Electric cars will continue to creep up silently on unsuspecting pedestrians after a study found they were scarcely more dangerous than their gas-guzzling counterparts.
The Government will this week reject calls for artificial warning noises to be broadcast by the zero-emission vehicles, despite concerns raised by campaigners for blind and partially sighted people.
A growing number of drivers facing rising fuel prices are opting for electric cars or hybrid models, which switch from petrol to electric and back. But they make almost no noise at all, making it hard for passers-by, particularly those with visual impairments, to notice them.
Safety experts and charities called for silent vehicles to emit noises, with some manufacturers suggesting motorists could choose from a range of sounds, from super-cars to the podracers from Star Wars. The Guide Dogs for the Blind Association has warned electric vehicles, and hybrid vehicles that operate on electric power at low speed, are "virtually silent". As a result there are "serious implications for the independent mobility and safety of blind and partially sighted people".
However, a study commissioned by the Department for Transport will warn that "careful consideration" needs to be given to the "challenging" idea of adding artificial sounds, because it risks having little impact against general background noise.
Norman Baker, the Lib Dem transport minister, said ahead of the report's publication that the Government remains "committed to the introduction of electric vehicles in a way that will complement long-standing efforts to protect vulnerable road users".
He added: "Concerns about quiet vehicles are understandable, and we need to make sure that electric vehicles do not pose any additional threat to pedestrians. All drivers have a responsibility to drive safely and with consideration for other road users."
A series of experiments on test tracks measured the noise produced by four electric and four internal combustion engine cars travelling at different speeds and performing manoeuvres including parking and pulling away.
The research, due to be published tomorrow, will show that at low speeds of 7-8 kmh (5mph) electric cars were just one decibel quieter than petrol cars. When speeds were increased to more than 20 kmh (12mph), the noise levels were "similar", with tyre noise dominating. "There does not appear to be any significant difference in the acoustic nature of [internal combustion engine] vehicles and [electric and hybrid] vehicles, and as such nothing suggests a pedestrian would clearly be able to differentiate between vehicle types," the report says.
In a separate test, 10 visually impaired people listened to audio recordings taken from the test track, as if they were waiting on a kerbside, to determine at what point they could hear the vehicle. It found that in a semi-rural environment, the risk posed by electric cars was 1.4 times greater than standard vehicles, and 1.3 times greater in urban conditions. Electric cars were "far more difficult to detect" when pulling away.
The study found that while electric cars may pose a "potential risk" to visually impaired pedestrians, especially in city centres, "the scale of the problem is currently very small". The issue is also complicated by the development of increasingly quiet petrol and diesel engines, in response to demand for a quieter driving experience.
Last month the coalition faced fierce criticism for pulling the plug on plans for a national network of "charging points", promised in the Conservative manifesto. Ministers said there was a lack of demand, because most electric car owners would charge them overnight at home.