Spotlight on Rural Road Intersection Safety – Are we applying cost-effective systems that can save lives?

Earlier in May 2022 was Road Safety Week in New Zealand.  As of 8 May 2022, there had been 138 fatalities in the calendar year, of which 98 (71%) were the driver or passenger of a motor vehicle. At the time of writing this piece on 11 May 2022, the overall figure had increased by two.[1]

New Zealand does not compare well to most of the OECD in terms of death rates.  The 2020 figures show that there were 6.25 deaths per 100,000 population.  This compares to 4.25 for Australia, 2.27 for the UK and 11.74 for the USA.[2]

Within the New Zealand road network, common locations for serious crashes are intersections, particularly in rural locations. These locations can often be poorly marked and involve high speed differentials between traffic approaching, entering or leaving the intersection. Data from Waka Kotahi NZ Transport Agency’s Crash Analysis System (CAS) Database for the three years between 2018 and 2021 (inclusive) indicates that up to 74 people died in crashes at or very near rural intersections.

Waka Kotahi do have a system, adopted from a Swedish concept, that is designed to reduce approach speeds through the detection of turning vehicles and those approaching on side roads and display of a mandatory, reduced speed limit on the mainline.  This Rural Intersection Active Warning System (RIAWS) is also used in Australia for the same purpose.

This is an effective system that has been in operation since 2012 and has been deployed at over 20 high-risk sites across New Zealand by the Armitage Group in conjunction with their partners.

One challenge with the system used (a combination of automated traffic detection and data collection, alarms, radar, variable mandatory speed signs and a control system that can be monitored remotely) is legislation.  Currently this requires any change in speed to be consulted on and gazetted. As with any consultation process, this introduces time and uncertainty.  In addition, the system and associated operational infrastructure is robust. Robust is never cheap.

This is not criticism of RIAWS or its purpose and use at all.  However, many of the fatalities that have occurred at intersections have done so in rural district councils. Due to the low ratings base, the site selection and justification process with Waka Kotahi and the consultation process, even with a 50% cost share it is a challenge for many rural district councils to treat the number of hazardous locations they and their communities may want to address.

There is the potential for a technology-based alternative that follows the principles of “good enough” when compared to RIAWS.  Council officers will know where their more dangerous intersections are through knowledge of their network. To be of value, any “good enough” system would need to be low-cost, rapidly re-deployable and effective.  This could be achieved by being:

  • Foundation-free (non-intrusive so avoids cultural and environmental impacts and is adjustable)
  • Based in the road reserve
  • Have simple illuminated messaging that is not mandatory or speed-based and so is easy to use (e.g. “Caution: Vehicle Approaching”) on a portable Variable Message Sign (VMS)
  • Solar or wind-powered
  • Standard design with installation instructions so can be done by maintenance crews
  • Wireless technology to detect vehicles and record behaviour.

A council could procure (or even lease) these as kits and then use them widely across their network to treat a multitude of locations without complicated planning, design and planning processes. It would give them flexibility and autonomy (off State Highways) to manage their own networks.

Even without technology, there are options that are cost-effective and technically effective.  DM Roads in Australia have started using innovative solar charged line markings that glow in the dark.[3]  Transverse rumble strips on the approach to an intersection can warn drivers of an upcoming stop or give way.  Even refreshing line markings and checking signage is clean and visible can help.

It might not always give the prettiest or most elegant solution, but being good enough can also save some lives.

This article was written by Morrison Low’s Bruce Walton, Associate Director, based in Wellington, with support from Kristina Foster, Project Support.