I conducted a little experiment this evening to see the aerodynamic effect of driving close to a large vehicle and where a good position to slipstream is.
The red/orange zone is where the air is at lower velocity and the idea would be to get the car in that zone so that the car is entering air at approx 20mph instead of 60mph (less resistance).
Looks like around 1 car length is the place to be at 60mph, however painful death is a risk and the grim reaper has to occupy your passenger seat.
