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1. Introduction

1.1 Status


This Welsh Government guidance on setting 30mph limits on restricted roads and other 20mph roads is an addendum to Circular No. 24/2009 Setting Local Speed Limits in Wales (SLSLiW)

It supersedes the section dealing with speed limits on restricted roads and 20mph limits and zones, except where specific parts are referenced. 

This guidance replaces ‘Setting exceptions to the 20mph default speed limit for restricted roads’. 

It applies equally to restricted roads and to roads where a 20mph speed limit has been applied by an order of the traffic authority under section 84(1)(a) of the Road Traffic Regulation Act 1984 (‘the 1984 Act’).


This guidance is being issued in advance of the revised SLSLiW, which will reflect the change to a 20mph speed limit for restricted roads. The updated SLSLiW circular will incorporate and replace this guidance.


This guidance is founded on the Safe System[footnote 1], advocating for safe speeds that are appropriate to the features of the road, the function it serves and the physical tolerance of its users[footnote 2]

1.2 The Restricted Roads (20mph Speed Limit) (Wales) Order 2022


The Restricted Roads (20mph Speed Limit) (Wales) Order 2022 was made by the Welsh Ministers on 13 July 2022 following a resolution of Senedd Cymru to approve a draft of the Order. It came into force on 17 September 2023.    


The Order reduced the general speed limit for restricted roads, set by section 81(1) of the Road Traffic Regulation Act 1984 (“the 1984 Act”) to 20mph.


The default position is that a road in England and Wales is a restricted road if there is provided on it a system of street lighting furnished by means of lamps placed not more than 200 yards apart (see section 81 of the1984 Act). 

Most restricted roads are in built-up areas.

Under section 82(2) of the 1984 Act, a traffic authority may direct that such a road is not a restricted road and may direct that a road that is not a restricted road shall become a restricted road. 

By virtue of section 84(3) of the 1984 Act, a road is not a restricted road while a speed limit order in relation to that road under section 84(1)(a) of that Act is in force. 

1.3 Purpose


This guidance aims to assist highway authorities in making well-reasoned decisions about setting 30mph speed limits.

It provides a framework for highway authorities in Wales (who are traffic authorities when regulating speed limits) to assess whether it is safe and appropriate to raise the speed limit to 30mph on restricted roads and other roads subject to a 20mph speed limit, while also accommodating local factors and circumstances.


This guidance has been developed with consideration of:

  1. the work of the review panel's initial report and final report
  2. feedback from the Welsh Government’s 20mph Listening Programme
  3. input from the County Surveyors’ Society Wales (CSSW)
  4. feedback from highway authorities, incorporating public viewpoints shared with the Welsh Government.


We anticipate that most speed limit changes from 20mph to 30mph will be made on A and B roads, which are typically main or strategic roads. 

A 30mph speed limit could be set on roads if they are located outside city, town or village centres and away from places that attract frequent pedestrian[footnote 3] and/or cyclist traffic or on roads with low housing density (less than 20 properties per km) and where if there are pedestrians and cyclists they are or could be segregated from motor traffic).

Consequently, there is no need to reassess all roads.


[1] The Safe System is based on the principles that:

  • people make mistakes that lead to crashes
  • the human body has a limited capacity to tolerate crash
  • road safety is a shared responsibility for those who design, build, manage and those who use roads and vehicles and those who provide post-crash care
  • all parts of the system must be strengthened in combination to multiply their effect, so that if one part fails, another part is still there to protect. 

Read more on the The Royal Society for the Prevention of Accidents (ROSPA) website.

[2] The ability of road users to withstand the forces of a crash without suffering serious injury.

[3] Throughout the document, references to pedestrians and walking include people using: mobility aids such as wheelchairs and rollators; 'invalid carriages' including mobility scooters designed for use on the footway, and people with physical, sensory or cognitive impairments who are travelling on foot.

2. Principles

2.1 The United Nations Stockholm Declaration


In line with the Welsh Government’s aspiration to support the aims of the Stockholm Declaration a 20mph speed should remain where pedestrians and/or cyclists and motor vehicles mix in “a frequent[footnote 4] and planned manner, except where strong evidence exists that higher speeds are safe”.

2.2 Guidance framework


The framework set out in this guidance aims to support highway authorities to:

  1. weigh potential benefits and disbenefits of raising the speed limit, taking into account their statutory duties and functions
  2. assess roads according to common criteria (place, movement, road characteristics) that are relevant in determining the appropriate speed limit, considering local circumstances
  3. ensure any trade-offs between the different criteria, and the justification for decisions taken, are clear, well-reasoned and documented in each case.


Highway authorities have the powers to set speed limits that are suitable for individual roads, considering specific local needs and conditions. 

Given the diversity of local roads and circumstances across Wales, it is impractical for this guidance to cover all scenarios. 

Highway authorities can deviate from this guidance. In such cases, they are advised to provide a clear and well-reasoned justification for their decision.


[4] To be determined by the highway authority

3. Weighing up benefits and disbenefits

3.1 Introduction


When considering whether a local speed limit can be set, highway authorities should weigh up the potential benefits and disbenefits of raising the speed limit. 

For example, authorities should consider the trade-offs between the disbenefits of the higher speeds, such as increased casualties and severity of injuries, noise and perceived risk (which may discourage walking, wheeling and cycling, impacting physical and mental health), with the benefits of reduced travel times, potential economic savings, and increased efficiency.


When determining speed limits, it may not always be possible to fulfil all objectives, for example: ensuring the road is safe for all users and reducing travel times.

As such, they should be considered on a case-by-case basis, using reasoned justification and referencing relevant evidence. 

In certain situations, it may be feasible to reconcile seemingly conflicting objectives, by adjusting the road infrastructure. 

For example, installing facilities for pedestrians and cyclists could effectively address both concerns. 


Highway authorities should also have regard to their wider duties and statutory functions, for example:

  • the Equality Act 2010
  • Active Travel (Wales) Act 2013
  • the Well-being of Future Generations (Wales) Act 2015
  • relevant duties in the Traffic Management Act 2004 (to expedite the movement of traffic) 
  • the Road Traffic Act 1988 (to prevent accidents)
  • the 1984 Act (duty on local highway authorities so far as practicable having regard to the matters specified in section 122(2) of the Act to secure the expeditious, convenient and safe movement of vehicular and other traffic, including pedestrians when exercising functions under the 1984 Act such as the setting of speed limits).

3.2 Benefits of higher speeds


Roads are essential corridors for movement, and safe reductions in vehicle travel times can yield significant social, economic, and operational benefits. Evaluating these benefits requires careful consideration of the route's importance and expected journey time savings for key users.


The potential benefits of setting a higher speed limit for a road should be evaluated by considering:

  1. the importance of the route as a movement corridor for motor traffic
  2. the expected journey time savings particularly for buses, freight and non-emergency services (in particular, for non-emergency ambulance transport, non-blue light emergency workers such as first responders, and reserve firefighters or social care workers), if the speed limit were raised to 30mph. 

3.3 Disbenefits of higher speeds


The potential disbenefits of setting a 30mph speed limit for a road should be evaluated by considering the following factors:

  1. impact on walking, wheeling and cycling safely: Raising the speed limit will have negative consequences on a range of important outcomes (e.g. safety, difficulties for pedestrians in crossing roads, potential to inhibit walking, wheeling and cycling and potentially leading to negative physical and mental health consequences), particularly due to the clear relationship between impact speed and the frequency and severity of casualties.
  2. collision data: A high frequency of collisions and casualties (when the limit was previously 30mph) would reduce the justification for raising the limit. However, the absence of collisions previously should not automatically justify a higher speed limit, as pedestrians and cyclists may have been deterred by high speeds.
  3. assessment of collision risk: The potential for collisions should be assessed by considering the number of pedestrian and cyclist movements, including for recreational purposes, and the risk of collision, taking into account traffic flow. 
    This can be determined mainly through factors such as whether there are destinations/trip attractors for walking, wheeling and cycling, and if the route is an important walking, wheeling or cycling corridor (such as a public right of way or a route which is identified on the Active Travel Network Map).
  4. perceived safety and community cohesion: Higher speeds can create real and perceived dangers that may make places less attractive and hinder community cohesion and interaction.
  5. air quality: Higher speeds have the potential to discourage walking and cycling leading to increased reliance on private motor vehicles (in turn leading to pollution and poor air quality).
  6. noise pollution: Evaluate noise levels considering traffic flow patterns, vehicle types, and the proximity of residential properties to the road.

3.4 Summary


Balancing these competing objectives necessitates a holistic approach that takes into account statutory duties and broader legislative frameworks.

Ultimately, highway authorities should exercise their discretion and judgement to ensure that speed limits are set in a way that promotes safety, efficiency, and community wellbeing.

4. Criteria

4.1 Introduction


Most speed limit increases to 30mph are expected to be made on A and B classified roads. These generally form the main or strategic routes carrying traffic through urban areas.


C-class and unclassified roads in urban areas typically carry mostly local traffic and mainly serve residential properties. They are usually important routes for people walking, wheeling and cycling. 

A speed limit of 30mph is generally not expected to be made for these roads However, authorities may decide to raise them based on this guidance and a reasoned case referencing local factors.


In determining whether a speed limit should be raised to 30mph, highway authorities should consider various criteria, including place, movement and road characteristics and any additional local conditions deemed relevant.

4.2 Place criteria


30mph would not be appropriate on sections of roads which may have significant demand for walking, wheeling and cycling, such as: 

  1. within a 100m walk of any educational setting (e.g. nurseries, primary, secondary, further education and higher education)
  2. within 100m walk of any community facility
  3. within 100m walk of any medical facility, e.g. hospitals, GP surgeries etc
  4. where the number of residential and/or retail premises immediately fronting a road exceeds 20 properties per km.


In terms of ‘place’ criteria, 30mph limits could be used on:

  1. main or strategic roads outside city/town/village centres or high streets
  2. roads outside other high-density areas and away from other places that attract frequent pedestrian and/or cyclist trips[footnote 5]
  3. roads with very low density of housing and/or very few houses altogether (fewer than 20 properties per km)
  4. roads with residential and retail premises only on one side and no need to cross the road to access services or facilities (or if safe crossings are available or made available, as per Active Travel Act Guidance).

4.3 Movement


In terms of ‘movement’ criteria, 30mph limits could be used on:

  1. strategic roads, such as those for freight or important bus corridors, where evidence exists[footnote 6] that journey times have increased significantly since the speed limit was changed to 20mph
  2. minor roads in industrial areas with low demand for pedestrian or cyclist traffic, or areas surrounded by open land (excluding sports grounds, parks or playing fields that need to be accessed via said road).

4.4 Road characteristics


In terms of ‘road characteristics’, 30mph limits could be considered: 

  1. where there are segregated facilities (of sufficient width, as per Active Travel Act Guidance) along the road and safe crossings for pedestrians and cyclists (and/or these could be made available, in which case changes to the speed could be considered once in place). It will be necessary to separately consider the degree and quality of protection along (the footway/cycle track) and across the road (this would require safe facilities to be provided for pedestrians and cyclists which meet the Active Travel Act Guidance).
  2. where there is low demand (or no potential demand e.g. planned future trip generators) for pedestrians and cyclists to cross the road (e.g. development is only on one side).
  3. where the road has been designed so that the highway geometry and features support a higher safe speed of 30mph.

4.5 Speed limit assessment


When assessing roads using the criteria outlined above, some evaluations will strongly indicate the appropriateness of a 20mph or 30mph speed limit. However, in cases where the criteria yield mixed results, engineering measures could be implemented to support an increase from a 20mph speed limit to 30mph.


If the assessment undertaken largely supports retaining the 20mph speed limit, but evidence shows that there are significant impacts on bus routes, resulting in increased journey times and subsequent cuts to services or areas served, then the implementation of bus priority measures along the affected routes should be considered).

4.6 Minimum lengths of speed limits


When applying this guidance, frequent changes in speed limit should be avoided, to avoid driver confusion.


As per SLSLiW, the minimum length of a speed limit should generally be not less than 600 metres to avoid too many changes along the route. This can be reduced to 400 metres for lower speed limits, or even 300 metres on roads with a purely local access function. Anything shorter is not recommended.’ These minimum lengths do not apply to buffer limits, detailed below.

4.7 Buffer speed limits 


Highway authorities should evaluate situations where a buffer speed limit may be appropriate, particularly in the following scenarios:

  1. significant stepped changes in speed limits when approaching communities, where the difference exceeds 20mph and where approach speeds are not limited by features of width, alignment or any other visible cues.
  2. locations where highway alignment limits visibility to speed limit terminal signs, potentially not meeting the criteria set out in Chapter 3 of the Traffic Signs Manual. The repositioning of speed limit terminal signage should also be explored in the first instance.
  3. retrospective implementation in areas identified through the need for regular enforcement activities, such as high collision rates or excessively high actual speeds on 20mph roads.
  4. changes in highway characteristics between communities (e.g. rural to urban transitions) where physical features may not be easily visible to drivers.


Highway authorities may also want to consider other alternative speed management measures to reinforce the message that drivers are entering a lower speed limit and encourage compliance. 


Highway authorities should use their discretion and judgement to determine whether a buffer speed limit is suitable in areas where the speed limit reduces to 20mph from a higher speed, and the length of that buffer speed limit depending on approach speed and other features on the approach to the 20mph speed limit.

Other options, such as gateway treatments and advance signage on the approach, may be more appropriate.

Collecting post-intervention speed data and safety-related evidence may help authorities justify additional measures at problematic sites, supported by other evidence such as collision records or community concerns.


[5] 20mph default speed limit review of exceptions and Guidelines for setting local speed limits in Wales, section 6.12.

[6] Transport for Wales will provide information on bus journey times (pre and post legislation change).