08 January 2019
Efficient engines, advanced aerodynamics and low-rolling-resistance tyres have all helped to cut fuel consumption for truck operators in the past decade.
The next big breakthrough could come not from the technology in the trucks themselves, but from how they are operated.
In recent years there has been considerable discussion around HGV platooning, in which multiple trucks run closely together to reduce aerodynamic drag. With around 25% of a truck’s fuel used to overcome that drag, there are substantial benefits to be unlocked.
Depending on the terrain, even current adaptive cruise control (ACC) can yield a 3-4% reduction in fuel consumption with trucks travelling around 40m (1.5 seconds at 60mph) apart.
“There will be further savings when we have a smaller gap and much richer information being transmitted between the trucks,” says Christian Bergstrand, a customer project manager at Scania. “When we introduce autonomous technologies as well and no longer have to take the driver into consideration, we can have a really short gap. In the case where we will have one driver for a platoon of four trucks, we could cut fuel consumption by 10% or more for the time the trucks are in the platoon.”
In the short term, the biggest obstacles to the widespread adoption of platooning could be operational and legal. Bergstrand recognises that platoonable trucks can only be adopted if the operational processes around forming and dissolving a platoon are been defined. Therefore, it is likely that large fleets will initially lead the way in Europe by creating platoons of in-house trucks.
“We want to pinpoint those operators who can achieve platooning within their own organisation,” he confirms. “They can plan for coordinated departures and matchmake within the fleet. We want to then grow the volume so that [in time], smaller customers can benefit from more ad hoc platooning.
“We have to create a safe and stable platform to enable services to build upon the platooning capability,” he added. “But I see plenty of business opportunities for startups to create services for transport companies that enable them to platoon with anyone in a safe way.”
Cross-industry collaboration is key to solving the problems and Scania has been gathering feedback on the operational challenges in different markets. It conducted a trial in Spain with Acotral and is part of the Sweden4Platooning project in its home country, where the partners include DB Schenker and Volvo Trucks. Scania does not yet have a project in the UK, but it’s something that the Transport Research Laboratory is looking to develop.
“The biggest challenge (in the UK) is traffic congestion.” Says Bergstrand. “That would improve if we could use platooning to put all the trucks in one lane instead of having them spread out across multiple lanes.”
UK law specifies ‘driving with due care and attention’ and the Highway Code recommends a two-second gap to the vehicle in front, but it’s not a legal requirement that could stand in the way of the smaller gaps that platooning trucks will require. Other European countries do enforce minimum distances or time intervals however – 50m for fast-moving HGVs in France and Germany, for example – and these will prove an obstacle to implementing platooning unless there are changes in the law in those countries.
“Platooning is not allowed yet and we need countries to harmonise the legislation,” urges Bergstrand. “We are trying to collaborate on a local level with as many transport authorities as we can to explain the benefits and the issues, and to bring this to the attention of the decision makers. But it’s a challenge. There are many aspects to developing these new concepts – technology, legislation, driver acceptance, operational processes and so on. We have to work on these things in parallel because otherwise we will end up hitting a bottleneck at some point.”
Scania envisages a four-step process on the road to fully autonomous platooning. In Step 1, drivers maintain a gap of around 40m (1.5 seconds), assisted by ACC. In Step 2, the vehicles are wirelessly connected for simultaneous braking, which enables the gaps to be cut to 20m. It’s down to 10m in the next step, where the trucks become semi-autonomous for the first time: the first driver takes the lead and others behind are able to rest or sleep. Finally, in Step 4 only the lead truck has a driver while the others are autonomously driven.
Bergstrand is optimistic that Step 2 can be achieved very soon. But even before vehicle-to-vehicle technology is deployed, Scania is due to release an upgraded ACC system that’ll help achieve fuel savings from platooning. Rather than maintaining a fixed distance to the truck in front, the ACC will manage the gap dynamically to avoid unnecessary braking and optimise fuel consumption.
“The step to the semi-autonomous concept on a large scale is harder to foresee,” he assesses. It’s a challenge to determine what level of autonomy we need. Is it OK to have technology through which the drivers could resume control in 10-15 seconds, or should they be allowed to fall asleep? That’s partly regulated by laws and policies as well. The requirements have not been defined that would determine a possible introduction in, say, 3-5 years. Even so, I strongly believe that before 2025 we will have many semi-autonomous platooning trucks on European roads. Hopefully we will see many commercial trials on the roads even before that.”