One wintery day last December at the Volvo Proving Grounds near Gothenburg, Sweden, Erik Coelingh sat behind the wheel of a Volvo S60, drinking coffee and reading the newspaper, seemingly oblivious to the fact that his car was tailgating close behind a Volvo Technology FH 480 tractor-trailer truck. But despite the engineer’s complete inattention to driving, he was in no real danger. The modified S60’s steering wheel moved by itself as his car smoothly followed the lead truck around the track.
Coelingh, Technical Leader for Active Safety at Volvo Car Corp., was demonstrating a new prototype highway platooning system that is being developed with European Union (EU) support. If the R&D project is successful, a motorist could one day join a prescheduled, long-haul road-train that is led by a professional driver. As the car approaches the convoy, the driver would safely relinquish control and the vehicle, under wireless control, would automatically play “follow the leader” with the rest of the procession. Those trailing behind in the road-train would be free to read, eat, sleep, or do whatever they like until they reach their drop-off points.
“We were pleased to see that the various systems work so well together already the first time,” he said, noting that each component came from seven corporate and research partners.
“This is a major milestone for this important European research program,” said Tom Robinson, SARTRE (SAfe Road TRains for the Environment) project coordinator at Ricardo U.K. Ltd., which is leading the effort. “Platooning offers the prospect of improved road safety, better road space utilization, improved driver comfort on long journeys, and reduced fuel consumption and hence CO2 emissions.” The project, he added, aims to achieve this type of fail-safe autonomous driving “with existing sensor, automatic cruise control, and vehicle-to-vehicle (V2V) communications technology—and without large investments in infrastructure.“
Platooning addresses several big road-transportation challenges simultaneously, Coelingh noted. “For one, drafting closely behind another vehicle saves fuel and therefore lowers CO2 emissions,” he said. “We estimate platooning could save from 10 to 20% in fuel use, but that’s not confirmed yet. We’re doing extensive simulation to help find out.”
In addition, by packing vehicles into a smaller space, platoons can make better use of the road-surface capacity at a time when traffic congestion worldwide is getting progressively worse, he continued. Road-trains would also help to smooth out highway flow by opening up larger gaps in the traffic.
Another benefit of platooning is improved traffic safety, given that “human error—often distracted or inattentive driving—plays a role in 80 or 90% of all accidents,” Coelingh noted. “With automated or autonomous driving, you remove the human factor.”
“Finally, you can partially turn around the problem of increased driver distraction by avoiding some of the problem in the first place with automated driving,” he concluded. “This capability would provide new convenience and comfort benefits for drivers. With platooning, they can do the activities they want—talking, texting, or SMSing on a mobile phone, eating breakfast, reading the newspaper, watching video, and so forth—activities that previously would have distracted them from driving safely.”
With its multimillion Euro investment in the SARTRE project in the fall of 2009, “the EU announced that it was looking for step-change improvement in all these areas,” Robinson reported. The three-year, multidiscipline program is also distinguished by the need to study and master a raft of interrelated technologies that need to work together flawlessly to provide an effective, fail-safe service including sensors, communications, human-machine interfaces (HMI), vehicle safety and control systems, computer integrated engineering, aerodynamics, and traffic monitoring.
A diverse team of 15 to 20 full-time and other part-time engineers and researchers at seven organizations is working to meet the challenge, according to Robinson. “At the top level, we’re doing systems engineering to determine the types of fundamental interactions that will be required, and then we’re feeding the resulting control strategies we develop back into the simulation model to better understand the various constraints and parameters,” he explained. “Similar work is continuing on the vehicle interface, sensor integration, the autonomous (lateral and longitudinal) control system in the vehicle, its safety system, V2V communications, and so forth.”
Diverse engineering team
The Ricardo team is focusing primarily on “the strategies for the interactions with other road users such as how to handle road-train joining and leaving maneuvers, how to best resolve safety issues, etc.,” Robinson said. To understand the potential hazards associated with platooning, researchers are testing what is feasible by injecting faults into the models, doing analysis to define potential hazards, and compiling fully vetted operating scenarios. He noted that SARTRE’s autonomous control system is not just following the prior vehicle but tracking the platoon’s trajectory as set by the lead vehicle.
Volvo Cars is supplying the vehicle sensor system, which essentially provides a surrounding sensory envelope whose integrated or “fused” output is then passed to the automated control system. “We’re trying to use existing sensors as much as possible, though we might need more sophisticated ones,” he said.
Volvo Technology, a separate Swedish company, is providing the SARTRE project with lead trucks and motor coaches, following trucks, as well as the integrated sensor suite on each vehicle. Volvo’s SP Technical Research Institute in Sweden is meanwhile developing the V2V communications capabilities and performing certain safety analyses. Spain’s Applius+ IDIADA is to validate the operations of the system on its test tracks.
Researchers at the Robotiker-Tecnalia Technology Center in Spain, experts in human factors, are working to produce the onboard HMI systems by clarifying what communications the drivers will need to ensure road-train joining or leaving maneuvers are safe. They are, for instance, developing feedback mechanisms such as prompts and checks to ensure the drivers are ready to take control when they detach from a road-train convoy.
Germany’s Institut für Kraftfahrwesen Aachen (IKA), which has previous experience with truck platooning, is providing “back office” technology that will handle any commercial and logistical transactions that will be required when interacting with a road-train, Robinson noted. A prospective user will, for example, need to be told where to link up with a scheduled platoon, while the system would determine whether there is space in the platoon. Other crucial issues include what to do in emergencies, the specific responsibilities of the lead vehicle, and so forth.
Future platooning progress
Robinson said that there is some possibility that some dedicated highway lanes may be introduced in early implementations until drivers become more familiar with platooning, “but our goal is to avoid them to keep infrastructure costs down.” He added that he suspects truck drivers will be the early adopters of practical road-train technology.
“We’re talking about at least 10 years until we see a large-scale implementation of platooning,” Coelingh stated, especially since wide public acceptance, the adoption of the necessary enabling legislation in 25 EU countries, and professional drivers licensing will be needed beforehand. “On the other hand, we’ll see spinoffs that go into production earlier,” he predicted. These spinoffs might include advanced road radars, next-generation versions of the new ACC curve-control systems that take over and track the curve radius when danger is sensed, or low-cost V2V communications systems that talk to the highway infrastructure as well.