Platooning: Follow the Leader to Fuel Saving and Operating Efficiency
July 25, 2018
If you’ve ever played “Follow the Leader” as a child, you’ll remember that one person is the leader, and the others follow along, copying whatever the leader does. In trucking there’s a similar concept where one truck (or a string of trucks) follows closely behind one another thus reducing wind resistance. Whether you refer to it as Platooning, Drafting or the Buddy System, it’s no game. Yet there are substantial rewards and everyone involved is a winner.
• Platooning can save costs.
• Trucks can drive closely together at a constant speed, reducing aerodynamic drag, which means increased fuel economy.
• It can improve trucking safety — communication and automation technologies hold the potential to reduce driver-related accidents and driver stress while improving operational efficiency.
• And, platooning boosts traffic flows. The short distance between vehicles means less space taken up on the road, which leads to reduced congestion.
According to the North American Council for Freight Efficiency, truck platooning represents a very valid method of reducing fuel consumption for tractor-trailers running in long-haul applications. Once the trucks have moved into close following distances, all of the engaged vehicles receive a significant fuel economy boost thanks to increased aerodynamic efficiencies. The lead vehicle, which bears the brunt of the aerodynamic load, typically sees only a modest fuel economy boost. But the trailing trucks, now operating in an aerodynamic “sweet spot,” can see significant increases in fuel economy performance at highway speeds.
Keep Your Distance
The potential fuel consumption savings versus a vehicle traveling alone varies depending on the separation distance of the trucks. NACFE determined that with a 40- to 50-foot following distance the lead truck can save 4 percent on fuel and the rest of the formation can save 10 percent. That’s an average of 7 percent (versus the two trucks not platooning). The fuel savings is likely a 4 percent average savings over real-world conditions after accounting for traffic and terrain.
Need more convincing? The science-minded television show Mythbusters conducted experiments with platooning and results proved even more substantial. Traveling 100 feet behind the leader increased overall mpg for the rear truck by 11 percent. Traveling 10 feet behind produced a 39 percent gain in efficiency.
Of course with every upside comes a potential downside.
On the same episode, Mythbusters showed that it could be very dangerous for a following vehicle if a tire delaminates. Chunks of ejected rubber can be large enough to cause serious harm to truck and driver following too closely. In addition, if the vehicle in front brakes suddenly, there is little time to react and stop safely.
Peloton, a leader in automated and connected vehicle technology. Founder and CEO Josh Switkes, speaking at the Automated Vehicle Symposium in San Francisco, California, promoted the role technology plays in improving safety of platooning. According to Switkes’ presentation, as reported by Trucks.com (bit.ly/2O5p9Yd), tech such as radar and lidar (used to create 3D images of distant objects), adaptive cruise control and autonomous braking can shrink the safe following distance between trucks from over 500 feet to as low as 30 feet.
A common argument against digitally linking vehicles through automated platooning is that it dulls driver reaction time. Autonomous does not equal “driverless.” Operators are still required to steer the vehicle and can manually override the system to brake in emergencies.
Volvo Trucks North America, together with FedEx and the North Carolina Turnpike Authority, has also used advanced driver assist technology as part of ongoing platooning research. One demonstration consisted of three Volvo VNL tractors, each pulling double 28-foot trailers. The convoy remained in constant contact utilizing wireless vehicle-to-vehicle (V2V) communications, and safely traveled at speeds of up to 62 mph while keeping a time gap of 1.5 seconds. Staged and unplanned vehicle cut-ins showed how the system effectively handles common traffic situations.
All signs point to the strong potential for fuel savings and increased fleet efficiency through platooning. Early platooning adopters will likely be large, line-haul fleets where multiple trucks are heading toward the same destination at the same time. NACFE predicts that over time, as both industry and general public comfort levels concerning platooning rise, the scope and scale of platooning, as an industry practice will grow.