tractor-trailers are able to maintain pretty good speeds. At 55 miles per hour, half of your fuel is going toward overcoming drag.”
Smith says he’s been dreaming about advanced transportation technologies at least since he was in sixth grade, when he bought his first Car & Driver magazine and was dismayed to discover that Ferraris and Lamborghinis get terrible mileage. “I told my parents confidently that I was going to build an electric vehicle company,” Smith says.
A series of accidents steered him toward the trucking industry instead. At Tuck, back in 2005 or so, Smith and a team of B-school classmates were searching for a transportation-related idea to enter in business plan competitions—an annual rite of passage for entrepreneurship-minded business school students. Smith had a friend named Cam Brensinger who had founded New England Mountain Equipment (NEMO), which is famous among hikers and climbers for its inflatable tents. During an ice-climbing trip, Brensinger told Smith about Kyril Calsoyas, an Arizona-based inventor, entrepreneur, and school administrator who had contacted NEMO with a concept for an inflatable device that could be attached to the back of a trailer to reduce drag. Smith’s team licensed the idea, came up with a plan for selling it, and ended up taking the 2006 grand prize at the nation’s largest business plan competition at Rice University in Houston.
Calsoyas is still an advisor to the company today, and the seed of his idea is alive. But Smith says ATDynamics has taken quite a few twists and turns on the way to building an affordable, manufacturable, street-legal product.
U.S. Department of Transportation regulations say that aerodynamic extensions for semi-trailers can extend the length of the trailer by no more than 5 feet. “The question was, how do you put this on the back of a trailer and still allow the trailer to go up to a loading bay without issues,” Smith says. With swing-door trailers, a driver who wants to back into a loading bay has to open both rear doors and swing them back 270 degrees until they’re flush against the side of the trailer itself. It turned out that the only arrangement that fit all these requirements was a hollow, tapered, four-sided box that’s rigid and extended on the highway, but also flattens into a space so thin that it doesn’t stop the doors from opening all the way.
Designing for that kind of collapsibility was essentially a geometry problem—and Smith says he spent hours on his living room floor, cutting, folding, and taping pieces of cardboard until he had his first working model. (He still keeps it on his office desk today; it resembles a school-cafeteria milk carton.) Once the basic shape was established, he says, it took the startup two years, $2 million, and 15 to 20 prototypes to identify the best materials and get the design working in real life. In the final TrailerTail, the outer panels consist of woven fiberglass and plastic resin, held open by aluminum struts. “The biggest hurdle was having a design that would endure hundreds of thousands of miles of bouncing around on the highway, at temperature extremes from Death Valley to northern Canada, with drivers who occasionally forget to shut the TrailerTail and back it into walls,” Smith says. (The origami-like design collapses automatically under these circumstances.)
Simulations using computational fluid dynamics software had predicted that the hollow, tapered shape of the TrailerTail would smooth out the lines of air flow around a semi-trailer, preventing
