Cars make noise. Or at least conventional cars, with internal combustion engines, do. But electric vehicles don’t. And that’s not unfortunate not only for those of us who cherish the sound of a performance car, but for pedestrians and other road users who rely on sound to tell when a vehicle’s approaching. And it’s especially dangerous for the visually impaired.

That’s why Jaguar worked with Guide Dogs for the Blind to develop an Audible Vehicle Alert System for its all-electric I-Pace crossover. The system emits specially designed sounds from behind the grille at low speeds to give an audible cue that a vehicle is in motion nearby.

And it’s not just a flat sound, either, or a consistent chirp. Jaguar’s AVAS caters its pitch and volume along with the vehicle’s speed, and adds an additional tone when it’s turning. It can’t be disengaged, but only works at speeds below 12.5 mph (20 km/h), above which the wind and tire noise are deemed sufficient to warn of the vehicle’s approach.

“The absence of traditional engine noise from electric vehicles creates a problem for vulnerable pedestrians, such as the blind or visually impaired,” explained Jaguar NVH engineer Iain Suffield. “We developed the Audible Vehicle Alert System for the I-PACE to ensure the safety of all road users. Our potentially life-saving technology cannot be switched off and as the leading charity for people with sight loss, we are pleased to have the support of Guide Dogs to ensure real people are at the heart of our product testing.”

The technology was developed in conjunction with the charitable organization for the blind over the course of four years, and already exceeds European regulations, mandating a noise of at least 56 dB(A), set to come into effect in July 2019.

Why did it take so long to develop? The automaker initially experimented with a sound “closer to a sci-fi spacecraft”, but found that pedestrians reflexively looked upwards towards the sky. So they went back to the audio drawing board, as it were, and tested different sounds in anechoic chambers and various urban scenarios until they arrived at the right combination of noises.