In the late 1970s, a NASA research engineer named Edwin Saltzman was working at the Dryden Flight Research Center in California’s Mojave Desert when he stumbled upon a problem that had nothing to do with spacecraft or supersonic jets. Driving along the highways near Edwards Air Force Base, Saltzman noticed something that his trained aerodynamicist’s eye couldn’t ignore: the enormous flat fronts of semi-trucks were pushing through the air with all the grace of a brick wall. What followed was a decades-long obsession that would quietly reshape the trucking industry and save billions of gallons of diesel fuel — even if most people have never heard his name.
As The Drive recently detailed in a comprehensive account, Saltzman’s story is one of those rare intersections between aerospace engineering and the unglamorous world of long-haul freight. It’s a tale that begins with the 1973 oil crisis, winds through NASA wind tunnels, and ends with the curved, aerodynamic cab designs that dominate American highways today.
The Oil Crisis That Made Engineers Look at Trucks Differently
The 1973 Arab oil embargo sent shockwaves through every corner of the American economy, but few sectors felt the pain as acutely as trucking. Diesel prices spiked, and suddenly the fuel consumption of the nation’s freight fleet became a matter of urgent national interest. The U.S. government began pouring research dollars into anything that could reduce petroleum dependence, and that included a hard look at the aerodynamic efficiency — or rather, the staggering inefficiency — of the Class 8 trucks hauling goods across the interstate system.
At the time, the typical long-haul tractor was a boxy, flat-nosed machine designed with virtually no consideration for aerodynamic drag. Engineers at NASA, the Department of Energy, and several universities began studying the problem, and what they found was remarkable: at highway speeds, aerodynamic drag accounted for roughly half of a semi-truck’s total fuel consumption. A vehicle that might get 4 or 5 miles per gallon was burning enormous quantities of diesel simply fighting the air. For Saltzman, who had spent his career measuring drag on experimental aircraft, the numbers were almost offensive in their wastefulness.
From X-Planes to 18-Wheelers: Saltzman’s Unlikely Pivot
Edwin Saltzman was no amateur tinkerer. At NASA Dryden (now Armstrong Flight Research Center), he had worked on some of the most advanced flight research programs in history, including drag studies on the X-15 rocket plane and various lifting body configurations. He understood aerodynamic drag at a fundamental level — the pressure distributions, the boundary layer effects, the wake structures that trail behind bluff bodies. When he turned that expertise toward semi-trucks, he brought a rigor that the trucking industry had never seen applied to its vehicles.
According to The Drive’s reporting, Saltzman began conducting informal tests and calculations, eventually producing research that quantified exactly how much fuel could be saved through relatively simple aerodynamic modifications. His work complemented broader NASA efforts during this period, including full-scale wind tunnel tests of modified truck cabs conducted at the Ames Research Center in Mountain View, California. The results consistently showed that rounding the edges of a truck cab, adding fairings to smooth the transition between the cab and trailer, and installing roof-mounted deflectors could reduce aerodynamic drag by 20% to 40%.
The Physics of a 70-MPH Brick
To understand why these modifications matter so much, consider the basic physics. Aerodynamic drag increases with the square of velocity, meaning that a truck traveling at 70 mph encounters four times the drag force it would at 35 mph. At highway speeds, a standard flat-fronted semi-truck creates a massive high-pressure zone in front and a turbulent low-pressure wake behind it. The pressure differential between front and back is the primary source of what engineers call “pressure drag,” and it dwarfs the skin friction that dominates on sleeker vehicles like passenger cars.
Saltzman’s aerospace background gave him an intuitive understanding of these forces that most truck designers of the era simply didn’t possess. The trucking industry in the 1970s was focused on durability, engine power, and payload capacity. Aerodynamics was an afterthought at best. But the numbers didn’t lie: NASA’s research demonstrated that a well-designed aerodynamic package could save a long-haul truck operator thousands of dollars per year in fuel costs. Multiply that across the hundreds of thousands of trucks on American roads, and the national fuel savings were staggering.
Industry Resistance and the Slow March Toward Adoption
Despite the compelling data, the trucking industry was slow to embrace aerodynamic improvements. Fleet operators were skeptical of modifications that added cost and complexity to their vehicles. Owner-operators, who often prized the aggressive, flat-nosed look of traditional trucks, resisted changes to cab design on aesthetic grounds. And truck manufacturers, operating in a conservative industry with long product development cycles, were reluctant to invest in radical redesigns without clear market demand.
The transition happened gradually over the course of the 1980s and 1990s. Kenworth, Peterbilt, Freightliner, and other major manufacturers began incorporating aerodynamic features into their cab-over and conventional designs. The Kenworth T600, introduced in 1985, was one of the first trucks to feature a dramatically sloped hood and rounded edges specifically designed to reduce drag. It was met with resistance from some quarters of the trucking community — drivers derisively called it the “anteater” — but its fuel savings were undeniable. The truck industry’s gradual acceptance of aerodynamic design principles can be traced in a direct line back to the NASA research that engineers like Saltzman helped produce.
Modern Trucking Owes More to NASA Than Most People Realize
Today, virtually every long-haul truck sold in the United States incorporates aerodynamic features that would have been unthinkable in the 1970s. Side skirts that smooth airflow beneath the trailer, boat-tail devices that reduce wake turbulence at the rear, and carefully sculpted cab profiles are now standard equipment or widely available options. The Environmental Protection Agency’s SmartWay program and the federal greenhouse gas emissions standards for heavy-duty vehicles have further accelerated adoption of these technologies, but the scientific foundation was laid decades ago in NASA facilities.
The scale of the impact is enormous. The American Trucking Associations estimates that the U.S. trucking industry consumes approximately 54 billion gallons of diesel fuel annually. Even modest percentage improvements in fuel efficiency translate into billions of gallons saved and millions of tons of carbon dioxide emissions avoided. According to the Department of Energy’s Office of Energy Efficiency and Renewable Energy, aerodynamic improvements remain one of the most cost-effective ways to reduce fuel consumption in heavy-duty trucks, with some devices paying for themselves within a year or two of installation.
The Ongoing Push: Platooning, Electric Trucks, and Persistent Drag
The aerodynamic challenges facing the trucking industry haven’t been fully solved. The gap between the tractor and trailer remains a significant source of drag, and the blunt rear end of a standard 53-foot trailer still creates a large turbulent wake. Companies like Stemco, Wabash National, and various startups continue to develop and market aftermarket aerodynamic devices, while researchers at institutions including Lawrence Livermore National Laboratory have studied truck platooning — where multiple trucks follow each other closely to reduce collective drag — as another approach to the problem.
The rise of electric trucks from manufacturers like Tesla, Volvo, and Daimler has given aerodynamics renewed importance. While electric powertrains are more efficient than diesel engines, their range is limited by battery capacity, making every source of energy loss a critical concern. Tesla’s Semi, for example, features a dramatically tapered cab and smooth underbody designed to achieve a drag coefficient far below that of conventional trucks. The aerodynamic principles being applied are the same ones that Saltzman and his NASA colleagues identified half a century ago — the physics hasn’t changed, even if the propulsion technology has.
An Engineer’s Legacy Written in Fuel Savings
Edwin Saltzman’s story is a reminder that engineering breakthroughs don’t always come from deliberate, well-funded programs aimed at specific problems. Sometimes they emerge from a curious mind noticing an inefficiency that others have accepted as normal. Saltzman spent his career measuring drag on some of the fastest and most exotic aircraft ever built, but his most consequential contribution to American energy efficiency may have come from looking at the lumbering trucks sharing the highway with him on his commute to work.
As The Drive noted, the full scope of Saltzman’s work on truck aerodynamics has received far less attention than it deserves. In an era when fuel efficiency and carbon emissions dominate public discourse about transportation, the foundational research that made modern truck aerodynamics possible is worth remembering. The next time you see a sleek Freightliner Cascadia or Kenworth T680 cruising down the interstate, its carefully sculpted nose slicing through the air rather than bulldozing it, you’re looking at the legacy of a NASA engineer who saw a problem nobody in the trucking industry was trying to solve — and couldn’t resist working on it anyway.
The trucking industry burns through more diesel fuel than any other sector of the American economy. Every percentage point of drag reduction matters, and the cumulative effect of five decades of aerodynamic improvement has been measured in tens of billions of gallons of fuel saved. That’s a legacy any aerospace engineer would be proud of, even if it was discovered entirely by accident.