The EPA estimates that motor vehicles contribute about half of America's smog-forming volatile organic compounds and nitrogen oxide emissions every year. And given that the average fuel efficiency of your average 18-wheeler only hits about 6 miles per gallon, these big rigs can be big polluters too. But this new prototype from Daimler Trucks North America, built as part of the US Department of Transportation's SuperTruck Challenge, sips just half as much gas.
When the DOT started the SuperTruck Challenge in 2009, organizers hoped to see a 50 percent efficiency increase over that year's "average" semi. Daimler's "Freightliner SuperTruck" more than doubled that goal, boasting a 115 percent increase over the baseline standard. Most of that improvement comes from simple aerodynamic tweaks like adding an adjustable ride height, rear wheel fairings and articulated side extenders to cover gaps between the cab and trailer. The SuperTruck is also 700 pounds lighter than the baseline, thanks to a reengineered tractor frame.
What's more, its hybrid diesel/electric 10.7-liter power plant supplements the diesel fuel source with recaptured waste heat from the exhaust and brake. Roof-mounted solar panels draw in enough energy to independently run the trailer's air conditioning system on sunny days. The SuperTruck even leverages GPS tracking to automatically shift gears and modulate the vehicle's speed to maximize efficiency given upcoming terrain changes. All this translates into one seriously efficient vehicle -- at least as far 18-wheelers go. A recent test run through Texas saw the Freightliner hit 12.2 miles per gallon at 65 miles per hour. That's not bad for a truck pulling more than 65,000 pounds.