for pedestrians, as they argue that the proposed system will only increase the noise in the environment. They also opposed U.S. pending legislation that would require generated warning sounds with no off switch for the driver.

Robert S. Wall Emerson of Western Michigan University
Western Michigan University
Western Michigan University is a public university located in Kalamazoo, Michigan, United States. The university was established in 1903 by Dwight B. Waldo, and as of the Fall 2010 semester, its enrollment is 25,045....

 has argued that several high-end gasoline-powered luxury cars are already quieter than hybrids, and according to his most recent studies, hybrid
Hybrid electric vehicle
A hybrid electric vehicle is a type of hybrid vehicle and electric vehicle which combines a conventional internal combustion engine propulsion system with an electric propulsion system. The presence of the electric powertrain is intended to achieve either better fuel economy than a conventional...

 SUVs were noisier than many internal-combustion vehicles. He concludes that pedestrian safety is not a hybrid issue but rather "a quiet car issue."

Market availability

Summary of electric-drive cars
Electric vehicle
An electric vehicle , also referred to as an electric drive vehicle, uses one or more electric motors or traction motors for propulsion...


launched/scheduled with electronic warning sound system incorporated
Vehicle Powertrain
Powertrain
In a motor vehicle, the term powertrain or powerplant refers to the group of components that generate power and deliver it to the road surface, water, or air. This includes the engine, transmission, drive shafts, differentials, and the final drive...


type
Sound
activation
Type of sound Launch date Markets
2011 Chevrolet Volt
Chevrolet Volt
The Chevrolet Volt is a plug-in hybrid electric vehicle manufactured by General Motors. The Volt has been on sale in the U.S. market since mid-December 2010, and is the most fuel-efficient compact car sold in the United States, as rated by the United States Environmental Protection Agency...

 
Plug-in hybrid Manual Intermittent chirps November 2010 U.S.
2011 Nissan Leaf
Nissan Leaf
Nissan introduced its first battery electric vehicle, the Nissan Altra at the Los Angeles International Auto Show on 29 December 1997. The Altra EV was produced between 1998 and 2002, only about 200 vehicles were ever produced, and it was mainly used as a fleet vehicle for companies such as...

 
All-electric
Battery electric vehicle
A battery electric vehicle, or BEV, is a type of electric vehicle that uses chemical energy stored in rechargeable battery packs. BEVs use electric motors and motor controllers instead of, or in addition to, internal combustion engines for propulsion.A battery-only electric vehicle or...

Automatic with
manual turn off
Forward: continuous
Reverse: intermittent
December 2010 Japan and the U.S.
2011 Nissan Fuga Hybrid
Infiniti M35
Hybrid electric
Hybrid electric vehicle
A hybrid electric vehicle is a type of hybrid vehicle and electric vehicle which combines a conventional internal combustion engine propulsion system with an electric propulsion system. The presence of the electric powertrain is intended to achieve either better fuel economy than a conventional...

 
Automatic with
manual turn off
Forward: continuous
Reverse: intermittent
Late 2010/2011 Japan (2010) and U.S. (2011 as 2012 Infiniti M Hybrid)
2011 Fisker Karma
Fisker Karma
The Fisker Karma is a plug-in hybrid luxury sports sedan produced by Fisker Automotive and manufactured at Valmet Automotive in Finland. The United States Environmental Protection Agency rated the Karma's combined city/highway fuel economy at equivalent in all-electric mode, and at in...

 
Plug-in hybrid Automatic Continuous July 2011 U.S. and Europe
2011 Hyundai Sonata Hybrid  |Hybrid electric Automatic n.a. March 2011 U.S.
2012 Toyota Prius v
Toyota Prius v
The Toyota Prius v, also named Prius α in Japan, and Prius + in Europe, is a full hybrid gasoline-electric compact MPV/station wagon produced by Toyota Motor Corporation introduced in Japan in May 2011 and in the U.S. in October 2011. It is scheduled to be released in the European market by mid 2012...

 
Hybrid electric Automatic Continuous October 2011 U.S.
2012 Toyota Prius Plug-in Hybrid
Toyota Prius Plug-in Hybrid
The Toyota Prius Plug-in Hybrid is a mid-size plug-in hybrid electric vehicle to be produced by Toyota Motor Corporation and scheduled to be released to the market beginning in January 2012...

 
Plug-in hybrid Automatic Continuous 2Q 2012 U.S.
2012 Toyota Prius  Hybrid electric Automatic Continuous 2012 U.S.

See also

  • Advanced driver assistance systems
    Advanced Driver Assistance Systems
    Advanced Driver Assistance Systems, or ADAS, are systems to help the driver in its driving process. When designed with a safe Human-Machine Interface it should increase car safety and more generally road safety.Examples of such a system are:...

  • Road traffic safety
  • Traffic psychology
    Traffic psychology
    Traffic psychology is a young, expanding and wide field in psychology. Whereas traffic psychology is primarily related to the study of the behavior of road users and the psychological processes underlying that behavior as well as to the relationship between behavior and accidents, transportation...


External links



Videos with demos of warning sounds
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