Daimler Trucks North America is performing trials on Oregon highways of tractor-trailers with driver-assist technology, the same technology that keeps cars in their own lanes and provides automatic braking.
The technology is not new, much of it is available in passenger cars and trucks, but Daimler is testing its application on its big rigs. Specifically, Daimler is pairing two of its own Cascadia model trucks to see how they perform together and what fuel efficiencies they achieve. The trials could result in running as many as five trucks together, a practice called platooning.
“What they’re testing is truck platooning with a driver-assist system,” said Andrew Dick, the connected, automated and electric vehicle adviser at the Oregon Department of Transportation. “Drivers are always at the wheel. The system is closely coordinating the acceleration and braking systems on the two vehicles so that they’re capable of safely traveling at a close following distance, maybe 45 feet.”
Daimler Trucks North America, headquartered in Portland, publicized its trials this week at the 2017 North America Commercial Vehicle Show in Atlanta. It first put the paired-truck concept through coordinated braking tests at its High Desert Proving Grounds in Madras, said Kary Schaefer, general manager of product marketing and strategy for Freightliner and Detroit. Freightliner is a truck brand, and Detroit is a brand name for engines, axles and other Daimler components.
“The main purpose (of the Madras trials) is to do the brake test on a test track before going on a public road,” she said Thursday. “You want to test the reaction and latency for different types of brake events.”
The road trials take place primarily on Interstate 84 between Portland and Pendleton, Schaefer said. Dick said the trucks carry a banner attached to inform other motorists the trial is underway. So far, the trials have resulted in no incidents involving other motorists, both said.
“The first test was a single-day demonstration late last year, Nov. 1, and then intermittently (on I-84) in May after the winter and on through the summer,” Dick said.
The two vehicles communicate automatically, by short-range radio, a system called vehicle-to-vehicle communications, or V2V, that allows the lead truck to automatically signal the trailing truck when it brakes or accelerates, according to Daimler. The automated system allows the trucks to react faster than humans could react. The trucks show a 0.2- to 0.3-second delay between the time the lead and trailing trucks brake, according to Daimler. By traveling closer together, they reduce aerodynamic drag and increase fuel efficiency.
Vehicle-to-vehicle communications are part of a suite of systems incorporated into the Cascadia that include lane correction, adaptive cruise control, hazard warning and braking for stationary and moving objects and pedestrians, according to the truck maker.
Daimler Trucks North America coordinated with ODOT before taking its truck trial to the highways, but was under no legal obligation to do so, Dick said. Some states have laws regulating this type of open-road trial, but no Oregon law required the truck maker to seek state permission to test the system on the open road, he said Wednesday.
“When the codes were being written, no one thought to say a human must be behind the wheel,” Dick said. “This was just a notification, but with all the development in this space, this is an opportunity for bidirectional education.”
The Federal Motor Carrier Safety Administration, an arm of the U.S. Department of Transportation, in an email response to questions, wrote that the agency has jurisdiction over truck platooning only if the trucks cross state lines.
“If the truck platoon remains intrastate, it is the domain of the individual states to determine how to govern and provide oversight for this research,” wrote spokeswoman Sharon Worthy on Friday.
Arkansas, for example, enacted a law that allows truck platooning provided the trucking companies or manufacturers apply to the Arkansas State Police to arrange the trials.
“Other states have not passed any type of guidance and the interested parties either work directly with the state’s department of transportation or state police, or they just take their chances in a state that they believe would be open to such testing,” she wrote.
The technology being tested by Daimler does not create a strictly autonomous, or self-driving, vehicle, Dick said. A driver with a commercial license is at the wheel, “ready to take control at a moment’s notice,” he said. The trailing driver may override the vehicle-to-vehicle system by moving the wheel or tapping the brakes, or if a passing vehicle attempts to enter the space between the two trucks, he said.
“If a vehicle enters that space, that platoon will instantly dissolve,” Dick said. “That back vehicle will stop closing and retreat.”
ODOT expressed some concerns about the trials before the Daimler trucks hit the road, he said. One, state highway officials questioned what implications several heavily laden trucks traveling close together might have on bridge load limits. Highway engineers concluded that bridges could safely hold a limited number of platooning trucks, Dick said.
Interchange traffic was another question, as well as what effect platooning trucks would have in congested traffic, he said. He said ODOT communicated those concerns to Daimler, which, so far, operates on a relatively open highway stretch relatively free of complicated infrastructure.
Schaefer said Daimler has used the same stretch of I-84 where the trials mostly take place to gather information on truck performance and fuel efficiency for about 10 years. That means the company, based in Germany, has data against which to compare the driver-assist technology. Trials are also taking place in Nevada, she said.
Daimler is not alone in applying vehicle-to-vehicle communications and adaptive cruise control to tractor-trailers. Volvo and Peloton are two competitors. A consortium of government agencies led by the Netherlands last year initiated a push to bring truck platooning to the European Union.
Schaefer said the trials may move to more challenging routes with more vehicles. One question yet to answer is how paired or platooning trucks with varying load weights will perform together on roadways through terrain that dips and climbs.
Daimler is not on a strict timetable to bring its driver-assist tractor-trailers to market.
“We’re really not trying to force ourselves to hit a committed schedule,” Schaefer said Thursday. “We’ll roll it out when it’s ready.”
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