Te Waka Rangahau me Puukahatanga o Aotearoa


Drivers, Vehicles and Infrastructure

The safety and performance of the transport system depends on interactions between drivers, vehicles and the infrastructure. Many of the projects TERNZ has undertaken have investigated key aspects of these interactions.


Current and recent projects

Curve speed management:
This project identified ways of reducing the number of curve related crashes by determining the relationship between safety and curve speed through an analysis of crash data, surveying a number of representative curves, determining the appropriate safe curve speed for different vehicles and investigating in a simulator the effect of different warning sign and road marking treatments on drivers' curve speed selection and lateral positioning.

The cost-effectiveness of delineation improvements for safety:
Road-markings are an important component of the interaction between the driver and the infrastructure. It has been shown internationally that the use of audio tactile profile markings, known locally as rumble strips, significantly improves road safety by reducing "run off the road" crashes and "head-on" crashes. This study used international research to quantify these benefits and then develop a tool to evaluate the cost-effectiveness of applying this treatment to different road and traffic environments.

Tyre scuffing forces from multi-axle groups:
Over the years heavy vehicles have become larger and heavier to improve productivity and efficiency. To reduce the impact on the roads this has resulted in the increased use of multi-axle groups - tandem, tridem and recently quad axles. These multi-axle groups distribute the vertical load loads over a greater area and reduce the resulting pavement wear. However, when cornering these multi-axle groups apply greater shear forces at the road-tyre interface leading to the likelihood of increased road wear at intersections and roundabouts. This study investigated the effect of a range of vehicle and road geometry parameters on the magnitude of the scuffing forces generated by multi-axle groups.

Optimising heavy vehicle weights and dimensions:
The aim of this project is to improve the performance of heavy vehicles as a means of improving their productivity and safety while reducing their impact on the infrastructure and the environment. It has reviewed current vehicles by benchmarking them against overseas practice, determining what prevents the best vehicles from being used in New Zealand and what new initiatives could be introduced that will improve heavy vehicle performance.


    Other projects:

  • Performance-based standards
  • The effect of cross-sectional geometry on heavy vehicle performance and safety
  • Vehicle stability analysis including the development of the Static Roll Threshold (SRT) Calculator
  • Stability effects of sloshing liquids and hanging meat
  • Future options for road-worthiness enforcement for the European Union
  • Heavy vehicle brake testing and the development of the Brake Rule Compliance software
  • Self-explaining roads
  • The reduction of inadvertent speeding through road design
  • Dynamic wheel loads and pavement wear
  • Influences of vehicle loading on pavement wear
  • Small diameter tyres and pavement wear