Engine for change

SIR – The planned switch to electric cars (report, July 6) made me think of the electric trolley buses which swept along the high street in Palmers Green, north London, in the Fifties.

The electricity supply came from cables running along the road. Each bus was connected to the cables by two rods. However, it was impossible to hear buses coming when crossing the road. Fortunately, the rods became detached from the cables quite frequently and had to be replaced by the driver using a pole. This gave pedestrians time to cross.

Electric cars will need to make enough noise to be heard. How about artificially generated engine noise? Hopefully not the sound of horses’ hooves or ducks quacking (Letters, July 1). Allan Bocci

Kempston Rural, Bedfordshire