Silent EVs need noises

Researchers in England considering noises to alert pedestrians and cyclists to the presence of oncoming electric cars say legislation to force silent electric vehicles EVs to make a warning noise is inevitable.

"It's definitely coming," Warwick University Professor Paul Jennings told Reuters. "It's being prompted by the fact that there are now real statistics."

Figures compiled by the U.S. National Highway Traffic Safety Administration show pedestrians and cyclists are twice as likely to be hit by a hybrid electric vehicle running silently at low speed than by a car with a normal engine.

The research team at Warwick University's Manufacturing Group WMG who have spent years helping the car industry make vehicles quieter now find their work in reverse gear.

"We want... to investigate sounds that are going to be safe, have minimal effect on the environment and are going to give some creativity to the manufacturers," Jennings said.

The team wants to know what kind of warning noise is the most effective and have adapted an electric delivery truck on campus to make different noises on different days. They then canvass opinion from students.

"If you ask the general public what an electric vehicle should sound like you are more likely to get an answer that relates back to science fiction movies — we've had all sorts of suggestions from the Jetsons to Star Wars, Star Trek," research team member Seb Giudice said.

Jennings said the sound of a normal vehicle tells us if it is idling, accelerating or braking and that the sound of an EV must convey as much information.

"It's possible that you create a sound that is above a certain level, people may even like that sound, but if you don't recognize it as an oncoming vehicle it is defeating the object."

So classical music or birdsong may be out as possibilities.

"The most pleasant sound might not be the best, most significant as a warning," Jennings said.

Car manufacturers are investing huge sums developing the next generation of electric vehicles and are keen to protect their brands and differentiate themselves from the competition.

Jennings said that years of working with carmakers on interior sounds have shown researchers that manufacturers are very interested in sound.

"It tells you such a lot about the brand and quality of the car. It almost gives it some personality," he said.

Researchers also said the level of refinement of modern cars, electric or not, is such that future legislation may not differentiate between EVs and internal combustion engines.

"Most vehicles are just getting too quiet for most people to hear," Giudice said. "So we may get to a stage where these sound emitting systems have to be fitted to every new vehicle."