Dear Stephanie,

Improving transparency of Welsh Government’s 20-mph speed limit data

I am writing today to outline my concerns with the transparency of sources supporting claims on the implementation of the Welsh Government’s 20 mph speed limit, particularly in a promotional leaflet sent to households in Wales.

While the claims in the promotional material cited the sources for the figures quoted, I consider that improvements could have been made to aid transparency and better support users.

The source used for the claim that ‘most journeys will be around one minute longer’ was from an Explanatory Memorandum to the Restricted Roads (20 mph Speed Limit) (Wales) Order 2022 from June 2022. This document was a Regulatory Impact Assessment and sets out the likely economic costs and benefits for the then proposed legislation as well as the rationale for the proposal, objectives of the policy, and details how the policy will be monitored. The document itself did include some high level information on how the increase in overall journey times was derived and the uncertainty and limitations of the estimate was acknowledged. I consider, however, that it would be challenging for a reader to unpick this detailed document to find and understand the data and calculations used to support this claim, and that it would not be reasonable to expect people who read the leaflet to do so.

In the course of engaging with your team on this matter, they helpfully shared a technical note on the journey time calculations within the Regulatory Impact Assessment. This more clearly sets how the claim was derived in a way that would allow scrutiny from readers, but this technical note was not publicly available for citizens to access.

In short,  I do not consider that the presentation of this analysis in the leaflet fully aligns with our expectations for Intelligent Transparency.

I do recognise that other, more detailed data are available for people to understand the impact on journey time through the monitoring report from phase 1 of the 20mph trial and that Transport for Wales will be developing its plans for future reporting including an interim monitoring report expected in June 2024. I also understand you now intend to publish the technical note which I welcome.

To better support users in future, I recommend that:

• As part of planned monitoring, the Welsh Government and Transport for Wales should continue to review the evidence on journey times and cite the most appropriate evidence source when communicating the impact on journey times.
• Analyst teams in the Welsh Government should continue to support and work with communications and policy colleagues in the preparation and presentation of data and statistics.
• Transport for Wales, in conjunction with Welsh Government, should consider how it can make improvements to data and statistics on the implementation of the 20mph speed limit, including considering the accessibility of data and supporting information. Transport for Wales should seek feedback from users as it starts develops its new outputs.

Thank you for engaging with us on this matter.

I am copying this letter to Geoff Ogden, Transport for Wales.

Yours sincerely,

Ed Humpherson
Director General for Regulation