Midway through a cross-country demonstration run converging on Atlanta late last fall, the seven tractor-trailers participating in the “Run on Less” truck efficiency roadshow had posted impressive double-digit miles per gallon (mpg) results. But when real-world conditions got factored in, they highlighted the challenges truck operators face in squeezing the most optimal fuel efficiency from their equipment.
Sponsored by Shell and PepsiCo and hosted by the North American Council for Freight Efficiency (NACFE) and Carbon War Room (CWR), Run on Less put seven tractor-trailers on the road from owner-operator Albert Transport, PepsiCo’s Frito-Lay division, Hirschbach, Mesilla Valley Transportation, Nussbaum Transportation, Ploger Transportation, and U.S. Xpress.
“These were real drivers on real routes hauling real freight,” said Mike Roeth, executive director of NACFE and operations lead for Trucking Efficiency, a joint NACFE-CWR effort that studies and reports on various heavy truck fuel efficiency technologies.
The Run on Less trucks took normal routes and used Geotab telematics devices to stream data to the team monitoring results like vehicle speed, elevation, gallons of diesel burned, and miles traveled.
“It’s consistent across all seven trucks, and we’re using that to populate our RunOnLess.com website. These were not test vehicles that have been designed specially for fuel [economy]; they were not on special tracks or anything like that,” Roeth noted.
Roeth said the Run on Less tractor-trailers averaged 10.1 mpg, nearly 4 mpg higher than the 6.4 mpg average of all Class 8 trucks operating across the U.S. and Canada.
Over the 31,000 collective miles they’d traveled, that meant the Run on Less trucks saved some 1,800 gals. of diesel fuel, worth about $4,500 per tractor-trailer, compared with that Class 8 average.
If all those 1.7 million U.S. and Canadian trucks were as efficient as the seven vehicles in the Run on Less roadshow, “we would save 9.7 billion gal. of diesel fuel, $24 billion and 98 million tons of CO2” every year, Roeth pointed out.
Yet those gains didn’t come easy. Among the Run on Less trucks, the highest daily fuel efficiency observed at this point was 12.8 mpg and the lowest was 7.4 mpg. The differences were factors like the weight of the payload in the trailer, wind direction and speed, elevation, and speed at which the trucks were driven.
“The last few weeks of the trip were really challenging for moving freight around our country,” Roeth noted, especially with the stiff winds generated by Hurricane Harvey in the Gulf of Mexico and in Texas and Hurricane Irma in the Caribbean and Florida.
The hurricanes affected the Run on Less trucks, with some having to alter routes, encountering problems getting fuel, and experiencing high winds that affected their fuel efficiency. On that latter point, wind can be a benefit if it’s coming from behind, but any other direction is a detractor.
Meanwhile, Frito Lay’s snack manufacturing operations in Georgia and Florida were disrupted for many days, “challenging that particular Run on Less truck to catch up,” Roeth said.
Another observation gleaned from the Run on Less exhibition is that the trucking industry’s common “drop-and-hook” operations can have a big effect on fuel economy. A driver takes a load to its destination, drops it off and takes on another load, and the trailer that’s picked up might not have the same aerodynamic and other fuel-saving technologies.
Drivers in the Run on Less lineup pointed that out. They cited trailer tails as a big loss if they switched from a trailer equipped with one to another without it; handling also isn’t as good in that case, with more wind drag forming in the “boxed-off” standard end of a trailer. One driver said the lack of a good trailer tail could shave off half a mpg in fuel efficiency.
Trailer wheel aerodynamic fairings and dual wheels versus “super single” wide-base tires are a few more efficiency technologies that drivers may find themselves suddenly with or without.
“From a fuel efficiency standpoint, the difference between the same tractor hauling a highly efficient trailer—one with these technologies we’ve talked about versus one that doesn’t—can be 10% to 15%,” Roeth said.
That can make a big difference for fleets. With just that 10% to 15% difference, hauling a less-efficient trailer can add up to about $4,000 per year for a single truck. What’s more, older trailers may also be poorly maintained.
“Maybe it has poor alignment, poor tire pressure, or other things that could negatively affect fuel economy,” Roeth explained. Thus even fleets that are equipping their trucks with the latest fuel-efficiency technologies may find reaching that optimal mpg in the real world to be elusive.
Shooting for the stars
There’s a neat truck making the rounds within the industry: a futuristic rig largely financed by Shell Lubricants. Christened the Starship Project, the truck is a joint initiative between Shell and the AirFlow Truck Co., and it’s designed to discover what’s possible in reducing energy consumption in transportation.
The body of the Starship Project tractor is an aerodynamic design made of carbon fiber. This includes the side skirts, hood, and front end. A custom, Dept. of Transportation-approved wrap-around windshield was designed for the truck. The trailer has energy-efficient features such as full side skirts to reduce drag and a 5,000-watt solar array atop the trailer to power interior accessories and reduce the energy load. A 2017 Cummins X15 Efficiency 6-cyl. diesel with 400 hp. and 1,850 lbs.-ft. of torque powers the Starship Project truck.
While the truck looks different from many trucks on the road, it’s fully street legal. Shell plans to take it on a coast-to-coast run sometime this month that will begin in California and end in Florida carrying a real load of cargo: “clean reef” material destined to form the backbone of a man-made reef off the coast of Florida later this summer.
NACFE will be providing third-party validation of the freight ton efficiency of the truck. Using techniques that proved successful in the “Run on Less” cross-country roadshow, we’ll be following the Starship on its route to substantiate efficiency claims.
Shell is focusing on freight ton efficiency, which in essence is mpg multiplied by payload tons. Shell believes it makes more sense to talk about truck efficiency this way and so do I. Here’s how freight ton efficiency works: One truck carrying one ton of cargo that achieves 10 mpg is the equivalent to 10-ton mpg. But one truck carrying 20 tons of cargo, even though it may only get 7 mpg, gets better freight efficiency due to the heavier payload. That truck achieves 140-ton mpg.
However it’s measured, improving fuel efficiency is something all fleets should strive for. Back when we started working on Run on Less last year, we had a modest goal of 9 mpg, but by the time the event concluded, we discovered that fleets using a variety of technologies and practices were able to average 10.1 mpg. And in one four-day stretch during the run, a truck actually broke the 12-mpg mark.
It’s hard to know where we’ll end up in terms of mpg or freight ton efficiency. Like Shell and Air Flow and their Starship Project, we need to keep trying along with validating that the efficiency numbers being shared are correct and true. — Mike Roeth
