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CAS, Crash Analysis System – a crash analysis tool

The CAS is an integrated computer system that provides tools to collect, map, query, and report on road crash and related data. It contains data from all traffic crashes reported by police. It provides a platform for the development and implementation of new road safety initiatives, making a huge contribution towards crash prevention.

The information provided by CAS is used to determine and analyse trends, which help direct recommendations around road safety funding allocations, target road safety programmes and monitor their performance.

As part of the NZ Transport Agency's commitment to the government's Safer Journeys (external link)  strategy we have revamped our crash analysis reports (external link) . These reports identify and discuss issues of high strategic priority at a local authority (external link)  level where the highest risk of death or serious injury exists.

What does CAS do?

CAS is a tool that manages, analyses and maps traffic crash and related data. It is a computer system in which people can:

  • select crashes for analysis
  • map crashes
  • view images of the crash report diagrams
  • locate and map crash clusters
  • report on crashes or crash clusters
  • monitor trends at crash sites
  • automate the production of collision diagrams
  • identify high-risk locations.

What are crash analyses?

Crash data is analysed at different levels:

For example to identify trends in alcohol-related night-time crashes, or trends in truck crashes

Examples are crash trends on major local roads, or the location of wet-road crashes

For example the types and locations of crashes at a particular roundabout or intersection.

Typically, crash analysis is undertaken by selecting crashes and then using some of the many reporting tools provided by CAS. The information provided by the reports allows the NZTA  and our road safety partners to identify problem areas and trends that can then be focused on.

Who analyses crashes?

Many organisations in New Zealand contribute to improved road safety through road crash prevention. Major users of crash data include the NZTA, NZ Police, local authorities, engineering consultants, ACC, and universities.

Who ‘owns’ CAS?

The CAS system is managed by the NZTA, but decisions around the system are made by a governance group comprising the NZTA, NZ Police and Ministry of Transport.

What crash information does CAS hold?

CAS brings three main sources of road safety data together: crash reports, diagrams of crashes, and roading data, which includes road categorisation and traffic flows. The crash data collection is based on the fatal, injury and non-injury crashes reported to us by the Police.

Crash reports include:

  • Where the crash occurred
  • When and how it happened
  • Who was involved
  • The type of vehicle drivers or passengers were travelling in at the time of the crash
  • The people involved who were not in vehicles
  • Information about the crash environment
  • A crash diagram.

The NZTA then codes this information according to the type of crash movement involved (e.g. overtaking or right-angle intersection collision) and the factors contributing to the crash (e.g. driving too fast for the conditions or failing to stop at a Stop sign).

How is CAS linked to road information?

CAS has been designed to systematically link crash data with data from the road maintenance and management system (RAMM) used by all road controlling authorities in New Zealand. It does this by linking the road data to maps of the roads. Crash data is also linked to these maps, allowing road data to be combined with crash data.

What is mapping data?

The mapping data includes state highways, motorways, arterial roads, all roads, railways and railway stations, rivers and lakes, built-up areas, cities, towns, places of interest, territorial authority boundaries, regional government boundaries, census meshblocks and area units, , and police station, area and district boundaries.

When crash map co-ordinates are calculated by CAS, all the boundary-based information is automatically calculated, along with the crash location in terms of RAMM and the State Highway route position. The latter two linkages allow CAS crash data to be used externally to CAS in other systems, and data from other systems to be linked to crash data.

How is CAS made available?

CAS is available via the internet, using the Citrix Metaframe Technology which will download the first time you connect to CAS (external link) . The CAS session seen by the user is running on a server at Unisys in Auckland, and the screen produced there is accessible through the internet.  However, to access this you must first obtain a CAS licence, you can do so by contacting the IS service desk at NZTA.

There are a limited number of licenses and a license fee is required if you intend to connect to CAS directly.

Other ways of getting information from CAS include:

CAS video lessons are now available for new users.

Page updated: 30 March 2012