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Why we introduced a 20mph speed limit.

First published:
8 July 2021
Last updated:

Are you reviewing the 20mph speed limit?

There is a growing consensus on safe speeds in communities that we can build from. We still believe that 20mph is right, but we want to make sure we are getting the right speeds on the right roads.

Between April and July 2024, Ken Skates MS, Cabinet Secretary for Transport is undertaking a programme of listening which will cover all parts of Wales putting communities at the heart of our thinking and listening to the voices of citizens.

He’ll be meeting citizens, bus drivers, emergency services, the police, young people, vulnerable people, businesses, county, town and community councillors and many others – to engage with them and understand their views on road safety in residential areas.

The Cabinet Secretary has already met and listened to all Welsh local authorities to prepare for change. 

We are working in partnership with highway authorities to prepare for change. Councils are already looking at local roads where changes might be needed. We are also encouraging people to get in touch with their local council to tell them where they think 20mph should be targeted.

We will continue to work in partnership by revising our guidance to make it clearer which roads should have 20mph and 30mph limits. The revised exceptions guidance is expected to be ready and published in summer 2024.

Once local authorities have worked with communities and new guidance is finalised, highway authorities will be able to start the process of adjusting speed limits on affected roads. We expect this process to begin from September 2024. 

What if I think a road is the wrong limit currently?

Not all 30mph roads changed to 20mph in September 2023.

You can see a map on DataMapWales that shows which roads have stayed at 30mph.

But as you travel, you may find a section of road that is:

  • currently 20mph, and you believe it should have a 30mph limit, or
  • currently 30mph, and you believe it should have a 20mph limit.

You can ask for a road to be reconsidered by contacting the relevant highway authority.

The highway authority will then consider community feedback and the revised exceptions criteria before deciding on the speed limit on a section of road.

How do I know if a road is 20mph?

If you are driving in a residential or built-up area, and there are streetlights, then drive at 20mph unless you see a sign telling you otherwise.

See streetlights, think 20mph.

There are gateway speed limit signs, the larger signs shown as you enter a different speed limit area, to clearly indicate the correct speed.

Repeater signs, the small circle signs often seen on streetlights, are no longer allowed on roads where the default speed limit is 20mph. However, since they display the correct speed, highway authorities will have until September 2024 to remove these signs. This is also applies to 20mph zone signs outside schools and highway authorities have until 2028 to remove 20mph signs painted onto road surfaces.

In any 20mph areas without streetlights, additional signs are in place to indicate the speed limit.

But in built up areas, see streetlights think 20mph, unless you see a sign that says otherwise.

What impact has the new speed limit had?

Early 20mph data published by Transport for Wales in February 2024, shows that speeds have reduced by an average of 4mph on the main roads that were monitored since the national rollout of the default 20mph speed limit. The monitoring took place at 43 locations within the 8 first phase settlements.

Transport for Wales (TfW) has now published the 20mph phase 1 air quality monitoring report. The data show no material effect on local air quality to date.

Monitoring continues and will be published as available.

Will I be fined if I don’t stick to the new limit?

GoSafe and police partners are using a combination of engagement and enforcement. 

More information can be found on the GoSafe website.

Does Welsh Government receive money from speeding fines?

Welsh Government does not receive any money from speeding fines. As with all speeding fines, any money generated goes to HM Treasury.

Does the speed limit apply to emergency vehicles, e.g. police, fire, ambulance?

Police, fire and ambulance services are allowed by law to exceed speed limits to respond to emergency calls. The introduction of the 20mph default speed limit does not change that and so should not delay their response.

The police believe response times will not be affected and that the roads being slower could make it easier for emergency services to make progress.

Has the new speed limit increased traffic congestion?

So far there's no indication that congestion has increased as a result of the new speed limit

Does driving at 20mph cause damage to cars?

Lower driving speeds should result in lower tyre, road and brake abrasion. Smoother driving, with fewer accelerations and decelerations, generates fewer particulate emissions from tyre and brake-wear. You can read more in this Transport for London report from 2018.

Does driving at 20mph use more fuel?

Fuel consumption is mainly influenced by the way we drive – driving at a consistent speed is better than stopping and starting (see NICE Overview | Air pollution: outdoor air quality and health | Guidance | NICE). A default 20 mph limit and a smooth driving style, can help avoid unnecessary speeding up and slowing down, saving fuel.

Accelerating up to 30mph can take twice as much energy as speeding up to 20mph.

Does driving at 20mph increase air pollution?

Imperial College London found that 20mph limited areas were “pollution neutral”. Many things contribute to pollution levels. 

They include:

  • driving style
  • acceleration
  • braking
  • vehicle condition
  • distance travelled
  • engine temperature

We believe the lower speed limits may encourage more people to choose active ways to travel and there will be fewer polluting cars on the roads.

Transport for Wales (TfW) has now published the 20mph phase 1 air quality monitoring report. The data show no material effect on local air quality to date.

Why did you introduce a 20mph speed limit?

The evidence from around the world is very clear – decreasing speeds will reduce collisions, save lives, and reduce injuries – helping to improve quality of life and make our streets and local communities safer for all.

Research undertaken by public health practitioners and Edinburgh Napier University suggests that the 20mph default speed limit in Wales could result – every year – in around:

  • 40% fewer collisions
  • 6 to 10 lives saved
  • 1,200 to 2,000 people avoiding injury

The change is also intended to:

  • make streets safer for playing, walking and cycling
  • encourage more people to walk, wheel or cycle
  • makes our communities safer
  • improve health and wellbeing
  • reduce noise pollution

The legislation was approved by the Senedd in July 2022.

How much did this change cost?

The implementation of the 20mph speed limit has cost around £32 million.

Research undertaken by public health practitioners and Edinburgh Napier University suggests that the estimated reduction in casualties each year from the introduction of the 20mph default speed limit in Wales, could provide around £92m in prevention savings.

This includes, but is not limited to, reduced impact on the NHS and emergency services. Other savings included are human costs and lost output (including future lost earnings). 

It does not include the potential wider health benefits of people walking and cycling more. 

Will this change negatively impact Wales’ economy?

Our assessment shows that reducing speeds to 20mph could result in an average increase of one minute per journey, balanced against saving up to 9 lives and preventing up to 98 serious injuries each year.

Before the law was passed, we produced an impact assessment that considered all the potential estimated costs and benefits. This was included in the explanatory memorandum.

It included the costs of any delays to travel time, including journeys for leisure, over 30 years. There has been some academic debate about this method

Therefore, some elements of the estimated cost to the economy may be more uncertain.

Research undertaken by public health practitioners and Edinburgh Napier University suggests that the estimated reduction in casualties each year from the introduction of the 20mph default speed limit in Wales, could provide around £92m in prevention savings.

Where did you trial this, and what were the results?

We trialled the introduction of a default 20mph speed limit in 8 areas. These were: 

  • Abergavenny and Severnside, Monmouthshire
  • North Cardiff
  • Buckley, Flintshire
  • Cilfrew Village, Neath and Port Talbot
  • St Dogmaels, Pembrokeshire
  • St Brides Major, Vale of Glamorgan
  • Llanelli North, Carmarthenshire

You can visit the Transport for Wales website to read the final monitoring report and first monitoring report on the Transport for Wales website, detailing some of the impacts introduction of 20mph has had in these communities. Overall speed has reduced in these areas.

Transport for Wales (TfW) has now published the 20mph phase 1 air quality monitoring report. The data show no material effect on local air quality to date.

How do slower speeds increase safety?

The World Health Organisation states that the most effective way to improve pedestrian safety is to reduce the speed of vehicles.

In 2022, police force figures indicate that 51% of collisions happened on 30mph roads.

Transport for London report  shows considerable improvements in road safety since the introduction of 20mph speed limits. Collisions resulting in death or serious injury within the central London Congestion Charging Zone showed a decrease of 25%, compared with a decrease of 10% across London as a whole.

By reducing the default speed, it will make it easier for drivers to stop in time to prevent collisions.

According to the Highway Code, in the distance a 20mph car can stop, a 30mph car will still be doing 24mph.

Edinburg Napier University Transport Research Institute points to evidence shows a person is around five times more likely to be killed when hit by a vehicle travelling at around 30mph than they are from a vehicle travelling around 20mph.

Transport for Wales’ 20mph monitoring framework includes the number of casualties on roads in Wales. Multiple years of collision data would be needed from the start of the default speed limit for comparisons to be meaningful.

What effect will the speed limit have on journey times?

Journey times on roads in urban areas tend to be determined by junctions and signals, rather than the speed limit.

In many cases lowering the speed limit to 20mph will have little or no impact on journey times. Where there is an impact, our analysis showed us that the average journey would only be around 1 minute longer but this would make the roads safer for pedestrians and cyclists.

The subsequent final monitoring report from first trial areas for 20mph has found in main through routes, average journey time changes are generally not more than one minute, with some exceptions of up to 2 minutes.

Why can’t the 20mph limit be only used around schools?

Introducing a 20mph default speed limit should make children safer from the moment they leave home – regardless of where they are going, and keeps them safe – inside and outside of school hours.

A 20mph speed limit outside the school won’t protect children for the whole journey as they walk or cycle from home, it would only protect them near the school.

But it won’t just protect children. This change is designed to make streets safer for all of us.

Where else have 20mph speed limits been introduced?

20mph speed limits and zones are common in other parts of the UK and in Europe.

There are 20mph speed limits in many cities in England. Scotland and Ireland are set to extend the use of 20mph and 30kmph speed limits, respectively.

30kmph and 20mph limits are being introduced across the world including in:

  • Spain
  • France
  • Italy
  • Finland
  • Germany
  • Ecuador
  • England
  • Scotland

20mph isn’t in the Highway Code. I’ll keep driving according to that.

The Highway Code was updated online on 17 September 2023 to reflect the 20mph speed limit in Wales.

The driving theory and practical tests have also been amended by the DVSA.

Will the roll-out involve money being spent on speed bumps?

There is no plan to include traffic calming (including speed bumps) as part of the change to speed limits. There are other ‘softer’ measures that might be introduced, such as using buffer speed limits, removing the centre line, narrowing the carriageway visually, using planting etc.

Why are bicycles allowed to overtake me when I am driving at 20mph?

Speed limits in the Road Traffic Regulations and the Highway Code apply to motor vehicles only and not to bicycles.

The Highway Code has been updated to include 3 new rules about the new ‘hierarchy of road users’.

The hierarchy places those road users most at risk in the event of a collision at the top of the hierarchy. It does not remove the need for everyone to behave responsibly.

It’s important that all road users:

  • are aware of The Highway Code
  • are considerate to other road users
  • understand their responsibility for the safety of others

How will a lower speed limit promote walking and cycling?

Lower speeds mean that people feel more comfortable to walk and cycle and it is safer for children to walk to school. Older people, disabled people or people with additional needs will feel more able to travel independently.

Vehicle speeds are one of the key reasons why people do not walk or cycle or do not allow their children to walk or cycle to school.

Why is the fire service involved in 20mph enforcement events?

As the Fire and Rescue Service attend more calls to road traffic collisions than house fires, they have a dedicated road safety team. These teams are not involved in callouts to emergencies and aim to inform drivers about the consequences of collisions caused by speeding.

Having seen the results of many collisions, they are well placed to engage drivers and are involved in this aspect of the 20mph roll-out.