Using a new 14.6-liter Detroit DD15 engine with BlueTec and revised aerodynamics, Freightliner claims its new Cascadia Evolution improves fuel economy by up to 7 percent over the EPA 2010 model, backed up by an independent, two-truck test across a 2400-mile route. In a demonstration test in Texas, a Cascadia Evolution equipped with Detroit's DT12 automated transmission, a trailer with optimized aerodynamics and low rolling resistance tires, the 34-ton rig traveled exactly 1000 miles at 60 mph and recorded 10.67 miles per gallon. Truck Trend has tested big-block pickups that did no better.