The trucking industry is going to have to learn about living with AEB, when it becomes a required system on trucks. The government is proposing to require autonomous emergency braking (AEB) to be fitted to all new model trucks by November 1 2020 and to be fitted on all new trucks sold in Australia by November 1 2022. The ADR in development will be based on the European UNECE 131 specifications.
A truck colliding with a car is almost always going to see the occupants of the car coming off worse. No matter who is to blame for the collision, the idea behind this latest move from the Department of Infrastructure is to find a technological solution to an ongoing problem, a way to reduce the death toll on our highways.
The fact of the matter is, in fatal crashes involving a truck, the other vehicle is at fault in up to 83 per cent of the time. Due to their size and weight, trucks have longer stopping distances than cars. As a result, fewer fatal accidents involve a car colliding with the rear of a truck, but there are many more with the truck rear ending the car.
The Regulatory Impact Statement published by the Department of Infrastructure in the run up to this proposed legislation tells us Australian research has found that living with AEB systems meeting the requirements of UNECE 131 could, ‘alleviate or reduce the severity of almost 15 per cent of all Australian heavy vehicle crashes, predominantly those involving a heavy vehicle impacting the rear of another vehicle’. The figures also suggest that in such collisions, truck AEB reduces all forms of trauma by up to 57 per cent.
Living with AEB in Europe became mandatory in Europe in 2013. The process of getting the technology introduced here had to follow a logical path. Working towards the mandating of AEB has had to wait for the other supporting technologies of Anti-lock Brake Systems (ABS) and Electronic Braking Systems (EBS) to be mandated across Australia.
Running something like AEB without ABS or EBS would be impractical. AEB needs these technologies to guarantee the stability of a combination under the severe conditions of automatically generated braking by AEB systems. An AEB prime mover with dumb trailer will often only activate the engine brake not the emergency brake.
How the System Works
The truck uses a radar system, sometimes aided by a forward facing camera to detect vehicles or obstacles in front of the truck. The radar is good at measuring relative speed and distance, while the camera, which is not used in all of the systems on the market, can see the shape of the object and whereabouts on the road it is. The camera helps the system to avoid a false positive.
The computer system on the truck uses all of this data to analyse the situation. Alongside this, it also monitors the information it gains from the CANbus about how fast the truck is going, estimated mass of the combination, what the driver is doing, accelerator and brake position.
This data is brought together to constantly monitor the situation. If the AEB calculates there is likely to be a collision, this sets off a series of actions on the part of the truck systems. The first port of call is to alert the driver to a potential problem ahead.
“It’s not about slamming the brakes on, because there’s something in front of you, it’s actually trying to avoid the accident it thinks may happen,” said Scott Simpson, Senior Product Manager Volvo Group Australia, explaining living with AEB at the TMC. “It has visual and audible warnings. “One thing it is important to remember is that you need to have ABS or EBS trailers coupled onto the prime mover.
“The visual can be done in a couple of different ways. Either a light in the dash or through a heads up display onto the windscreen. It depends on how the truck is configured. The audible alarm will simply go off in the cab, so that the driver gets a warning.
“In the Volvo the first visual warning is a red light across the top of the dash. The second warning sees a flashing heads up display alert comes up as well as an audible alar. Then we go into the pre-brake stage, which brings up both warnings again as it starts to apply the brakes.”
By starting to apply the brakes, it is hoped this will alert the driver to the situation and prompt them to act. This next stage in the process sees the system start to really intervene. It will start to put the brakes on, if it has not seen the driver take any action as a result of the warning. This action could be turning the steering wheel, applying the brakes or applying the accelerator to try and steer out of the way.
“All of this takes place before we go to the final stage where it applies all of the braking capacity to enable a full emergency stop.” said Scott. “It is possible for the truck to brake down from 80km/h to 12km/h in four seconds.
“Although the headline here is about the emergency braking, but it’s not just about that. It’s about the driver being warned and getting them to take evasive action, before emergency braking is needed.”