Pace of fuel economy improvements has slowed, NACFE Fleet Fuel Study finds

After a three-year hiatus, the North American Council for Freight Efficiency (NACFE) returned with its Fleet Fuel Study in 2021, and found that fleet-wide average fuel economy from participating fleets held steady at 7.24 mpg (32.49 litres/100 km).

However, the U.S. fleet as a whole saw fuel economy jump from 5.98 to 6.24 mpg as the broader population played catch-up with fuel-saving technologies in the last few years.

“This is a significant improvement and has helped the operators of the 1.7 million tractors operating in the U.S. reduce their fuel costs,” said Mike Roeth, NACFE’s executive director.

Nussbaum truck
(Photo: Nussbaum)

The pace of improvement among participating fleets slowed, however, which could in part be due to supply-chain-related issues that weighed down the uptake of fuel-saving equipment and new, more fuel-efficient trucks. Fleets in the study submitted data for 2019, 2020, and 2021.

86 fuel-saving technologies

NACFE officials said the flatlining of fuel economy improvements seen in the study could also be due to a change in routing (more regional haul vs longhaul), effects of the pandemic (increasing idle time as drivers spent more time in their cabs than in truck stops), and trade cycles that were extended due to new truck build backlogs. Roeth also noted fleets have been increasing road speeds, which has offset some fuel savings, and that some linehaul fleets that traditionally took part in the study were swapped out with regional fleets.

The study looked at 86 different technologies that help save fuel. Roeth noted the study shows there’s plenty fleets can do to reduce fuel consumption using readily available technologies.

“Increasing fuel efficiency is a definite sustainability action taken by fleets today. They don’t have to wait to deploy zero-emission trucks to make a difference,” he said.

“In addition, we believe many of these technologies and practices will transfer to alternative-fueled vehicles where they will help extend range,” added Yunsu Park, NACFE’s director of engineering and the study report’s author.

Increasing adoption rates

The study found fleets continue to increase their adoption of fuel-saving technologies. The average adoption rate of the 86 technologies covered surged from 17% in 2003 to 41% in 2021. Roeth said fleets realized an average 2% fuel economy improvement every year from 2011 to 2017 before gains stalled.

NACFE also produced an interactive benchmarking tool that enables fleets to see how their own fuel-saving initiatives compare to those of industry leaders. It will generate a report fleets can use to see where they can improve relative to their peers.

As a result of the study, NACFE recommends fleets: collect and monitor fuel economy by vehicle, set long-term fuel economy targets and measure performance using the new benchmarking tool; commit to an ongoing plan for fuel economy improvement; assign a test route and driver to test new technologies; purchase used equipment only from fleets known to have good fuel mileage; and allow for failure, keeping in mind not all technologies will work in every application.

In the meantime, Roeth wants fleets to remember that decarbonizing is a journey that’s ongoing today and doesn’t have to wait for zero-emissions trucks.

“What we find far too often is that decarbonization is only thought of as zero-emissions trucks,” Roeth said. “That’s wrong. Any time a fleet burns less fuel to ship the same amount of goods, they are decarbonizing.”

The full report and benchmarking tool are available free of charge at

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James Menzies is editor of Today's Trucking. He has been covering the Canadian trucking industry for more than 20 years and holds a CDL. Reach him at or follow him on Twitter at @JamesMenzies.

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