Electric cars are a hazard for blind people

Electric cars are a hazard for blind people
Research scientists carrying out an experiment involving adaptive sound as an aid for blind people. Tests were performed at a quiet location in Tiller, near Trondheim. Credit: Bent Lindsetmo/NRK

Electric cars are good for the environment – but not for people who cannot see. They have problems detecting the silent vehicles. However, Norwegian research scientists are working on a solution.

In noisy surroundings it can be impossible for people who cannot see to detect an electric car, but from next year new international requirements will be in place. All must then be modified to emit a warning , making it easier for pedestrians to hear them approaching.

"An electric car must emit an artificially produced sound of varying frequency but fairly constant intensity when travelling at 20 km/h or less," says Truls Berge, an acoustics research scientist at SINTEF.

He has been carrying out research for many years on sound and noise in connection with motor vehicles and participates in several international forums working on noise and associated problems. His reaction to the introduction of requirements for sound to assist blind people is basically positive, but he feels that the specifications are inadequate and that they represent only a temporary solution.

"The new requirements do not take into account the environment in which a is operating. There is a big difference between the sound needed in a street on a peaceful evening and in a busy urban traffic environment," he says.

Making quiet-running electric vehicles emit an artificial sound as required by the new regulations may make the work of reducing traffic noise in general more difficult. In his opinion, this must be weighed against the need to ensure that blind and visually impaired people can move around safely among traffic.

How much sound is actually needed?

Berge and his colleagues recently carried out an experiment in which they tested a solution which they have developed themselves. They equipped an electric car to produce a so-called "adaptive sound" and tested this with the help of a number of blind volunteers. The research scientists also used loudspeakers producing different sound levels to simulate background noise in a busy urban street.

The concept of "adaptive sound" is that the vehicles can be fitted with microphones which sense the sound level in the surroundings, and the sound the vehicles produce is adapted to suit this ambient sound level. The aim was to find out what level of warning sound was needed under different ambient sound conditions, thereby determining how much sound it is actually necessary to use.

The experiment was carried out using a test panel whose members pressed a button when they heard the sound. In this way one can, for example, determine how close a vehicle is, to ensure safe crossing of a road at a pedestrian crossing.

It is hoped that the international automotive industry will make use of the results.

"A number of car manufacturers, including Nissan, General Motors and Renault, have shown interest in the results of this project.

Norway has the highest density of electric vehicles in the world, so it's natural that electric car manufacturers look to us with regard to traffic safety and research in this field," says Truls Berge at SINTEF.

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User comments

Oct 24, 2018
Sighted people also rely on the sounds that cars make, particularly from the tires and engine. If electric cars are silent the answer is simple--fit them with sound-making devices so that they sound more like the older variety!

Oct 24, 2018
The Rolls-Royce in sight and sound

The gold standard for car in sound is the quiescently English Rolls-Royce!
It is the tyres and that silky smooth hum of an IC engine in full working order that alert us to a car on the road sighted or blind,
So the noise essentially is the same as a Rolls-Royce, Bentley, Mercedes, Jaguar, Audi
In other words the silky smooth noise these quality cars make
That especially Blind people have become accustomed to the silky smooth and gravely tyrely noise of an oncoming car
As do cyclists on country lanes become conscious of a car in their rear without it being in their sight

So there it is
To all who are Blind, we Sighted also are Blind and use the sense of sound every day, just as you do in your world of Sound

As to all who live in their world of sound take heart in the fact the Queen in her years still owns her Rolls-Royce, as that is the sure and certain sign of what is best in this world – The mark of English Quality and Elegance

Oct 24, 2018
No one cares for the deaf.

Oct 24, 2018
From my perspective, electric cars provide us with a unique opportunity to reduce all the traffic noise, especially from loud mufflers. Now let's all provide a "noise maker" into this opportunity to completely nullify the sound decrease. I understand the plight of the blind in this situation but find it troubling that we should start introducing more noise from otherwise quiet cars. There must be a better solution. The last thing we need is all the traffic to start intentionally "whining" to be heard thus keeping transportation a noisy experience.

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