WASHINGTON, D.C. – New fuel-efficient technologies continue to be cost-savers, to the tune of over $7,000 per truck, per year, according the 2017 annual Fleet Fuel Study conducted by the North American Council for Freight Efficiency (NACFE).

The sixth annual study, conducted on over 71,000 Class 8 trucks across 19 fleets in 2016, showed total savings in 2016 of nearly $500 million, with an average of 7.11 miles per gallon (mpg) – a 1% increase over the year before. The national average was 5.89mpg, a difference of $7,000 per truck on average.

Although the fuel efficiency keeps improving, the results for 2016 are just a third of those for the year before. In 2015, fleets reported a fuel efficiency increase of 3% compared to 2014.

NACFE says the decline in fuel efficiency improvements is due to several factors, including less of a focus on fuel economy because of falling fuel prices, increased speeds on the road, older trucks being kept in service longer, and increased use of air conditioning for the hot summer of 2016.

NACFE also blames the decline on a slowdown in adding technology which showed significant savings, like 6×2 axles.

In both the 2014 and 2017 Confidence Reports, NACFE found the axleswere some of the biggest fuel-savers on their list, with an average savings of 2.5%. With increased tire wear, traction challenges, and a lower resale value, the number of fleets adding them was cut in half over two years.

The same can be said for back-of-trailer aerodynamic devices like trailer tails, which can show a fuel economy savings of up to 5%, but saw a 7% decrease in fleets buying them in 2016 over the year before. Fleets said improper driver use, and driver damage were some of the reasons for the significant drop in their use.

Decreases were also seen in switching to compressed natural gas, the downsizing of engines, and using aluminum wheels on tractors.

Despite a slow-down in adoption of some fuel-saving technologies, overall fleets continue adding new ways to save, and it’s adding up at the pumps.

The number of ways to increase fuel efficiency is up to 85 from 69 in last year’s study, with fleets in the study using 42% of them, up from just 17% in 2003. According to the report, when added to the movement to adopt Environmental Protection Agency (EPA) greenhouse gas phase 1 products, and systems using diesel exhaust fluid, this increase means big bucks.

The most consistently adopted fuel-saving techniques in the study were aerodynamic hoods, fenders, bumpers, and mirrors, having been 100% adopted across all 19 fleets.

The biggest gainers in adoption in the 2016 study were switching to automated transmissions, a lower viscosity engine oil, and adding predictive cruise control.

Fleets participating in the study include Bison Transport, Challenger Motor Freight, United Parcel Service, Frito-Lay, Ryder System Inc., and 12 other companies, with one company’s data from previous years being used in the study even though it is no longer providing new data.