Vehicle platooning

Time to fall in line

Recent trials suggest that electronically linking trucks together in platoons can reduce fuel consumption and emissions levels, while increasing road utilisation – and safety, too

Mercedes-Benz truck platoonIn April 2016, a fleet of trucks – some of which had driven almost 2,000km – arrived in the Dutch port of Maasvlakte and made modest headlines around the world. A few months later, a three-strong convoy of Volvo trucks hauled three containers on the interstate highway from the port of Los Angeles, again attracting extensive media coverage.

The reason? These were both trials of platooning technology. This system allows a number of autonomous or semi-autonomous trucks to be linked electronically behind a lead vehicle, so that they can all drive much more closely together than would be safe with human drivers. 

In such tight convoys, considerable savings in fuel consumption can be achieved, thanks to greater aerodynamic efficiency. Linked by wireless technology, the trucks’ onboard computers control acceleration and braking, and sometimes also steering, depending on the precise set-up. 

“While a human driver has a reaction time of 1.4 seconds, our platooning trucks transmit braking signals to the vehicles behind in less than 0.1 seconds,” explains Martin Zeilinger, head of advanced engineering at Daimler Trucks, which has conducted on-road platooning trials in Europe, Japan and the United States. “Connected vehicles in a platoon achieve a much closer separation distance, allowing a much more efficient use of road space: a platoon of three linked trucks might have a length of only 80 metres, as opposed to 150 metres.”

 The Californian trials, jointly sponsored by United States Department of Transportation and the California State Transportation Agency, involved the three Volvo trucks driving at speeds of 88kph while keeping just 15 metres apart. The European trials – part of the EU’s European Truck Platooning Challenge – involved similar separation distances.

Elsewhere around the world, platooning trials are either planned or already underway. Fuel consumption savings of 10-15% are being demonstrated, with similar reductions in CO2 emissions, while road utilisation is improved and driver fatigue is reduced. Given that driver error is stated as a causal factor in up to 90% of road accidents, improved road safety is a very real prospect. For truck manufacturers as well as logistics operators, such gains are likely to deliver real competitive edge.

Daimler platooning graphic

Truck in platoons take up much less road space than those travelling individually

“Platooning trials aren’t about demonstrating that platooning works,” stresses David Wright, interim director of the National Transport Design Centre at Coventry University, UK. “The energy benefit and aerodynamics of a convoy of platooned trucks is well understood. The challenge is to achieve reduced separation distances with automated interlinked acceleration and braking, and to be able to exploit, for the benefits of all the trucks in the convoy, the better visibility into road conditions ahead that the lead truck possesses. True optimisation will call for some very complicated algorithms. It’s not just about making a platoon happen, it’s about making it happen to best effect.” 

Moreover, adds Hayder Wokil, mobility and automation director at Volvo Trucks, platooning’s efficiencies are attainable across a wide range of truck weights, vehicle lengths and road conditions, as the 2016 platooning convoy to Maasvlakte demonstrated.

“Where legally permitted, we ran with three different lengths: 18.5 metres, 25 metres, and 32 metres,” he reports. “The message was that platooning delivers benefits on all the vehicle lengths that we tested. The technical issues lie in finding the ‘sweet’ spot that delivers optimum fuel savings in different road conditions, different weather conditions, and at different traffic densities. It’s complicated: compared to manual driving, for instance, the algorithms can actually create fuel consumption penalties in some conditions.”

 The regulatory hurdles

When it comes to regulating platooning, there are still more questions than answers, especially as platooning technology creeps closer to full autonomous operation.

“Currently, there are no clear regulations – whether in Europe, the United States, or Japan,” says Daimler Trucks’ Martin Zeilinger.

Take the basic question of the distance to be maintained between platooned vehicles, for example. 

“Connected vehicles in a platoon require a closer separation distance – for example, 15 metres, but in Germany, the legal minimum distance is 50 metres,” says Zeilinger. “In the US, the law is that the trucks should keep a safe distance. But ‘safe’ is not specified.”

Already, says Richard Saady, technical business manager at engineering consultancy Ricardo, platooning technology has advanced close to the point where adding more trucks to a platoon will deliver more benefit than further decreasing the separation distance between vehicles. But clearly, he adds, there are limits to how many trucks can be added to a platoon without compromising road safety.

 “There will need to be rules about the maximum number of trucks that are permitted to platoon together: ten trucks, for instance, is likely to be too many for safe operation. Most observers are expecting somewhere between two and five trucks to emerge as the likely limit.” 

Legal liability if things go wrong is another concern, adds Zeilinger. “As of now, the driver still has to constantly monitor the vehicle and the traffic situation at any time, so as to be able to take over full control of the truck again – and therefore the current law on liability remains valid,” he says.

But take away that safety driver and the picture suddenly becomes murkier, prompting Daimler to assemble a steering committee of experts to consider the legal and ethical issues involved.

“If there is a lead driver of the platoon, is he or she responsible for any incidents involving autonomous trucks following behind?” asks Amar Ramudhin, director of the Logistics Institute at the University of Hull, UK. “Or does the liability lie with the truck manufacturer, or the software developer? These are complex issues to resolve.”

Certainly, recent crashes and, indeed, fatalities stemming from the testing of autonomous cars in the US has prompted the realisation that autonomous operation is more challenging than had been anticipated, adds Richard Wilding from the UK’s Cranfield School of Management. 

“There’s been a wake-up call in the last six months,” agrees Alexander Mastrovito, head of sustainable transport solutions at Scania. “When you put autonomous vehicles on public roads, there’s no way that the current generation of software can deal with all the exceptions that exist in the real world when something unexpected happens. It’s resolvable, but it will take time.”

Government interest
Consequently, as truck manufacturers’ R&D teams wrestle with such questions, along with technology firms such as Peloton Technology, in the US, governments around the world are also taking a keen interest. 

The government of Singapore, for instance, has engaged Volkswagen’s truck manufacturing subsidiary, Scania, to conduct trials. The UK government has announced a platooning trial that is set to start at the end of 2018, carried out by the UK’s Transport Research Laboratory, using truck testbeds being prepared by engineering consultancy Ricardo, which has been involved in a number of such platooning trials around the world. And a number of Japanese truck manufacturers – among them Hino, Isuzu and Daimler subsidiary Mitsubishi Fuso Truck and Bus – have begun highway testing of truck platooning in Japan, in a project backed by the Japanese government.

“Some countries lend themselves more readily to platooning than others,” notes Christophe Domke, director of KPMG’s Mobility 2030 transport practice. “Real-world deployment of platooning in practice is going to take off fastest in countries where either the operating environment best lends itself to the concept, or where the business case is strongest. Think of Australia and the United States’ long stretches of low traffic density roads, for instance, or certain European countries. Although the UK government is backing trials of platooning, the UK is probably less suited to platooning than many other European countries – road conditions are poor and traffic density is high.”

That said, the country’s transport companies are not writing off platooning technology just yet. While acknowledging that other countries may offer longer distances and less congested roads, John Court, chief information officer at truck operator Eddie Stobart Logistics, which has a fleet of 2,200 vehicles, reckons his firm may be better able to exploit platooning than some of its competitors.

“Platooning is of particular interest to us as we have one of the most extensive road networks in the UK, which means that the opportunity to platoon our vehicles is probably greater for us than it is for many of our competitors, who don’t necessarily have the same density of fleet,” he explains. “We see it as a way of leveraging our transport network in order to drive further efficiencies, so we’re monitoring progress and working with technology partners to identify the most appropriate way forward.”

Real-world challenges
Despite such optimism, the challenges facing real-world platooning – as opposed to trials in controlled circumstances – are obvious. How closely will real-world fuel savings match those achieved under laboratory conditions, for instance? How will different truck manufacturers’ platooning technologies integrate and interoperate with each other? What standards and regulations will be required? How will truck platoons interact with other road users at critical points, like freeway exits and entrances? And what should be the maximum number of trucks in a platoon? Even now, with platooning trials well advanced, the answers to such questions are not obvious, say observers.

In practice, both regulators and truck operators may elect to feel their way towards the answers, with a process of gradual adoption, suggests Richard Wilding, professor of supply chain strategy at Cranfield University’s Cranfield School of Management, UK.

“Night-time operation on specific motorways is an obvious place to start: regulatory concerns will be fewer and traffic density will be lower, meaning it will be easier to maintain the constant speeds that maximise fuel efficiency,” he points out. “But perversely, congestion can be higher in specific locations at night, as lanes are closed off for road repairs, so as to avoid disruption to day-time journeys. The key thing is that regulators appear to be broadly supportive, seeing the obvious benefits that platooning can confer.” 

Compounding all these challenges is a certain lack of clarity around what level of platooning is most desirable. Is it so-called Level One platooning, which delivers the longitudinal coordination of trucks, achieved by control of acceleration and braking? Or Level Two platooning in which lateral coordination is added in the form of steering? Should platooning be restricted to groups of trucks from the same manufacturer, using identical platooning technology, or is multi-brand platooning, with a mix of trucks brands using disparate platooning technologies, the best way forward? 

 


Richard Wilding, Cranfield School of Management“Night-time operation on specific motorways is an obvious place to start: regulatory concerns will be fewer and traffic density will be lower, meaning it will be easier to maintain the constant speeds that maximise fuel efficiency.” – Richard Wilding, Cranfield School of Management

 


There are also difficult questions to be answered on the role of human drivers in the equation: should just the lead truck be manned, with following trucks being truly driverless, or will human operators still be required in every vehicle? And as autonomous vehicles are clearly on the way, could even that lead truck be driverless? 

 To some in the industry, there is no doubt that fully autonomous operation should be platooning’s logical objective. Take ride-hailing app provider Uber, for instance, which is among a number of firms pushing ahead with self-driving vehicle technologies. According to a spokesperson for Uber’s advanced technologies group, its view is that platooning should only be adopted in trucks that can already operate autonomously on a standalone basis. This, in Uber’s view, is the “only safe way” to roll platooning out in the real world.

Certainly, fully autonomous trucks would dramatically extend the business case for platooning, says Amar Ramudhin, director of the Logistics Institute at the UK’s University of Hull.

Fact 0.1“At present, the benefits of platooning for truck operators – as opposed to benefits to society at large, through things like lower CO2 emissions and better road utilisation – are really limited to improved fuel efficiency. Going much beyond that will require autonomous vehicles, which hold out the promise of reducing the trucking industry’s need for drivers – an obvious attraction, given that there are driver shortages in Europe, North America and parts of Asia. But that won’t be easy, as there are obvious regulatory challenges to address. And it may call for changes in road infrastructure, with a new kind of ‘mixed mode’ operation coming into play: autonomous operation on freeways, say, and then human drivers picking up the trucks from parking lots by the freeway, and taking over for ‘final mile’ deliveries into urban environments.”

Some go even further, envisaging platooning as part of a technology-led redesign of how trucks operate and interface with each other and the wider world. Prasad Satyavolu, chief digital officer at technology services provider Cognizant, for instance, considers such issues to be platooning’s biggest challenge.

“Platooning is going to work and it’s going to happen: those challenges are going to be overcome. But it needs to be easier for trucks to join platoons on an ad hoc basis, to take advantage of any existing platoons that they happen to encounter, as opposed to relying on platoons that are planned in advance. And roads and roadside technology will need re-designing so as to maximise the opportunity of platooning – changes to highway entry and exit points, for instance, and dedicated platooning lanes where it will be easier to maintain constant speeds for long distances. And there’s an obvious need for digital links to third-party applications: GPS data, weather data, data on traffic conditions, and so on.” 

Scania truck platoon

Several key questions remain over the role of human drivers in platoons

That might sound fanciful, but it is precisely such a vision that lies behind Singapore’s interest in platooning, says Alexander Mastrovito, head of sustainable transport solutions at Scania, the manufacturer tasked by Singapore’s government with conducting platooning trials. In addition to facing a driver shortage, some 12% of Singapore’s total land is used for road and land transport infrastructure, he explains, and having tested the autonomous operation of cars, taxis, utility vehicles and buses, the Singaporean government’s attention has now turned to platooning.

 “Unlike Europe and the US, where the primary attraction of platooning is improved fuel consumption, the goal in Singapore is to reduce the need for drivers,” explains Mastrovito. “Their vision is of a lead truck with a human driver, and then autonomous vehicles following behind, like a railway train – and not just within Singapore’s port operations but on the public highway.”

Turning that vision into reality, he concedes, is still some way off, but trials proceed. A year-and-a-half into the project, the various Singaporean government-specified use cases have been demonstrated on Swedish test tracks, he explains, and the next stage is to take the vehicles to Singapore itself for further development work.

“The key learning so far is that the goal is achievable, but that it is more challenging than first anticipated,” Mastrovito sums up.

Meanwhile, in Germany, a collaboration between MAN Truck & Bus, logistics services provider DB Schenker and technical university Hochschule Fresenius has just deployed platooned trucks for the first time in a practical application in the logistics industry.

“Once an intensive training phase has been completed, there will be weekly test runs, and then daily test runs,” explains MAN Truck & Bus chief technical officer, Frederik Zohm. “These will then be extended to include regular operations with actual cargo during the course of 2018, with platoons deploying up to three times daily between DB Schenker logistics centres in Munich and Nuremberg.”

 It is clear from this alone that platooning has begun to move out of the laboratory and into the real world. One way or another, it seems, we’re all about to discover a lot more about how platooning works in practice.

 

 Mixed views on platooning’s true potential 

Scania truck platoonWhile the benefits of platooning will apply to trucks of many kinds – including traditional curtainsided or box van vehicles carrying pallets of inbound parts for car assembly lines, say – its appeal to those moving finished vehicles in open car transporters is less clear, leaving vehicle operators in this sector with mixed views on its true potential. 

In the US, Jack Cooper Logistics is working with Kettering University as part of its programme studying the potential of platooning, says the car carrier’s president, Andrea Amico.

“We’re following with interest the evolution of technologies that enable safe platooning,” he comments. “The estimated savings are substantial.”

At the same time, however, Amico recognises that the technology is at a very early stage of development and faces some obvious challenges – some relating to trucking in general and some to finished vehicle transport.

 “Important limiting factors for trucking in general include safety, reliability and the cost of platooning technologies, and also the fact that the necessary regulatory environment is not there yet, with no significant record on litigation to help estimate the exposure,” he says. 

“For car-hauling specifically, the calculations on fuel savings need to be validated with car-haul trailers, because their form factor, drag and configuration – for example, whether they are full, half-loaded, or empty – may severely affect potential fuel savings, and it may be difficult to achieve the required density of distribution compared to other industries. 

“In short, we continue to follow the evolution of platooning technology but at this time, we’re expecting adoption in car-hauling to trail adoption in other sectors of trucking,” he concludes. 

In the UK, truck operator ECM – a specialist in final-mile delivery to dealers as opposed to full-load transport to ports or railheads – is similarly unconvinced. 

Allen Stuart, ECM’s commercial and finance director, points out that the company’s transporters operate on a highly dispersed basis, with each transporter potentially carrying vehicles for multiple dealerships. 

Stuart says ECM currently sees little opportunity for platooned transporters. The congested locations of most dealerships – even when located in out-of-town retail parks – hardly lend themselves to the arrival of multiple vehicles and autonomous operation is even more problematic, he adds, with the human driver playing a key role in the handover process.

“Today, the reality is that vehicle delivery volumes are fluctuating significantly and unexpectedly, which means that a high degree of operational flexibility is required,” he comments. 

“The worry is that setting up a platoon of trucks may lead to a reduction in operational flexibility, resulting in a less agile truck and driver resource base,” Stuart continues. “That said, if platooning were possible, it might reduce driver stress and fatigue, therefore mitigating two factors that contribute towards the unpopularity of truck driving as a profession.”