Statistics on Road Traffic Safety Relating to Proposed 20mph Limits

Summary

The requester asked for Isle of Man-specific data and impact assessments supporting the proposed 20mph speed limit rollout, but the Department of Infrastructure stated it does not hold this information as the policy was mandated by Tynwald.

Key Facts

• The Department of Infrastructure does not hold the requested data or statistical analysis regarding the 20mph policy.
• The policy to convert non-20mph residential roads to 20mph was mandated by Tynwald, not developed by the Department.
• No impact assessments were carried out by the Department prior to the implementation of the 20mph speed limits.
• Requests for information on policy formation and justification should be directed to Tynwald.
• The Department provided links to published Tynwald questions and answers concerning the 20mph changes as an alternative source of information.

Data Disclosed

• 2025-07-02
• 2025-07-31
• 20mph
• 30mph
• 7th March 2025
• 140 locations
• 2021
• GD 2025/0026
• W-202501-1530
• W-202501-1531
• W-202501-1537
• W-202501-1663

Exemptions Cited

• Information not held

Original Request

I am writing to request information under the Freedom of Information Act regarding the proposed rollout of 20mph speed limits on the Isle of Man. In recent communications and public messaging, the Department of Infrastructure (DOI) has made strong efforts to promote the merits of this rollout. However, no Isle of Man-specific data has been presented publicly to support the need for or projected impact of this measure. Accordingly, I request the following information: Any and all data or statistical analysis the DOI has used or commissioned that specifically relates to road safety, vehicle speeds, casualty rates, pedestrian or cyclist incidents, or other traffic-related factors on the Isle of Man that were considered in support of the 20mph policy. Specifically, this should make clear the propensity for serious accidents involving a driver not exceeding a speed limit of 30mph in a 30mph zone. Internal reports, briefing documents, meeting minutes, or correspondence which reference the use of Isle of Man-specific data in evaluating or justifying the 20mph policy. If no Isle of Man-specific data has been used, please confirm this explicitly and provide details on what external sources (e.g., UK or international studies) were relied upon instead, and the rationale for applying them to the Isle of Man context. Any evidence of impact assessments conducted on the Isle of Man regarding the introduction of 20mph speed limits. Yours faithfully,

Data Tables (1)

Full Response Text

Department of Infrastructure Sea Terminal Building, Douglas, Isle of Man, IM1 2RF

Contact: FOI Response Team Telephone: (01624) 686785 Email: dpo-doi@gov.im

Our ref: 4769397 29 July 2025

Dear ###

We write further to your request received 2 July 2025, which states:

"I am writing to request information under the Freedom of Information Act regarding the proposed rollout of 20mph speed limits on the Isle of Man.

In recent communications and public messaging, the Department of Infrastructure (DOI) has made strong efforts to promote the merits of this rollout. However, no Isle of Man-specific data has been presented publicly to support the need for or projected impact of this measure.

Accordingly, I request the following information:

Any and all data or statistical analysis the DOI has used or commissioned that specifically relates to road safety, vehicle speeds, casualty rates, pedestrian or cyclist incidents, or other traffic-related factors on the Isle of Man that were considered in support of the 20mph policy. Specifically, this should make clear the propensity for serious accidents involving a driver not exceeding a speed limit of 30mph in a 30mph zone.

Internal reports, briefing documents, meeting minutes, or correspondence which reference the use of Isle of Man-specific data in evaluating or justifying the 20mph policy. If no Isle of Man-specific data has been used, please confirm this explicitly and provide details on what external sources (e.g., UK or international studies) were relied upon instead, and the rationale for applying them to the Isle of Man context.

Any evidence of impact assessments conducted on the Isle of Man regarding the introduction of 20mph speed limits.

Yours faithfully,"

While our aim is to provide information whenever possible, in this instance the public authority does not hold or cannot, after taking reasonable steps to do so, find the information that you have requested.

This is because the policy to convert non-20mph residential roads to 20mph was mandated by Tynwald. Therefore, requests for information on formation, justification

and evaluation of the policy should be directed to Tynwald and its members. The Department was instructed to implement this mandate.

There have been no impact assessments carried out by the Department of Infrastructure, prior to the implementation of 20mph speed limits.

In the interest of providing information, below are links to the published answers for Tynwald questions directed to the Department concerning the 20mph changes.

• W-202501-1530 - Q. What information regarding objections received following the statutory notice of the all-Island 20mph residential speed limit Order will be published; and when and where. - https://www.tynwald.org.im/spfile?file=/business/BusinessHansardIndex2126/ W-202501-1530.pdf

• W-202501-1531 - Q. What road, and time specific, average speed and traffic count information has been collected for Douglas and Onchan; and what speed and traffic count reduction is expected from a 20mph residential speed limit. - https://tynwald.org.im/spfile?file=/business/BusinessHansardIndex2126/W- 202501-1531.pdf

• W-202501-1537 - Q. If both the 20mph speed limit Road Traffic Regulation Act Order, for which a Statutory Notice was given on 7th March 2025, and any advice or decision paper considered before this statutory notice was issued will be published. - https://www.tynwald.org.im/spfile?file=/business/BusinessHansardIndex2126/ W-202501-1537.pdf

• W-202501-1663 - Q. If she will list the 140 locations referred to in the 20mph Project Implementation Plan (GD 2025/0026) as having been identified by 2021 as needing some form of physical carriageway change to achieve a self- enforcing 20mph speed limit ; and what if any changes have been made in those locations since they were so identified. - https://www.tynwald.org.im/spfile?file=/business/BusinessHansardIndex2126/ W-202501-1663.pdf

• W-202501-1664 - Q. If she will publish the 20mph speed limit implementation plan documents and slides considered at her Department's Policy and Strategy meeting on 29 April 2024; and, if so, when and how she will publish them. - https://www.tynwald.org.im/spfile?file=/business/BusinessHansardIndex2126/ W-202501-1664.pdf

• W-202501-1675 - Q. What Manx evidence there is of the impact of signed-only 20mph speed limits on a) median speed and b) collisions and casualties; how this compares to UK evidence including the Atkins study published in 2018; and whether her Department's view of this evidence has changed since 2020. - https://www.tynwald.org.im/spfile?file=/business/BusinessHansardIndex2126/ W-202501-1675.pdf

• W-202501-1679 - Q. Whether, and if so when and how, she will publish, for each street and road proposed for a 20mph signed-only speed limit in Douglas

and Onchan, the considerations undertaken and allocation decisions reached by her Department with reference to the five step process in the Manual for Manx Roads [GN-00-019]. - https://www.tynwald.org.im/spfile?file=/business/BusinessHansardIndex2126/ W-202501-1679.pdf

Please find below a link to all responses issued by the Department of Infrastructure under the Freedom of Information Act, along with research studies concerning the implementation of 20mph speed limits.

Department of Infrastructure

Please quote the reference number 4769397 in any future communications.

Your right to request a review

If you are unhappy with this response to your freedom of information request, you may ask us to carry out an internal review of the response, by completing a complaint form and submitting it electronically or by delivery/post.

An electronic version of our complaint form can be found by going to our website at https://services.gov.im/freedom-of-information/Review . If you would like a paper version of our complaint form to be sent to you by post, please contact me and I will be happy to arrange for this. Your review request should explain why you are dissatisfied with this response, and should be made as soon as practicable. We will respond as soon as the review has been concluded.

If you are not satisfied with the result of the review, you then have the right to appeal to the Information Commissioner for a decision on; 1. Whether we have responded to your request for information in accordance with Part 2 of the Freedom of Information Act 2015; or 2. Whether we are justified in refusing to give you the information requested.
In response to an application for review, the Information Commissioner may, at any time, attempt to resolve a matter by negotiation, conciliation, mediation or another form of alternative dispute resolution and will have regard to any outcome of this in making any subsequent decision. More detailed information on your right to a review can be found on the Information Commissioner’s website at www.inforights.im. Should you have any queries concerning this letter, please do not hesitate to contact me. Further information about freedom of information requests can be found at www.gov.im/foi.
I will now close your request as of this date.

Yours sincerely