Many a bet has been made, and many a friendly, and not-so-friendly, argument has been waged over whether you get better gas mileage in a pickup truck with the tailgate up or down. Even those gurus of auto advice Click and Clack were thrown by it. The intuitive answer is that it is better to open the tailgate so the air can rush out the back, or use one of those tailgate nets which lets air flow through, supposedly cutting down drag. Well, as aerodynamics engineers have worked to streamline vehicles, they have certainly looked into the tailgate question. When they did drag tests on pickups, what they found out surprised even them. They discovered there was less drag with the tailgate closed!