Why 20mph?
Early results from Wales show a 26% reduction in casualties in the first year.
It gives drivers more time to stop and avoid animals.
Reducing traffic speeds lowers both the likelihood and seriousness of collisions involving children.
Studies show smoother driving and fewer sharp accelerations can reduce pollution from tyres, brakes and exhausts.
Research shows traffic moves most smoothly at speeds around 18–20mph under real world conditions.
Lower speeds encourage active travel and protect vulnerable road users.
Even small reductions in speed reduce the risk and severity of injury.
Why not use the funding for potholes?
The funding has been set aside for 20mph schemes, so it can't be used for other repairs. Road maintenance is funded separately and is ongoing.
What we'll do
Prioritise areas
We are prioritising areas where:
- residents and businesses support lower speeds
- existing speeds, vehicle numbers, nearby schools and other local factors show the need and benefit of change.
We plan to introduce 20mph limits across whole areas, not just on single streets. We'll also include no-through roads and short streets in those areas. A consistent speed limit is less confusing, reduces speeding between zones and minimises clutter from speed limit signs.
Some main roads will not be included because they carry more traffic, have a different road layout or are important for keeping vehicles moving around the wider area.
Consultations
Before any changes are made, we'll ask local residents, councillors and community groups for their views through consultations.
We will clearly explain:
- what is being proposed
- how to take part in consultations
- how feedback will shape the final design.
As plans progress, we’ll keep residents updated through a variety of different ways such as letters, posters and online.
Install signs, road markings and traffic calming measures
Once we've got a legal order to change the speed limit, we will install signs and road markings. These works are usually quick and done in stages over several days to minimise disruption. Some markings need dry weather.
What signs and markings we'll install and why
If needed, we'll also install traffic calming measures. We plan this work to keep disruption low. Some work may take place at night, or use temporary traffic lights or short road closures.
Traffic calming measures we may use
We'll tell local residents:
- when the work will happen.
- how long it will last.
- any local impacts to expect.
You may notice new signs appearing first, followed by new markings or other measures.
Monitor
We monitor speeds for up to 12 months after a new 20mph area is put in. This gives drivers time to get used to the new limit and provides more accurate before-and-after data. If speeds do not drop as expected, we review the area and may add more measures.
Traffic calming measures we use
Speed cushions
Speed cushions are small, raised bumps placed in pairs or sets across the road. They slow cars down while allowing larger vehicles to pass more smoothly.
Why?
- Slow down cars but do not hold up emergency vehicles.
- Buses can travel over them more easily.
- Cyclists can avoid the bumps, making routes safer and more comfortable for cycling.
- Do not block road drains or gutters.
Raised crossings
Raised crossings are zebra or signal controlled crossings (e.g. pelican crossings) lifted to the same height as the pavement.
Why?
- Easier for wheelchair users, mobility scooters and people with pushchairs.
- Slow vehicles as they reach the crossing.
- Improve safety and accessibility in busy areas where lots of people cross.
- Help drivers notice that they are entering a pedestrian focused space.
Raised tables
Raised tables are larger flat raised areas of road, often used at junctions or where slower speeds are needed.
Why?
- Slow vehicles without creating sharp bumps or jolts.
- Help keep speeds low without making journeys uncomfortable.
- More comfortable for buses and cyclists.
- Can be shaped to fit different types of roads and junctions.
Speed humps
Speed humps are full width bumps that stretch from one side of the road to the other.
Why?
- Very effective at reducing high vehicle speeds.
- Useful in school streets and residential areas.
- Help keep speeds low where buses may not need to pass over them.
Speed limit signs and road markings
National rules require:
- clear signs at the start and end of each 20mph zone.
- smaller signs or road markings every 80–100 metres within the zone (unless there are physical measures like speed humps).
We'll add or refresh markings on the road, including painted ‘20’ roundels and white lines.
We know that signs outside homes can be frustrating, so we choose sign locations carefully and try to keep signage to a minimum. Where possible, we use existing posts and pillars.
Why?
- Makes speed limits easy and clear to see for all road users.
- Supports safer and more consistent driving behaviour.
- Ensures speed limit is clear and enforceable.
- Repeaters provider clear reminders of the speed limit.
- Helps highlight crossings and traffic calming features.