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20mph speed limits

Image promoting the benefits of a 20mph speed limit with the text, 'Life's better at 20mph'

Cornwall is one of the first rural areas to reduce speed limits from 30mph to 20mph on residential roads and in built-up areas. It will make roads, safer, healthier and greener for everyone.

After a successful pilot (Phase 1) in Camelford, Falmouth and Penryn during 2022, a countywide roll out programme has been approved.

Cornwall Council aims to reduce both death and serious injury by 50% on our roads by 2030, and 20mph limits will support this.

The benefits of reducing speeds to 20mph

Research provides a strong link between traffic speed and the severity of injury when a collision occurs. If someone is struck at 20mph they have a 90% chance of survival compared to a 50% chance if struck at 30mph.

Travelling at 20mph provides many other benefits too:

  • Increasing child and adult activity levels. This will improve health and wellbeing.
  • Providing a safer environment. This will encourage more people to walk and cycle.
  • Supporting climate change declaration. This will include lower emissions and tackling congestion, as well as supporting our ambition to be Carbon Neutral by 2030.
  • Creating a stronger sense of community as more people come together to use the space.

Walking and cycling

Villages, towns and cities should be places where people are free to travel in ways that are:

  • Safe
  • Sustainable
  • Healthy
  • Fair

Higher speeds negatively impact safety where people live, work and play. This particularly affects our more vulnerable road users such as children and the elderly.

Lower speeds improve both actual and perceived safety and may mean people feel more comfortable to walk and cycle. Children will also have a safer environment to walk to school and the elderly will feel more able to travel safely.

Lower speeds benefit air quality

There is little evidence to suggest that reducing vehicle speeds to 20mph increases pollution. It is not as straightforward as more time driving equals more pollution. Driving styles, acceleration and braking are all contributory factors to increased emissions. Other research has shown that up to 75% of road transport particulate emissions come from tyre and brake wear, not exhausts. Slower speeds encourage a smoother driving style, which ultimately decreases emissions.

Research has found that reducing speeds from 30mph to 20mph reduced CO₂ emissions up to 37.8% and NOx emissions by 51.0%. This is while only having a minimum impact on journey times. The impact of different driving styles, vehicle size, and fuel type were also investigated and found to impact the results.

Journey times

Journey times on roads in urban areas tend to be determined by junctions, crossings and parked vehicles, rather than speed limits. Often lowering the speed limit to 20mph will have little or no impact on journey times. Where there is an impact, this would be negligible, but in turn would make the roads safer for everyone; including pedestrians and cyclists.

Bus journey times were reviewed during Phase 1 and were found to be negligible. We will continue to monitor bus journey times throughout the programme.  

Less acceleration and braking smooths traffic flow, reduces gaps between cars and reduces idling.

Lower speeds benefit noise pollution

Noise research studies show about a 3 decibel (dB(A)) reduction when reducing a 30mph speed limit to 20mph. This is perceived as halving ambient noise.

The impact on fuel consumption

Fuel consumption is mainly influenced by the way we drive. Driving at a consistent speed is better than stopping and starting. Accelerating up to 30mph can take over twice as much energy as accelerating up to 20mph. A 20mph speed limit and a smooth driving style, can help avoid unnecessary speeding up and slowing down, saving fuel.

A study by the Transport Research Board identified that 30km/h zones (18.6mph) have a 12% reduction in fuel consumption. 

Where 20mph won’t be introduced

We will review all roads on a case-by-case basis where the existing limit is 30mph, with the intention to reduce to 20mph. Urban areas with high pedestrian and cyclist movements will be prioritised. This could include areas around schools, shops, markets, playgrounds.

For some roads, it may be appropriate to keep 30mph or deliver a more focused 20mph section. This will be a considered decision, based on local circumstances. Exceptions will generally be major roads and where vehicles are the primary function.

An exceptions process and associated assessment criteria has been developed. This is to help support the process.

Speed limits higher than 30mph will not qualify for 20mph. We appreciate that communities with speed limits of 40mph or above, may face difficulties. There may be opportunities to improve the local environment through other initiatives. For example, the Community Highway Scheme.

Police enforcement

Devon and Cornwall Police can and will enforce 20mph limits. The Traffic Regulation Orders associated with this programme will support this. Enforcement will be carried out in places where the new speed limits are regularly being broken, and where there is a risk of injury to other road users. Enforcement has already taken place in a number of Phase 1 areas. 

Road safety is something all road users have responsibility for. Road user respect and positive driver behaviour is crucial. Whether you live in a 20mph or travel through 20mph, we ask you to respect those limits in place.

Police 20mph Enforcement Position Statement

Why 20mph funding cannot be spent on potholes

Department for Transport funding provided to local councils can only be spent on its defined purpose. Cornwall Council cannot spend 20mph programme funding on highway maintenance issues such as:

  • potholes

  • cutting hedges

Nor can it spend highway maintenance funding on the 20mph programme.

Why our approach is different to Wales

In Wales, the law changed the default speed limit on restricted roads from 30mph, to 20mph. In Cornwall, each 30mph speed limit is being assessed on a case by case basis. The majority of roads will be reduced to 20mph. However, not every road is appropriate for 20mph so will remain at 30mph. 

We are taking a very careful and considered approach. We are listening to our communities through:

  • early meetings held with Cornwall Councillors and Town/Parish Councils
  • statutory public consultation  

If you see a 20mph limit in place across Cornwall there is a good reason for it, it just may not be immediately apparent. It may be a school or playground entrance set back from the road for example.  

Costs of the 20mph programme

The countywide programme is estimated to cost £4m. 

The Department for Transport estimate the real costs linked with collisions. These include costs of lost output, medical and ambulance, police, insurance and admin, and damage to property: 

  • £2.25m per fatal collision 
  • £289,949 per serious collision
  • £29,127 per slight collision

Speed was recorded as a contributory factor in 189 collisions across Cornwall between 1st January 2020 and 31st December 2022. All of these were within 30mph limits. Of the 189 recorded injury collisions:

  • 4 were fatal (£9million)
  • 43 were serious (£12.47m)
  • 143 were slight (£4.17m). 

Introducing safer speeds will reduce collisions. It will also support economic savings through reduced lost output costs. Ultimately, reducing collisions will avoid the , the sheer devastation left with all those who are affected by them.  

Timelines for the rollout of 20mph

Statutory public consultation will be undertaken for each phase of delivery.

Using road collision and casualty data we have identified the priority order for the rollout.


  • Camborne, Pool, Illogan and Redruth
  • West Penwith
  • Truro and the Roseland


  • Hayle and St Ives
  • St Austell and Mevagissey
  • Newquay and St Columb
  • Cornwall Gateway
  • Liskeard and Looe
  • China Clay


  • Helston and South Kerrier
  • Bude
  • Launceston


  • Wadebridge and Padstow
  • Bodmin
  • Caradon
  • St Blazey, Fowey and Lostwithiel
  • St Agnes and Perranporth

Life's better at 20mph resource pack

Community support has proven integral to the successful implementation of 20mph limits elsewhere.

We have created a resource pack to help spread the word and engage your community at a local level. This will support the work of the wider campaign to make Cornwall's roads safer.

20mph Resource Pack

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