Kia ora Nigel

 

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Official Information Act 1982.

 

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-----Original Message-----
From: Nigel Gray <[FOI #34901 email]>
Sent: Tuesday, 16 June 2026 8:31 am
To: Official Correspondence <[email address]>
Subject: Official Information request - Request for information —
Classification of “drug‑related” crashes

 

[You don't often get email from
[4][FOI #34901 email]. Learn why this is
important at [5]https://aka.ms/LearnAboutSenderIdentific... ]

 

,

To: Official Information Act Team, NZ Transport Agency Waka Kotahi

From: Nigel Gray

Subject: Request for information — Classification of “drug‑related”
crashes

 

Dear New Zealand Transport Agency

1. Purpose of this request

This request follows a recent OIA response from New Zealand Police
(IR‑01‑26‑18611, 12 June 2026), in which Police confirmed:

 

they do not classify crashes as drug‑related

 

they do not hold definitions of “drug‑related crash”

 

they do not apply thresholds, criteria, or decision rules

 

they do not determine impairment or causation

 

they do not reconcile the contradiction between “no single cause” and the
use of causal labels

 

they do not audit the accuracy of any such classifications

 

Police further stated that NZTA is responsible for any classification used
in national reporting.

 

Accordingly, this request seeks the classification logic, definitions, and
evidential basis NZTA uses when publishing “drug‑related crash”
statistics.

 

2. Request

2.1 Definitions and classification rules Please provide all NZTA
definitions of:

 

“drug‑related crash”

 

“drug‑impaired driver”

 

“drug involvement”

 

For each definition, please provide:

 

the date it was adopted

 

the reason for adoption

 

any changes over the last 10 years

 

the scientific, legal, or policy basis for the definition

 

2.2 Evidential thresholds

Please provide the evidential thresholds NZTA uses to classify a crash as
drug‑related, including:

 

presence of a substance

 

impairment

 

contribution

 

causation

 

For each threshold, please provide:

 

how it is determined

 

who determines it

 

whether Police evidence is required

 

whether coronial findings are required

 

whether toxicology presence alone is sufficient

 

2.3 Classification workflow

Police have stated they do not classify crashes and hold no workflow for
doing so.

 

Accordingly, please provide NZTA’s workflow for assigning the
“drug‑related” label, including:

 

the staff, units, or contractors responsible

 

the decision‑making process

 

any internal guidance or SOPs

 

any automated or algorithmic processes

 

any quality‑assurance or review steps

 

If no workflow exists, please confirm this explicitly.

 

2.4 Source data and authority

Police have stated they:

 

do not determine impairment

 

do not determine causation

 

do not classify crashes

 

do not define “drug‑related crash”

 

do not audit accuracy

 

Given this, please provide:

 

the source data NZTA relies on to assign the “drug‑related” label

 

whether NZTA receives coronial toxicology

 

whether NZTA receives coronial causation findings

 

whether NZTA uses Police TCR fields that Police themselves state are not
causal determinations

 

2.5 Reconciliation of the contradiction

Police have stated:

 

“Police does not hold internal documents reconciling this distinction.”

 

Accordingly, please provide NZTA’s reconciliation of the following
contradiction:

 

NZTA publishes statistics claiming specific causal categories (e.g.,
“drug‑related”), while

 

Police state no single factor can be confidently identified as the primary
cause of a crash.

 

Please provide:

 

all internal documents, emails, memos, or guidance addressing this
contradiction

 

any risk assessments relating to misclassification

 

any limitations statements used internally or externally

 

2.6 Accuracy, audits, and validation

Please provide:

 

any audits, reviews, or assessments of the accuracy of NZTA’s
“drug‑related crash” classifications

 

any documents discussing limitations, uncertainties, or risks associated
with assigning causal labels

 

any correspondence with Police or the Ministry of Transport regarding
classification accuracy

 

If no audits exist, please confirm this explicitly.

 

3. Time period

Unless otherwise stated, this request covers the period 1 January 2014 –
present.

 

4. Format

Please provide all documents in searchable electronic form (PDF, DOCX,
XLSX, or equivalent).

 

5. Right to complain

I note my right to complain to the Ombudsman if this request is refused or
delayed.

 

Yours faithfully,

 

Nigel Gray

 

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