OC251136
19 December 2025
J. P. W Pit
[FYI request #33141 email]
Tēnā koe J.
I refer to your email dated 5 December 2025, requesting the following under the Of icial Information
Act 1982 (the Act):
I seek documents created or used by the Ministry of Transport that describe how the Ministry
interprets or normalises the presence of drugs in road crashes or fatalities, especially in relation
to population-level drug use. This information is required to understand the basis on which any
causal or contributory claims are made from drug-detection data.
Please provide:
1. Any documented methodology, guidance, or analytical notes held by the Ministry that explain
how drug-detection data (from Police, ESR, coronial toxicology, or the Crash Analysis System)
is interpreted for:
- official publications,
- road safety reporting, or
- policy advice.
2. Any documents that describe whether, and how, the Ministry compares drug-presence in
crashes to baseline population drug-use prevalence, including:
- the data sources used, and
- whether any statistical adjustments are applied (e.g., for detection windows, testing likelihood,
or relevance to impairment).
If no such methodology or normalisation process exists, please confirm this explicitly.
If part of this request is more appropriately answered by Waka Kotahi NZTA, NZ Police, ESR,
or another agency, please transfer those portions under section 14 of the Act.
I am refusing your request under section 18(g) of the Act, as the Ministry of Transport (the
Ministry) does not hold the information requested, and I do not have grounds to believe that the
information is held by another agency.
This is as the Ministry of Transport (the Ministry) does not hold formal documentation that
describe [sic]
how the Ministry interprets or normalises the presence of drugs in road crashes or
fatalities, especially in relation to population-level drug use for either parts one or two of your
request.
However, you may be interested to know when working with data extracted from New Zealand
Transport Agency’s (NZTA) Crash Analysis System (CAS), the Ministry’s statistics pages note how
drug crash information has been identified in the CAS data. This includes caveats around how the
transport.govt.nz | hei-arataki.nz
HEAD OFFICE: PO Box 3175, Wellington 6140, New Zealand. PH: +64 4 439 9000
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Ministry has interpreted it. These caveats may sometimes be reflected in our policy advice and
internal working papers. This information and the caveats in relation to drug driving road crashes or
fatalities are publicly available here:
https://www.transport.govt.nz/statistics-and-insights/safety-
annual-statistics/sheet/alcohol-and-drugs.
Your request is for material created or used
by the Ministry of Transport. We have no grounds to
believe that other agencies would hold the Ministry material described and which we ourselves do
not hold, and so I am unable to transfer your request.
However, I would encourage you to seek similar material setting out how agencies interpret or
normalises the presence of drugs in road crashes or fatalities from the agencies you suggest such
as New Zealand Police, New Zealand Transport Authority (NZTA), and the recently renamed New
Zealand Institute for Public Health and Forensic Science (formerly ERS).
You have the right to seek an investigation and review of this response by the Ombudsman, in
accordance with section 28(3) of the Act. The relevant details can be found on the Ombudsman’s
websit
e www.ombudsman.parliament.nz
The Ministry publishes our Of icial Information Act responses and the information contained in our
reply to you may be published on the Ministry’s website. Before publishing we wil remove any
personal or identifiable information.
Nāku noa, nā
Roselle Thoreau
Manager, Insights and Analytics
transport.govt.nz | hei-arataki.nz
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