As the only road vehicle designed to be crashed into, it is important TMAs receive regular maintenance to help in providing safety to vulnerable road users. Tim Eato from Innov8 Equipment discusses the importance of TMA maintenance requirements.
The National Heavy Vehicle Regulator (NHVR) recognises the use of Truck Mounted Attenuators (TMAs), in the road construction and maintenance sector, is now a regular part of ensuring the safety of vulnerable road workers.
To keep traffic flowing during maintenance and other roadworks, it is important for asset owners to keep as much of the road open as possible.
However, traffic flowing in close proximity to workers presents safety risks. These are commonly reduced with safety features such as cones, lower speed limits, TMAs and sometimes physical barriers.
As TMAs act as the last line of defence between a car and a road worker, in many cases they are placed at the front of a worksite in the way of oncoming traffic.
In the event a TMA is hit, while the attenuator catches the oncoming vehicle, the brakes and tyres on the truck stop the oncoming vehicle from progressing too far into the worksite.
It’s for this reason that Tim Eato, Innov8 Equipment Business and Compliance Manager, believes brakes require regular maintenance as he says they are the most important feature of a TMA.
His belief is they should be tested beyond the registration stage, recommending tests every three months thereafter. As many TMAs use a compressed air braking system, not conducting regular maintenance of this system could increase the risk of brake failure.
“Without regular maintenance and checks to the compressed air system, the risk of brake failure is imminent. Our TMA’s have a regular maintenance check at heavy vehicle inspection stations every three months. As we hire out our vehicles it is important to ensure they are performing safely,” Mr. Eato says.
Hand in hand with the brakes, tyres play an important part in ensuring the truck’s roll ahead distance is safe for workers. It is for this reason Innov8 implements periodic inspections of both brakes and tyres instead of a kilometre-based service.
The NHVR Standards Guide (VSG-12) states that when designing the installation for a TMA, it is important to take into account the position of the attenuator unit on the vehicle.
This ensures when the unit is deployed, in any position, the minimum front axle load is suitable to allow effective steering and braking.
The NHVR guide cites the Performance Based Standards (PBS) steer tyre friction demand standard as a reference for suitable steer axel loading.
To ensure road worker and vulnerable road users are protected and the TMA is compliant with Australian standards, INNOV8 Equipment’s Blade TMA comes standard with weight distribution.
Mr. Eato says this is a crucial factor for safety. Moreover, if the weight distribution between the front and back axel on the TMA is too large, when the TMA is hit, it may force one end of the vehicle up into the air, compromising the vehicle’s safety benefits.
Another important obligation to be considered for the operation of TMAs is the disengagement of the automatic brake system. Stationary TMA’s have an automatic brake system that activates in the event that another vehicle crashes into the attenuator.
The NHVR G6 checklist, when certifying the fitting of air operated accessories, specifies the additional method of brake application on a truck or trailer mounted attenuator must be disengaged when the vehicle is travelling faster than 45 kilometres per hour.
For quick brake engagement, it is important to mount the automatic brake impact box as close as possible to the park brake.
“The unit has to be tested to ensure the automatic brakes are disengaged, but also to ensure the brakes will engage over 45 kilometres, especially if the TMA is covering rolling works. A key factor in ensuring quick brake engagement is for the air to travel the shortest path possible,” Mr Eato says.
“On Innov8 TMAs, the air travels roughly four inches out of the brake system and back in, so when the TMA is hit it reacts almost instantaneously,” he says.
Innov8 Equipment stresses that rear underrun protection is imperative to the safety of vulnerable road users. In 2018, it was federally mandated that, under section seven of the Motor Vehicle Standards Act 1989, with some exceptions, every ‘semi-trailer’ must be provided with a continuous rear bumper.
“The Blade TMA has a rear underrun protection device so that when the truck is stowed or travelling to its next location, and it gets hit, the oncoming vehicle will hit the rear underrun protection,” Mr. Eato says.
The Innov8 Equipment Blade TMA also features G force reduction technology, to slow the impact down and reduce the likelihood of injuries and fatalities to the driver of the errant vehicle.
“Innov8 TMAs use steel and aluminium to cause friction and heat upon impact, so the aluminium starts melting into the steel and melts it down, dissipating the energy rather than storing it and therefore reducing the G force,” Mr. Eato says.
He says it is important to note that for each of the MASH G force tests, the Blade TMA was not bolted to the ground.
“It’s imperative the product is tested in the conditions under which it would be used every day, then we can be sure the brakes and tyres will act the same when they are used in the field, which would not be bolted,” he says.
All of these safety factors work together on the Blade TMA to provide the best possible protection to vulnerable road users.
INNOV8 Equipment tests to the Australian Standard (AS/NZS 3845.2:2017) and other standards such as the NHVR and MASH, while completing regular maintenance to ensure quality performance.
“We are using proper engineering practices and independent engineers to test our TMAs. A TMA is the only device on the road that is designed to be crashed into and you want it to be working at 100 per cent, all the time,” Mr. Eato says.
INNOV8 Equipment are confident in the performance and quality safety features built in the Blade TMA.
While also testing the Blade TMA to the highest standards in Australia and fulfilling legal obligations, the company is working towards building traffic management equipment for the future, with the aim of protecting more vulnerable road users and road workers on Australian roads.
INNOV8 Equipment are business as usual at this time, with their team ready to discuss specific project needs to provide any project with a traffic solution.
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