Risk Maps – how the sections were identified

For the purpose of comparing the level of risk of crashes between different parts of the network, the state highway network was broken up into road sections (known as 'links').

When the first KiwiRAP Risk Maps were developed using 2002-2006 fatal and serious crash data, the state highways were split into links using three criteria:

To increase the statistical reliability of the results, each link should be long enough to have a minimum of 20 fatal or serious crashes over the last five year period.
Links should be meaningful and distinct to drivers and riders, i.e. trips between locations that are understandable and recognisable, such as major towns or major intersections.
Links should have broadly similar road characteristics along their length, such as one lane in each direction without a median barrier, and traffic volume.

The same links that were developed and used for the first Risk Maps released in 2008 were used, where possible, in developing the updated 2012 Risk Maps.

The 2012 Risk Maps include results for a total of 168 links, and 10,849 kilometres of the state highway network. The links range in length from 7.3 to 318 kilometres, with an average length of 65 kilometres.