From July 2019, all new electric and hybrid vehicles sold in Europe must be equipped with sound devices.
Older electric cars must also be retrofitted with sound devices by 2021.
Safety activists argued that pedestrians are at risk of being hit by electric vehicles travelling in relative silence at low speeds.
Kevin Clinton of the Royal Society for the Prevention of Accidents said: “The greatest risks associated with electric vehicles are when they are travelling at low speeds, such as in urban areas with lower limits, as the noise from tyres and the road surface, and aerodynamic noise, are minimal at those speeds.”
Chris Hanson-Abbott of Brigade Electronics said: “The object is to have warnings which are audible but which are not the least bit environmentally disturbing.”
He explained that the sounds will likely be a combination of white noise and sound effects, that will cut out once the vehicle gets to about 20mph.
Experts predict there to be up to nine million electric cars on UK roads by 2030.