NACFE stressed that the terms “accurate” and “precise” are not interchangeable in fuel economy testing. (Photo by Sean Kilcarr/Fleet Owner)
The latest “confidence report” compiled by the North American Council for Freight Efficiency (NACFE) calls for the wider sharing of fuel economy test data within the trucking industry, as such sharing can potentially drive greater and faster advances in fuel savings.
“The [diesel] fuel costs faced by the tractor-trailer industry have been swiftly and steadily rising over the past decade,” the group noted, reaching 58 cents per mile in 2014, or as much per annum as the costs of drivers’ wages and benefits combined for that year.
“Despite recent fuel cost decreases, all indications are that fuel price volatility will continue, forcing the industry to find solutions that increase its fuel efficiency in order to stay profitable,” NACFE said in its Determining Efficiency report.
“Our recommendation is that a lot of data exists and steering of it is needed,” Mike Roeth, NACFE’S executive director, explained in a conference call with reporters. “We don’t need a lot more testing; what we need is a lot more sharing of what testing has been done.”
A lot of challenges of doing that surrounds the variances in testing methods, how to extrapolate data from those tests, the existence of sometimes “old” data, which component is attribute with specific fuel mileage gains, and so on, he said.
“With more data sharing, the industry will have more confidence and be likely to pursue specific technologies,” Roeth noted. “The challenge is that there is no one place for fleet to go get an answer. So we’re trying to consolidate that information into a place where people have confidence in the reporting.”
He added that the goal here is trying to learn from testing conducted by “early-adopting” fleets as well as from truck and trailer manufacturers.
“We want to help bring this information, since it is of higher quality and more understandable, to the masses in the industry,” Roeth said. “Most importantly, we need to look at multiple methods to seek trends. Don’t fall in love with a single test – one test is one test.”
NACFE believes that multiple tests allow the industry to better illuminate trends. “Multiple data sets [will generate] the most confidence where payback can be found,” he emphasized.
To that end, the group emphasized that gaining a more “comprehensive overview” of the fuel and freight efficiency measurement and estimation methods used within the trucking industry, and broadly sharing the results of those tests, will allow fleets to make better investment decisions, no matter the technology they are considering.
NACFE’s report offers six “insights” that could foster more cooperative use of test results and thus broader fuel economy gains:
- Understand Accuracy vs. Precision: The terms “accurate” and “precise” are not interchangeable. “Precise” is how closely a test result will be repeated by additional tests. “Accurate,” though, is how well the test compares to a known reference value. Claims that a fuel-saving device is precise don’t mean it is accurate. These two terms are often misused or incorrectly conflated.
- Recognize that Data Exists and Sharing is Needed: A large amount of testing data for various technologies from many individual manufacturers exists already, yet it is mainly kept private, even when no competitive advantage is gained. All “stakeholders” – OEMs, suppliers and fleets – should work to uncover and share the best available data for decision making. This will also reduce the resources being spent on redundant testing.
- Clarify Objectives: All stakeholders should be clear in advance on what their review of testing data seeks to confirm or discover. For instance, manufacturers may want to learn how a device performs in many configurations and duty cycles, or may want to determine a metric such as drag coefficient, while fleets may want to confirm how a device performs in their very specific configuration and duty cycle, or seek a metric such as fuel burn. Different testing methods would be most appropriate for each.
- Adjust to Real-World Operations: The results from various tests must always be adjusted to the particular duty cycle under consideration before paybacks can be calculated. For example, while track testing may be performed at a consistent speed of 65 mph, trucks in a fleet may spend the majority of their time at 58 mph. Thus such deviations must be overlaid onto the test results.
- Be Comfortable with a Range: Adopting many proven fuel-efficiency technologies can reasonably be expected to improve performance, but the exact degree of improvement will depend on a fleet’s specific operations, and will likely vary over time in response to many other real-world factors. The metric of “degree of improvement” is likewise key and efforts to determine efficiency should be conducted relative to a baseline of current performance, and not an absolute.
- Seek Multiple Methods and Look for Trends: In determining efficiency, multiple sets of test results likely cannot be compared or averaged in order to determine the exact performance of a technology. Rather, data from a variety of test methods should be considered side by side, keeping the particulars of each method in mind, in order to look for trends and gain confidence on results such as the minimum efficiency gain a technology will offer.