The TruckLabs TruckWings tractor-mounted active aerodynamic device is deployed at highway speeds (less than 50 mph) to improve aerodynamics, and therefore fuel efficiency. The improvements can be as high as 6%, with an average around 3 to 4% for sleeper cabs. Unlike traditional side extenders that close the tractor-trailer gap, TruckWings retract at slower speeds, preventing potential damage that may occur during city driving, sparing maintenance technicians from unplanned service work.