NEW YORK, N.Y. – The improvement of fuel economy has slowed in 2016, according to the Annual Fleet Fuel Study that was released today by the North American Council for Freight Efficiency (NACFE).

According to the numbers, the 19 fleets studied that operate more than 71,000 tractors and 234,000 trailers saw a 1% increase in fuel economy from 2015-2016. While this is the tenth consecutive year that mpg has improved in the fleet, from 2014-2015 the fleet saw a 3% improvement.

According to Mike Roeth, executive director of the North American Council for Freight Efficiency, and Operation Lead of Trucking Efficiency, the decrease is due to a number of reasons including, fleets eliminating certain technologies, lower fuel prices, and hotter weather.

“Even though (the fleets studied) continue to save fuel on a fleet-wide average, year over year it was much less. And we spent the last two months of our study period digging into this, as to why their improvement declined,” Roeth explained during a press conference call.

Roeth explained that the decline is a result of a decreased interest in 6x2s and increase in use of CNG tractors by a couple of fleets, namely Frito-Lay and UPS.

“We also talk about a somewhat diminished focus on fuel economy given a second full year of lower fuel prices (in the study),” he said. “Truck speeds have also increased…and finally 2016 was a hot summer. So a number of these fleets told us their idle time increased (to run air conditioning) and did affect their fuel economy.”

Together, the nineteen fleets, that included Canada’s own Bison Transport and Challenger Motor Freight, reached an average fuel economy of 7.11 mpg. The average U.S. fleet averages just under 5.9 mpg. NACFE said that reaching 7.11 mpg resulted in a combined savings of nearly $500 million or $7,020 per year per truck with fuel at $2.34 a gallon.

Moreover, NACFE said the 2017 model trucks operated by the 19 fleets in the study, achieved even better fuel economy, between 7.8 and 9.2 mpg.

“That of course varies with load and so forth, but those are pretty impressive numbers for model year 2017 trucks,” Roeth confirmed.

The 19 fleets reached 7.11 mpg in 2016 by adopting a combination of 85 currently available technologies and engaging the resources and guidance of Trucking Efficiency, a joint effort of NACFE and Carbon War Room (CWR).

Roeth said that automated transmissions, tire pressure systems, and predictive cruise control all saw increased adoption by fleets. Trailer skirt technology had the quickest increase to widespread adoption.

To collect the needed data for the study, the fleets provided their purchasing experience for the 85 technologies for tractors and trailers they procured from 2003 to 2016, providing over 21,000 data points to the NACFE team.

You can download the full report by clicking here.