Santa, Reindeer, and Freight Efficiency

"Truck"It’s Christmas Eve, which means that millions of children are counting on Santa Claus and his reindeer to deliver presents under the tree by tomorrow morning. For the rest of us, though, there’s America’s trucking industry.

The National Retail Federation expects total holiday sales to top $586 billion this year. That’s a lot of presents and gift giving. Whether you do your shopping via an online retailer such as Amazon, or you brave the crowds and visit a brick-and-mortar store, one way or another, all those goods have to travel from where they’re made to where they’re sold and ultimately to their recipient.

Nearly 70 percent of that goods transport is accomplished by America’s trucking industry. Some 15.5 million trucks—2 million of them tractor-trailers—occupy our nation’s roads and highways. They are the backbone of North American goods movement. And they have an impact—economic, environmental, and otherwise.

A single long-haul, sleeper tractor-trailer averages 100,000 miles per year, consuming upwards of $80,000 in diesel fuel. And that’s just one truck of millions.

Tractor-trailers like that average six miles per gallon, which might sound paltry, until you consider the fact that they weigh some 80,000 pounds fully loaded. That equates to 240 ton-miles per gallon. By comparison, America’s freight railroads average about 480 ton-miles per gallon, while your average 5,000-pound pickup truck getting 20 mpg averages about 50 ton-miles per gallon.

Regardless, improving the efficiency of our trucking industry starts with decreasing its fuel consumption. Already, there are signs that such a shift is happening. Some of the best trucking fleets on the road today get better than 7 mpg, and last year the Obama administration announced carbon emissions and fuel economy standards for big rigs: a 20 percent improvement by 2018. (Earlier this year, Daimler’s 2014-model Freightliner became the first to meet that mark, demonstrating 9.3 mpg under “realistic” driving conditions.)

Meanwhile, the North American Council for Freight Efficiency, an independent industry group (which grew from some of RMI’s work in the transportation sector) focused—as its name implies—on improving the efficiency of trucks for freight movement across the country, is working to raise the industry average “to 8 or 9 miles per gallon in the next few years,” says Mike Roeth, the group’s executive director. That’s a 50% improvement over the current average, no small piece of change.

One trucker on the Ecomodder forum even boasted of squeaking up to 11 mpg out of his rig. But such extreme efficiency is the exception, rather than the norm. RMI, NACFE, and others are moving the needle for the entire industry average. So how do we make America’s trucks more fuel efficient? The answer—it turns out—depends. A number of crucial levers help to make that happen, including technology and truck design, driver behavior and skills (such as smoother acceleration and braking), traffic avoidance, fleet segmentation, and system-level efficiency.

"TrucksFor example, aerodynamic modifications such as a tapered tail (aka boat tail) can improve fuel economy at least 7.5 percent. Side skirts, which smooth airflow under the trailer and around its wheels, likewise can yield a 5 to 15 percent improvement in fuel economy. Changes such as these are increasingly popular on the road today, thanks in part to their emergence from California, where they were first mandated. That said, “the best, most efficient fleets are the ones that drive slower, and the slower you go, the less aerodynamics matter,” explains Robert Hutchinson, managing director at RMI.

NACFE, for its part, is working on other technological innovations, such as a 6×2 tractor system. Most tractor-trailers are 6×4, which means the tractor has three axles, two of which are powered. That’s good for traction, but it sacrifices fuel efficiency. NACFE is working on the broader adoption of a 6×2 system that can shift the drive from one axle to another, depending on which is getting better traction. Roeth says that change alone promises 2.5–3 percent better fuel economy, which may not sound like much, but adds up to quite a bit when you scale to the numbers of trucks on the nation’s highways and the sheer mileage they cover. Another major NACFE effort is maintaining proper tire pressure for optimum fuel economy. The organization is looking at novel tire pressure monitoring and maintenance systems; if a tire loses air, the system can use the truck’s air brake system to “top off” the tire and maintain proper pressure. Finally, NACFE is also looking at ways to reduce idling and provide heating/cooling in sleeper tractors without the need to run the engine.

Fleet segmentation—choosing the rights trucks for the right job—also features prominently. For tractor-trailers doing high mileage at high average speeds (the ones barreling down the Interstate system), factors include aerodynamics (for example, Renault debuted its aerodynamic Optiful setup in 2009, boasting 13 percent better fuel economy), low-rolling-resistance tires, and engine and transmission efficiency at steady state. For delivery trucks—the USPS, FedEx, and UPS trucks so common this holiday season—the levers are different, thanks to primarily urban and suburban driving, with average speeds down around 20 mph. In those cases, hybrids could be a good solution, because of the frequent start, stop, and braking.

But it’s the system-level efficiencies and logistics, such as not running empty or partially loaded rigs, that may offer the most promise. Such efforts comprise fully 75 percent of one major retailer’s program, which will double fleet efficiency. Further, palletized fleets that figure out how to fit more pallets onto the same trucks will ultimately pull trucks off the road entirely.

It’s already clear: fuel efficiency and system logistics improvements will have tangible environmental benefits through reduced fossil fuel consumption and climate change mitigation. An efficient trucking industry will divert massive amounts of CO2 emissions from the atmosphere. It will also have a very real economic impact in fuel costs. Consider that in 2003 the average price for a gallon of diesel was $1.40. Today, truckers commonly pay $4 per gallon. “Fuel is now a fundamentally important competitive matter,” explains Hutchinson. “Fleets that do better on fuel are going to be the winners.”

Ultimately, a more efficient nationwide freight system is a win-win for all involved through reduced fossil fuel consumption, money saved, emissions avoided, and goods still getting where they need to go, whether a gift ordered for a loved one this holiday season, or the many more billions of dollars of goods that move the rest of the year. That system is coming down the highway, full speed ahead.

Some images courtesy of