A new problem

* EVs pose silent threat * Could cause many injuries * Audio solutions sought...

A new problem

Next years electric car sales are bringing a new problem

By early next year Nissan, Citron, Peugeot and Mitsubishi will be able to offer you a viable, all-electric commuter car, and thats just the vanguard of a movement that will have just about every big player offering some form of all-electric propulsion within four years.

Also on the way is a glut of new hybrids capable of all-electric running. The absence of noise and tailpipe emissions this will bring will be a godsend for many city dwellers, but its not such good news for others.

Silent danger
Blind or partially sighted people are going to be at particularly high risk from cars they can neither see nor hear, but cyclists, children, animals and anyone who is momentarily distracted could well find themselves stepping into the path of a silent missile. There are maximum noise limits for vehicles just about everywhere in the world, but no minimum noise regulations.

How loud is loud?
10db Tyre noise below 25mph

15db Heavy breathing

30db Background noise in typical, calm room

50db Typical conversation 1m away

75db Typical motorway noise 10m away

120db Vuvuzela at 1m away

150db Jet engine 30m away

170db Gun being fired 1m away
Americas National Highway Transport Safety Administration (NHTSA) conducted a study in 2009 that claimed hybrids were twice as likely as cars with internal combustion engines (ICEs) to be involved in an accident with a pedestrian while slowing down, stopping or manoeuvring.

In 2008, Lawrence Rosenblum, a professor at the University of California-Riverside, found that people could hear ICE cars approaching at up to four times the distance they could detect a hybrid.

The good news is that legislators are beginning to do something about this. Japans Ministry of Transport is leading the way: in January this year it issued sound guidelines for quiet vehicles. The NHTSA in conjunction with American car makers and associations representing the blind is also looking into the issue. It is widely expected that the European Union will follow suit.

Turning up the volume
Engineers who have spent years dialling noise out of new cars are going to have to start putting some back. A straw poll of people involved in electric car development at the Paris motor show suggests manufacturers are fully prepared to have to inject artificial sounds into their EVs. One day there will be some legislation and we are preparing for that, said Thierry Koskas, the head of electric vehicle development at Renault.