WASHINGTON, DC — Technology that allows two trucks to travel in tight platoons promises to improve fuel economy, a report by the North American Council for Freight Efficiency and the Carbon War Room concludes.

The latest Confidence Report – a research series that explores the viability of fuel-saving devices and practices – determined that setting a following distance of 40 to 50 feet can lead to average fuel savings of 4% when compared to real-world operating conditions after accounting for traffic, terrain and time when the trucks operate on their own.

The gains are realized when the following distances are close enough to improve aerodynamics.

“The lead vehicle, which bears the brunt of the aerodynamic load, typically sees only a modest fuel economy boost. But the trailing truck in a platoon, which is now operating in a low air pressure aerodynamic ‘sweet spot’ can see significant increases in fuel economy performance at highway speeds,” the report explains. At 40 to 50 feet, the lead vehicle’s fuel efficiency improves 4%, while the following vehicle sees gains of about 10%. If the trucks are linked in a platoon 75% of the time, the gains would average about 4% for both trucks. But the gains still depend on factors such as congestion, terrain, weather and construction.

“Two-truck platooning is showing real promise as a fuel-saving technology, even when considering the actual performance in real-world use,” says Mike Roeth, operation lead – trucking efficiency and executive director at the council.

Several technologies make it all possible, including collision avoidance systems, adaptive cruise control, mile per gallon optimization systems, the transfer of sensor data between vehicles, and platooning-specific software.

Legislation is evolving to allow for the approach. On September 20, for example, the U.S. Department of Transportation issued its Federal Automated Vehicle policy, making way for researching, testing and implementing platoons.

The approach is not without its challenges. The report notes how driver acceptance, platoon integrity, system security, and the time spent platooning still need to be addressed. Any systems, for example, need to be protected from hackers. The council also suggests that the potential systems are being unfairly grouped into discussions about fully autonomous vehicles that wouldn’t rely on drivers.

But some of the challenges are a matter of perception. Concerns about the way platooning trucks will react if drivers cut between them can be addressed with knowledge that the safety systems would react exactly if someone cut in front of one of the individual trucks, the report says.

Just don’t expect the systems overnight. Says Trucking Efficiency: “The potential for fuel savings with platooning is strong, but it is likely that platooning opportunities in real-world fleet operations will initially be extremely limited. Early platooning adopters will be large, dedicated fleets with numerous trucks operating on a given stretch of highway.”