CAS Data Quality
Lewis T made this Official Information request to New Zealand Transport Agency
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From: Lewis T
Dear New Zealand Transport Agency,
Kia ora
As a member of the public with a keen interest in evidence-based policymaking, I am writing to better understand the governance and quality assurance frameworks that underpin the Crash Analysis System (CAS), which I understand is the authoritative dataset for road safety in New Zealand.
Part 1: Data Input and Verification Standards
Could you please provide:
A copy of the official data quality assurance framework, service level agreement, or memorandum of understanding currently in place between NZTA and the NZ Police. This document should outline the agreed-upon standards for the accuracy, completeness, timeliness, and reliability of the Traffic Crash Report (TCR) data that is supplied by NZ Police for inclusion in the CAS database.
A copy of the official training materials, manuals, or curriculum documents that are provided to NZ Police officers regarding the correct and consistent completion of TCRs to ensure the integrity of the data being fed into CAS.
Part 2: Management of Known Data Errors
Waka Kotahi's 2022 research report, "Alcohol-related crash trends" (Report 694), identified several significant, systemic errors within the CAS data from late 2018 onwards, including the "breath refused" and "blood pending" issues, leading the report to conclude that the data for this period is "unreliable."
Could you please provide:
A copy of the final-version internal risk assessment report or briefing note that details the discovery of these systemic errors, their root cause, and their impact on the overall reliability of the CAS database.
A copy of the official project plan, timeline, and budget that has been approved by Waka Kotahi senior leadership to correct these historical data errors and to prevent their recurrence.
Yours faithfully,
Lewis T
From: Official Correspondence
New Zealand Transport Agency
Kia ora Lewis
This email acknowledges your below request for information made under the Official Information Act 1982.
Your request has been forwarded to the appropriate section of NZ Transport Agency Waka Kotahi for response. They will contact you if they require clarification of your request, more time to respond, or if your request has been transferred to another organisation to respond to. Unless more time is required, NZ Transport Agency will send a response to you within 20 working days of receiving your request – in this instance on or before 28 October 2025.
If you would like to discuss your request with NZ Transport Agency, please contact us by email at [NZTA request email].
Ngâ mihi
Ministerial Services
Te Waka Kôtuia | Engagement & Partnerships
NZ Transport Agency Waka Kotahi
Connect with us on Social Media
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From: Official Correspondence
New Zealand Transport Agency
Kia ora Lewis
Partially transferring the request you made under the Official Information Act 1982
Thank you for your email below requesting information under the Official Information Act 1982 (the Act).
The following information you have requested is more closely connected with the functions of New Zealand Police than with NZ Transport Agency Waka Kotahi:
A copy of the official training materials, manuals, or curriculum documents that are provided to NZ Police officers regarding the correct and consistent completion of TCRs to ensure the integrity of the data being fed into CAS.
Therefore, NZ Transport Agency is transferring this part of your request to New Zealand Police under section 14 of the Act.
The time limit for their response to you is 20 working days from 23 October 2025 so you can expect a response from New Zealand Police on or before 21 November 2025.
Ngā mihi
Ministerial Services
Te Waka Kōtuia | Engagement & Partnerships
NZ Transport Agency Waka Kotahi
Connect with us on Social Media
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From: Official Correspondence
New Zealand Transport Agency
Kia ora Lewis
Please find attached the response to your request of 29 September 2025 for
information under the Official Information Act 1982.
Ngā mihi
Ministerial Services
Te Waka Kōtuia | Engagement & Partnerships
NZ Transport Agency Waka Kotahi
[1]Connect with us on Social Media
[2][IMG]
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From: Ministerial Services
Tēnā koe Lewis,
I acknowledge receipt of your Official Information Act 1982 (OIA) request below.
Your reference number is IR-01-25-38979.
You can expect a response to your request on or before 21 November 2025 unless an extension is needed.
Ngā mihi
Jonelle|Advisor: Ministerial Services |(she/her)
Policy & Partnerships |Police National Headquarters |
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From: Ministerial Services
Kia ora
I refer to your request below. I have been asked to advise you that Police requires an extension of time in which to respond to your request, pursuant to section 15A(1)(b), consultations necessary to make a decision on the request are such that a proper response to the request cannot reasonably be made within the original time limit.
Police requires until 28 November 2025 to provide a substantive response to your request, however we are endeavouring to provide this to you as soon as possible.
You have the right, under section 28(3) of the OIA, to make a complaint to an Ombudsman about this extension. Information about how to make a complaint is available at http://www.ombudsman.parliament.nz/ or freephone 0800 802 602.
Ngā mihi,
Siena (she/her)
Advisor - Ministerial Services
Police National Headquarters
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From: Ministerial Services
Tēnā koe Lewis
Please find attached the response relating to your Official Information
Act request, received by Police on 23 October 2025.
Please accept our apologies for the delay in providing you with a response
to your request.
Ngā mihi
Lisa
Ministerial Services
Police National Headquarters
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