Crash Analysis System (CAS) data

Crash Analysis System (CAS) data – user guide

This data comes from the Waka Kotahi Crash Analysis System (CAS), which records all traffic crashes reported to us by the NZ Police. CAS covers crashes on all New Zealand roadways or places where the public have legal access with a motor vehicle.

The data updates monthly, in the first week of each month.

Data is currently available from 1 January 2000. The dataset includes crash variables that are non-personal data.

To give you a quick overview of the data, see the charts in the ‘Attributes’ section below. These will give you information about each of the attributes (variables) in the dataset.

Each chart is specific to a variable, and shows all data (without any filters applied).

Crash Analysis System data - field descriptions


Data reuse caveats: we’ve taken reasonable care in compiling this information, and provide it on an ‘as is, where is’ basis. We're not liable for any action taken on the basis of the information. For further information see the terms of the CC-BY 4.0 International license.

CC-BY 4.0 International licence details

Variables in the dataset are formatted for analytical use. This can result in attribute charts that may not appear meaningful, and are not suitable for broader analysis or use. In addition, some variables aren't mutually exclusive – do not consider them in isolation.

You must not take and use these charts directly as analysis of the overall data.


Data quality statement: we aim to process all fatal crashes within one working day of receiving the crash report from NZ Police.

We aim to process all injury crashes (serious and minor injury) within 4 weeks of receiving the crash report.

It may take up to seven months for non-injury crashes to be processed into CAS.

Up-to-date information on current number of outstanding crash reports

Most unprocessed crash reports will be for crashes where there weren’t any injuries.


Data quality caveats: this data comes from the road traffic crash database Crash Analysis System (CAS) version 2.1.0. As the data is live, data can sometimes change after we receive it – that is, the data is not static after we publish it.

Waka Kotahi NZ Transport Agency maintains the Crash Analysis System. This open data is an appropriately confidentialised version of that.

After a crash, NZ Police send us a Traffic Crash Report (TCR). This may not happen immediately.

A crash must have happened on a road to be recorded in CAS. The CAS definition of a road is any street, motorway or beach, or a place that people can access with a motor vehicle.

There is a lag between the time of a crash to CAS having full and correct crash records. This is due to the police reporting time frame, and data processing.

People don’t report all crashes to the NZ Police. The level of reporting increases with the severity of the crash.

Crash severity is the severity of the worst injury in the crash. There may be more than one injury in a crash.

2020 and 2021 data is incomplete.

For API explorer users, there is a known issue with number-based attribute filters where the “AND” operator is used instead of the “BETWEEN” operator. Substituting “BETWEEN” for “AND” manually in the query URL will resolve this.Update 13/07/2021: previously, there was a 5 month buffer between our internal CAS data and our CAS open data. We have reduced this buffer to 1 month, due to user demand and improved systems.Update 10/12/2020: field type change. The field type for ‘crashFinancialYear’ has changed from integer to text.

Data and Resources

Additional Info

Field Value
Theme ["geospatial"]
Author Waka Kotahi
Maintainer Open.Data_NZTA
Maintainer Email Open.Data_NZTA
Source Created 2020-03-24T19:23:28.000Z
Source Modified 2023-09-18T05:23:32.791Z
Language English
Spatial { "type": "Polygon", "coordinates": [ [ [167.1006, -46.8560], [-177.6367, -46.8560], [-177.6367, -34.0715], [167.1006, -34.0715], [167.1006, -46.8560] ] ] }
Source Identifier
Dataset metadata created 10 August 2023, last updated 24 September 2023