Electric cars are a wonderful invention, reducing pollution and the demand for oil. They are also killers. The main problem is that they are so quiet. Blind people, animals and those trusting souls who walk through car parks while checking their mobile phones, all rely on the noise of an approaching car to warn them of its existence. Electric and hybrid vehicles, at low speeds, are virtually silent, or at least inaudible over normal levels of noise around them. People have been complaining about this since the 2000s, when those who follow these things noticed an increase in accidents involving…