MASH meets wire rope safety

The Towards Zero website states flexible safety barriers are a proven treatment to save lives.

Following Austroads’ MASH transition of the current suite of wire rope safety barriers Roads & Infrastructure looks at other indicators and initiatives working to improve road safety.

Over the past two years the eligibility for product submissions to the Austroads Safety Barrier Assessment Panel (ASBAP) has been evolving.

Since the introduction of the Australian New Zealand Standard 3845, the standard has used the National Cooperative Highway Research Program Report 350 (NCHRP 350) as a guideline to assess safety barriers, and the Austroads Panel has reviewed products based on the report.

In 2017, two sections of the standard changed to use the American Association of State Highway and Transportation Official’s, Manual for Assessing Safety Hardware (MASH) guidelines as the basis for crash testing. The ASBAP has now updated its product submissions criteria and updated the current suite of accepted road safety barrier systems and devices to reflect this.

Since April 2018, all submissions received by ASBAP must meet MASH guidelines, or an equivalent, in line with the Australian and New Zealand standards 3845 Parts 1 and 2.

The Austroads Panel is currently working to transition the suite of temporary road safety barrier systems, transitions and part 2 products in the Australian and New Zealand market to MASH.

Austroads’ transition began with steel rail barriers and permanent concrete barriers on 31 December 2018, then terminals on 30 June 2019 and wire rope safety barriers and crash cushions on 31 December 2019. The final set of products to make the change are transitions, temporary barriers and Part 2 products which will come into effect on 31 December 2020.

MASH guidelines released in 2016 included a new matrix for cable barrier testing on slopes, modification to several test vehicle parameters and updated test documentation requirements.

The guidelines look to present parameters for crash testing of both permanent and temporary highway safety features and recommended evaluation criteria to assess test results. MASH provides minimum requirements for roadside safety features to meet, in order to demonstrate acceptable impact performance.

Improvements to the MashFlex barrier have included a height increase .

Following the introduction of MASH guidelines for product submissions, an Austroads guide – Network Design for Road Safety was released in May. The guide features a five-step process for roads which helps to determine road safety treatments based on levels of funding.

Each treatment option shows improvements in star rating using the International Road Assessment Program (iRAP). This allows asset managers to compare the crash risk benefit and cost of treatment, matching the solution to the available funding to get the best outcome.

The iRAP Star Rating Guide presents features and safety considerations that make a road safe. A basic five-star rating includes having a safety barrier separating oncoming vehicles and protecting roadside hazards, among other features.

One of the safety features that can be used to achieve the separation of oncoming vehicles and roadside hazards is a wire rope safety barrier. As of 31 December 2019, all wire rope safety barriers were subject to the Austroads transition.

Luke Gallagher, product Manager at Ingal Civil Products, says testing for wire rope safety barriers under MASH included vehicle size increases and a wider array of impact angles.

MASH has six test levels with vehicles ranging from a passenger car to a tractor-tank trailer with different speeds and angles applied to the impacts.

“The MASH guidelines modernise the previous NCHRP 350 recommendations that were published in 1993,” Gallagher says.

In Australia, Victoria has a major focus on safety barrier implementation under its Towards Zero campaign. By 2020 the Towards Zero Campaign will aim to install 330 kilometres of flexible wire rope safety barriers on high risk, high volume roads with speeds upwards of 100 kilometres per hour.

The initiative states that flexible barriers have been shown to reduce run-off road and head-on crashes by 85 per cent. The Towards Zero website states flexible safety barriers are a proven treatment to save lives, preventing vehicles from leaving the road and potentially hitting unforgiving roadside objects or rolling over.

MashFlex, from Ingal Civil is a four-rope, wire rope safety barrier assessed in accordance with MASH test Level 3 (TL3). Available across Australia and New Zealand, the barrier has been designed specifically to increase safety.

“The main benefit of the MashFlex Barrier is the increase in the height of the cables to offer better containment and protection for larger vehicles,” Gallagher says.

MASH TL3 involves two tests with heavy and light vehicles. The heavy vehicle impact test for MashFlex was performed using a 2270 kilogram truck travelling at 100 kilometres per hour and impacting the barrier at 25 degrees. The smaller vehicle test included the same speed and angle, but with a 1100-kilogram car.

Alongside the increased height of the barrier wires, the design of the MashFlex barrier focused on quick installation and repair.

“One of the key aspects is that our footing design has stayed the same, we knew MASH was going to come into place and we designed our footings to meet these standards. With many of our existing installations the footings can be reused, leaving only the above ground parts to be replaced with MashFlex,” Gallagher says.

The process to repair MashFlex barriers after an impact will depend on the magnitude of the crash however, in the vast majority of cases the wire cable is reusable and only the posts need replacing.

“NCHRP 350 was released in 1993 and the current version of MASH was released in 2016 so it’s a much more modern performance evaluation and it better reflects the vehicle fleet that we see on the roads today. MashFlex meets those guidelines whilst also being quick and easy to install and repair,” Gallagher says.

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