20mph speed limits

Cornwall is one of the first rural areas to reduce speed limits from 30mph to 20mph in built up areas.  This will make roads safer for everyone.

An early phase of delivery (referred to as Phase 1) has been implemented and the results of this will help inform future phases.  Agreement to deliver countywide 20mph programme received Cabinet approval in March 2023 (refer to Agenda item 13).  Work to deliver this programme is now underway.

This page will be updated periodically.  Please see information below on current progress and to help answer your queries.

Case for 20mph across Cornwall

Research provides a case for introducing 20mph limits.  There is a strong link between traffic speed and the severity of injury when a collision occurs.  Chances of survival if struck at 20mph (90%) are much greater than 30mph (50%).

Residential roads and built-up areas should be 20mph.  20mph provides many road safety, social and environmental benefits.  Slower speeds help to promote liveable streets and encourage active travel.  This will support Cornwall’s ambition to be carbon neutral by 2030.  Benefits to our communities include, but isn’t limited to:

  • Making our streets safer.  This will reduce casualties and community inequality.
  • Increasing child and adult activity levels.  This will improve health and wellbeing.
  • Providing a safe environment.  This will encourage more people to walk and cycle.
  • Supporting climate change declaration.  This will include lower emissions and tackling congestion.
  • Creating a stronger sense of place.

The most effective way to improve pedestrian safety is to reduce the speed of vehicles.  This is according to The World Health Organisation.  Between 2017-2021, speed was a contributory factor in 980 collisions in Cornwall.  This resulted in 1,483 casualties (all severities).  Sadly, this involved 39 fatalities of which 4 were pedestrians, 2 of these within a 30mph limit. A further 275 resulted in serious injuries.  This involved 7 pedestrians and 7 cyclists, all within an existing 30mph limit.

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

Lower speeds benefit walking and cycling

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

  • Safe
  • Sustainable
  • Healthy
  • Fair

Inappropriate speed limits make movement dangerous where people live, work and play.  This particularly affects vulnerable road users, including children and the elderly.

Lower speeds mean people feel more comfortable to walk and cycle and it is safer for children to walk to school.  Older people also feel more able to travel safely. Vehicle speeds can barrier to walking or cycling, the can also be a reason why children may not be allowed to walk to school.

Wider impacts of 20mph speed limits:

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 that up to 75% of road transport particulate emissions come from tyre and brake wear. Slower speeds encourage a smoother driving style, which ultimately decrease's 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 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, this would be negligible, but in turn would make the roads safer for pedestrians and cyclists.

Bus journey times were reviewed as part of Phase 1 and were found to be negligible.

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

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.


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 default 20 mph 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. 

Phase 1: 20mph rollout delivered

Phase 1 of 20mph application has been delivered across following areas:

  • Camelford
  • Falmouth and Penryn

In March/April 2022, 76% (Falmouth and Penryn) and 86% (Camelford) positive feedback was received in support of Phase 1 20mph.

We reviewed all existing 30mph speed limits, with the majority reduced to 20mph.  We selected these areas for many reasons.  This includes, but not limited to:

  • Deliverability within required timescales
  • Building on existing or advancing 20mph provision, closing gaps
  • Mix of built-up areas, towns and rural villages, providing optimal monitoring opportunities
  • Synergy with other investment.

The results so far: 

20 out of 22 sites saw positive reduction in traffic speeds.

Falmouth and Penryn:
Reductions in mean speed of up to 6.9mph and reductions in 85th percentile (speed at or below which 85% of vehicles are travelling) of up to 8mph

Reductions in mean speed of up to 5.7mph and reductions in 85th%ile of up to 5.5mph

Targeted support will be provided to non-compliant sites.

Data to show the impact on collisions and air quality will need to be collected and analysed over a long period to show any significant change.

Future phases

We appreciate the disappointment for areas not in Phase 1.  Please know that every area in Cornwall is important to us.

Work to develop a countywide programme is now complete. This process reflected on:

  • Impact of Phase 1; considering any adjustments required in our approach.
  • Lessons learned.
  • Timescale and cost for implementation.

An evidence led approach was taken to determine the delivery order for this programme,. Killed and Seriously Injured (KSI) collision data has been reviewed within existing 30mph limits only.  This review concluded with the following delivery order:


  • 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

Where 20mph might not be introduced

The 6th United Nations Global Road Safety Week (May 2021) called for policymakers to use low speed streets worldwide.  This involves limiting speeds to 20mph where people walk, live and play.  The benefits being that streets would be safer, healthy, green and liveable.

We are reviewing all roads where the existing limit is 30mph, with the intention to reduce to 20mph.  Urban areas with high pedestrian and cyclist movements will be higher priority.  This could include areas around schools, shops, markets, playgrounds.

For some roads, it may be appropriate to retain 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 has been developed to help support this process.  This will be applied consistently to any 20mph scheme, regardless of how it is funded.  Consistency is critical.

Speed limits 40mph and above

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. Such Initiatives could be nominated through the aforementioned Community Area Partnership Highway Scheme.

Communications and engagement strategy

A comprehensive communications and engagement strategy will support this work.  This will communicate the negative impacts of speeding in residential areas.  This will set out the scheme’s rationale, objectives and outcomes.  Local acceptance and behaviour change is the key.

Communities can support us by spreading information messages through communication channels. Community support has proven integral to the successful implementation of 20mph sites elsewhere.

A good community support network will change behaviours and attitudes towards traffic speeds.  This will increase the likelihood limits become self-enforcing.

Local communities can help enforce low-level speed breaches through campaigns.  This ensures the longevity of a successful scheme and increased speed compliance.

Police enforcement

Devon and Cornwall Police can and will enforce 20mph speed limits.  This will be targeted based on evidence.  We must not rely on legal enforcement as the only means to drive compliance.  Road safety is something all road users have responsibility for.  Road user respect and driver behaviour is crucial.

Cornwall Council will work with the Police during Phase 1 and beyond.  Enforcement will be deployed for consistent high levels of non-compliance and risk to health (injury).

Whether you live in a 20mph or travel through 20mph, we ask you to respect those limits in place.

20mph signage

Schemes are signed in accordance with the Traffic Signs Regulations and General Directions.  Additional guidance is provided within the Traffic Signs Manual.  Within delivery we are using two different sign sizes as per the guidance.  The larger 20mph 600mm diameter signs should be used at the entry location of each speed limit.  The smaller 300mm diameter signs can be placed to serve as a reminder.  Whilst we appreciate the smaller signs are sometimes missed, the larger signs cannot be used throughout.  The larger signs at the entry to the 20mph speed limits are also obvious to drivers.

To accompany signage, all relevant Traffic Regulation Orders will be put in place. This enables Police enforcement as and when required.

Supporting traffic calming

We will not be applying traditional traffic calming.  Delivery includes legal signage and low-cost gateway features, where required.

Transition into a community needs to be clear to drivers.

Targeted support will be provided to non-compliant sites with increased activity through our communications and engagement strategy, as well as mobile speed activated signs and/or lining works.

We need communities to work with us through initiatives such as:

  • Community Speedwatch
  • Operation Snap
  • Deployment of mobile speed signs

This will be supported by our communications and engagement strategy.  This will deliver the message of 'Life's Better at 20mph; it's Safer, Greener, Healthier too'.  This messaging is already in communities where 20mph has been delivered to date.

Community support

There are many ways that communities can help to be the local eyes on the ground through initiatives such as:

  • Community Speedwatch - this site tells you more about the scheme and how to get involved.
  • Operation Snap - you can provide photographic or video evidence of driving incidents on this website.   

Other committed 20mph schemes

There are other 20mph schemes advancing.  The majority of these are through the Community Highway Scheme programme.  We recognise communities want to see 20mph delivered as early as possible, but this change will not happen overnight.  Delivery of a countywide programme required Cabinet approval, and now it has been approved, delivery will take a number of years.

20mph speed limits can still be nominated through the Community Highway Schemes for early delivery. These will be designed with assessment criteria developed to ensure consistency across Cornwall.

Please note- 20mph speed limit schemes progressed early via this route will not benefit from the coordinated programme of communications & engagement support that would otherwise be provided alongside the rollout.

Measures to support the 20mph rollout can also be nominated through this process.

Statutory consultation

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

Wider communication and engagement will also continue alongside the delivery programme.  Continuous messages to reinforce 'slower is safer' is important.  

If you are interested in other Cornwall Council consultations in your area you can access them via the consultation finder.

Data collection

We will track collision data, traffic speed and volumes.  We will also review air quality where applicable.  Other data aspects could include:

  • Surveys of school children and parents.  This is to see if the 20mph has made any difference to their travel to and from school, and within their social activities.
  • Working with Parish and Town Councils to get qualitative information. This will be the positive or negative impacts communities have experienced.

All data gathered will help inform how best to deliver the 20mph rollout.

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