Toyota is to fit Prius models in Japan with a noise-making device to warn pedestrians of the car's presence.
The Prius is near-silent at low speeds and has attracted criticism from pedestrians who are unaware of it approaching. The ‘on-board approaching vehicle audible system’ will initially only be available in Japan, where earlier this year the government issued guidelines on hybrid noise; it will cost 12,600 yen (£100).
The sound comes from a speaker mounted under the bonnet, and will vary in pitch relative to the speed of the car to help indicate the vehicle’s proximity and movement.
Groups representing blind people have led calls for regulations on noise, requiring manufacturers to add a sound that would alert cyclists and pedestrians alike.
Last year a study by the National Highway Traffic Safety Administration in the US found that hybrids were twice as likely to be involved in a pedestrian accident as conventional cars.
When Nissan launches its electric Leaf next year, it will equip it as standard with a turbine sound akin to an aeroplane taking off. The device will only work at speeds up to 30mph; at higher speeds tyre and aerodynamic noise will be sufficiently loud.
Rules regarding the noise of electric and hybrid vehicles are also expected to be introduced in the US and Europe.