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Official Information Act Request – Crash Classification Logic and Causation Determination

Nigel Gray made this Official Information request to New Zealand Transport Agency

This request has an unknown status. We're waiting for Nigel Gray to read recent responses and update the status.

From: Nigel Gray

To: Dear New Zealand Transport Agency,
From: Nigel Gray
Date:23 May 2026
Official Information Act 1982 Request
I am requesting the following information regarding the classification of road crashes as “drug‑related”, “alcohol‑related”, “medical‑event‑related”, or any similar causal category used in official reporting, dashboards, or public statements.

This request arises from the contradiction between:

Agency statements that no single factor can be confidently identified as the primary cause of a crash, and

The agency’s practice of classifying crashes into specific causal categories such as “drug‑related”.

To resolve this contradiction, I request the following information:

1. The decision rules used to classify a crash as “drug‑related”
Please provide:

The criteria, thresholds, decision rules, or tests used to determine that a crash is “drug‑related”.

Whether toxicology detection alone is sufficient to classify a crash as “drug‑related”.

Whether impairment must be established, and if so, how impairment is determined.

Whether causation must be established, and if so, how causation is determined.

2. The process for moving a crash from “pending toxicology” to “drug‑related”
Please provide:

The workflow, internal guidance, or standard operating procedures governing this change.

The roles or units responsible for making the classification decision.

Any quality‑assurance or review processes applied before the classification is finalised.

3. The evidential standard required to classify a crash as “drug‑related”
Please provide:

The evidential threshold required (e.g., presence, impairment, contribution, causation).

Any scientific, legal, or policy basis for this threshold.

Any documents that define or describe the difference between:

presence of a substance

impairment

causation

contribution

4. Reconciliation of the contradiction
Please provide:

How the agency reconciles the statement that “no single factor can be confidently identified as the primary cause of a crash” with the practice of assigning crashes to specific causal categories such as “drug‑related”.

Any internal documents, emails, memos, or guidance that address this issue.

5. Classification audit or accuracy checks
Please provide:

Any audits, reviews, or assessments of the accuracy, consistency, or validity of crash‑cause classifications.

Any documents discussing limitations, uncertainties, or risks associated with assigning causal labels based on toxicology results.

6. Historical or current definitions
Please provide:

All definitions of “drug‑related crash” used by the agency in the last 10 years.

Any changes to these definitions, including the dates and reasons for the changes.

Format
I request that all information be provided in electronic form.

If any part of this request is refused, please provide the grounds for refusal under the OIA and identify the person responsible for the decision.

Purpose (not part of the request, but for clarity)
This request seeks to understand the methodology and evidential basis for assigning causal labels to crashes, particularly where the agency has stated that causation cannot be confidently determined.

Yours faithfully,

Nigel Gray

Link to this

From: Official Correspondence
New Zealand Transport Agency

Kia ora Nigel

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 22 June 2026.

If you would like to discuss your request with NZ Transport Agency, please contact us by email at [NZTA request email].

Ngā mihi

Ministerial Services
Te Waka Kōtuia | Engagement & Partnerships
NZ Transport Agency Waka Kotahi
Connect with us on Social Media

-----Original Message-----
From: Nigel Gray <[FOI #34772 email]>
Sent: Saturday, 23 May 2026 3:45 pm
To: Official Correspondence <[email address]>
Subject: Official Information request - Official Information Act Request – Crash Classification Logic and Causation Determination

[You don't often get email from [FOI #34772 email]. Learn why this is important at https://aka.ms/LearnAboutSenderIdentific... ]

To: Dear New Zealand Transport Agency,
From: Nigel Gray
Date:23 May 2026
Official Information Act 1982 Request
I am requesting the following information regarding the classification of road crashes as “drug‑related”, “alcohol‑related”, “medical‑event‑related”, or any similar causal category used in official reporting, dashboards, or public statements.

This request arises from the contradiction between:

Agency statements that no single factor can be confidently identified as the primary cause of a crash, and

The agency’s practice of classifying crashes into specific causal categories such as “drug‑related”.

To resolve this contradiction, I request the following information:

1. The decision rules used to classify a crash as “drug‑related”
Please provide:

The criteria, thresholds, decision rules, or tests used to determine that a crash is “drug‑related”.

Whether toxicology detection alone is sufficient to classify a crash as “drug‑related”.

Whether impairment must be established, and if so, how impairment is determined.

Whether causation must be established, and if so, how causation is determined.

2. The process for moving a crash from “pending toxicology” to “drug‑related”
Please provide:

The workflow, internal guidance, or standard operating procedures governing this change.

The roles or units responsible for making the classification decision.

Any quality‑assurance or review processes applied before the classification is finalised.

3. The evidential standard required to classify a crash as “drug‑related”
Please provide:

The evidential threshold required (e.g., presence, impairment, contribution, causation).

Any scientific, legal, or policy basis for this threshold.

Any documents that define or describe the difference between:

presence of a substance

impairment

causation

contribution

4. Reconciliation of the contradiction
Please provide:

How the agency reconciles the statement that “no single factor can be confidently identified as the primary cause of a crash” with the practice of assigning crashes to specific causal categories such as “drug‑related”.

Any internal documents, emails, memos, or guidance that address this issue.

5. Classification audit or accuracy checks Please provide:

Any audits, reviews, or assessments of the accuracy, consistency, or validity of crash‑cause classifications.

Any documents discussing limitations, uncertainties, or risks associated with assigning causal labels based on toxicology results.

6. Historical or current definitions
Please provide:

All definitions of “drug‑related crash” used by the agency in the last 10 years.

Any changes to these definitions, including the dates and reasons for the changes.

Format
I request that all information be provided in electronic form.

If any part of this request is refused, please provide the grounds for refusal under the OIA and identify the person responsible for the decision.

Purpose (not part of the request, but for clarity) This request seeks to understand the methodology and evidential basis for assigning causal labels to crashes, particularly where the agency has stated that causation cannot be confidently determined.

Yours faithfully,

Nigel Gray

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

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

Please use this email address for all replies to this request:
[FOI #34772 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.

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Link to this

From: Official Correspondence
New Zealand Transport Agency

Attachment OIA 22302 Nigel Gray extension letter.pdf
152K Download View as HTML

Kia ora Nigel

Please find attached a letter advising of an extension to your request of 23 May 2026 for information under the Official Information Act 1982.

A response will now be sent to you on or before 6 July 2026.

Ngā mihi

Ministerial Services
Te Waka Kōtuia | Engagement & Partnerships
NZ Transport Agency Waka Kotahi
Connect with us on Social Media

-----Original Message-----
From: Nigel Gray <[FOI #34772 email]>
Sent: Saturday, 23 May 2026 3:45 pm
To: Official Correspondence <[email address]>
Subject: Official Information request - Official Information Act Request – Crash Classification Logic and Causation Determination

[You don't often get email from [FOI #34772 email]. Learn why this is important at https://aka.ms/LearnAboutSenderIdentific... ]

To: Dear New Zealand Transport Agency,
From: Nigel Gray
Date:23 May 2026
Official Information Act 1982 Request
I am requesting the following information regarding the classification of road crashes as “drug‑related”, “alcohol‑related”, “medical‑event‑related”, or any similar causal category used in official reporting, dashboards, or public statements.

This request arises from the contradiction between:

Agency statements that no single factor can be confidently identified as the primary cause of a crash, and

The agency’s practice of classifying crashes into specific causal categories such as “drug‑related”.

To resolve this contradiction, I request the following information:

1. The decision rules used to classify a crash as “drug‑related”
Please provide:

The criteria, thresholds, decision rules, or tests used to determine that a crash is “drug‑related”.

Whether toxicology detection alone is sufficient to classify a crash as “drug‑related”.

Whether impairment must be established, and if so, how impairment is determined.

Whether causation must be established, and if so, how causation is determined.

2. The process for moving a crash from “pending toxicology” to “drug‑related”
Please provide:

The workflow, internal guidance, or standard operating procedures governing this change.

The roles or units responsible for making the classification decision.

Any quality‑assurance or review processes applied before the classification is finalised.

3. The evidential standard required to classify a crash as “drug‑related”
Please provide:

The evidential threshold required (e.g., presence, impairment, contribution, causation).

Any scientific, legal, or policy basis for this threshold.

Any documents that define or describe the difference between:

presence of a substance

impairment

causation

contribution

4. Reconciliation of the contradiction
Please provide:

How the agency reconciles the statement that “no single factor can be confidently identified as the primary cause of a crash” with the practice of assigning crashes to specific causal categories such as “drug‑related”.

Any internal documents, emails, memos, or guidance that address this issue.

5. Classification audit or accuracy checks Please provide:

Any audits, reviews, or assessments of the accuracy, consistency, or validity of crash‑cause classifications.

Any documents discussing limitations, uncertainties, or risks associated with assigning causal labels based on toxicology results.

6. Historical or current definitions
Please provide:

All definitions of “drug‑related crash” used by the agency in the last 10 years.

Any changes to these definitions, including the dates and reasons for the changes.

Format
I request that all information be provided in electronic form.

If any part of this request is refused, please provide the grounds for refusal under the OIA and identify the person responsible for the decision.

Purpose (not part of the request, but for clarity) This request seeks to understand the methodology and evidential basis for assigning causal labels to crashes, particularly where the agency has stated that causation cannot be confidently determined.

Yours faithfully,

Nigel Gray

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

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

Please use this email address for all replies to this request:
[FOI #34772 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

Link to this

From: Nigel Gray

Dear Official Correspondence,
Subject: Clarification of extension grounds – OIA‑22302

Kia ora,

Thank you for your letter of 22 June advising an extension under section 15A of the Official Information Act.

To ensure the extension is properly grounded, please provide the following information:

1. The specific consultations relied upon under s15A(1)(b)
– Who is being consulted (roles or units, not individuals)
– What parts of my request require consultation
– Why consultation is necessary to make a decision
– Why the consultations cannot reasonably be completed within the original 20‑working‑day timeframe

2. Whether the extension indicates that NZTA does not hold some or all of the requested information
If any part of the request cannot be answered because the information is not held, please identify those parts so that I can consider whether a refusal under s18(g) would be more appropriate than an extension.

3. Confirmation of the revised due date
Your letter states that a response will be provided “on or before 6 July 2026”. Please confirm that this remains the intended date.

I would appreciate this clarification promptly, as the information requested is time‑sensitive.

Yours sincerely,

Nigel Gray

Link to this

From: Official Correspondence
New Zealand Transport Agency

Attachment image002.png
12K Download

Kia ora Nigel

 

Thank you for your email following receipt of the letter extending the
timeframe for responding to his request for information under the Official
Information Act 1982 (the Act) OIA-22302.

 

Regarding consultation, we are needing to consult external organisations
on some of the information we are proposing to release under the Act, such
as NZ Police, the Ministry of Transport, Auckland Transport.

 

The reasons for consulting externally on proposed release of information
is when the information was created by a third party or the information
relates to them.

 

Regarding section 18(g) of the Act, that the information requested is not
held by the department or venture or Minister of the Crown or organisation
and the person dealing with the request has no grounds for believing that
the information is either –

(i)                  held by another department (for itself and for a
departmental agency hosted by it or an interdepartmental executive board
serviced by it) or interdepartmental venture or Minister of the Crown or
organisation, or by a local authority; or

(ii)                 connected more closely with the functions of another
department (for itself and for a departmental agency hosted by it or an
interdepartmental executive board serviced by it) or interdepartmental
venture or Minister of the Crown or organisation or of a local authority:

 

This is a reason for refusing a request for information and is not a
consideration for extensions of deadlines.

 

Finally, yes as per our email we are intending to provide a response to
your request by or before 6 July 2026.

 

Ngā mihi

Ministerial Services
Te Waka Kōtuia | Engagement & Partnerships
NZ Transport Agency Waka Kotahi

[1]Connect with us on Social Media

 

[2][IMG]

 

-----Original Message-----
From: Nigel Gray <[3][FOI #34772 email]>
Sent: Monday, 22 June 2026 9:54 pm
To: Official Correspondence <[4][email address]>
Subject: Re: OIA-22302 NOTIFICATION OF EXTENSION

 

Dear Official Correspondence,

Subject: Clarification of extension grounds – OIA‑22302

 

Kia ora,

 

Thank you for your letter of 22 June advising an extension under section
15A of the Official Information Act.

 

To ensure the extension is properly grounded, please provide the following
information:

 

1. The specific consultations relied upon under s15A(1)(b) – Who is being
consulted (roles or units, not individuals) – What parts of my request
require consultation – Why consultation is necessary to make a decision –
Why the consultations cannot reasonably be completed within the original
20‑working‑day timeframe

 

2. Whether the extension indicates that NZTA does not hold some or all of
the requested information If any part of the request cannot be answered
because the information is not held, please identify those parts so that I
can consider whether a refusal under s18(g) would be more appropriate than
an extension.

 

3. Confirmation of the revised due date Your letter states that a response
will be provided “on or before 6 July 2026”. Please confirm that this
remains the intended date.

 

I would appreciate this clarification promptly, as the information
requested is time‑sensitive.

 

Yours sincerely,

 

Nigel Gray

 

-----Original Message-----

 

Kia ora Nigel

 

Please find attached a letter advising of an extension to your request of
23 May 2026 for information under the Official Information Act 1982.

 

A response will now be sent to you on or before 6 July 2026.

 

Ngā mihi

 

Ministerial Services

Te Waka Kōtuia | Engagement & Partnerships NZ Transport Agency Waka Kotahi
Connect with us on Social Media

 

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

Please use this email address for all replies to this request:

[5][FOI #34772 email]

 

Disclaimer: This message and any reply that you make will be published on
the internet. Our privacy and copyright policies:

[6]https://aus01.safelinks.protection.outlo...

 

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.

References

Visible links
1. https://www.nzta.govt.nz/contact-us/conn...
2. https://nzta.govt.nz/
3. mailto:[FOI #34772 email]
4. mailto:[email address]
5. mailto:[FOI #34772 email]
6. https://fyi.org.nz/help/officers

hide quoted sections

Link to this

From: Official Correspondence
New Zealand Transport Agency

Attachment image002.png
12K Download

Attachment OIA 22302 Nigel Gray response.pdf
193K Download View as HTML

Attachment Attachment 1 Rationale for news codes 29032016.pdf
571K Download View as HTML

Attachment Attachment 2 Code appendices Redacted.pdf
548K Download View as HTML

Attachment Attachment 3 MINUTES Crash Data Working Group 22 Sep 2025 Redacted.pdf
657K Download View as HTML

Attachment Attachment 4 MINUTES Crash Data Working Group 13 April 2026 Redacted.pdf
591K Download View as HTML

Attachment Attachment 5 Crash Data Quality Report Nov 2025 Redacted.pdf
589K Download View as HTML

Attachment Attachment 6 Crash Data Quality Report Dec 2025 Redacted.pdf
628K Download View as HTML

Attachment Attachment 7 Crash Data Quality Report Jan 2026 Redacted.pdf
589K Download View as HTML

Attachment Attachment 8 Crash Data Quality Report Feb 2026 Redacted.pdf
582K Download View as HTML

Attachment Attachment 9 Crash Data Quality Report Mar 2026 Redacted.pdf
586K Download View as HTML

Attachment Attachment 10 Crash Data Quality Report Apr 2026 Redacted.pdf
594K Download View as HTML

Attachment Attachment 11 Crash Analysis System Movement and Factor Codes excerpt Redacted.pdf
1.0M Download View as HTML

Kia ora Nigel

 

Please find attached the response to your request of 23 May 2026 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]

 

 

From: Official Correspondence <[3][email address]>
Sent: Wednesday, 24 June 2026 11:14 am
To: [4][FOI #34772 email]
Subject: RE: OIA-22302 NOTIFICATION OF EXTENSION

 

Kia ora Nigel

 

Thank you for your email following receipt of the letter extending the
timeframe for responding to his request for information under the Official
Information Act 1982 (the Act) OIA-22302.

 

Regarding consultation, we are needing to consult external organisations
on some of the information we are proposing to release under the Act, such
as NZ Police, the Ministry of Transport, Auckland Transport.

 

The reasons for consulting externally on proposed release of information
is when the information was created by a third party or the information
relates to them.

 

Regarding section 18(g) of the Act, that the information requested is not
held by the department or venture or Minister of the Crown or organisation
and the person dealing with the request has no grounds for believing that
the information is either –

(i)                  held by another department (for itself and for a
departmental agency hosted by it or an interdepartmental executive board
serviced by it) or interdepartmental venture or Minister of the Crown or
organisation, or by a local authority; or

(ii)                connected more closely with the functions of another
department (for itself and for a departmental agency hosted by it or an
interdepartmental executive board serviced by it) or interdepartmental
venture or Minister of the Crown or organisation or of a local authority:

 

This is a reason for refusing a request for information and is not a
consideration for extensions of deadlines.

 

Finally, yes as per our email we are intending to provide a response to
your request by or before 6 July 2026.

 

Ngā mihi

Ministerial Services
Te Waka Kōtuia | Engagement & Partnerships
NZ Transport Agency Waka Kotahi

[5]Connect with us on Social Media

 

[6][IMG]

 

-----Original Message-----
From: Nigel Gray <[7][FOI #34772 email]>
Sent: Monday, 22 June 2026 9:54 pm
To: Official Correspondence <[8][email address]>
Subject: Re: OIA-22302 NOTIFICATION OF EXTENSION

 

Dear Official Correspondence,

Subject: Clarification of extension grounds – OIA‑22302

 

Kia ora,

 

Thank you for your letter of 22 June advising an extension under section
15A of the Official Information Act.

 

To ensure the extension is properly grounded, please provide the following
information:

 

1. The specific consultations relied upon under s15A(1)(b) – Who is being
consulted (roles or units, not individuals) – What parts of my request
require consultation – Why consultation is necessary to make a decision –
Why the consultations cannot reasonably be completed within the original
20‑working‑day timeframe

 

2. Whether the extension indicates that NZTA does not hold some or all of
the requested information If any part of the request cannot be answered
because the information is not held, please identify those parts so that I
can consider whether a refusal under s18(g) would be more appropriate than
an extension.

 

3. Confirmation of the revised due date Your letter states that a response
will be provided “on or before 6 July 2026”. Please confirm that this
remains the intended date.

 

I would appreciate this clarification promptly, as the information
requested is time‑sensitive.

 

Yours sincerely,

 

Nigel Gray

 

-----Original Message-----

 

Kia ora Nigel

 

Please find attached a letter advising of an extension to your request of
23 May 2026 for information under the Official Information Act 1982.

 

A response will now be sent to you on or before 6 July 2026.

 

Ngā mihi

 

Ministerial Services

Te Waka Kōtuia | Engagement & Partnerships NZ Transport Agency Waka Kotahi
Connect with us on Social Media

 

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

Please use this email address for all replies to this request:

[9][FOI #34772 email]

 

Disclaimer: This message and any reply that you make will be published on
the internet. Our privacy and copyright policies:

[10]https://aus01.safelinks.protection.outlo...

 

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.

References

Visible links
1. https://www.nzta.govt.nz/contact-us/conn...
2. https://nzta.govt.nz/
3. mailto:[email address]
4. mailto:[FOI #34772 email]
5. https://www.nzta.govt.nz/contact-us/conn...
6. https://nzta.govt.nz/
7. mailto:[FOI #34772 email]
8. mailto:[email address]
9. mailto:[FOI #34772 email]
10. https://fyi.org.nz/help/officers

hide quoted sections

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