Artificial noise and aromas are being added to a new generation of electric cars by Renault. The French manufacturer, which unveiled four new models at the Geneva Motor Show, is trying to tackle to major issues faced by motorists. One is driver stress. In co-operation with L’Oreal, the cosmetics giant, Renault intends to install a sophisticated air purifier in the Zoe - an electric version of the Clio supermini - which goes on sale next year. If a driver is stressed, then there will be the option of wafting in a soothing smell. On the other hand a sleepy driver would have the option of choosing something more stimulating. The growth of electric cars, which Renault believes will account for 10 per cent of total sales by the end of the decade, has triggered concerns about pedestrian safety. With a range of around 100 miles before the batteries need recharging, the cars are seen as an ideal vehicle for commuters. While conventional cars make a noise, electric models are silent. This means that they could catch somebody crossing the road by surprise. Renault’s scientists are developing artificial noises which would kick in when the car is travelling at less than 30 kilometers (18.6 miles) an hour. Simon Luque, one of the directors of Renault's electric vehicle programme, said the sounds would be mechanical. A number of options are under consideration including allowing drivers to download a noise of their own choosing. Last year, during a House of Lords debate, Lord McColl, a Tory peer, suggested that silent cars should be fitted with a Swiss cowbell. A Labour peer, Lord Grenfell, suggested such cars should be preceded by somebody carrying a red flag.