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An RACQ study conducted in Brisbane has found no discernible difference in audible detection of approaching vehicles between petrol-electric hybrids cars and conventional cars from the same manufacturer.
The study by RACQ researchers Russell Manning and John Ewing follows complaints in the US by organisations representing pedestrian and blind people that hybrids are dangerous to them because they are so quiet. Manning said the study, conducted with the help of Vision Australia, tested four vehicles with 11 volunteers, five of which were blind.
"There was no significant difference in the detection distances between hybrid and similar-sized conventional vehicles in a typical urban environment with typical urban ambient noise levels," his report reads.
"This is not to say that hybrids are not a risk, only that they are no more of a risk than equivalent conventional vehicles under these conditions." Manning said noise regulations are not a concern.
"To suggest that modern cars, be they hybrid or conventional, are too quiet could lead to the conclusion that noise regulations are too stringent," he says. "We believe lower noise levels are, on balance, good from an environmental and social aspect."
Volunteers in about 40 per cent of cases were unable to detect vehicles approaching at 60km/h from a safe distance. "Had they been in the path of the vehicle then contact would have resulted and in several cases potentially serious injury or fatality may have occurred," the report found.
Manning said tyre and wind noise were the main audible signals of approaching vehicles, either hybrid or conventional. "The lack of, or reduction in, mechanical noise from hybrid vehicles did not appear to significantly increase the risk factor," the report said.
Several manufacturers of hybrid and electric vehicles have been working to create artificial noise to overcome concerns expressed by pedestrian and blind representative groups. Nissan engineers worked with blind people to create special frequencies for their quiet Leaf electric vehicle, expected to arrive in Australia in the next year.
Toyota and its luxury branch, Lexus, which account for the bulk of hybrid cars available in Australia, are also developing a solution to the noise concerns. Lotus Engineering, a division of sports car maker Lotus, has developed a realistic engine sound for electric motors that varies with speed and the world's first all-electric supercar, the Tesla Roadster, is getting a "space sound generator" on its Brabus-tuned models.
Owners will be able to set their Tesla to make noises similar to a V8 engine, a racecar engine or two "futuristic soundscapes" named "Beam" and "Warp". However, it is expected that more sound effects will be added to electric cars until governments step in and legislate for the new technology.
The Pedestrian Council of Australia has previously called for changes to the Australian Design Rules to set a minimum noise for vehicles powered by an electric motor. Similar standards are being considered in the US.
PCA chairman and CEO Harold Scruby said the group supported a hybrid noise requirement being legislated by the Federal Government before the vehicles became too popular. "With an ageing population and the expectation of millions of these vehicles on our roads in the next five to 10 years, there will be a dramatic increase in pedestrian and cyclist road trauma unless this is done and without delay," he said.
Vision Australia has called for hybrid vehicles to be fitted with beepers to operate when the vehicles are running on electric power only. Spokesman Michael Simpson said Vision Australia advocated a beeper for all reversing vehicles, but believed hybrids should have a beeper when operating in electric-only mode.
