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The Environmental Impact of Long-Haul Trucking

Barring some monumental development that disrupts cargo shipping entirely, we’re stuck with trucking. So how can we minimize the industry’s massive environmental tolls?
(Illustration: Gizem Vural)

(Illustration: Gizem Vural)

When Mike Roeth sees pictures of tractor-trailer trucks from over a decade ago, he has a visceral reaction, a kind of shudder meets a wince.

“I see those old trucks hauling down the highway, belching black smoke—it’s not real pleasant,” says Roeth, director of the North American Council for Freight Efficiency.

There’s a popular conception of the diesel semi—the only big truck for many decades—as a monster of the road, ripping down the highway at reckless speeds, guzzling gas with abandon, leaving a toxic trail of exhaust. It’s something of a pop culture parable, thanks to Smokey and the Bandit, Maximum Overdrive, and the rest of our trucking lore. But this mythology has its roots in reality. Not so long ago, semis were grimier, drivers more aggressive, regulations laxer.

Over the last couple of decades, however, a quiet revolution has upended the industry. A combination of increased environmental regulations and fleet owners looking to cut fuel costs has led to some radical changes. The technology and design of big trucks, as well as the behavior of those operating them, have shifted drastically.

“Our industry is just too modest,” Roeth says. “Every now and again it would be good to look around and say, ‘Damn we’ve come a long way!’”

And of course, we’re only partway down the road to reform.


There’s a clear ubiquity to the trucking industry. Today, roughly 70 percent of our consumer goods are shipped via truck, and even the environmental groups that rail hardest against the industry don’t have comprehensive alternatives to offer. Air transport is too costly. Cargo trains are effective, but limited by narrow shipping routes and dwindling numbers. Similarly, aquatic shipping has its benefits—most overseas imports still arrive by boat—but (at the risk of explaining something most first graders understand) there simply isn’t water everywhere.

So what are our domestic shipping alternatives: Hot air balloon? Hovercraft? Drone? Not likely. Barring some monumental development that disrupts cargo shipping entirely, we’re stuck with trucking. This leaves us with one basic goal: minimizing the industry’s massive environmental tolls.

• Keep on Truckin': The Keep on Truckin' project is an effort to shine a light on the past, present, and future of the truck driving industry in America, exploring all facets of our most pivotal, and overlooked, economic engine.

Twenty-Four Hours at a Truck Stop: The ever-shifting landscape of truck stops, from sunrise to sunrise.

Sounds From the Road: Spend even the slightest amount of time around 18-wheelers and it quickly becomes very clear that truck driving is a full-on sensory assault.

There are currently 15.5 million commercial trucks on the road, two million of them tractor trailers, and their impact on the environment has been huge. Decades ago, as the causal lines were drawn between pollution and, say, Southern California’s perpetual haze, trucks bore an increasing degree of scrutiny. As a result, increasingly strict federal emissions standards were rolled out again and again over the last two decades.

The truck manufacturing industry—and, by extension, the truck driving industry—has spent those years scrambling to keep up.

According to the Environmental Defense Fund, freight movement (which also includes air and water-based transport) currently accounts for 16 percent of all corporate greenhouse gas emissions. There was a time, though, when that percentage was much, much higher. And in many ways that reduction has to do with industry-wide shifts toward cleaner machines. Roeth says it would take 70 trucks built today to replicate the emissions from just one truck built in 2002.

Twenty years ago, the approach to reducing truck-based pollutants largely targeted emissions and how to make cleaner exhaust. An evolving combination of low-sulfur diesel fuel, cleaner burning engines, and potent emissions controls then led to a near-total turnaround. According to Roeth, in certain parts of North America (e.g., a small industrialized town in Mexico) the air is now cleaner leaving trucks than it was coming in.

Naturally, these technologies did not come free. Trucks that were kitted out with clean engines and sophisticated controls drove up the cost of doing business. Similar to factory owners facing stricter pollution regulations, trucking executives would plead poverty. How could they turn a profit when forced to shell out for all this clean technology? It’s a familiar refrain.

But at some point, emissions advances leveled out, even while stricter guidelines from the Environmental Protection Agency kept coming. If diesel emissions had become about as clean as they could get, what was left to fix?

The amount of fuel used, of course.


Once the focus shifted toward fuel economy, government regulators found a more willing ally in the trucking industry. The reason was simple: Cutting down fuel use translates to a direct cost savings, while also reducing CO2 output. The American Transportation Research Institute releases granular statistics each year on the cost of trucking. Out of the estimated $1.70 per mile it now costs fleet owners to run a truck, ATRI says that over a third of that goes toward fuel.

Consider this: A new sleeper tractor, averaging around seven miles per gallon, will run you about $130,000. At 120,000 miles per year, you’re looking at $50,000 to $60,000 in fuel per year (at current prices). Last year, when diesel was averaging $4/gallon, it was more like $75,000 annually. Just two years of fuel consumption could run a fleet owner more than the cost of the truck itself.

Costs like these breed innovation quick. Over the years, truck aerodynamics have been heavily tweaked to increase fuel economy. When you’re running long hauls, a simple adjustment to, say, side mirrors or bumpers can lead to thousands in savings over a vehicle’s lifespan. Similarly, little adjustments to tire technology, to skirts (devices affixed to the underside of a trailer to decrease wind resistance), to transmissions or engine programming, all can lead to significant payoffs down the line. When truck manufacturers announce their new lines each year, you best believe they’re highlighting the fuel-reducing features.

There is also an evolving bag of tricks which fleet owners can implement to pack more cargo in every load. Paul Menig, a trucking efficiency consultant, points to innovations like thinner trailer walls and horizontal rods that allow you to stack more pallets on top of each other. “We’ve also gotten better at packaging things,” Menig says. “Look at how manufacturers are producing more items in concentrate form, which allows for more product to be shipped.” In essence, the more cargo you can pack into a load, the fewer trips you have to make. And fewer trips means less fuel.

Of course, cutting down on fuel costs also requires some driver compliance. Roeth says he has one overarching suggestion to cut down fuel use—drive slower. For just one coast-to-coast trip, driving 65 versus 75 miles per hour can lead to hundreds of dollars in fuel savings.

But picture the old trucker movie dilemma: How you gonna get that load of flatscreen televisions to Reno, Nevada, on time, without giving your truck some juice? Industry veteran Darry Stuart, who rose from mechanic to executive to “truck maintenance coach,” recalls the bad old days, when it was all about “how fast you could take off from a traffic light, and how much black smoke you could release while you did it.” But as industry attitudes have shifted, so has this behavior. “[Truck drivers] are still cowboys,” Stuart says, “but they’ve had to adjust.”

Technology has advanced such that smart engines adjust speeds based on terrain and load without driver input. But beyond that, Stuart says fleet owners aren’t as die-hard about pushing their drivers to achieve untenable delivery windows. It’s now fashionable to give deadlines that don’t depend on a lead foot.

This is anecdotal, of course, and industry executives don’t often cop to the fact that their prior business model required breaking speed laws. Certainly, there are plenty of truckers still pushing the speed envelope—we’ve all seen them on the road. But in general, the trucking industry seems to have cooled its engines, a boon to other highway drivers and to the ozone layer.


If diesel driving has become almost as clean as it’s going to be, do we have other options? Namely, are there other ways to power a truck?

Electric may be your first thought, and it is certainly hyped as the future of passenger vehicles. Menig says there are some small-to-mid-size electric trucks being used for short hauls and in-city driving. BMW rolled out an electric semi this year, but it can only go 60 miles on a charge. Daimler unveiled its first autonomous (a.k.a. self-driving) truck this May, but for all its claims of high efficiency, it still uses diesel. Tractors that can make long trips on electric power are still a long ways in the future.

Natural gas-powered trucks are making more headway, but slowly (three percent of trucks are powered by natural gas today). There are hurdles to industry-wide acceptance, starting with the cost. Roeth says you can expect to pay $25,000 to $50,000 more for a natural gas-powered sleeper tractor straight out of the gate.

If you match diesel fuel to natural gas, mile for mile, there’s an estimated 20 to 40 percent cost savings for the latter. This can compensate for the costlier vehicles over time, but a bigger challenge is the lack of infrastructure for natural gas-powered trucks. It’s one thing to power a fleet of municipal buses with natural gas after your city builds reliable filling stations. But what of the long-haul driver, marooned in unfamiliar territory?

Large companies like Walmart and Pepsi own their own fleets of truck, and often drive reliable, consistent routes (e.g., from distribution centers to retail stores). If these companies introduce natural gas-powered trucks to their fleet, they can make sure to have filling stations along known routes. This is happening already, with Frito Lay and Ryder serving as a couple of early adopters. Consumer-facing companies also get the side bonus of some green public relations: “We’ve reduced our carbon footprint!”

But there is still a large contingency of trucks for hire, manned by drivers who might bring toasters to Tallahassee one week and strollers to Syracuse the next. For this kind of driving, it can be a serious liability to not know where you’ll fill up next. That said, we may still be in an early phase for natural gas-powered trucks, a time when early adopters test viability for the rest of the industry. If it works, the infrastructure will surely follow.

Roeth says natural gas has tested well with drivers. It’s a cleaner, less smelly product to work with, especially when you’re filling up on a daily basis. Roeth laughs, “I’ve heard of wives who notice their husbands smell better at the end of their drives, once they switched [to natural gas]!”

Natural gas certainly has its share of skeptics. Stuart, an industry vet of many decades, calls it part of an aggressive environmentalist agenda. He doesn’t think it’s realistic that an industry built on diesel will be upended. “Natural gas may find its niche,” Stuart says, “but we’re not going to have this big wave like the green movement would have you believe.”

That green movement is not exactly sold on natural gas, though, starting with the contentious issue of fracking. The EDF has long made freight emissions a cornerstone issue, publishing some highly skeptical studies on trucking with natural gas. Their argument hinges on the methane released during natural gas extraction and usage, which is a side effect they say negates any CO2 reduction from abandoning diesel.

They also point to its inefficiency: Some studies have found natural gas engines are up to 15 percent less efficient than diesel. “We will always encourage companies to just use more efficient modes of transport when they can,” says EDF Senior Manager Jenny Ahlen, who works to help Walmart reduce its carbon footprint. “The best mode is by sea, then rail.”

Whether switching to natural gas would ultimately be a net gain for the industry will require extensive research and testing. But it can be tricky to keep people exploring alternatives to diesel when petroleum prices dip, as they did this year. After four years at four dollars a gallon— a period that will be remembered in the industry for years to come—diesel leveled off well below three dollars per gallon in 2015.

In his role as director of the North American Council for Freight Efficiency (a group funded by Richard Branson’s Carbon War Room initiative), Roeth is circumspect. He sees potential benefits to adopting natural gas, but also continues to work on strategies to reduce diesel emissions. Roeth has faith that fleet owners will be interested in fuel-cutting strategies—no matter what the fuel—even as prices dip.

“In this industry, memories are long,” he says. “Our days of guzzling gas are gone.”


The Keep on Truckin' project is an effort to shine a light on the past, present, and future of the truck-driving industry in America, exploring all facets of our most pivotal, and overlooked, economic engine.