Printed from https://fyi.org.nz/request/33141-normalisation-of-drug-detection-data-from-crashes-and-fatalities on December 26, 2025 08:12

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Normalisation of drug detection data from crashes and fatalities

J. P. W. Pitt made this Official Information request to Ministry of Transport

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From: J. P. W. Pitt

Tēnā koutou,

I am requesting the following information under the Official Information Act 1982.

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:

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.

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 happy to receive the information in electronic form.

Ngā mihi,
J. Pitt

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From: OIA
Ministry of Transport

Kia ora J,

On behalf of the Ministry of Transport, I acknowledge your Official Information Act request of 5 December 2025 seeking:

"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.

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."

We will endeavour to respond to your request as soon as possible, and in any event no later than 26 January 2026 being 20 working days after the day your request was received. If we are unable to respond to your request by then, we will notify you of an extension of that timeframe.

The Ministry publishes Official Information Act responses on our website when there may be wider interest in the information released. This means the information provided to you might be published after you have received it.

Ngā mihi nui,
Heather

Heather
OIA Adviser | Ministerial & Executive Services
Ministry of Transport Te Manatū Waka
transport.govt.nz

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From: OIA
Ministry of Transport

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Attachment OC251136 J Pitt OIA CE Response letter.pdf
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Kia ora J. Pitt,

 

Please find attached our response to your Official Information Act Request
of 5 December.

 

Ngā mihi

 

Ministerial and Executive Services

 

 

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