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

-----Original Message-----
From: Lewis T <[FOI #32419 email]>
Sent: Monday, 29 September 2025 10:55 pm
To: Official Correspondence <[email address]>
Subject: Official Information request - CAS Data Quality

[You don't often get email from [FOI #32419 email]. Learn why this is important at https://aka.ms/LearnAboutSenderIdentific... ]

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

-------------------------------------------------------------------

This is an Official Information request made via the FYI website.

Please use this email address for all replies to this request:
[FOI #32419 email]

Is [NZTA request email] the wrong address for Official Information requests to New Zealand Transport Agency? If so, please contact us using this form:
https://fyi.org.nz/change_request/new?bo...

Disclaimer: This message and any reply that you make will be published on the internet. Our privacy and copyright policies:
https://fyi.org.nz/help/officers

If you find this service useful as an Official Information officer, please ask your web manager to link to us from your organisation's OIA or LGOIMA page.

-------------------------------------------------------------------

This message, together with any attachments, may contain information that is classified and/or subject to legal privilege. Any classification markings must be adhered to. If you are not the intended recipient, you must not peruse, disclose, disseminate, copy or use the message in any way. If you have received this message in error, please notify us immediately by return email and then destroy the original message. This communication may be accessed or retained by NZ Transport Agency Waka Kotahi for information assurance purposes.

hide quoted sections