In the past, we've looked at a variety of techniques for saving fuel in the article "Improve MPG: The Factors Affecting Fuel Efficiency"; one of those factors included the fuel saving effects of drafting tractor trailers, a dangerous practice. Going beyond the speculative mathematics of fluid dynamics equations, the Mythbusters demonstrated the principle scientifically in episode #80, confirming the improvements to fuel economy. Using a NASA wind tunnel, the Mythbusters used scale models to demonstrate wind resistance was reduced up to 93% (with a dangerously close simulation of a ten foot following distance). Following the wind tunnel experiment, the Mythbusters hooked a computer directly to the fuel injectors and tailed a truck in a controlled environment, demonstrating gains of 20-40% in fuel efficiency.