July 24, 2019 by Sam Holland
The shift to EVs has been a hot topic in recent years. As part of the efforts to combat the far-reaching effects of fossil fuel emissions on the global climate, the automotive industry has tilted its focus towards the research, design, and production of vehicles that run on alternative energy sources, such as hydrogen, solar panels, and powerful batteries.
Electric and electric-hybrid vehicles do, however, have their fair share of challenges. Owing to safety concerns, the European Union has mandated automakers to install sound emitters in all EVs developed or sold within the EU from July 2019. EVs produced before this time will have to be retrofitted with the sound devices to comply with the new directive.
EVsrun much quieter than petrol and diesel-driven vehicles, mainly because they don’t rely solely on combustion engines. Battery-powered EVs (BEVs) utilise power stored in a high-power density battery pack; this is to turn the vehicle’s motor, which effectively rotates the wheels. Given that there is no piston motion (as there is in a combustion engine), minimal noise is produced under the hood. A low-pitched hum from the powertrain, and contained acoustics from the infotainment system, is typical of many EVs.
At first glance, this should be an advantage: quieter EV engines reduce noise pollution that is otherwise conventional of personal and commercial vehicles in major EU cities across.The impact of EVs on public safety, however, is equally of great concern.
A 2008 article from the University of California at Riverside predicted that EVs would pose significant safety risks to blind people and other pedestrians: in fact, they may only hear them coming as little as one second before impact. Also, a 2015 study by Guide Dogs, an association for the visually-impaired, states that pedestrians are 40% more likely to be hit by an EV or hybrid-electric vehicle than petrol or diesel-powered vehicles. The Guardian also cites an incident in Japan where a man and his guide dog were killed by a reversing vehicle.
Any sound-emitting device for EVs may fall under the umbrella of an ‘Acoustic Vehicle Alert System’ (AVAS). An AVAS can be any acoustic, auto-switched EV device that produces a low or high-pitched sound: one that is instantly perceivable to the human ear (so a blind person can hear it, even from a considerable distance).
An electric vehicle (the Jaguar I-PACE) whose driver waits as a woman with her guide dog crosses a zebra crossing. Image courtesy of Flickr.
At this point, it is unclear what the sound produced by the targeted EVs will be, or whether there will be a unified sound in all vehicles. Perhaps it could be a mix of tonal sounds and unidirectional white noise—nothing like the sounds produced from conventional car engines.
The EU specifies that EVs must produce this sound when reversing or travelling less than 20 km/h (12 mph). However, when the EV is travelling at higher speeds (e.g., along a highway), it will not need to have the device turned on as it will generate enough sound to inform pedestrians of its presence.
According to RNIB (the UK organisation, the Royal National Institute of Blind People), it is essential for vehicles to emit some level of noise to ensure road safety. RNIB says that automakers must set this noise at a level that pedestrians and other road users can easily hear—and that the sound emitter should not be something that can be removed or turned off.
The new initiative has also gained approval from the political community. Nottingham City councillor, Sally Longford, for instance, said that the city council is in support of calls for EV automakers to address road safety concerns that affect pedestrians and other road users—as Nottingham plans to have 8,000 more EVs on its roads by 2020.
However, some people assert that implementing artificial sounds in EVs as a warning for pedestrians only further increases the noise pollution in cities. Notably, Robert S. Wall Emerson, a professor at the Department of Blindness and Low Vision Studies at Western Michigan University, believes that the safety of pedestrians is a “noisy car issue”, rather than a hybrid issue.
Leading automakers have begun complying with the new regulation.
Nissan has developed an AVAS that produces a high-pitched whistle when its EVs move forward, as well as a light beep when the car is in reverse mode. Mercedes AMG has even collaborated with Linkin Park (the U.S. rock group) to create artificial sounds for its upcoming sports utility vehicle (named 'EQC'). BMW is also putting forward its AVAS, 'IconicSounds Electric', which produces emotive sounds for EVs that drivers can connect to.
Safety is critical in automotive applications. Besides securing the driver and the vehicle, the safety of pedestrians and other road users should be taken into consideration with adequate provision for accident mitigation.
According to Eurostat, around 2 million vehicles registered in 2017 in Europe were EVs or electric-hybrid models. This was an unprecedented rise from the 200,000 vehicles recorded in 2013. The National Grid predicts that there will be as many as 9 million new EVs on UK roads by 2030. Given these trends, the EU appears to be justifiably concerned about the impact that these vehicles will have on public safety—as they’ll be increasingly commonplace in the near future.
