Truck-mounted attenuators (TMAs) are a critical piece of equipment to protect roadside workers from oncoming traffic.
In 2019, INNOV8 Equipment’s Blade TMA stopped a car-carrying truck from harming six roadside workers during night-time construction on an Australian road.
In just one of many examples, workers were less than 30 metres ahead of the TMA which absorbed the high-speed impact of the car carrying vehicle. Had the TMA not been there, in this instance, the outcome could have been much more sinister.
As of 1 January 2021, the Austroads Safety Barrier Assessment Panel (ASBAP) will only recommend TMAs that have been rated under the new Manual for Assessing Safety Hardware (MASH) standards. Existing TMAs can be used until impacted, but must be replaced with a MASH-approved crash cushion.
Already MASH-approved and recommended for national acceptance by Austroads, INNOV8 Equipment’s Blade TMA works to significantly reduce the danger of oncoming traffic to road construction workers.
The impact speed requirement for the MASH level TL-3 tests 3-50, 5-51 and 3-52 is 100 kilometres per hour at specified impact angles. Test 3-54 is the latest to be added to the standard, in which the vehicle collides with the attenuator at an offset angle. This test is currently optional and the Blade TMA has passed this test.
Nigel McKinley, Owner and Managing Director of INNOV8 Equipment, says in addition to the TMA crash cushion, these vehicles also warn and advise drivers of changed conditions.
“While the crash cushion is an excellent safety device, of course there are advanced warnings in place to try and prevent any impact in the first place,” he says.
In a usual site set up, there are warnings to drivers of changed conditions ahead in the form of signs or perhaps traffic cones placed strategically alongside the worksite. A TMA is then placed several metres before the working crew for extra protection.
In a last attempt to avoid an impact, the trucks are also equipped with arrow boards, beacon lights and Variable Messaging Sign (VMS) boards to alert drivers of lane closures. The TMAs are deployed at a safe distance before the start of the work zone. This ensures that if a vehicle does breach the work zone, despite advanced warnings, the impact will be safely absorbed by the attenuator and will not collide with the workers on the ground.
The Blade TMA features a unique design of 12 blades which strategically engage the safety mechanisms that make up the attenuator.
Another distinctive feature of the Blade TMA is the large size of the impact plate. When a vehicle hits the impact plate at the rear, the first section of the attenuator, called the H-beam, is smoothly pushed forward. After safely cutting through the aluminium frame, the nylon track gear and drive motor work together to actively slow the colliding vehicle to a safe stop.
The system also ensures any debris is pushed out and away from incoming vehicles, which works to keep the car in a direct line with the truck and reduce further damage. The design ensures minimal damage to the driver of the errant vehicle, the person inside the TMA truck and the workers ahead of the TMA.
“The bottom middle strips which cut the attenuator drop to the ground. These are referred to as the tongue. The tongue then carries the impacting car along while attached to the attenuator, as opposed to the car bouncing backwards,” Mr. McKinley says.
The results for the Blade TMA show exceptional performance across the four MASH tests with ride down values (measured in G-force) below the preferred values.
As the attenuator retracts in a smooth motion, it is designed to reduce whiplash by slowing the force and then safely bring the impacting vehicle to a slow and controlled stop.
As a result, the Blade TMA safely absorbs the force of the crash and brings the colliding vehicle to a safe stop from workers should an impact occur.
In addition to being nationally recommended by Austroads Safety Barrier Assessment Panel, the use of the Blade TMA has been formally approved by state road regulators in NSW, VIC, QLD and WA. There are no special conditions for the use of the Blade TMA due to its non-fixed testing conditions.
INNOV8’s vehicle of choice is the IVECO Eurocargo. Proposed changes to make Autonomous Emergency Braking (AEB) systems mandatory in all heavy vehicles across Australia from December 2022 will not impact the Blade TMA package as AEB is already a standard safety feature in the IVECO Eurocargo.
Other standard safety features include stability control and a lane departure warning system. The Eurocargo also features a Euro6 environmental rating which can assist during the tendering process on large projects.
Furthermore, IVECO has given approval for the Blade TMA to be fitted onto their trucks. IVECO is the only truck manufacturer in Australia that has approved the fitting of a TMA to their truck chassis.
For protection on arterial roads with lower speeds, INNOV8 Equipment also offers the Light TMA. The Light TMA currently does not fit under the category required for MASH testing and adheres to the NCHRP 350TL-2 standard.
The versatile Light TMA TL-2 crash cushion can add a layer of protection to a range of traffic management vehicles, including cone trucks, and is approved for impacts up to 70 kilometres per hour. Mr. McKinley says the attenuator also helps protect road workers or drivers that may come into harm if a vehicle hits the truck.
The Light TMA is also smaller and weighs less than a regular-sized TMA. This reduces wear on arterial roads and helps minimise traffic congestion during peak times.
For further protection, the Light TMA can be customised with arrow and visual messaging boards. It also features flashing and beacon lights to aid awareness of night-time works.
These extra steps are extra elements of Innov8 TMAs that ensure the best protection of workers.
“The purpose of these attenuators is to save lives. Ultimately it’s a safety device to protect road workers and it is essential these devices meet standards.”
To learn more about INNOV8 Equipment, visit www.innov8equipment.com.au