KiwiRAP

Risk Maps - Defining Sections

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').

KiwiRAP focuses on state highway links that are typically outside the urban area - that is, state highway links that have speed limits of 80km/h or more.

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, i.e. trips between locations that are understandable and recognisable, such as 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.

The Risk Maps include results for a total of 172 links, and 10,856 kilometres of the state highway network. The links range in length from 2.4 to 318 kilometres, with an average length of 63 kilometres.

Each of these links has been assigned a rating for both Collective and Personal Risk. The methodology used to do this is discussed in "Levels of Risk".