Volos Ident


30th March 2023

Categories: Volos News

How the Drive for 20 mph Zones is Benefiting UK Cities

Ollie Marsh, Managing Direct, Volos

Volos is working extensively throughout Wales, leading the way in the design and project management of new 20 mph zones and speed limits in major cities. We are also providing QS services in addition to engineering and Project Management on these 20mph default projects.

Prior to their establishment of Volos, our engineers completed a number of 20 mph schemes in the Welsh capital. We are currently working on the implementation of a 20mph zone for the Vale of Glamorgan.

Ollie Marsh, Volos

Ollie Marsh, Volos

September 17th sees the introduction by The Welsh Government of a default 20mph speed limit on ‘restricted roads’ across Wales. Restricted roads are those that are usually located in busy, built-up residential areas. 

This will be the first national scheme of its kind in the UK, and one of the first in the World.

In advance of the national roll-out, in 2021, our engineers worked on a trial in Cardiff, which was one of eight trial areas in phase 1 of the 20mph programme. This covered Central North Cardiff, where we implemented a new 20mph infrastructure.


Here, we take a look at the benefits these new speed reduction measures bring to the urban environment and what changes to road infrastructure include.

Speeding is a major cause of accidents in the UK, especially in urban areas. Therefore, many cities across the UK are adopting 20 mph zones and limits to improve safety and reduce accidents. 

This blog will discuss the benefits of 20 mph zones and limits to UK cities, including environmental benefits, accident prevention, and pedestrian safety. 

Additionally, we will look at some surveys and findings that show the benefits of these initiatives.

Environmental Benefits

Reducing speed limits to 20 mph can reduce air pollution, noise pollution, and carbon emissions. 

A study by the Campaign for Better Transport found that if all cars drove at 20 mph instead of 30 mph, there could be a 10% reduction in CO2 emissions in urban areas. 

Additionally, a reduction in speed limits can lead to a decrease in the use of private cars, as more people opt for walking or cycling. This, in turn, can reduce congestion and improve air quality.

Accident Prevention

Speeding is one of the leading causes of road accidents in the UK. According to RoSPA, reducing the speed limit from 30 mph to 20 mph can reduce the number of fatal accidents by 6%, while the number of accidents resulting in serious injuries can be reduced by 20%. 

This is because slower speeds give drivers more time to react to hazards and reduce the stopping distance.

Pedestrian Safety

Pedestrians are the most vulnerable road users, and they are at a higher risk of injury or death in accidents. 

A study by the Department of Transport found that the likelihood of a pedestrian being killed in a collision with a car increases dramatically with speed. At 20 mph, the risk of fatality is 2.5%, while at 30 mph, it increases to 20%. 

Reducing speed limits can therefore improve pedestrian safety.

Findings and Surveys

Several surveys and studies have been carried out to assess the benefits of 20 mph zones and limits. In a survey by YouGov, 69% of people who live in 20 mph zones felt that the lower speed limit had made their area safer, while 77% supported the introduction of 20 mph zones in residential areas. 

Another survey by Brake, a road safety charity, found that 75% of people support 20 mph limits in all residential areas.

20mph Infrastructure

The introduction of 20mph zones and speed limits in the UK typically includes a range of signage and traffic calming measures to encourage drivers to slow down and improve safety. These measures can include:

  1. Speed limit signs: These signs are used to inform drivers of the change in speed limit from the previous limit.
  2. Advanced warning signs: These signs are placed before the start of the 20mph zone or limit to alert drivers of the upcoming change in speed limit.
  3. Enforcement signs: These signs are used to inform drivers that the speed limit is being enforced and that there may be speed cameras or police patrols in the area.
  4. Feedback signs: These signs are placed in areas with high pedestrian activity and display the speed at which drivers are traveling. They can be effective in reminding drivers to slow down and encouraging them to comply with the speed limit.
  5. Traffic calming measures: These measures are designed to reduce vehicle speeds and improve safety for pedestrians and other road users. They can include speed humps, chicanes, road narrowing, and pedestrian crossings.
  6. Road markings: Road markings can be used to reinforce the speed limit and indicate areas where pedestrians may be present.

The exact signage and traffic calming measures used will depend on the specific location and the needs of the area. 

In some cases, additional measures such as education campaigns and community involvement may be used to support the introduction of 20mph zones and limits.

In conclusion, there are many benefits to adopting 20mph zones and limits in UK cities. These initiatives can lead to a reduction in accidents, improved pedestrian safety, and environmental benefits such as reduced air pollution and carbon emissions. 

Surveys and studies have shown that there is strong public support for these initiatives, and they can make a significant difference in making our roads safer and more sustainable.

Related News

  • Hefyn Rosser Promoted to Quantity Surveyor

  • In 2024 the Water Tables will Turn Forever – and Here’s How

  • Meet Jerrine Jose, Our new Highways Engineer

  • How 20 mph Default Zones Benefit UK Cities