Truck owners often have their own theories on how to improve gas mileage and reduce the air drag on their pickup trucks. One simple solution is to lower the tailgate. Another is to replace the tailgate with a cargo net. Bed caps or tonneau covers can be added as well. According to a report from the Specialty Equipment Manufacturer’s Association (SEMA), two students from Western New England College’s Department of Mechanical Engineering did a study in 1997 on improving aerodynamic characteristics of a Dodge Ram pickup. The study indicates that the best way to reduce drag, and thereby improve fuel efficiency for pickup trucks, is to add a tonneau cover, unless an improved cap design is developed. Studies have indicated that other factors can also contribute to improved fuel efficiency, including choices in air filters, aftermarket grilles and by keeping tires properly inflated. Also, it is important to remember that drag depends on the size and shape of the vehicle, and therefore a Chevrolet, a Dodge, and a Ford pickup with the same cap might have different drag coefficients because of different design features.