Dear New Zealand Transport Agency,
Kia ora,

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

1. Research, studies, or analysis held by Waka Kotahi
Please provide all documents, reports, internal analyses, briefings, memos, emails, or data extracts relating to:

The relationship between traffic‑signal outages (planned or unplanned) and traffic‑crash frequency or severity.

Any assessment of whether crash rates increase, decrease, or remain unchanged during periods when traffic signals are non‑operational.

Any monitoring, modelling, or risk assessments involving signal‑failure events and road‑safety outcomes.

If Waka Kotahi holds no such research, please confirm this explicitly.

2. International evidence held or reviewed by Waka Kotahi
Please provide:

Any literature reviews, international research summaries, or comparative assessments relating to crash risk during traffic‑signal outages.

Any documents referencing overseas findings (e.g., Netherlands, UK, Japan, US) where signal outages or deliberate signal removal were associated with changes in crash rates or driver behaviour.

Any internal consideration of whether such international findings have implications for New Zealand’s road‑safety framework.

If Waka Kotahi has never reviewed international evidence on this topic, please confirm this.

3. Data held on traffic‑signal outages
For the period 1 January 2010 to the present, please provide:

Any datasets, logs, or records of traffic‑signal outages, including date, time, duration, and location.

Any metadata describing how outages are recorded, categorised, or stored.

Any documents describing how outage data is used operationally or analytically.

If Waka Kotahi does not hold this information, please identify the agency that does.

4. Crash Analysis System (CAS) capability and limitations
Please provide:

The list of CAS variables relevant to intersections and traffic‑control devices.

Confirmation of whether CAS includes any field that captures signal‑status (e.g., “lights out”, “malfunctioning”, “flashing”, “power outage”).

Any internal guidance, schema documents, or data dictionaries describing how CAS handles traffic‑control device failures.

Any documents discussing the feasibility, limitations, or implications of analysing crash risk during signal outages using CAS.

If CAS has no ability to record signal‑status, please confirm this explicitly.

5. Internal consideration of the issue
Please provide any documents, emails, or internal discussions relating to:

Whether Waka Kotahi has ever considered studying the safety impact of traffic‑signal outages.

Whether such analysis has been proposed, rejected, deferred, or deemed unnecessary.

Any reasoning provided for not undertaking such analysis, if applicable.

6. Future plans or system upgrades
Please provide:

Any planned or proposed upgrades to traffic‑signal monitoring systems.

Any consideration of integrating signal‑status data with CAS or other safety‑analysis tools.

Any documents relating to improving the ability to analyse safety outcomes during signal‑failure events.

7. Clarification of responsibilities
Please identify:

Which agency or agencies are responsible for monitoring, recording, and analysing traffic‑signal outages.

Which agency or agencies are responsible for assessing the safety implications of such outages.

Format
Please provide all information in machine‑readable format (CSV, XLSX, or searchable PDF) where possible.

Withholding grounds
If any information is withheld, please specify the exact grounds under sections 6, 9, or 18 of the OIA and the public‑interest considerations applied.

Ngā mihi,
Nigel Gray

Yours faithfully,

Nigel Gray

Dear Official Correspondence,
Kia ora,

Thank you for your email of 19 May. I am happy to refine the request in a way that avoids any unnecessary collation while still enabling access to the information held.

1. Timeframe refinement
I accept your suggestion of refining the first part of item 3 to a 12‑month period. Please provide:

Traffic‑signal outage datasets, logs, or records for the period 1 May 2025 to 30 April 2026, including date, time, duration, and location.

2. Clarification of “metadata”
By “metadata”, I am referring to:

any data dictionary, field definitions, or schema describing how traffic‑signal outages are recorded in your system(s)

any classification rules, coding conventions, or system documentation that explains how outages are categorised, stored, or updated

any system‑level metadata that describes the structure of the dataset (e.g., field names, field types, units, code lists, or status categories)

This clarification should allow you to identify the relevant documents without substantial collation or research.

Please let me know if you require anything further.

Ngā mihi,
Nigel Gray

Yours sincerely,

Nigel Gray

Dear Official Correspondence,
Kia ora,

Thank you for your email of 19 May. I am happy to refine the request in a way that avoids any unnecessary collation while still enabling access to the information held.

1. Timeframe refinement
I accept your suggestion of refining the first part of item 3 to a 12‑month period. Please provide:

Traffic‑signal outage datasets, logs, or records for the period 1 May 2025 to 30 April 2026, including date, time, duration, and location.

2. Clarification of “metadata”
By “metadata”, I am referring to:

any data dictionary, field definitions, or schema describing how traffic‑signal outages are recorded in your system(s)

any classification rules, coding conventions, or system documentation that explains how outages are categorised, stored, or updated

any system‑level metadata that describes the structure of the dataset (e.g., field names, field types, units, code lists, or status categories)

This clarification should allow you to identify the relevant documents without substantial collation or research.

Please let me know if you require anything further.

Ngā mihi,
Nigel Gray

Yours sincerely,

Nigel Gray

Dear Official Correspondence,
Hi Chanell,

Thank you for your further email of 21 May.

1. Scope of data (1 May 2025 – 30 April 2026)
I confirm that I am happy to receive all traffic‑signal outage data held by NZTA, including:

data for NZTA‑owned assets, and

any data held by NZTA for assets managed by ATOC or WTOC, regardless of ownership.

To be clear, I am requesting all outage data that NZTA holds, whether the underlying asset is owned by NZTA or another Road Controlling Authority.

I understand that local councils may hold additional data for their own assets. I am not asking NZTA to obtain information from other agencies.

2. Scope of metadata
I confirm that I am happy to receive metadata, system documentation, schemas, data dictionaries, field definitions, and classification rules that relate to NZTA’s own systems and datasets.

Again, I am requesting only the information that NZTA holds. I am not asking NZTA to obtain metadata from local councils or other RCAs.

Please proceed on this basis.

Regards,
Nigel Gray

Yours sincerely,

Nigel Gray