A new guide from the Australian Road Research Board is providing insights into the selection and application of high friction surface treatments – compounds designed to improve road skid resistance.
This September, findings from an inquiry into Australia’s National Road Safety Strategy 2011–2020 (NRSS) was delivered to the Federal Government at Parliament House in Canberra.
The NRSS inquiry panel made 12 key recommendations in its final report, one of which was setting a vision zero – or no deaths or serious injuries on the country’s roads – target of 2050. This included an interim target of vision zero from all major capital city CBD areas and high-volume highways by 2030.
The Bureau of Infrastructure, Transport and Regional Economics’ monthly bulletin on national road deaths reported 102 road deaths during August 2018 alone. While the figure was 8.3 per cent lower than the average for August over the previous five years, there is still a long way to go to reaching even the 2030 target.
For local councils and asset managers, being able to contribute effectively towards reaching that zero target could be achieved through mitigating risks and dangers on the roads through effective road treatments and proactive maintenance measures.
For the Australian Road Research Board (ARRB), identifying best practice in implementation and use of specific road technologies may also have role to play in reducing the road toll on Australia’s network.
This September, the national transport research organisation introduced new guidelines to assist local councils and road asset managers and engineers in properly using high friction surface treatments (HFSTs) and maximise its performance and durability.
HFST are compounds designed to make road more skid resistant, which ARRB says – used appropriately – can help stop vehicles from skidding on or off roads and increase a vehicle’s ability to brake at critical times.
ARRB says identified accident blackspots, approaches to intersections, pedestrian crossings and even tricky-to-negotiate corners can all benefit from the proper use of HFSTs. The High Friction Surface Guide – 2018 aims to represent good practice for the selection and application of HFSTs and identify the important aspects of this process.
Steve Patrick, ARRB Senior Professional Leader, Future Transport Infrastructure, compiled the guide and says the organisation recognised that there wasn’t any current guide on the selection and application of HFSTs in Australia and decided to fill that gap.
“The issue came direct from our CEO – he wanted to get things going and talk to the industry about the products out there and what was available in the market for local government, road authorities and contractors,” Mr. Patrick says.
For the purpose of the guidelines, the High Friction Surface Guide – 2018 defines HFSTs as a compound comprising a polymer resin adhesive binder that should bond to a high polished stone value (PSV)/low aggregate abrasion value (AAV) aggregate.
“The way define it in this guide, we’re talking about one potential kind of treatment and just one part of the road – you can’t use a blanket approach in its use as its application often is more to do with the specific characteristics of that section of road,” Mr. Patrick says.
Big sharp bends on rural networks and black spots – known danger spots on the network – are key areas where the application of HFST can be a viable addition to safety measures already in place.
“You can’t put this technology everywhere just through the nature of economy, but it is incredibly important to make sure we’re using them in the best way possible for areas where that kind of level of skid resistance is needed,” he says.
“There are other treatments out there, obviously. With asphalt, for instance, you can design asphalt including materials that will offer a high level of skid resistance, but this is a particular product with that high friction performance at its core.”
Mr. Patrick says HFSTs have been used historically in the UK and there is a developing market for the use of the technology in Australia.
The guide highlights international experience on HFSTs, citing a survey of HFSTs in the UK issued by the Association of Directors of Environment, Economy, Planning and Transport, which suggested the average design life of a HFST was between eight and 12 years.
Despite nearing the end of its functional service life, the oldest recorded site in Australasia was installed in 1998 and is still serviceable after 19 years, according to the guide.
“The technology has been under development for a while and we are seeing an increase in awareness, especially in how local government has been involved and has helped develop a greater understanding of the technology,” Mr. Patrick explains.
“The importance of the guide is to help anyone that does want to use it make informed decisions and maximise its use.”
To help define the selection, use and application of HFSTs, given the variables involved, the guide provides a model specification for HFSTs, which Mr. Patrick says is intended to be used as a framework for the development of local government, state or national specifications.
The guide says the model specification is primarily a performance-based one, with the onus for performance and compliance placed on the material manufacturer and contractor.
With no formal pre-qualification for products or contractors in place for HFST in Australasia, the guide outlines the importance of material manufacturers and contractors having a full and detailed understanding of the specification and what is required to achieve compliance. It outlines how this can be achieved through aspects such as criteria for HFST selection, information to be provided by a client; planning and coordination, occupational health, safety and environment requirements, planning and execution; surface preparation and installation processes.
Mr. Patrick says there is existing information from each state road authority on the selection, use and application of HFSTs. However, there is no one national source or specification – which ARRB is aiming to provide.
“There is always room for improvement, especially in road asset management and construction practices, which are under pressures to deliver optimal performance under state budgets. It’s a very hard thing to manage more tasks while still making more informed decisions around maintaining the network,” Mr. Patrick says “We can’t gold-plate our network, but we can definitely help encourage people to make good, informed decisions with road safety in mind.”