WHAT THE RULES SAY

The sound effect
on every street.

Electric cars are quiet. Too quiet, at walking pace.

Below about 20 km/h, electric and hybrid cars make so little noise that people who rely on hearing traffic can miss them. So the law now requires a sound effect: the Acoustic Vehicle Alerting System, or AVAS.

UNDER 20 KM/H and when reversing

Check a speed

A quiet, unbranded electric car moving slowly along a residential street as a pedestrian waits at the kerb, seen from behind — AI-generated image, not a photograph of a real person or place.

Sound on at low speed
Sound on when reversing
Back on at every restart
A designed sound for safer streets

THE SHORT ANSWER

Slow and quiet
must make a sound.

The rules apply to quiet electric and hybrid cars.
They focus on low speeds and reversing.

LOW SPEED

Up to about 20 km/h

The AVAS must automatically make a sound from start up to approximately 20 km/h, about 12 mph, where a quiet car is hardest to hear.

Check a speed

REVERSING

Backing out

It must also sound when reversing, unless the car has a reversing warning device that meets the same standard.

What drivers can do

WHY

For people who listen

The Department for Transport said the rules let people who are visually impaired hear vehicles more easily. RNIB and others campaigned for nearly a decade.

See the numbers

A QUICK SPEED CHECK

Should the car
be making a sound?

Pick what a quiet electric or hybrid car is doing to see what the rules require. The bar shows how firmly the AVAS must sound.

Speed check

Choose a situationStanding still, switched onPulling away up to 20 km/hReversingHybrid with its engine runningAbove about 20 km/h

Standing still, switched onOptional

The vehicle may emit a sound when stationary, but the rules do not require it.

Pulling away up to 20 km/hSound on

The AVAS must automatically generate a sound from start up to approximately 20 km/h, and it should vary with speed.

ReversingSound on

The AVAS must sound while reversing, unless a reversing warning device does the job to the same standard.

Hybrid with its engine runningNot needed

If the combustion engine is running in that speed range, the AVAS must not add a sound.

Above about 20 km/hNot required

The requirement covers the minimum speed range from start up to approximately 20 km/h, plus reversing.

Source: Regulation (EU) No 540/2014, Annex VIII, as substituted by Commission Delegated Regulation (EU) 2017/1576 (legislation.gov.uk).

Based on Regulation (EU) No 540/2014 Annex VIII as amended, as published for the UK on legislation.gov.uk. General information, not legal advice.

TWO NUMBERS WORTH KNOWING

A speed limit
for silence.

The speed below which the sound must play,
and the year it became universal for new cars.

20 km/h

Sound required up to about

About 12 mph. Below this speed, RNIB says, electric and hybrid vehicles emit so little noise that they earned the nickname ‘silent vehicles’.

SPEED · DfT

2021

All new quiet electric and hybrid cars

The rule applied to new types of quiet electric and hybrid cars from 1 July 2019, and to all new quiet electric and hybrid cars registered from July 2021.

DATES · DfT

RNIB noted in 2019 that the rule did not cover quiet vehicles already on the road, and argued that drivers should not be able to pause a safety sound.

FOUR THINGS TO KNOW

Designed to sound
like driving.

The rules say what the sound must do, not exactly what it must sound like. These are the main requirements for new cars.

It should sound like a car
A continuous sound, similar to a vehicle of the same category with a combustion engine.
It changes with speed
The sound should be indicative of what the car is doing, for example varying in level or character with speed.
It can be paused, then resets
A pause function is allowed, but the AVAS must default to on every time the car is restarted.
It must not be louder than an engine
The AVAS must not exceed the approximate sound level of a comparable petrol or diesel car in the same conditions.

A small electric car reversing slowly out of a driveway with its white reversing lights on — AI-generated image, not a photograph of a real person or place.

The smooth front of an unbranded electric car creeping through a car park at walking pace — AI-generated image, not a photograph of a real person or place.

SOUND AS SAFETY

Hearing is how
many people cross.

RNIB explains that the sound of a moving vehicle is critically important for people who cannot see, to judge when to step out to cross a road or move through a shared area.

The European Commission described the AVAS as a new safety device, alongside measures such as electronic stability control. Manufacturers may also let drivers choose between different sounds, within the rules.

Questions

Questions people ask

Why do electric cars make a humming sound?

Since 2019 for new types and 2021 for all new registrations, quiet electric and hybrid cars must be fitted with an Acoustic Vehicle Alerting System that makes a sound at low speed and when reversing.

At what speed does the sound stop?

The AVAS must sound from start up to approximately 20 km/h, about 12 mph. Above that, the requirement no longer applies.

Can the driver turn it off?

The rules allow a pause function, but the system must switch itself back on every time the car is restarted. RNIB has argued drivers should not be able to disable a safety sound.

Do older electric cars have to add one?

No. The rules apply to new vehicle types from 1 July 2019 and new registrations from July 2021. RNIB noted in 2019 that vehicles already on the road were not covered.

Does a hybrid make the sound too?

Only when it is running quietly. If its combustion engine is running in the low-speed range, the AVAS must not generate a sound.

The sound effect
on every street.