The NZ Transport Agency’s monitoring of road safety trends is vital in helping to keep everyone safe on our roads. WSP Opus joined forces with the NZTA to provide a smarter and more efficient way of reporting quarterly road safety monitoring for a number of networks throughout New Zealand, so they can continue to improve road safety and reduce the occurrence of serious injuries and deaths on our roads.

We analysed data from the Transport Agency’s Crash Analysis System, a tool that stores information on where, when and how road crashes occur, along specific State Highways, rural and urban road links as well as the full road network for each area. This analysis also included an additional network wide summary of head on crashes and crashes on out of context or high risk corners.   

Our point of difference is our Geospatial team, who used Geographic Information Systems (GIS) to develop an automated process to analyse and present vehicle crash data. GIS provides an efficient means to better identify and understand spatial and temporal or the “where” and “when” trends across a network. The spatial trends identify problem areas that may need safety improvements, and insight into whether the number and severity of crashes is increasing, decreasing, or remaining relatively unchanged. The trend also allows us to see the impact following changes made to the network such as safety improvements which should help reduce the severity of crashes at previously identified problem spots.

One of the important decisions was identifying the length of road to be monitored. This needed in depth local knowledge and awareness of the Safe Systems approach to road safety which is supported by a plethora of national and international studies, guidelines and software.

Using GIS means we can provide valuable information more efficiently for the Transport Agency, saving both time and money. The application of GIS in safety trend reporting provides a consistent approach and aids our road safety engineers in their informed analysis, reporting, and decision making about how to improve road safety and minimise the occurrence of serious injuries and deaths on our roads.

Our GIS data modelling and analysis means the quarterly reporting can be conducted more efficiently, ultimately saving lives, time and money. After initially developing this process for the Taranaki state highway network, the approach was adapted for Central Waikato, Northland, Westlink, and Northern Gisborne.