New Zealand roads ranked by crash risk

CrashMap is a free, interactive map of New Zealand roads ranked by their expected number of fatal and serious-injury (DSI) crashes per kilometre per year. Machine-learning models trained on the NZ Transport Agency Waka Kotahi Crash Analysis System (CAS) predict how likely each recorded crash was to kill or seriously injure someone. Adding those probabilities up along each stretch of road gives its expected DSI: how often crashes happen comes from the crash record, and how severe they are comes from the model.

The map covers about 121,500 crashes from 2022 to 2025, snapped to 39,330 road lengths (about 26,500 km). Each year is scored by a model that never saw that year, and you can switch between 86 model configurations or average the five leading ones.

What you can do with it

• See the highest-risk roads in the country, grouped by road and district, and jump to any of them on the map.
• Filter by conditions such as weather, light, road surface, speed limit and road type. For example, rank roads by their wet-night risk or look at open-road state highways.
• Check how well the models tell serious crashes from minor ones in the model diagnostics view.
• Share any view: the link keeps the whole selection.

Read the risk bands with care

Roads are banded by their share of the ranked road length: the top 2 per cent are High, then Medium-high (to 5 per cent), Medium (to 15), Low-medium (to 40) and Low. The bands are relative and move with the filters. CrashMap measures risk per kilometre, not per vehicle, because no traffic volumes are used, so busy roads rank high partly because they are busy.

More: how the ranking is calculated, the data, sources and API, and who built CrashMap.