The U.S. national fuel economy average for a Class 8 truck is about 6.4 mpg, but every year that number inches upward as a host of aerodynamic add-ons and more efficient modern engines hit the highway.
If you could boil it all down, the mpg potential for a line-haul U.S. Environmental Protection Agency 2017-compliant Class 8 truck is probably around 8, while aggressive and complementary aerodynamic efficiency packages – along with persistent driver training and education – have pushed those figures to above and beyond 10 mpg.
As recently as just a few years ago, 10 mpg seemed like the kind of pie-in-the-sky figure that only truck stop braggarts would claim, but it’s real-world feasible as of this year.
In this 11th edition of CCJ’s Tech Toolbox, we look at the role technology has played in boosting fuel economy and, in at least one case, how it can have unintended negative effects.
This installment comes just more than a month after seven trucks, each driving specs common in their respective fleets, participated in the North American Council for Freight Efficiency’s Run On Less program. The trucks averaged 10.1 mpg over 99 days of driving and a combined 50,107 miles.
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With all the aerodynamic upfits on the market today, it’s easy to focus on optimizing airflow around the truck to decrease fuel consumption.
But Jerry Morrow, vice president of Bellevue, Ohio-based regional carrier Ploger Transportation, says it’s critical that you first begin with the right truck for the job.
“You want to spec to your application,” Morrow says. “You want to get the right engine, transmission and [rear-end] ratio for your application. That would be the number-one thing that I would say someone needs to focus on. The other stuff, it’s just add-ons.”
Early on, Ploger recognized the impact that fuel efficiency could have on its bottom line. Morrow says the fleetwide average is about 7.6 mpg – more than a full mpg over the national average and the fruit of nearly 20 years of work crafting the company’s truck specification.
“Before achieving fuel mileage was cool, we’ve been doing this,” he says. “Back in the early ’90s, we were working on it.”
Part of that work involved getting a drive axle off the ground. Ploger, primarily a Volvo fleet, worked with the truck maker on the development of an adaptive loading lift axle.
Nussbaum Transportation made a similar change, leaving an axle down but taking power away from it. The Hudson, Ill.-based company has been spec’ing a 6×2 configuration since 2010 and fully converted its fleet of Freightliners by 2012.
That change has helped push the fleet’s warm-weather mpg average to 9.25 across 320 trucks per day.
“That means I’ve got drivers getting 10, 10.5, 11 miles a gallon,” says Brent Nussbaum, chief executive officer. “As a fleet on a year-round basis, we’re running about 8.5 miles a gallon.”
Nussbaum says dropping power to one drive axle hasn’t resulted in traction concerns.
“We have had very few jackknives on a 6×2 versus a 6×4,” he says. “If we have one or two a winter, it’s pretty rare.”
Ploger also was an early player in the lightweighting movement by adopting 11-
“We went to that probably six years ago,” Morrow says of Volvo’s D11 engine, adding the benefits of the shorter hood and smaller sleepers also were attractive.
“Some people question our preference of 11-liter engines, but they’re ideal for general freight applications, allowing us to haul heavier loads while providing more than enough pulling power to tackle any hill,” adds Joel Morrow, Ploger’s senior driver and vice president for fleet equipment procurement. “It just makes good business sense.”
As recently as last year, Nussbaum Transportation looked at migrating to Detroit’s DD13, a reduction in size from the fleet’s preferred DD15. However, Nussbaum says he couldn’t make the same business case for the transition.
“If we could save some money on the 13-liter and a few pounds of weight, why would we not do that?” he says. “When we got done, we decided to stay with the 15-liter. There aren’t that many 13-liters out there in the over-the-road application.”
Nussbaum says comparing the fuel economy potential of the 13-liter versus the 15-liter didn’t make a strong case for the change, either. “They were absolutely identical,” he says.
The fleet doesn’t trade in its used tractors, opting rather to sell them to smaller fleets that are drawn to the company’s fuel-friendly specs.
“They’re used to buying 15-liters, and they like 15-liters,” Nussbaum says. “Yeah, [a 15-liter engine] is a little bit more money, but ultimately I want to be able to sell the truck in the end.”
The automation of many driver functions was designed for safety, but in the cases of automated transmissions and cruise control, more fuel efficiency has come along for the ride.
Prior to joining Las Cruces, N.M.-based Mesilla Valley Transportation (CCJ Top 250, No. 72), Emmanuel Santiago had grown accustomed to his manual transmission and plodding along at around 6 mpg.
Now outfitted in an International LT Model with an Eaton 10-speed automated transmission, Santiago almost has doubled that mark.
“It was new to adapt to it, but overall I’m happy with it,” he says, noting his personal average mpg can hit 12 under normal conditions. “It just depends on if we hit Rocky Mountain areas. Sometimes I’ll go down as low as 10.5.”
Even at 10.5, Santiago is getting 4 mpg more than the national average and about 3 mpg more than what some OEMs consider average for EPA 2017 engines. He says his attention to fuel efficiency rivals only the checks he gives his mirrors on the highway.
Jerry Morrow, vice president of Ploger Transportation, says the regional carrier is also a believer in the impact an automated transmission can have on fuel consumption.
“For a typical driver, the [Volvo] I-Shift [AMT] takes the driver out of the equation if it’s spec’d right and it’s programmed right,” Morrow says.
“I would never buy anything else other than an AMT,” adds Brent Nussbaum, CEO of Nussbaum Transportation.
Mike Kelley, MVT chief information officer, says the company originally began spec’ing AMTs nearly a decade ago but abandoned that effort after seeing little benefit.
In the 10 years since, AMT technology and reliability have blossomed, and Kelley says MVT re-embraced them on new truck specs.
“I think that with the current AMTs that are out there, they are so much better,” he says. “The newer transmission will help you do the shifting at the right rpm and keep you in the lower spectrum of the rpm but will give you enough power. It does have a good effect on the mpg and helps you maintain that because it’s taking away the driver’s ability to over-rev [the engine].”
Around 2010, Nussbaum Transportation switched from a 10-speed AMT to a 12-speed to capitalize on emerging optimized shifting technologies on Detroit’s DT12.
“That 12-speed has definitely made a difference,” Nussbaum says. “The 12-speed is a skip-shift transmission, so it senses your payload, and it will skip-shift to get you up to speed if you’re running empty or you’re running with a light load. If you’re at a traffic light and need to take off, it’s going to sense your load and determine that maybe you need to start in second, maybe then jump you up to fourth and then to sixth. It has kept the truck from having to go literally through every gear.”
By relying on the AMT to handle shifting and leaning on more advanced cruise controls, Santiago has been able to focus more on fuel efficiency and less on the intricacies of shifting patterns and fighting traffic.
“Smooth driving,” he says of one of the benefits of predictive cruise control. “It’s knowing the terrain, slowing down when you hit a hill, adjusting to the road and conditions.”
International’s predictive cruise control uses preinstalled GPS maps and the latest commercial route data to adjust cruising speed without the need to pre-drive the route.
Santiago uses a combination of the capabilities of the technology and his own know-how to optimize his haul’s efficiency potential.
“If it’s flat, I’ll use it, but if I’m about to hit a hill or something, I’ll turn it right off and adjust,” he says. “Personally, I love the adaptive cruise. It gives me a little break.”
Santiago says he’s made comparisons of runs using the adaptive cruise and assuming control himself and found the difference to the fuel tank negligible.
“I’ll put the cruise on just to make sure it isn’t hurting me,” he says. “Sometimes if you hit just a small elevation, the boost goes up, and you’re burning more fuel, and I end up turning it off and on. Overall, I don’t think it hurts the fuel. I think overall that when the driver does it himself, it’s better, but the difference is so miniscule, I would say it’s almost exactly the same.”
Looming over trucking next month is a nationwide mandate for electronic logging devices – a tool largely designed to increase transportation efficiency.
However, not all good intentions bear good results. While some argue the long-term benefits of ELDs are worth the short-term pains, raising your operating efficiency can have a negative impact on fuel consumption.
Jerry Morrow, vice president of Ploger Transportation, says the implementation of ELDs dragged the regional carrier’s average mpg down as the company raised speed limits on its trucks to make up for lost time.
“About four years ago, we were averaging about 8.3 mpg in the summertime,” he says. “Now that’s slipped. We’re down to about 7.6, but we sped up eight miles an hour.”
Ploger raised its speed limiters to 70 mph, while Mesilla Valley Transportation dialed up three extra miles per hour, jumping from 65 to 68.
“Anything over 60 mph, for every mile per hour you increase, you decrease your mpg by .1,” says Mike Kelley, MVT CIO. “Any time drivers are stuck in traffic or delayed at a shipper, any of those hours where the wheels aren’t turning, there’s no chance to make it up. The only way to make it up is to allow them to go a little bit faster.”
Nussbaum Transportation, which logs an annual fleet average of about 8.5 mpg, has been running ELDs for a decade. However, CEO Brent Nussbaum says the company elected not to adjust its governed speed of 63 at the pedal and cruising speed of 65, opting rather to adjust and optimize routes.
“You’re going to bump your governors up to try and get as many miles out of the truck as possible,” he says. “But in the meantime, you’re going to wind up burning fuel in the process. If they get down to 59 and 60 miles an hour, that’s where we get our best fuel economy.”
Nussbaum says his fleet of trucks is governed only a little higher than the optimal fuel window for the driver’s safety.
“We also realize they’re out on the road, and they’re dealing with drivers that are running 75 miles an hour,” he says. “We’re cognizant of the fact that we don’t want them to be run over.”
Ideally, ELDs help fleets optimize routing and maintenance and can help them improve fuel economy by tracking aggressive driving, harsh braking and idle time.
However, that is low-hanging fruit for fleets new to focusing on fuel efficiency or companies hoping the access to the kind of data an ELD can capture will help drive efficiencies across the board. For fleets that have had a fuel-friendly focus for decades, those strategies have long been implemented.
“If you haven’t been running any kind of telematics device until you add an ELD, now you suddenly have vision into your [engine control module],” Kelley says. But extracting better fuel economy through an ELD isn’t realistic unless you have systems in place to monitor driver behavior, he says.
“One of the other ironies here is that all of those things have nothing to do with the ELD, nothing to do with the managing of the logs and the safety aspect,” Kelley says. “All of that comes from leveraging all the ancillary systems that the ELD happens to have access to. The ECM data doesn’t really have anything to do with the ELD other than, maybe, speed.”
Drivers – specifically their right foot – play a significant role in fuel consumption, but many fleets lack the level of detail needed to coach them on their fuel economy impact.
Through the implementation of the SmartDrive platform, Nussbaum Transportation has seen an improvement of about 0.5 mpg across its driver force.
The idea was born in 2010 when Jeremy Stickling, vice president of human resources, and the fleet’s IT department created an automated driver scorecard and performance-based pay program.
Drivers are awarded or deducted points based on the year and model of truck, use of auxiliary power unit, trailer type and length of haul. Heavier loads get more points. Lighter loads take points away.
Excelerator, Nussbaum Transportation’s proprietary software program designed to measure mpg data, captures data every 15 minutes and updates the driver’s score.
In 2015, Stickling began the integration of SmartDrive’s driver insights as he sought to create better driving habits rather than focus on results.
Through the platform, the truckload carrier can glean data that can measure behavior that may indicate inefficient engine operation – such as harsh braking or aggressive throttle use – and reward drivers for more efficient driving.
While the driver earns a score based on his fuel-friendly habits, low scores are not penalized formally since the driver technically hasn’t done anything wrong.
“Since it’s not a safety issue, we don’t treat lower scores as any kind of violation,” Stickling says. “It’s really more about measuring driver habits than it is about correcting driver behavior.”
The system captures real-time data from the engine control module, including G-force sensor data, time spent at different speed intervals, idle time and throttle actuation. All that is aggregated with following distance observations from onboard event recorders.
Stickling says the driver’s score is essentially a “skills rating,” measuring smooth driving, speed management, throttle usage and space management.
“It gives us a way to reward drivers, but not just for results,” he says. “It’s more about rewarding them for the skills that lead to the results.”
The incentive for drivers to get better mpg comes from payouts, Stickling says, since the ones with higher scores tend to have an easier time making their bonuses.
Stickling says an internal recognition system has been instrumental to the program’s success. He says it’s also helped foster a spirit of competition among the drivers, as the ones with lower scores press to catch those who are ahead.
“Our top driver, he has been number-one for more than a year,” Stickling says. “He has people calling him, asking him questions, asking advice, and he likes that.”
Jet Express, a Dayton, Ohio-based carrier with lanes extending into the Southeast and West, also leans on technology to help tutor its drivers on fuel consumption.
Vnomics’ True Fuel platform establishes a truck’s potential fuel economy considering only the factors that a driver can control, such as engine speed, truck speed and idle time. Payload, route, weather and the truck’s configuration are normalized automatically.
True Fuel then assists drivers to achieve the truck’s potential mpg through in-vehicle coaching, such as audible alerts when they should act to reduce fuel consumption.
Jet Express driver Tammy Newcomer recently drove almost 2,500 miles with an efficiency of more than 99.92 percent of potential mpg, meaning only two-tenths of a gallon of fuel – of the more than 280 gallons her truck used – was consumed in excess of the fuel a “perfect” driver would have used under the same conditions.
Newcomer’s achievement translates to a monthly savings of about $350 in fuel, says Ed McCarthy, vice president of operations and customer success for Vnomics.
“In addition, due to Newcomer’s skill, last year alone her truck emitted 13.2 tons less CO2 compared to a typical driver,” McCarthy says.
Fleets can spec the most fuel-efficient truck on the highway, but unless they also account for the 53-foot-long block it’s dragging down the road, fuel-friendly technologies can’t help it reach its full potential.
With the truck spec’d properly for its application, Jerry Morrow, vice president of Ploger Transportation, begins to evaluate how aftermarket add-ons can help increase the trailer’s performance.
Ploger has added FlowBelow wheel covers and tandem fairings, along with a lift axle with slotted skirts on the sides. Approximately 25 percent of the company’s trailer fleet already has skirts, and that number is growing.
“Besides the fuel mileage gains, with side winds, [the trailers] are a lot more stable,” Morrow says. “When you put all of the bottom skirts, the nose cone, the tail fin on it, we’re seeing nearly a mile a gallon [improvement].”
Before adding trailer tails, Nussbaum Transportation saw its fuel savings benefit capped at about 3 to 4 percent, thanks mostly to skirts and wide-base tires. The carrier was among the first fleets to adopt aerodynamic tails widely, and Brent Nussbaum, the company’s CEO, says his employees regularly fielded phone calls early on from other fleets wondering what they were.
“Or people calling saying, ‘Hey, your driver’s running down the road with their doors open,” he says.
Of all the fuel-sipping technologies Ploger has embraced, capturing the full benefit of trailer tails has been “tricky,” says Morrow, who’s undecided if the fleet will continue to spec them on orders going forward.
“There’s no doubt about it, [trailer tails] work, but we’ve driven down the highway too many times and seen them folded up,” he says, “That is a concern of ours, because it does work, but how are we going to get a benefit out of it if it’s not deployed?”
Nussbaum says he’s looked at systems that deploy the tails automatically once the truck reaches 45 mph and closes them below 45, but he has yet to test them.
In the meantime, he’s relying on the almighty dollar to remind the driver to make sure the tails are extended. Drivers can earn up to an extra 5 cents per mile for the safe and fuel-efficient operation of their truck.
“If a driver is running down the road and doesn’t have his tails open, he’s only hurting himself,” Nussbaum says.
To take the driver’s mindfulness out of the equation and eliminate the risk of smacking a dock with extended tails, U.S. Xpress (CCJ Top 250, No. 16) recently began spec’ing SmartTruck’s TopKit on all its trailers.
TopKit offers a similar aerodynamic benefit to trailer tails by reducing the drag of the low-pressure wake that forms just behind the trailer and creates back-pressure on the vehicle. However, the TopKit system doesn’t have to be opened and closed by the driver.
“Drivers have no interaction with it whatsoever,” says Gerry Mead, formerly senior vice president of maintenance for Chattanooga, Tenn.-based U.S. Xpress. “That way, the driver’s job is easier, friendlier, and they can focus on the job at hand, which is driving safely down the road and delivering the freight.”
There’s also the added benefit of style. “It really looks good when you look at it on the trucks,” Mead says. “It’s red, and it matches the U.S. Xpress red trucks that are out there.”